ALL about the IFSM

The IFSM is the heart of the fuel system on the ISX engine. This fuel system has been on the engine from its beginning until 2010 when common rail replaced it. It is an amazing piece of technology in my opinion. This is an overview of the parts bolted on the IFSM and what they do.

[@andrewloucks6568]

Well said again great stuff sir

[@billarroo1]

Great information, THANKS

[@1010109999999]

Wow Joe thank you so much and you really know your engines❤

[@ENGINESHOPJOE]

I know enough about cummins to be dangerous...;-))

[@kbrooks3974]

Thanks very informative video Sir.

[@hashamrash4974]

Good job thank you sir

[@nickagravante6917]

Thank you. Sir.. For video

[@eagletran9]

Thank you sir

[@TopFlightGarage]

Good info

[@downunderjuice]

Just found out last week after replacing all the metering and timing actuators that there is a new style and an old style actuator. the old style needs o rings to seal and the new style has the ridged plates. Thank you for the video.

[@ENGINESHOPJOE]

Yes and they are interchangeable as long as you use the correct gasket or oring. There are also a couple different part numbers depending on the horsepower. You probably found out you cant bolt them in the wrong place. IE put a timing where a metering should be and visa versa. One mounting hole wont line up.

[@ENGINESHOPJOE]

There is a way to tell if the metering actuators are starting to become inefficient at precise metering. I will talk about that in the future it is a bit advanced for this general discussion.

[@downunderjuice]

@@ENGINESHOPJOE Something that often gets overlooked is the dampers on the rear and the leaks they develop.

[@ChrisTheMobileMechanic]

​@Jeff Andrejas yes this, I would love to see a video about them

[@maypenclock]

@Jeff Andrejas they leaking on my truck right now...smh smh

[@PoliticalGangster]

this was the fuel system on the isx cm870 and cm871

[@ENGINESHOPJOE]

Correct and the 570 too. The 570 was the very first generation of this engine then called the Apex. The 570 is the ecm platform or generation. It had no emissions items on it at all. It was a running beast with 650 horsepower at the flywheel at 1800 rpm. Even though it was only "rated" at the time for 600 MAX hp.

[@jessedriedger8022]

Great video, where is the fuel pressure sensor located?

[@ENGINESHOPJOE]

under the housing pointing to the street. Forward of the fuel filter.

[@schenk16]

Hey Joe, Do you think it would be a good idea to clean the fuel and timing actuators to see if they work better?

[@ENGINESHOPJOE]

No. They are precision devices set up on a test stand and calibrated. If you want to put a cleaning additive in your fuel that is as far as I would go.

[@user-rp1lj8nz4k]

Good video. Noticed you didn't cover the dampers on the back of the ifsm.

[@ENGINESHOPJOE]

Function wise they rarely fail and will sometimes leak fuel. But they are just gasket /oring changes to rebuild. I wanted to address what people see when they look at the side of the engine. I may do an IFSM rebuild in the future. Thanks for your comment

[@penguinmater1206]

I have a fuel leak, possible from the solenoid gasket. It is possible to have a crack solenoid, I have a lot of fuel leak. Thank you!

[@ontiverosruben7491]

I have a ticking noise coming from under the valve cover. I was told maybe it can be an actuator? The truck feels like it has a misfire or hesitation when I press the accelerator. What are your thoughts? Thanks

[@ENGINESHOPJOE]

What engine are you running ? If it is an isx and has jake brakes it is most likely a jake brake lever is not locked into "off" position. They will tick. The fix is replace the rocker shafts-the jake "off hole" becomes egg shaped and the lever is not exactly where it should be. This does not cause any problems that I ever say short of the ticking. You could buy a jake brake overhaul kit and two rocker shafts and the tick would be fixed. Of course verify that the tick is the jake lever. if you pull the cover and run it you can see the jake levers slightly rocking and put a finger on it and you will feel the tap. You could also have a broken injector spring- very rare i only saw that once. That would cause a tick and the hesitation you mentioned.

[@kodykj2112]

This is a amazing I'm in México working on my neighbors truck and this was great info thank you. I saw another video that says the fuel from the lift pump goes to the fuel filter (number 10) first, is that right? Or does it go to the gear pump first? According to a diagram that I found I thought on the one I'm working on it goes from the lift pump to the gear pump and then to the main fuel filter

[@ENGINESHOPJOE]

You are correct lift pump to gear pump to filter then into the actuators

[@kodykj2112]

@@ENGINESHOPJOE thank you for the reply sir. The system was sucking tons of air into the system so they are going to replace all the quick connect lines from the tank to the engine because all their clips are broken and then we'll go from there. Also gonna replace the lift pump.

[@kodykj2112]

@@ENGINESHOPJOE is it common for the gear pump gear shaft to break or come un seated in the gears? We replaced the gear pump on this engine because we found the internal gears weren't turning when we turned the drive gear.

[@ENGINESHOPJOE]

@@kodykj2112 Not common but yes I have seen it a few times. The gears are press fit on a small diameter shaft. There is also an alignment key in the shaft as there are(used to be anyway) two gears pressed against each other so it looked like one longer gear. Over time the press fit is lost and then the key is worked back and forth until it shears. That gear set makes 320 psi when the engine is running so it has a lot of torque applied against that press fit. Air in the fuel shortens that press fit life because you now have spikes (air/fuel/air/fuel being pumped) instead of just a smooth hydraulic (just fuel) load.

[@ENGINESHOPJOE]

By the way welcome to my channel. Thanks for the excellent comments

[@adrianmadera9203]

Great video I have a 1999 isx signature series that’s cutting out and throwing code 482 and I’ll shut the truck off and start back up and will be cleared for a little while?

[@ENGINESHOPJOE]

Check for a plugged screen in the fuel inlet where the fuel line bolts to the ifsm. They put a small screen almost the size of a sewing thimble for your finger. I took a lot of those out. If your screen is gone no problem then look at fuel lines or something in a fitting on the suction side. Could be a collapsed fuel suction line etc.

[@ldraaum]

Can you tell me which timing and metering actuator is considered #1 and #2 actuator? When there is faults, it will say #1 or #2. Thanks.

[@ENGINESHOPJOE]

Think about it like this Lonnie, There are two three cylinder engines in one package. The two actuators one timing, one metering that are towards the front of the engine fuel cylinders 1,2 and 3. The shutdown solenoid feeds both the front and rear bank.Then there is a timing and metering actuator for the back three cylinders. Inside the cylinder head there are two completely separate fuel systems. The front bank and the rear bank. The engine ecm makes it run smoothly but it thinks it is running a couple three cylinder engines. A fuel engineer told me that back in 1999. Each actuator has it own separate fault codes so you can not mistake which one you need to check out.

[@edsongoncalves4583]

Good evening, I'm from Brazil and your videos are perfect! Can over speed and under speed problems be caused by the fuel injection system? we use the Cummins qsx coupled to a generator sometimes it exceeds 1,800 RPM! failure started after 10 years of use, thank you.

[@ENGINESHOPJOE]

Yes. Generator sets typically have high load transitions. So the fuel system can cause problems if there is a part not performing to specifications. There are of course other things that cause this. I would start by checking for faults in the engine for the fuel system. There are a vast number of controls and generator configurations so I cannot comment on the generators controls doing this but they could be playing a part in this.

[@edsongoncalves4583]

@@ENGINESHOPJOE Thank you very much for your attention, I will first check the fuel supply system!

[@ChrisTheMobileMechanic]

Is there any videos on the ifsm feel dampener?

[@ENGINESHOPJOE]

I don't think i have one on the dual dampeners on the back of the ifsm but they are simple to rebuild. There is an oring and a couple nylong spacers and the new disk. Just a few parts. Take it apart and lay it out and reassembly with the new parts reverse order.

[@jordansutton7244]

great info ! thanks. i got a truck coming in the shop tomorrow driver states starts and runs fine when engine cold. once up to running temp. if he shuts engine off it wont start again until engine cools down. any insite? thanks ia

[@ENGINESHOPJOE]

Check the fuel solenoid magnet. when they get hot they lose magnetic pulling power and wont open the shut off plates. Sorry i took so long to get back to you.

[@elogon0850]

Is it safe to poke in the center of fitting 11 when primming after installing new fuel filters ?

[@ENGINESHOPJOE]

That fitting is where you measure total fuel restriction at the inlet of the gear pump. Yes it is safe as far as there is no extreme fuel pressure there. If you have. an electric lift or transfer pump on the engine pushing that poppet will let the air out and you may get 10-15 psi fuel spit at you. I would think a better option is to buy the fitting that connects on to that and put a line on it then run it into a bucket until fuel runs out. Then take it off the fitting and it should start. Cummins runs a "priming line" from that fitting to the one on the back of the gear pump and lets the fuel run in a loop to prime it. Then you remove the line before starting or it wont start.I never did that myself.

[@3406eJB]

Hey Joe 05 cm870 - was idling truck today and it ran out of fuel so I threw 5 gallons on in the tank. It had one of those longer starts as you know it would because it would have to prime up. So the engine starts to run and there was fuel running directly down the fuel filter. Any suggestions? Thanks

[@3406eJB]

This is a truck that hasn’t been sitting for 1 year but both primary and secondary filter was changed last year April. Is it possible the filter seal could go bad or I have to dig in that IFSM

[@ENGINESHOPJOE]

There is a number of places it could be leaking from I would clean it up with brake clean let it dry take a bright light start it and see if you can watch words coming from. You could also clean it and dust it down with talcum powder. Remember, there are pulsation dampers in the back you can’t see they can leak on the backside, if it sits O-rings tend to shrink, so that lands to multiple places you could have a fuel leak don’t overlook the shut down solenoid or the actuators when they leak it’s always a seeping type of leak.

[@3406eJB]

⁠@@ENGINESHOPJOE thanks for the reply, I’m going to check again next week I bought all the seals for both dampers and the whole ifsm gasket and the actuator gasket with another fuel filter. Will update you

[@nickdarling9557]

Isx DOHC engine miss and white smoke rough idle . Cylinder #6 extremely low on temprature when checked with Infared thermal gun . Replaced #6 injector . Engine runs a bit better but still have same symptoms . What do you reccomend next .?

[@ENGINESHOPJOE]

I will assume the cam lobes are good as well as the rocker roller and pins. I will also assume the jake is working correctly and everything is adjusted correctly. Swap both timing and metering actuators with the front bank actuators. If six still is cold with white smoke Off comes the head.

[@domenickcassanojr7604]

Hi Joe, I have a QSK15 running a gen set. At operating temperature, it has a misfire and excessive black smoke. No active faults and fuel pressure at 276.1 psi. I performed a cylinder cut out test and found number 4 cylinder not responding. Monitored percent fuel on all cylinder when cut out and did see an increase except for cylinder 4. Swapped both fuel-metering solenoids with no change. Problem did not follow solenoids. I performed an injector leakage test with no bubbles present for any cylinders. I suspect a faulty fuel injector, even though number 4 cylinder did not fail the test. Before I replace number 4 injector, do you have any recommendations? Thanks, Dom

[@ENGINESHOPJOE]

I am thinking you have a QSX 15 Not a QSK-19- Very different animal there. If indeed it is a QSX 15 It sounds like it has an ifsm. It could be a couple things. If you have injector orings handy swap out 1 and 4. There is a reason I chose 1 and that has to do with firing order in the banks. If the problem moves to number 1 it was the injector. I have seen valves "chip" of a piece or crack and you will get smoke due to very low compression. Make sure your injector cam lobe and roller are looking like all the others. If a a camshaft injector lobe has an issue causing this it will be very obvious to the eye. Check valve lash first and injector setting on number 4 before you disturb anything. You could also switch the timing actuators they actually can cause black smoke if it is NOT the injector doing this.(rare) From what you are describing I suspect a bad injector but it could be a valve sealing issue causing the smoke.(lower compression-You said smokes black when up to temp)When you start it as it is warming up if there is not puffing white smoke the valves are probably OK. Let us know what you find.

[@domenickcassanojr7604]

Hi Joe, you are correct QSK-15. I replaced injector number four. I did not see any issues with the cam lobes. I set the injector torque on number four injector and set valve lash to Cummins specifications. Did check the other cylinder valve lash. Found all to be in specification. Misfire is corrected and passed cylinder cut out test. Idles and accelerates to 1800 rpm’s with no issues, no more vibrations due to the misfire but still smokes black on acceleration. Once reaches 1800 rpm’s it clears up. Going to pressure test the air intake system for leaks next. I will try to swap the timing modules and see if there is a change with the smoke.

[@ENGINESHOPJOE]

Generator sets have isochronous governors so they very aggressively accelerate to the 1800 rpm. If the engine runs clear when it is under load I would not be overly concerned about the black smoke you see when it accelerates to 1800. If it has no problem carrying the load and and you don't have low hertz faults when load changes i think it is probably OK. @@domenickcassanojr7604

[@domenickcassanojr7604]

@@ENGINESHOPJOE Thanks Joe for your assistance. I will monitor the engines performance.

[@jameschristensen7862]

Hello Joe I have a 2011 peterbilt with the cm871 fully deleted and once it gets up to operating temperature it smokes, especially like cruising through a town and especially shifting up on lower side. And sometimes going down highway when you let of throttle. Any ideas?

[@ENGINESHOPJOE]

Did they remove the injector that sits behind the turbo and the fuel block that supplies that injector. It was for regen purposes. Did they remove the egr cooler? They can start leaking coolant and that would be whitish smoke and coolant smell. Are you using coolant? I am thinking the smoke is whitish? You could have an injector that lost a ball check sometimes they would cause whitish smoke and stumble. Do you have any problems with the jakes? I had a rocker shaft problem once that cause the jakes to bang the valves and it caused whitish smoke but the overhead was clicky when you listened to it. Last sometimes those would develop a crack in an exhaust port and coolant would come out only when the head was hot. But again you would have unexplained coolant loss to go along with that. You might have to get it hot and pull the exhaust off to check ports. They say you can lose coolant out of the turbo if the center housing cracks. I never saw that. Are you using oil? If yes it might be the turbo is passing oil and hot it will smoke whitish. Pull the exhaust pipe off the turbo and see if the impellar is light choclate brown. If yes that might be it. The impellar should be soot black or very dark gray.

[@jameschristensen7862]

@@ENGINESHOPJOE yes the egr cooler is removed, and I haven’t noticed any coolant being used at all

[@albertjackson3081]

Hey working on a CM871 and did a fuel tank cleaning and new filter were put on but still having issues when accelerating loss of power misfires and shutdown at times new gear pump was installed few weeks ago also

[@albertjackson3081]

And only code coming for fuel is a 2215 for fuel pump delivery pressure come active and inactive when accelerating truck

[@ENGINESHOPJOE]

I need more information. Fault codes? was there a lot of water and or dirt in the fuel tank? Why did you clean it? Why did you change the fuel gear pump? Shutting down pulling is a sign of total loss of fuel pressure. Check the fuel pressure. There is a fitting under the IFSM to the front of the on engine fuel filter. Put a line on there and run it up where you can see it. If you have a scanner that reads fuel pressure in the ifsm use that instead. There are a lot of roads to take on this and there is not enough information for me to choose one at this point. But the fuel pressure check is the starting place. Check fuel restriction at the inlet to the ifsm. Make sure there is no screen in the inlet. They used to put screens in them and they would plug with all kinds of debree. fuel restriction at the inlet to the gear pump should not be over 10 INHG

[@albertjackson3081]

Ended up finding the problem was fuel lines were rotten and clogging up inlet of the fuel filter on the frame and cause lack of fuel to create pressure causing the lag and random shut downs

[@atalia6159]

Hi Joe, the truck with cm871 engine won't crank and water separator is getting full I already replace the filters but is doing the same thing, what it could be.?

[@ENGINESHOPJOE]

Is the seperator getting full of water or engine coolant. If coolant that can come from a tank heater that runs coolant into the fuel tank or it can come from the injector wells in the head. The wells can leak coolant at the tops and it goes back with the return fuel to the fuel tank. Then the water seperator catches it. If it is that Cummins makes a "wedding that can be driven into the well to stop that problem. IT works!. A dealer or cummins sales and service can install the rings. you remove injectors -drive in rings with a tool that sets them to correct depth in injector well and then you put new orings on injectors and reinstall. I need more information on the wont crank, that can be battery or starter or coolant in a cylinder causing hydraulic lock. coolant in a cylinder is rare on your engine. If you have actual water in the fuel suspect where you fuel up or check your tank vents and caps (driving in rain)

[@atalia6159]

@@ENGINESHOPJOE you are great, knocking the ECM I found today that the ECM was killing the transfer fuel pump and the vgt actuator.

[@3406e]

this may be a dumb question but which one is the actuator im a bit confused i got the gasket for it

[@ENGINESHOPJOE]

The isx has two seperate fuel delivery systems in the head one for the front three and one for the back three cylinders. So there are two metering actuators and two timing actuators. A pair for each bank as they call them. The gaskets - unless orings- have to be bought for the metering or timing as bolt up pattern is slightly different. That is so you can't bolt the actuators into the wrong position.

[@3406e]

@@ENGINESHOPJOE thanks

[@davidstanmets2762]

Hello! CM870 starts and idles rough for about 10 to 15 minutes then gets smoother but will sometimes stumble a little after warmed up. Any suggestions?

[@ENGINESHOPJOE]

Any smoke while it is stumbling?. Last time the valves and injectors were adjusted properly? Air getting in fuel from suction side of fuel system?

[@davidstanmets2762]

@@ENGINESHOPJOE no smoke other than when I let off to shift and back on. New cams installed about 30k ago.

[@ENGINESHOPJOE]

Start it up cold and compare the manifold temperature at the exhaust ports by the head. you can use your hand or a thermal gun. Compare 1 to 6, 2 to 5 and then 3-4. If you have cold ports on 123 compared to 456 swap the metering actuators and see if the cold cylinders move and follow the metering actuator. If not you could have an injector or two that had a ball check come lose internally. They tended to cause this running issue at idle and low load. The ball check problem did not cause any other issues besides poor idle / rough running at low loads.

[@jaredlittle9647]

Joe I’ve got a cm871 that will not start. Cannot get it running on starting fluid. Any ideas. Curious if a cracked isfm would cause this

[@ENGINESHOPJOE]

Did you have an egr cooler failure and get water in the cylinders??

[@ENGINESHOPJOE]

I have seen that cause carbon to stick to the valve seats and you loose compression. It wont start on ether either. Just a guess but I would need more details to give a better answer

[@jaredlittle9647]

@@ENGINESHOPJOE Egr is deleted

[@ENGINESHOPJOE]

Did. you get this started? If not check cam timing with the wedges and pin. They did have an issue with the injector cam gear slipping if it is not loctited with 609. But you should have faults. The best way to figure it out and start a data logger > all parameters> and crank it 30 seconds. Look at that log or send it to me @[e-mail]. That is where I would start. We have to be sure the ecm even knows it is cranking and then that it is jumping into crankstate. Then we go from there

[@garyshope8378]

2002 isx 600 signature 570 at idle what should fuel pressure read on insight cold and warmed up

[@ENGINESHOPJOE]

idle at 700 rpm idle should be above 250 psi hot or cold. rev it up and if it goes up to 275-300 it is probably a worn fuel gear pump if idle pressure is too low. This of course assumes no air in fuel and fuel restriction is in normal ranges. There is a high and low fuel pressure regulator but my experience with those is they stay accurate until they fail and then the engine wont run or start (no fuel pressure). This will start logging fuel psi faults when pressure drops below 245 at 1800rpm

[@garyshope8378]

@@ENGINESHOPJOE that's the problem only 230ish with a new pump

[@garyshope8378]

Thks young man

[@troybachhofer3417]

Joe I need to ask you a few questions..I've been fighting my cm870 2003 isx fpr about a year..it will just start idling very bad at red light and the next red light will run fine..soon as I take off it runs fine.. so it will be loping very bad at low rpm. And go away soon as I give it fuel..any help would be great from anyone..thanks troy...

[@ENGINESHOPJOE]

There are a few possibilities of what could be causing this. I will do a video in the next couple days Discussing your issue. There is too much to type for an old guy like me LOL

[@troybachhofer3417]

@ENGINESHOPJOE okay thank you very much..

[@deepsouthoutdoors5737]

My engine loses fuel prime after it sits a couple hours and u have to let it sit with the 12v pump on and I have a small power loss, any tips?

[@ENGINESHOPJOE]

Generally speaking, from my experience and what I have read in channel comments, the culprit is usually the primary fuel filter assembly. Or its related fittings when they use orings to seal and not pipe thread. On subscriber said he had gotten undersized cap and bowl orings for his primary filter when purchasing replacement non OEM compatable fuel filter cartridges. So see try buying OEM orings for the filter assembly. It is interesting to note that orings may let air seep in but still seal fuel. It is all about the molecule size your attempting to contain.

[@deepsouthoutdoors5737]

Thank you so much that helped out a lot. I’ve got a lot of the kinks out of it now. Where is the fuel check valve to keep the fuel from losing pressure? Once again, thank you so much.

[@deepsouthoutdoors5737]

Also, my truck bubbles back through the fuel tank while it’s priming and after it’s ran for a little bit it’s like it’s got a white fog coming out the fuel tank

[@DustinWard-ye6bq]

04 ISX 435st. Truck is BARELY running. Throws spn 94 & 95 low fuel pressure. I tested at the #12 fitting (250-280psi@idle) (290psi to the floor). BUT, I tested at the # 11 fitting, and It reads 0. With the compucheck fitting, and with a directly threaded fitting, still 0 psi. Just curious your thoughts, thanks!

[@DustinWard-ye6bq]

Thinking maybe new pump but wanna be sure.

[@DustinWard-ye6bq]

Changed the pump and fuel shutoff solenoid. Still no go

[@ENGINESHOPJOE]

Fitting 11 is the suction side fitting and should read less than 12 INHG maximum with a dirty filter. Fitting 11 reads suction vacuum and never should have pressure on it so that is good. The gear pump is doing a good job at the pressures you listed. There is a compucheck fitting on the bottom of the IFSM pointing straight down and that should have the same pressure the fitting off the gear pump has. That is the pressure the actuators sees. If the pressure at the lower compucheck fitting is low you have a problem with the fuel pressure regulator that is screwed in under the fuel solenoid. But before you buy that take off the fuel solenoid ( wire on it) and take all the plates out and put the solenoid back on and see if it runs good. If yes replace the fuel solenoid magnet and all the plates inside. Also called the shutdown solenoid. The solenoid has the voltage system it needs stamped on it. IE 12/24/36 etc so buy the correct one if that is your engines issue.

[@DustinWard-ye6bq]

@@ENGINESHOPJOE thank you so much!! I will keep in contact and let you know how it goes.

[@DustinWard-ye6bq]

Ram the pressure checks, and test on shutdown solenoid as suggested, still barely running, still throwing low fuel delivery pressure. What should the lift pump pressure be? And where is the best place to test the lift pump pressure? I’m starting to scratch my head more and more with this truck lol. Any more suggestions would be greatly appreciated!

[@TheFredloc870]

Hey I change my fuel filter because my engine sounded like it had a light miss to it now my not running it will only run on starter fluid I had a guy hook up a computer to it and it said low fuelpressure. I put another fuel pump on there and it still doing the same thing.

[@ENGINESHOPJOE]

What engine and what year? Is it common rail? What fuel pump did you replace? The isx has 3 an electric priming pump and a gear pump and the high pressure pump. It sounds like you just got a dose of air in it. Loosen the fuel filter and cycle the key. you should hear the electric pump run. Do key cycles until fuel is running out of the filter then tighten the filter and try to start it. Sometimes they get air locked in the rail. If you can see with a computer there is no fuel pressure in the rail take a fuel line loose at the head. take the nut completely off so it cant build pressure. crank until fuel runs out the line then stop cranking and torque the line to spec. I cant tell you spec as i dont know what engine you have. Then it should start if all the pumps are working as they should. BECAREFUL of the high pressure fuel- watch my video on fuel faults for safety tips if you dont know how to properly open the fuel system. wear glasses and gloves.

[@TheFredloc870]

@@ENGINESHOPJOE It’s a 2005 international with the Cummins isx I replace the fuel pump the lift pumps comes on and goes off

[@ENGINESHOPJOE]

@@TheFredloc870 Ok what i told you does not apply to your engine. The electric pump should run for about 1-2 minutes then shut off. Look at my video on this and take out fitting number 11. The key has to be off about 30 seconds for the lift pump timer to reset. so then turn on the key and see if fuel runs out of fitting 11. if it does then the gear pump should be primed. Put the fitting back in. Next check the terminal on number 5 for 12 volts when the key is on. if that looks ok then take number 6 out. it is a pressure regulator. crank the engine and fuel should come out of there pretty good. if it does the gear pump is primed and working. You can start with number 6 if you think the pump is getting fuel and skip fitting 11. If fuel runs out of there then put that back in and crank the engine and look at fuel pressure on the laptop. it should be 125 psi cranking and go over 200 running. If you dont build any fuel pressure and you know the gear pump is working then 1 of 4 things is wrong. 1. fuel pressure sensor has failed (unlikely) and if it does it will not start. 2. one of the two regulators is failed or stuck open( you can't tell by looking) 3. the electromagnet has failed or the voltage to it cant open the shutdown plates behind it. If you think its this take out the 4 screws that hold it on and take the pieces out and look how they came out!. then leave them out and bolt the magnet back on and see if it starts. If it does replace the magnet if the power wire to it is good. 4. you could have a screen in the inlet where the fuel line screw on. Cummins had us remove them as they would plug up and shut the engine down. See if there is a screen in the inlet where the #10 line screws on the engine fuel inlet. You can still leave the fuel filter loose on this and the lift pump should fill it after about 5 key cycles. This is what I would do if it were my engine.

[@TheFredloc870]

@@ENGINESHOPJOE Ok thanks so much I’m try it soon i get back home

[@DineshKumar-se7ue]

⁠

[@snappingfingers8786]

10/2023-B, ISX 550, Tons of $$$$$, and still not fixed, Getting fuel rail pressure code, loss of throttle, I don't hear turbo/injector whistle, motor starving for fuel, Dealer changed 2 parts, they said the cause was old rubber from fuel lines, a few months later the same issues, a friend mechanic changed one part, Sorry not a mechanic so not sure of the parts, I know once the fuel filter is changed and I add diesel fuel additive it clears up for a few months. The last fuel filter I changed I saw very little black particles in the fuel. The injectors, fuel pump, and turbo have not been replaced yet, I think the check valve and pressure shutoff valve were replaced, and 2 other parts replaced, It does seem to act up more under a heavy load, not sure if that is a coincident

[@ENGINESHOPJOE]

What is your engine serial number. Can you have dealer send me an ecm image to [e-mail]. Do you have algae in the tanks? (black slimy film) If yes you have to add biocide to kill it or the problem never goes away. If it runs good after a fuel filter change most likely mechanically all parts are ok. The problem is fuel starvation (plugged filters, Lines) When ever Faults are active that relate to the fuel or boost or aftertreatment system the engine is derated so you wont hear the normal turbo sounds and sensed throttle loss is actually the ECM taking away torque because the active faults drive it into a derate. The key to this is when. you change the fuel filter and add additive it is ok for a few months. THe engine is ok the problem is fuel supply. Check for algae.

[@snappingfingers8786]

@@ENGINESHOPJOE I will get you #, I had the dealership do an alge flush a few months back, I thinkI'm getting carbon buildup in the fuel filter , Thanks for the reply

[@mhmedbadra1986]

Is it the same on Qsx??

[@ENGINESHOPJOE]

Yes. You always have to verify parts by engine serial number. There were cpl part # differences along with generational changes. The ifsm was used on the first apex generation through the CM-871.

[@mhmedbadra1986]

@@ENGINESHOPJOE many thanks

[@dortega1404]

Good morning Joe my Ifsm is leaking behind 3&4 there is triangle shaped with 3 bolts right behind the actuators can explain what is the function and how to fix the fuel leak thank you

[@ENGINESHOPJOE]

Those are called pulsation dampners. There are a couple orings , steel disk. that looks like a silver dollar but a tad larger, and a nylon ring. Just buy the orings, disk and nylon ring. It is very easy to rebuild. just change those parts. some times that disk cracks or the orings just fail. The disks bounce and absorb the gear pump pulsing so the actuators get STEADY pressure so the fuel is metered correctly.

[@ENGINESHOPJOE]

I did not give part numbers because I dont know your engine serial number. Generally speaking those parts are the same through all the generational changes but there could be material or diameter changes i dont know about. Always use your engine number to order parts.

[@dortega1404]

@@ENGINESHOPJOE good morning Joe thank you for taking the time response for sure you save a lots of money to all the truckers that like to fix and work on their own trucks have a good day

[@samcooke6207]

What would cause white smoke coming out the fuel tank

[@ENGINESHOPJOE]

The answer would change depending on the engine you have. Check the return fuel for bubbles. Is it running normally? Some injectors can have an issue where combustion gas goes up into the injector. The isx 870/871 old mechanical injectors could cause this if a ball check near the tip of the injector comes out. Normally you have a stumble or non steady idle if the injector causes this.

[@jhutchins118]

also where is the fuel transfer pump

[@ENGINESHOPJOE]

If you have a 570,870,or 871 it is bolted up to the bottom of the ifsm where the fuel line is hooked to supply fuel to the engine. If you have a common rail it is down by the oil pan rail behind the injection pump where the suction fuel line hooks up.

[@jhutchins118]

Thanks after looking I found it after removing the fuel filter.

[@jhutchins118]

I am watching to find my check valve

[@ENGINESHOPJOE]

If you have the isx 570,870 or 871 There are two check valves. One is located where fuel goes in the ifsm on the bottom right of the assembly where the number 10 line screws on. take out the fitting and any screens -you may not have a screen- and then you need a larger allen wrench to remove the check valve. the check valve looks like a 12 gage shotgun shell but stainless and will screw out. The other check valve is found in the center of the fuel filter threaded adapter. Remove the filter and look up inside the middle with a mirror and light and you will see the allen. Right hand thread. I dont remember the allen key size its around 1/2 ish

[@dortega1404]

Good morning I’m broke down the engine die just like it run out of fuel I check if there is fuel pressure after seeing your video and there’s nothing coming out can you please reply with some suggestions please thank you

[@ENGINESHOPJOE]

Remove number 7 regulator partially covered by the fuel return line fitting. Once the regulator is out crank the engine. If no fuel runs out of the hole then either the gear pump sheared and is not pumping fuel or there is no fuel going into the inlet fitting from the tank/frame filter. Put a bucket of fuel on the valve cover and put in a number 10 line and screw it to the fuel inlet. now it is gravity feed for test. crank it over and fuel needs to run out of that fitting cranking. The electric lift pump should pick up the fuel and start pushing it out the hole. once it does unplug the lift pump and crank it. if fuel does not continually pump out of that hole cranking the gear pump failed just replace it. If fuel comes out most likely either the pressure regulator you removed failed or the one under the fuel solenoid failed. Make sure you did not lose electrical power to the fuel pump solenoid- has one wire on it. Check for power at the stud- 12 volts on a truck. rarely the fuel solenoid goes bad and wont hold the shutdown plates open. you can take the guts out and bolt the solenoid back on if you think that is it. It will start and run with no solenoid guts but has slow shutdown but it will shutdown with the key and you will have an active fault for fuel solenoid failure (because it cant use the solenoid to shut it off it has to use the actuators)

[@dortega1404]

Thank you for your response

[@jrvillarreal2901]

@@ENGINESHOPJOE What would cause my cm870 to dump white smoke, and turn off, but when I cycle the key, it turns right back on. I’ve changed the gear pump twice lift pump all the sensors and it still acts up I push in the compuchek orifice, and diesel shoots out. I get plenty of prime from the lift pump, but when I started it and I accelerate it cuts off and shoots a whole bunch of white smoke. Thanks

[@Jreddygo]

My fuel shut off selanoid keeps burning out and idk if it’s my ecm or another issue. So I took out the accessories behind it and run it direct. And not even connected to the ecm and it’s running fine so far but I would like to understand why this issue persists I keep changing new fuel shut off seanoids….smh I even had one mechanic got wire it directly to a 12v source around the engine and it worked for almost a year like that until I had an issue with it again recently. It’s a nightmare these so called “mechanics” can’t figure it out..

[@ENGINESHOPJOE]

First those solenoids are made to run in specific voltages. The ecm calibration determines what voltage is sent to the fuel shut off solenoid. Most North American on highway is usually 12 volts. Have someone check what voltage your calibration is set too and then make sure you have that voltage stamped on the solenoid you buy. Next make sure the engine has a good ground. If you have a two terminal solenoid then you need to supply a remote ground to the solenoid and if you don’t it could cause early failure.