1996 - 2002 GM Truck 6.5L Turbo Diesel Fuel Lift Pump Replacement (Chevy & GMC)

This video is about replacing the 6.5L diesel engine fuel lift pump on GM full size old body style (OBS) trucks from Chevrolet and GMC. In this scenario the vehicle was operating fine, until the fuel filter was replaced, at which point the lift pump is discovered to be defective during bleeding air from the new filter. What happens in this scenario is the Injection Pump itself is able to maintain suction in the absence of the lift pump operation, until the line has air added such as when changing the fuel filter. Such a problem can go undetected for months. You do not have to bleed the water in the brass fuel petcock at the front for this particular kind of scenario, just the fuel filter bleed is sufficient to restore normal operation after replacement of the defective lift pump.
Illustrated using a 1999 Chevrolet Suburban K1500 LT, but the approach and process would be the same for 2002, 2001, 2000, 1998, 1997 and 1996 models. Not the same but similar enough for 1995 1994 and 1993 models. Applicable to Suburban, Silverado, Sierra, Cheyenne, W/T, Tahoe, Yukon models across Chevrolet, GMC, and Holden.
GM and ACDelco part numbers given for 1993 thru 2002 models, along with fastener torque values.
The eBay and Amazon search links below are paid links, for which I may be compensated and earn a commission, if you choose to buy the parts and tools shown in this video thru them:
GM part 15754298 (1999 - 2002), 25117340 (1994 - 1998), and 25115224 (1993) lift pump: ebay.us/PYFyMn or amzn.to/3lHzjOn
ACDelco part EP1000 (1999 - 2002), EP309 (1994 - 1998), and EP158 (1993) lift pump: ebay.us/ilrYPr or amzn.to/36GyscA (EP1000) and amzn.to/3lHiTWn (EP158) and amzn.to/3lD2t13 (EP309)
The metal fuel lines attaching to the fuel lift pump also have an o-ring seal that may need to be replaced, that would be GM 22514722: ebay.us/kf0YeT or amzn.to/3HLy5Ah
GM 12085524 wiring harness pigtail: ebay.us/YwaC03
ACDelco PT-134 wiring harness pigtail: ebay.us/vM8YpZ or amzn.to/3tVohNd
And if I've saved you some $$ here, consider some coins for the coffee tip-jar! ko-fi.com/drshock
Chapters:
0:00 - Problem overview
0:24 - Electrical analysis
1:10 - Lift pump location
1:34 - Wiring harness test
3:09 - Lift pump removal
6:44 - Replacement part numbers
7:15 - Lift pump installation
10:40 - Retest
#drshock #65diesel #dieselsuburban
Disclaimer: DrShock, the alias for the human content creator for this KZbin channel, is not responsible for any damages, injuries, losses, or liabilities associated with any repairs, upgrades, or maintenance performed on yours, or any other, vehicle whatsoever. No warranty, express or implied, is made as to the accuracy or completeness of any information provided within this channel. Viewing and using the “as-is" information of this channel is totally at your own risk. Always wear personal protection equipment and follow appropriate vehicle manufacturer service manual guidelines with original manufacturer parts only when performing any repairs, upgrades, or maintenance upon any vehicle.

[@tarbeau8561]

DrShock, I really appreciate this video that you made for us. I was able to change my filter off of your videos. But, I also had a hard start after the fix, thankfully after watching this video I believe I found the problem. I didn’t let the fuel bleed out multiple times like you just did. Those little things that are easily overlooked can make a huge difference in the outcome. Thanks again for your videos sir. Looking forward to the next one

[@petelove144]

Changed out my lift pump today. This video made a huge impact on it going smoothly. I had very little fuel spill but was prepared thanks to you. Used the cup and plastic wrap trick to bleed filter, worked awesome. Really appreciate your content and detail. Thank you!

[@MorganBurris]

Thank you so much for all your videos! I am a woman who does a lot of the her own work on her 1998 6.5 diesel K3500 since I no longer work full time. Your videos are always through and you take the time to explain step by step what and WHY you are doing things! Once again, I appreciate all the hard work you put into your videos, they are a HUGE help to me restoring this truck my husband and I purchased last year.

[@DrShock]

Thanks!

[@michaelmounts1269]

outstanding video!!! really comprehensive and thorough...I have a 94 suburban 2500 hd with 6.5 that I’ve lovingly restored over years. Couldnt have done it without people like you who take the time to do videos like this. Honestly-if there was an academy award for best you tube instructional..you should get it. 👍

[@StreetTalktv850]

I just bought a 94 and I'm new to the diesel truck world and I was wondering do you have to add def to a older diesel like a 6.5?

[@TheMcdrewb]

Keep the 6.5 vids comin!!!

[@mardellgriffin7276]

You did a great dam job, directive and vivid in your details. Thank you bro, you're a God send. They tried to chared me 400.00 dollars for that, and I did it for 45.00. Thank you again.

[@milesj6064]

Thanks for making the video, I have been wanting to change my lift pump, but was worried how much fuel was going to run out under the truck, now after seeing that, I feel once I run the tank down a bit I will change the pump out. I have had the truck for a couple years and it has 380,000 kms on it and so I have been changing some of the components since I don't know the history, and not wanting to have it break down on the highway

[@vanlife247]

Great job, what you lack in camera angle you more than made up for w/ excellent narration

[@MNDashcam]

Just did this on my truck. Fixed the surging under load issue.

[@VincentTony1]

Excellent video. Your bleeding process was very good. Very helpful.

[@greenthumb6875]

You are the man, love this. I subscribed at the introduction and I don’t own a suburban, I want one though. Now I’m prepared.

[@terrystinson]

Great video. Thanks for posting. I will watch your videos anytime, not to much double talk all info ! thanks again.

[@jerrycardwell9322]

Thanks so much for this video!! Very detailed and helpful! I think that this will solve my problem with my 99 3500 thanks so much!

[@robertcs68]

you can use some aluminum foil to make a "channel" for the fuel to run down and into your container. Way less mess! Good video tho!

[@jimmylee377]

thank you for a good video

[@tomrohn8607]

I replaced my factory lift pump with a Carter..and made my own relay.what a difference on top end

[@tristinbrietzke5649]

You made you're own relay?

[@jvm3753]

Good video; but even with a volt meter, I had high resistance on my ground; but just doing a voltage test, it looked good. I took jumper cables from the battery; 2 jumper wires to the lift pump connector; my pump worked good. So don't get bit by a bad ground, or even a 12v feed that's not carrying the load.

[@ronbenson4793]

Another great video, very well explained. What size are the flared fittings that go into the lift pump? Not sure if you mentioned it and I missed it

[@ishgilbertstone4887]

Thanks subbed!!

[@gregsmith6394]

Thank you

[@jimmylee377]

thank you

[@marktompkins3180]

Great video! Do you know what the spec is for the gm fuel line, and where to get adapters and parts to put in a an6 fuel line.

[@un-limited7009]

Thanks for the video. I was wondering is the Lift pump also responsible for keeping the engine primed? & Do you know if I can wire my 94-6.5 Lift pump to turn on when the key is like my 98-6.5 ?

[@DrShock]

The injection pump would keep the prime, not the lift pump. Your 1994 harness would route lift pump power thru the oil pressure switch as an early safety cutoff mechanism. The 1996 and later versions eliminated this circuit. So you would have to look for aftermarket bypass solutions to setup a similar to the one at this affiliate eBay link: ebay.us/zYjTMv This same seller also has the 1995 version of the bypass harness. Hope that helps.

[@lyndamccarthy9502]

Can i do this for a 1996GMC Sierra 2500 HD Diesel ? Also,need to see how you put cup onto fuel line in engine... does cup have a hole in bottom?

[@DrShock]

This video should apply to your 1996 GMC with the 6.5L diesel V8. You have to make that hole in a plastic cup, if you don't have any clear fuel line handy. Clear fuel line is preferred, but the cup can work in a pinch.

[@83malibuwagon]

What were the symptoms of your bad lift pump? My 98 6.5 box truck has a turbo surging problem under heavy acceleration and going up steep hills.

[@DrShock]

This kind of problem is typically discovered by accident tbh. The injection pump, presuming there are no fuel line leaks, will maintain fuel feed prime even after the lift pump has completely failed. When you let air into the feed, doing say regular fuel filter maintenance, you suddenly find you have a crank no start situation after installing the new fuel filter - caused by lift pump failure. The only other symptoms I've seen are the tell tale lack of pump noise during the glow plug cycle. The genuine GM ACDelco pumps typically just run fine until they die completely, I've not encountered any intermediate states with them.

[@brucemeyers4800]

Mine does that too the glow plug relays go through a cycle like that but if i try after the first cycle she fires right up but i live in Florida not sure if that disqualifies me

[@DrShock]

If you're getting fuel pumped thru during this cycle, then the lift pump is working. Another easy test for this is when changing the fuel filter, and seeing that the fuel comes thru when bleeding the air out - kzbin.info/www/bejne/lWGyaaCwhcpspqc

[@marktompkins3180]

The siphon problem was bad for me. If a valve is put into the line, will that work?

[@666Ekko]

Changed my liftpump today from a working one that was weak, to a new one. Problem is the new one dpesnt work, and the relay is good, and there is power out to the pump. Going to call the store when they're open again, but is there anything else I should check out?

[@DrShock]

@Aaron if your truck is a model year prior to 1996 I would check that the oil pressure switch is working correctly as that was part of the lift pump activation circuit in those earlier years. If you're getting 12VDC to the pump electrical connector, and it's still not activating that sounds like a defective pump to me for any year. It's a pretty simple circuit, even with the older ops style in the loop. Be sure you have the right pump too, there were several editions depending on the year. I mention the three different ACDelco numbers in the video description.

[@666Ekko]

@@DrShock Yeah, I jumped under to doublecheck and its the correct pump ( I have a 98 Tahoe). Im gonna call an complain on monday and they'll just have to send me a new one. Thanks for the quick answer!

[@bwet2901]

so your fuel filter is upside down to what I'm used to seeing heh, mine is a van and hangs upside down... which makes me wonder how they could operate the same with the sensor hmm

[@steve19745]

When i took my line off my lift pump itbwasnt flowing that much i used a manual pump and pulled fuel through mine fine but the lift pump wont pull fuel.

[@DrShock]

Sounds like you need to validate the lift pump is still up to spec. They due have to be replaced from time to time. You should be getting battery voltage during the glow plug cycle for 1996 and up models. You should be able to hear the pump going during this cycle, if not you'll need to check that voltage is being supplied. If it is, replace the pump.

[@markwilson9760]

Good video. Problem is the oil pressure switch controls the pump and its too much power runs thru it

[@DrShock]

FYI that use of the oil pressure sender as part of the circuit used during the lift pump prime phase (glow plug cycle) was discontinued starting in 1996.

[@sonyatipton7264]

We ordered a lift pump and installed it. It still doesn't work and the pump gets REAL hot. Could it be bad from the factory? It starts when we put fuel directly in it but not when we don't.

[@DrShock]

Unless its some Chinesium off brand, I would be surprised for it to be DOA out of the box. You can check that you have fuel pressure from the lift pump at the brass T valve at the front, where you would normally vent off water from the fuel filter manager (FFM). Or you could check for pressure at the fuel filter vent valve on top of the FFM. You may want to verify you do not have a wiring issue that is shorting out the unit as well.

[@Lilpupling]

May I ask you a question I just replaced my injection pump on my 2000 3500 6.5 and I replace my trickle pump my oil pressure sensor and my PMD but I'm still getting no fuel to through the lines to my injector I was wondering if you could help me out on that thank you very much

[@DrShock]

Check that the lift pump is operating, if it is you will absolutely have fuel at the filter housing. If you don't then your problem is aft of the filter (e.g. clogged fuel sock at tank). If you do have fuel at the filter, then your problem is between it and the new pump. For your model year the oil pressure sensor has nothing to do with the fuel circuit.

[@Lilpupling]

@@DrShock thank you very much I'll check today

[@TattedTommysTv]

Shouldn't the pump be making some type of noise when it's on mine isn't and can't feel any vibration I have a 6.5 L I true one with turbo in the center and my lift pump is making zero anything I've never had a single issue out of my bus thanks for any input in advance

[@DrShock]

The 1996 and later model years operate during the glow plug cycle (key on engine off), so you should be able to hear them yes. If not, try to feel for the vibration of the pump operating during this same glow plug cycle period.

[@videogames7032]

hey, I replaced the fuel pump, but now it's seems like I don't have any Air pressure, I have a 1996 GMC/Chevy diesel 6.5.. any idea's? fuse's are fine

[@DrShock]

When you say _air pressure_ I'm going to presume you meant _fuel pressure_ here. So it's a pretty simple setup to debug here, the lift pump has a straight shot to the fuel filter housing on these 6.5L diesels. If the pump is working, you will have fuel pressure at the filter housing (which you need to bleed the air out of the line from changing the pump anyway). If there's no pressure, or insufficient fuel pressure, then the pump is not working correctly. Why would that be? Well, setting aside the possibility of a defective lift pump I'd first be looking at the wiring harness to confirm the pump is getting the voltage supplied. If it is, then it's a defective pump if there's no fuel pressure at the fuel filter housing bleed hole. An easy check of voltage is to just listen, the lift pumps make a distinctive whrrr when first powered up during the glow plug cycle. The lost of this sound is often the first clue one has failed.

[@darrrenbetker4266]

Well how come when i remove my feul lines the feul doesnt stop fliwing out of the lines. Just keeps pouring. How do i stop it?

[@DrShock]

On a 6.5L diesel with the engine off for awhile shouldn't really be any pressure built up. Its normal to have some fuel loss during this particular repair. In my experience with this repair its either the residual fuel draining out of the lines, or a bit of siphon effect thru the line going on. A variant of this repair if you're seeing this is to quickly pop a rubber plug on each line as you remove them, then reinstall tank side line first then engine side on new pump. Still some fuel loss, but cuts down on it alot and no waiting.

[@darrrenbetker4266]

@@DrShock my feul does NOT stop flowing. I cant reach above the tank to clamp off the line coming outa the tank. I also dont have any plugs. What do i do

[@darrrenbetker4266]

I will bath in diesel feul by the time i can get the old pump out and the new one in. And at $140/l up here i cant stomach lising gallons while i try

[@DrShock]

If i had this situation, I'd defer the lift pump repair until I was down to a nearly empty tank and siphon out what's left to avoid this situation. While not ideal, the IP will run without it as long as you haven't changed the fuel filter or otherwise interrupted the suction on the engine side of the lift pump. Personally, I've never experienced this so gotta guess you have a siphon situation happening. If you can't defer, and can't plug the lines, all that's left is to siphon the fuel out of the tank then.

[@scottms05]

Is it possible to run only the main tank and bypass the auxiliary? Developed an issue with the rear and cannot find a replacement. Pulled it and now my fuel gauge goes from full to empty 10 seconds after startup and stays there. TIA

[@DrShock]

This being a diesel engine video, I presume when you _pulled it_ you mean you pulled the fuel sender in the aux fuel tank? If so, yeah that's going to cause a gauge problem because there are two fuel senders on a dual tank diesel, as well as a balance module. If you take alook at this diesel fuel sender repair video I posted last week, at the beginning I flash the schematic up for the dual tanks. That might help you debug that part. kzbin.info/www/bejne/mqiceZyXapqsr9U

[@scottms05]

​@@DrShock I meant that I removed the entire rear tank. The metal locking ring on top where the sender is was badly corroded and the tank needs replaced but I have been unable to locate one anywhere. Will I need to find a new tank or is there someway to only use the main tank? 96 C3500HD

[@DrShock]

You could switch to just the front tank, but you would have to eliminate the balance module from the circuit and that's not something I am familiar with to advise on. To repair the original design, I believe the 96 C3500HD sender for the aux tank would be GM 15708151 (or Spectra FG122A). The aux tank itself would be GM 15014017 but yeah it is a discontinued part and I also could not find any aftermarket replacements. The other GM numbers that this one superseded were 15708150 and 88944149. All are 18 gallon secondary rear mounted aux tanks (should have RPO K53 on your glove box sticker). You may have to look at having a shop repair the original tank, or fabricating something of similar size and capacity.

[@christopherzachary1075]

So I watched your video on how to change the fuel filter. Thank you it was smooth except with I went to bleed the air out no fuel came up. So I watched this video thinking it was the lift pump. I took off the discharge line on the lift pump and bumped the key. Fuel came out so I figured the pump was weak. Went to the parts store and replaced the lift pump. After replacing I loosened the fuel filter and still no fuel is coming out! Please help!! Thank you.

[@DrShock]

I'd check that the bleed hole in the fuel filter housing cover is not plugged up, and that you have opened it enough to get the bleed going. You may want to inspect the cover in general to see if there is some obvious obstruction. I've never encountered one where it wouldn't bleed air, then fuel, unless of course the lift pump was inoperative.

[@steve19745]

I have the same exact issue my pump isnt delivering fuel to the filter housing and my lines are clear the air wouldnt be pushing up uf they were plugged they actually look like new lines

[@yiog2047]

@@steve19745 how did you solve it?

[@judyullmann7655]

Actually, the entire tank siphoned out when the pump was disconnected. LOL Something to remember.

[@hdrjunkie]

Why would one of these leak? Is there a gasket or se that goes and can be replaced?

[@DrShock]

If the lift pump is leaking it has to be replaced, there is no rebuild procedure on them.

[@fahadharbi8137]

Thank you for the video, I just bought a 1998 c3500 truck, and the "water in fuel" sign light up, coud you tell me how to bleed the water!!??

[@DrShock]

Thanks, there's a brass relief valve near the front. One of the fuel lines from the fuel filter housing connects to it. The other end drains below the vacuum pump of the engine. You open that valve while running to purge the water out. This video might show some views of this valve - kzbin.info/www/bejne/kHWTnmOQm8h0eNE

[@fahadharbi8137]

@@DrShock Very useful advise, thank you sooooooo much

[@777Slots]

Thanks For Making this Video !!!! #777Slots

[@Ry-er4yv]

I can hear the pump when I turn the key or jump the relay but no fuel sprays from the bleed valve (also fuel pressure is less than 1 psi at t-valve), fuel filter is new. Truck runs (when it finally starts) and drives but is very hard starting (though on occasion it will start right away) and engine stutters above 2rpm while driving. Possibly tank sock ? Or weak lift pump ? I don't want to shop it but I may end up having too 😮‍💨

[@DrShock]

The injection pump, on the years this video covers, will pull the fuel on its own, as long as the lines remain primed with fuel. So a lift pump can still be faulty/weak and the engine will function. They do not necessary fail in a "dead" state. The service manual fuel pressure spec, at the fuel filter housing output into the injection pump input, should be no less than 4 psi with the engine running. Less than 1 psi, at that same measurement point, would point to a failing lift pump, or an obstruction in either the hose, the fuel filter housing, the hard line, or the sock. It can be a long and involved process to diagnose which.

[@Ry-er4yv]

@DrShock I'll check and or replace these and report back with the results for others

[@DrShock]

Well don't necessarily fire the parts cannon at it (replacing parts before confirming the diagnosis). That can get expensive. But definitely do check each for proper clearance (tank sock last as the most difficult to access). If it were me I'd check the lift pump flow first, to be sure it's not just a weak pump since its easy to access. This can automatically eliminate a number of lines, and the sock, from the suspect list. The GM spec on the pump output alone is _up to_ 15psi.

[@hdrjunkie]

I have a puddle under my truck right under this pump, the pump and all around it is wet. Do these things leak? Should I replace it? I can’t see if it’s a leak in the lines or not. But maybe the nuts loosened over time?

[@DrShock]

If the pump is leaking fuel, you must replace it. Be sure it's the pump though, and not the fuel line fittings just coming loose. You might also have corrosion of the fuel lines, in which case its not the pump that needs replacing but the fuel lines.

[@hdrjunkie]

@@DrShock thanks. Yeah I’m gonna check those lines and see if they are loose or rotting. I just didn’t know if these pumps were prone to leaking themselves.

[@partyboy1ize]

Just bought a 2000 gmc 3500 with this same setup I have the water in fuel light on the dash and was wondering if you have a video on that or have any suggestions on what to do to get it off this is my first diesel truck so I’m new to it and not really sure about what regular maintenance needs to be done with it

[@DrShock]

Gratz, that's a solid workhorse of a classic truck and one of the last made. I don't have a video on this, but the procedure is pretty simple. There's a brass petcock near the front top of the engine, by the air intake resonator (long black plastic cylinder/tube). You want to _slowly_ open that up while the engine is running. It has a hose that routes down past the vacuum pump and that should expel any water in the fuel filter housing, along with some fuel. Then watch this vid to replace the fuel filter - kzbin.info/www/bejne/lWGyaaCwhcpspqc If the warning light doesn't clear, then the sensor could be defective. Uncommon, but it does happen. GL.

[@partyboy1ize]

Hey I appreciate the reply. When I first bought the truck I took it to a diesel shop to have it looked over and they got the water In Feul light off so I’ve been driving it the last 3 months and just the other day the light came on again I went to go open the petcock your talking about in the front and nothing came out of the drain hose could the petcock be bad?

[@DrShock]

It would be more likely the lift pump isn't working anymore. You could test that by ear, when you first turn the key to the glow plug cycle the lift pump should be audible from inside the cab with the radio turned off. The symptom you're having with the water in fuel drain off, if you also don't hear anything I'd even more suspect the lift pump has failed.

[@partyboy1ize]

Are you referring to the lift pump in this video? The truck still runs good but I did notice when I go to start it it cranks a little longer than what I thinks normal before it fires

[@Koldun178]

Hello there! I have a problem with this pump . I found that it is not powered when the ignition is turned on! Should it always be there, or should it be in special cases?

[@DrShock]

For 1996 and up the pump will come on briefly when you are in the wait to start (glow plugs going) mode with the key (you should be able to hear it) so that you know the pump is working. If you're turning the key to that mode and you don't hear it then yeah something is amiss there. When a lift pump dies you don't always know as the injection pump can maintain the fuel suction for a long while, across many start/stop cycles, in many cases.

[@Koldun178]

@@DrShock every time the ignition is turned on, the pump connector is not powered!!! But the pump itself is working ( connected directly to 12v) The question is , where does the power to the pump come from? The wires seem to go into the tank . Thanks for the answer!

[@DrShock]

Is your truck a 1996 or newer? Very important question as the power routing for older trucks is quite different (thru the oil pressure switch during glow plug cycle). For the 96 and newer though it's just 12V direct power via the relay during the glow plug cycle. If voltage is not present you may have a break in the harness from the pump to the relay that you'll have to trace underneath the truck to locate. But first check that the relay is working, location that I show at 0:27.

[@Koldun178]

​@@DrShock Thanks for the answer! I have a 1995 Winnebago WCF25RC motorhome! Based on the Chevrolet P30 6.5 Diesel . I'm from Russia. There is very little information on this issue! Thank You again for your help! I'll look for a gap.

[@derangedgaming5514]

I am stumped as to what the unit under the intake in the forward of the engine is called. It's definitely fuel related as it's leaking fuel from a bad o-ring. It's a sensor of some type, I think. I have searched everywhere on Google for the part name, and cannot find what it's called. Would you happen to know? It's got a plug to it, cylinder in shape, goes into the engine, and requires snap ring pliers to get out. It's in the front of the top side underneath the intake plenum.

[@DrShock]

From the location you're describing, it's part of the fuel injection pump assembly. That in the front, and the fuel filter housing assembly in the rear, are the two fuel related major assemblies on top of the 6.5L (in addition to of course all the plumbing related to them). Take a look at my injection pump timing vid here kzbin.info/www/bejne/Z6i4d2yZmaeFhc0 , and see if you see the part. If so comment on that video with the time index where it appears, and I can identify the particular part you're looking at there.

[@craigberube9890]

I can not find a rely for my lift pump ,I do have a pmd , is that the same ? How ever I should be able to do electrical test to see if it’s getting voltage. Correct? Also I tried the cup trick and got no fuel ! Help please !

[@DrShock]

Nope, a relay is not a PMD. The video shows the relay in the underhood fuse box right at the beginning. If you have a truck for the years this video covers, yeah there will be voltage at the pump when the key is on, but engine off, position.

[@craigberube9890]

@@DrShock thanks , if no fuel enters cup and fuses are good , that would point to l.p. Being bad , correct?

[@DrShock]

If 1996 or newer 6.5L, and no fuel comes out of the fuel filter manager bleed valve at the top of the filter during the glow plug cycle, then you either have a wiring harness problem supplying power to the lift pump, or a bad lift pump. On 1995 and earlier, this could also involve the oil pressure sender as it was used as part of the lift pump power circuit, but not in 1996 and onwards.

[@hugoayala6472]

What is that fuel pump or filter

[@DrShock]

It's a lift pump. Part numbers in the description.

[@Chri56854]

Does anyone know what that rapid ‘clicking’ sound at 11:00 is? My truck does the same, but im not sure if its normal or not😅

[@DrShock]

Normal symphony of a genuine GM glow plug relay coupled with a genuine GM ACDelco lift pump. ;-)

[@Chri56854]

Thank you

[@spikes1529]

what if i have water in my fuel filter is there a good way to get it out?

[@DrShock]

You'll need to use the drain T valve to get the water out of the fuel filter housing. Use a clear container so you know when you are done, and you'll need the lift pump going during the procedure.

[@medinafrancisco12]

You mentioned to check the o-rings. By that you mean the built-in ones on the line, not rubber ones correct?

[@DrShock]

I was referring to the fuel hard lines, yes. Both inlet and outlet have a viton type o-ring seal. There are links in the video description for these parts.

[@medinafrancisco12]

@@DrShock I replaced my pump today, didn't even think about the o-rings. I guess I'll see if it leaks. Haven't started it, I had gotten the incorrect fuel filter.

[@misterjones9522]

I wish you could have shown which two metal prongs to jump

[@DrShock]

I did, check 12:08 again. It would be the fuel pump relay in the underhood fuse box next to the brake master cylinder that was removed, the cover has the diagram on which is which. You'll notice the empty socket is shaped like a letter U (two down, three over, and two up) when standing at the drivers side fender facing the brake master cylinder. The jumper goes from the lower leftmost connector (two down) of the U to the upper rightmost (three over and two up). Don't run it very long like this, just long enough to test or bleed the air.

[@vladpierre2694]

This pump is supposed to click when the key is in acc?

[@DrShock]

If it's a genuine GM ACDelco pump, and for the years this video covers, the lift pump will activate in the key on engine off (KOEO) position. Older models this would not be the case though.

[@blackincawston]

Hi there, wondering if you could help me out. I watched you video. I did the test on the lift pump wires to and I wasn't getting any 12 reading, the truck starts but once in a blue moon, it will stall... I did the jump wire on the reply and pump works. I don't know why I don't hear the pump when I turn the key, not even to start... I just had to think maybe ask this will like you said, it's the injectors that starts the truck. I bought a second pump just incase. I have a 1995 Chevrolet 6.5

[@DrShock]

There's some more technical info in the description text for this video that might be helpful. For a 1995 diesel truck, the oil pressure switch (OPS) is part of the lift pump circuit. This video is showing 1996 and up, which do not have that component in the lift pump wiring anymore. So if you are not getting any voltage at all, and you are sure you have a good ground for that test, I would check the wiring harness between the lift pump and the OPS, as well as OPS itself for that model year. The OPS can otherwise appear to be working fine (oil gauge fine, no PCM codes, etc) but this electrical safety for the lift pump circuit part of it can separately fail. There is also a relay in this circuit you should check as well if having a no-volt condition at the lift pump.

[@blackincawston]

@@DrShock thank you so much for the quick response... This is something I'll have to check from your details, would you know where the ground wiring is mounted, the wires is ofcourse wrapped. I guess I should get voltage when I turn the key without starting the truck? Even for this year?

[@DrShock]

For the 95 you would get that initial voltage via the relay, and then after the engine starts from the OPS.

[@blackincawston]

@@DrShock sorry with all questions. So would you say there is a problem that am not getting any reading if I turn the key without starting the truck and I am not getting any voltage read but I did what you did in the video with a wire on the replay port and I heard pump

[@DrShock]

Because of how the 1995 and earlier are wired, just turning the key won't be enough to get the lift pump going like on the 1996 and later. The OPS is used as a safety device in these earlier years and powers up the lift pump only once engine oil pressure is in place during cranking, or running. So you will not get the lift pump to come on without cranking a 95. An easy catch of a failed, or failing lift pump, is a fuel filter change. The air let in during this breaks any injection pump suction and forces a need for a good working lift pump to bleed the air out. Often times folks never realize they have a problem until they can't bleed out the air, or the engine won't start after simply changing the fuel filter. To bleed a 95 or earlier, you have to crank the engine for a few seconds with the air bleed valve on top of the fuel filter module open. And a small length of plastic tubing attached to catch any diesel fuel purged out with the air. I'd say, given how rare you describe this problem is, check all this out at your next fuel filter change. If there's no issues, then these _blue moon_ events are not lift pump related.

[@DaveFrockit]

What about a late 95 3500 6.5 single rear wheel...?

[@DrShock]

It would be a different pump. I listed all the ACDelco pump numbers in the description though. The pre-1996 wiring connection, and mounting, may differ from this 1999 model I showed as well.

[@brennandavidson-vermette2772]

What would be the part number for 1998

[@DrShock]

Part numbers are in the description, typically the 98 would be a 309 but you can verify that at parts-catalog.acdelco.com/catalog/catalog_search.php

[@bennyaguilera1158]

I have 2000 Chevrolet 3500 hd I don’t have power on the rear fuel line pump

[@DrShock]

By saying _rear_ I presume your 2000 6.5L setup has dual tanks then? If so, then you're talking about having no +12VDC at the rear aux tank transfer pump. You'll need a schematic from the service manual to follow, but power to that pump is controlled by the fuel tank balance module, main tank sending unit, and aux tank sending unit. So its either the wiring harness, or one of those three components involved would be my guess. I've not worked on a dual tank setup, but do recall these details.

[@nicholasnettles4632]

I changed my lift pump and fuel pump on my 1996 6.5 Detroit Diesel but I'm still not getting fuel to the engine somehow? Someone told me it could it be the fuel injection pump?

[@DrShock]

If you changed the lift pump (there is no fuel pump in the tank like a gasser just a sending unit) then you should get fuel to the filter assembly. Are you? If you're getting fuel there then the next stop is the injection pump. If you're not getting fuel to the filter should not be hard to track down, if you are getting fuel to the IP but no further that's way too complicated for a comment section. There are some vids out there on that.

[@psychoticbastard6271]

Is this the same as injection pump

[@DrShock]

No it's totally different.

[@chupacabra1765]

You should pin in your comment that it is crucial that the fuel tank be drained. The fuel line will syphon and if you think your just draining the line, you aren't. The whole tank is going to end up on the floor. This is not emphasized enough in your video. Im also confused about the bleeding usingvthe cup over the stock fuel filter housing. I though that little spigot at the top was a place to fit a hose, definitely not the case for my filter. How is the cup cut at bottom to interface with the knob on top of the filter housing so it doesnt come pouring out of the bottom.?

[@DrShock]

It's not practical to drain a fuel tank for this maintenance procedure. Few to no customers would reimburse for the time involved to do so. You just have to complete the job before the siphon effect gets out of hand, per the GM factory service manual. I mentioned in the video that I just grabbed the cup in lieu of a hose at that particular moment. You can either attach a hose at the top bleed nipple of an OEM fuel filter, or _in a pinch_ just punch a hole in a plastic cup with an awl as I did. It makes for a tight enough interference fit long enough to bleed out the air. Aftermarket filters may lack this air bleed nipple though.

[@chupacabra1765]

@@DrShock thank you for reply. Was thinking of removing sending and line unit from tank due to the gauge continually going bonkers and beating up the neighboring gauge. That would stop any syphoning. I cut a hole in the box to access it as pulling the tank is way too much work.

[@DrShock]

That fuel gauge behavior could actually just be the gauge - kzbin.info/www/bejne/aKKUgImNd8qXabc or it could be the fuel sender in the tank - kzbin.info/www/bejne/mqiceZyXapqsr9U

[@charlesstevenson5141]

I wouldn't replace a stock lift pump with another stock pump. Those pumps are really weak and deprive the engine of fuel. An aftermarket pump will wake it up and make it happier plus it'll send a lot more "cold" fuel that will help keep the IP a little cooler which will prolong the life of the IP and with the IP being buried under the intake and a estimated $2k, I'd definitely upgrade.