Can I get the idle problem sorted? Mercedes W124 E220 part 4

[@HomeBuiltByJeff]

Check out the fantastic EcoFlow Black Friday deals; Official Website: bit.ly/48SGzkU Amazon：amzn.to/3NWJ0sS ebay: bit.ly/3AvpG2W

Doesn’t want to go changing parts Willy nilly , then goes onto change parts Willy nilly 😂😂

[@djnmv]

Haha came here to basically say the same thing 😂

[@volvogt21]

A a restorer of this era bmw bikes throwing parts at it is the best option. Known good parts make the job way easier. This era of German vehicles is cheap for a very very good reason. Most people buy a spare identical vehicle for parts as they are basically worthless.

[@alastairbrown9528]

To be fair a lot of the parts changed were consumables that appeared like they needed changing anyway.

[@AMLagonda]

I think he was just giving it a much needed service....

[@jordankokolis]

You forgot to the golden rule of the 80's, go and thrash it for 5 miles (8 klm) and blow the webs out of it, was the cheapest tune available 👍

[@tanaseav]

Just as a note for future you: If the fuel filter is clogged, you will have the exact opposite behavior, the car might run ok at iddle, and low load, but when you demand high load, meaning high fuel volume, there will be no fuel available. The engine will want to suck more fuel than what can pass through filter. So a car that runs ok at high load, but shits the bed at idle cannot have a clogged filter or any fuel pressure issue for that matter. It's going to be something related to air, or maybe throttle body, MAF, or maybe idle control method (air circuit, or electronics, or whatever this car uses for idle control)

[@markalbert4652]

That's what I was thinking. I was in the trade a long time ago, and I always found that an engine could start and idle just fine with a very dirty fuel filter or dodgy fuel pump. However as soon as you drove the car (and therefore demanded more fuel), it would always starve the engine and start to cough & splutter. However, having said all that, I can't argue with the fact that as soon as he changed the fuel filter, the idle did seem to improve. It goes against the theory, but stranger things have happened I guess!

[@oyvand]

I did the same job rewiring the MAF sensor on my 600sel 91 mod. Merc. My wires were completly crusted all the way into the MAF plug itself. I used a sharp knife and cut open the plug and soldered the wires all the way into the plug pins. Then glued the two halves back together. I would recommend trying the same, it's a cheap fix to try if nothing else.

[@twcmaker]

Benny looked like you were holding him hostage 😂😂😂 I get the feeling he's not keen on Mercedes? 😂

[@johngibson3837]

Aye poor Benny used and abused

[@jasonscherf7553]

Had a 76 jeep pickup that I had the engine rebuilt, almost blew it up (went lean and toasted a spark plug) because it had a bunch of crap in the tank. I had replaced the filter twice in four months and they plugged up quick. Drop the tank and clean it out. It's a pain but it's also peace of mind!

[@middle-agedmtbhack8298]

Hey, congratulations on clocking over 200k subscribers. Just noticed it. Well deserved.

[@ConanMaguire]

G’day Jeff I’m not familiar with Mercedes products, but this sounds like a MAP sensor fault. These operate at idle and just off idle only. Easy to check. It is usually near the inlet manifold. Just a vacuum line and a 3 pin plug. Disconnect the hose while the engine is idling. If it runs the same, that’s your problem. Good luck. Conan

[@Bach_12]

If it has a MAP sensor, i'm on this one☝️☝️

[@jimclarke1108]

Jeff all these builds you have on the go at the same time.... im beginning to think you have a twin brother🤠🤠

[@deuce454]

it would seem more likely to be a vacuum leak since its low rpm and load. that would give a lean condition at idle .. and once the throttle is open a small vacuum leak won't affect the mixture as much

[@dummerdum4714]

doesn't explain different behavior when it's warm

[@gregsierra414]

​@@dummerdum4714 It could if it was leaking from a metal flange that expands and closes the gap as it warms up.

[@SpankysHotRodsandCustoms]

It’s always the simplest part and I always replace everything before I start with the simplest part. Thanks Jeff

[@jesperhougaard]

As far as I recall from my old E220, I repaired throttle body wiring, cleaned throttle body gears - and everything worked. Since the plugs could not be reused, I used computer male and female plugs for the wiring connection.

[@DawgmanNZ]

The car wizard had a case recently where the fuel return line was blocked and it caused running issues as the fuel pressure built up far too high and injectors shut off.

[@darrenpotter2553]

If its around the early 2000's bosch efi it could be the efi control unit, the unit fitted ro mk4 golfs and alfa 156's is known to fail. And its the idle that goes

[@avengervordred]

Would definitely waht to check the fuel pick-up tube in the tank. If the fuel was that dirty. They often have a filter bag over the end that gets blocked.

[@samramone84]

And maybe Dump the fuel and start with fresh fuel?

[@pashakdescilly7517]

Clean the tank.

[@natalinowerty]

check the tank pick up!! and clean the thank. major isue in those

[@davidlamport3178]

Just a thought, Try checking the fuel lines are clear. In addition how are the compressions on each cylinder. Good Luck

[@markalbert4652]

If it's idling when warmed up, but not when cold, then it sounds like an issue with the cold start injector (or cold start circuit). I've been out of the trade for a long time now (before this Merc was built), so I don't know if this injection system uses a cold start injector or not, but it will have a system of some sort to richen the fuel mixture at cold start up and cold idle. If you haven't already done so, then maybe look into the cold start/cold idle system.

[@chrisyes1629]

Hmmm. Maybe a long shot it's the crank sensor. At idle it gives all the indications of a air leak. If you disconnect the brake booster at the booster end and blow smoke into the inlet you can see if there are any leaks. Smoke will show the leak and if the only leak is through the throttle body butterfly then it would be suspect. Just a suggestion. Cheers.

[@gregorystidsen8910]

For idle problems I always check for vacuum leaks first. To check use a propane gas torch. Turn on the gas but don't light, and bring the tip close to all the areas of the intake system with the engine idling. If there is a leak the engine will speed up and smooth out when the gas replaces the air leaking in.

[@albertdewet1043]

I had similar issues with the Mercedes W124 series. My customers would not lay out the money for a new wiring harness and the waiting time was also a big issue. I ended up taking the wiring harness from the E.C.U. to the engine bay out and then redoing the complete harness. much cheaper than buying a new harness but that solved all the idling and some other issues that they had. With you that did the Link E.C.U. it should not be a problem. as you previously said " Just take it wire for wire"😁😁

[@HomeBuiltByJeff]

That is still a whole lot of work :D

[@albertdewet1043]

@@HomeBuiltByJeff Yes, I know it"s a lot of work but then you know it"s done right and it surely beats the price of a new harness from Mercedes agents😁😁

[@karl-heinzheuser2281]

Check the intake air flow using a fog machine. The engine gets additional air from somewhere else, which is not metered by the airmass sensor

[@henkresink5073]

I had a mayor charging problem with my Triking, and spend a lot of parts and money on finding out that the wiring was badly corroded like yours, Made a new loom and finally problem solved, those biodegradable wires are a real pain.

[@mosch9360]

I would recommend buing a new wiring loom regardless of it actually being the issue (they usually still run with bad looms - the wires are open but dont touch each other) -there are companys in germany that remake them. I think around 500€ :-/ Mercedes engines are solid dont scrap the car. I would try running the fuelpump from a bucket of fuel instead of the tank and see if that changes anything. I would also try to find a car workshop that has an fogmachine that way you can propperly check for vacuum leaks (they fill the intake with pressurised fog - easy and quick check) Ignition coils usually fail on these old ones however when they do they dont run at all, i'm not sure if they can fail in a low voltage/low rmp situation (It might be interesting to see on how much Volt they are operating on) Good luck

[@tonyjover]

I came here to recommend a fog machine test :)

[@kcoertzen]

Have you tried taking off the oil filler cap? If it idles without it your PCV valve is the culprit.

[@jameshobson6774]

I had something similar on a 1996 Peugeot 306 of mine many moons ago. It was the CRANK POSTITION SENSOR. As the temperature of the engine changed, the failing, but not failed, sensor would change its resistance in relation to the temperature. So it wouldn't show as failed on diagnostics, but would cause issues with idle, not idling etc. Just a thought.

[@paulstuart8676]

Jeff, I think you have fixed the main problem, however the remining problem seams to be a vacuum leak, difficult to find though, so try fitting small zip-ties to them. That worked on mine. Cheers

[@cameronmills8453]

I love dealing with idle issues. Good job though

[@panpantz]

Hi Jeff. Check the crank angle sensor. It will cause rough idle. Cheers

[@brianshorey]

Jeff, have you measured the actual fuel pressure? One trick I learned from a racer friend years ago was to install a fuel pressure gauge inline just before the fuel rail. It's always there, and will give a quick indication as to whether you've got pump or filter problems right away. You should also check to see if there is an in tank feeder pump. If so, that will also have a filter. If the in tank pump has failed, or the filter has clogged, that could also be part of your problem.

[@mgbrv8]

You still probably need to check fuel pressure to make sure it’s correct even though the diaphragm is not leaking. And honestly, it may be time to smoke test the induction system system. Also, sometimes the one-way valve on the brake booster can fail, causing vacuum issues.

[@gazzafloss]

Plugs look very lean Jeff, old MB from that era with "edible" wiring harnesses usually more problems than any one man can deal with. Use it as a "Garden Ornament".

[@mopedmarathon]

As others have said vacuum leak has to be the next check. Does the car have an idle control valve? If so that’s got to be worth checking as that’s its only role in life. You can test the loom with a multi meter at the Ecu plug which will test the sensors and loom at the same time. Just find the pin outs for the Ecu plug and the resistances for each sensor and away you go. Good luck dude!

[@savostanivukovic9801]

You should do M113 swap, they are very reliable, cheap and easy to find. I do a lot of those swaps here in California.

[@nerner67]

Can't remember if you have already checked, but did you check the fuel pressure at the rail at idle and under load. Just because the regulator is not leaking does not mean it is working 100% and if the fuel pressure is out of spec it can cause poor air fuel mix which might explain the white/grey spark plugs.

[@brettpearce687]

It gave me some ideas to fix my project car so thankyou !

[@chrisyes1629]

Ok Jeff. I made a comment on your latest video. I made a slight error on the throttle body problem as I thought you had a later model ( late W202 ). It's a W124. Maybe. Just maybe.I think you should check the wires to the crank sensor or the sensor itself. Those biodegradable wires are a crazy idea. To save the planet biodegradable wires! So turfing a whole car and making another one is betrer for the enviroment. Yeah? Well, hopefully, this is your problem. Don't worry about replacing the engine because it's capable of 200 hp or more with a few tweaks. The 2.3 had 190 hp so if you enlarge the bore to a 2.3 and add extractors you'll be dancing with 200 plus hp. The misses will never give you the keys back. Cheers.

[@tonyjover]

Jeff, I didn't follow your logic with the blocked fuel filter, nor those below who are focussed on fuel delivery. Classic symptoms of a blocked filter are the exact opposite of yours. It will rev and idle just fine, but as soon as you put a load on it (up a hill for instance) then the poor fuel delivery makes itself obvious.

[@michel360]

Just mount a $15 pwm print, and wire it to the idle air control valve. The you can adjust the idle from the cabin.

[@chrisyes1629]

Hey Jeff. I assume the wires you replaced were to the throttle body. From memory @ idle the voltage supplied to the throttle would be around 0.5 to 0.65 volts for most cars. You could measure this with a multi meter with the ignition on maybe. I am assuming that the idle voltage would be supplied on startup. If the voltage is way out you'll know it's a wiring issue. I also heard you say that a reconditioned throttle was 1600 bucks! Muchter automotive have the E220 TBs on sale for 250 at the moment. Hope this helps.

[@mikecurrie1795]

The one way valve in my Toyota’s fuel tank cap was sticking closed so there was a bigger and bigger whoosh when opening it to fill up. After fitting a new cap the whooshing stopped and the idle was much better. Still rough occasionally, so the crank sensor is next.

[@ianm2719]

Is it not perhaps faulty crank sensor, (upper right side of head), make certain you remove old seal too, when replacing

[@tang0au]

maybe try smoke test the intake tract after the afm ? baby oil soaked rag & a soldering iron in a jar to create smoke ... make sure there are no more air leaks ?

[@stevemundy3817]

Need to check fuel pressure hate a similar problem fuel pressure low dirty fuel tank replaced fuel tank job done

[@christianoliver5924]

Im not familiar with mercedes specifically but i’d start with an idle speed control solenoid/stepper motor and coolant temp sensor given the cold vs hot idle difference.

[@chrisyes1629]

Hey Jeff. I know you again! Another suggestion. I remember you saying the problem was gradually getting worse. I also saw in a previous video that you had a code indicating a faulty Lambda sensor. Faulty Lamda sensors usually cause a car to run rich. This in turn can cause your catalytic converter to clog up restricting flow. This might be your idle issue. If it's not too bad you can soak catalytic converter in a solvent to clean it. Just a thought. Cheers.

[@HomeBuiltByJeff]

O2 sensors take a little bit to wake up, so it wouldn't be a factor on start up.

[@chrisyes1629]

@HomeBuiltByJeff Hey Jeff. Merry xmas. Sorry I think you misunderstood. It's not the faulty Lambda sensor. The faulty sensor could cause your catalytic converter to clog up over time. The restricted air flow can effect idle. It doesn't cost anything but time to check it out. Just a thought. Cheers

[@xanevans4472]

Have you checked the EGR valve the diaphragm may be split and causing the rough idle.

[@csbpmg]

Throw a scanner on it and see what its doing at Idle. Need some data to work out what system is causing it.

[@scottwatson8648]

Between Benny and Turbo Yoda(AKA Al) you’ve got some great resources.

[@jdjh38]

I was reading on a forum on this idle issue someone suggested (throttle body air leak) or (purge valve blocked)

[@DAGGWOOD139]

I would be checking the fuel return line had a couple of cars that have done this and cause similar issues. at idle pressure too high in the rail one moving uses fuel pressure comes down

[@BrickDrifter-p2y]

Don't just rely on the diaphragm being good on the fuel pressure regulator. Check the pressure!

[@300DBenz]

I forgot if you’ve checked the coolant temperature sensor before, but a bad temp sensor (or sensor wiring) will cause idle and/or starting issues until the engine is hot.

[@karimhuerta597]

Ok fuel and spark looks to be good, now it has to be air, or vacuum, I think it can be a plugged part with crude on it

[@africanotaku5453]

5:21 Jeff, I've been chasing idling issues with my father and brother on a Mazda B2600 pick up, we've thrown many parts at it and we've had zero luck, the idle is very rough and when you drive it, it loses all power when there's an incline doesn't matter how small it is....anyway im rambling, to make it short...Cars will humble you and patience is important. And do you have any information on the Mazda G16E engine?

[@-MacCat-]

Replacement engineering is never the right way to solve a problem. Keep at at it Jeff.

[@stevenwest1494]

Lol Jeff, if you Google, "W124 e220 won't idle" Google AI search algorithm points you directly to this video! And I'm in the UK, so maybe Jeff has been the global leader in tracking this problem down in Google.

[@andrewbaluk1663]

check the ECU controlled fuel tank charcoal cannister purge valve and the associated charcoal cannister and rollover valve system and hoses back to the fuel tank. Could be a big vacuum leak at idle until the ECU closes the purge valve once it warms up. Sometimes it can present a big air leak...... or if the rollover valve is stuck and the charcoal cannister is saturated it can represent raw fuel pulled into the intake at idle.

[@oliverroedel1111]

and eliminate it hahaha only let the valve conected to the ecu to trick it

[@andrewbaluk1663]

@@oliverroedel1111 not so simple, while the ECU energises the valve it also makes assumption about how much air or fuel vapour it needs to compensate for from that source, especially since its in open loop warm up cycle. "just eliminate it" isnt so easy......

[@oliverroedel1111]

@@andrewbaluk1663 but the ecu has oxygen sensor and map, so it knows there wasn´t any gasoline vapor and adjusts the system. important is not eliminate the valve, let it connected and everything goes well.

[@andrewbaluk1663]

@@oliverroedel1111 oxygen sensor isnt used until car warms up ( oxygen sensor has to warm up before it reads properly)

[@oliverroedel1111]

@@andrewbaluk1663 só what?

[@Steve-jq4st]

Try the old rule. Start at the fuel tank and work your way through the system.

[@gothridercreations]

Time for you to make another custom wiring loom mate... 😂

[@billweston6579]

Check your fuel pressure. Does it have a idle control valve? Spray brake clean on and around the inlet manifold while idling. If it speeds up then you have a vacuum leak.

[@all-flat-engines]

Maybe in tank filter/pickup, if you knew the fuel filter helped then it might be up stream of that.

[@user-ux9ix5vv8z]

Probably been suggested, what about air leaks on the injectors etc?

[@georgs2057]

Hi Jeff, the W124 always had issues with the idle actuator

[@StevenRobbert]

Did you check the voltage going to the injectors, as well check the Ignition Coil the grounds on the engine management system the compression ratio of each Cylinder also a leak In the intake system

[@AaJii]

Like I said earlier. Cut open every plug. Wires are often shorted together inside the plug. The glue-filled ecu plug is the worst.. You'll need patience, heat, swear words, motivation.. Takes around one day to take harness off and rebuild completely. So not big job. I have many times tried to take shortcuts and it always has bitten me. In one of m111 I diagnosed injector ground wires were all touching, ran like shit on idle, flawless on driving rpm. It became ok with repaired wiring but ecu was hurt, it lost control of injectors sometimes.

[@peterferryman4905]

How about the sparkplug wires? And the distributor? I'm sure you had a boatload of people suggesting the same as me, but hopefully this keeps the algorithem in your favour 😊😊😊

[@southernduckied2710]

Check the fuel pump output at operating pressure. Either the fuel pressure is low because of a stuck open regulator or the fuel pump cannot supply enough fuel. You already identified it as fuel related and it’s not the injectors or the filter. So it must be the pump or regulator.

[@djambrosia]

My next check would be a smoke test for vacuum leaks based on the symptoms.

[@acalzetti]

Hi Jeff, I once had an early 80s BMW 320 which was misfiring. My trusted mechanic checked everything. At high revs it was fine. At lower revs it really struggled. You had to keep revving it to keep it alive. Eventually, we replaced the cables to the spark plugs and BOOM, the problem was gone!!! One of the cables was the issue. Could this be something to check? Great channel, thank you!

[@vinnierolla]

Can you factory reset the ECU? Maybe leaving the power disconnected for a bit then reinitialising the ECU as it relearns to idle again

[@ceesklumper]

I would still check the fuel pressure, is there a schrader valve someplace close to the fuel rail?

[@HomeBuiltByJeff]

I will check the fuel pressure to make sure that is not the issue.

[@tomlipscomb2211]

Yes, that’s wise. In your summary it was the only thing you were assuming. Once checked and OK’d it ticks off many of the other comments above. If low it gives you a starting point. Good luck Jeff 🇱🇺

[@tomsrensen3906]

Check the valve for the fuel vapor from the tank🇩🇰🇩🇰

[@asheq1980]

Just based on my history with same issue but with different engine it could be bad valve or valves , it cause a small leak that affects the idling but not on running , you can check it by simple compression test, my hopes to you that I'm wrong , if not it mean engine head out for rebuild , so good luck

[@huijskes]

Is there nothing wrong with the ecu or so Jeff? Maybe a tore in the print or so?

[@arcotaur]

Check the return fuel line to the tank.

[@graemeconijn31]

Hi Jeff does this car use a cold idle valve. Looks a bit like that valve you removed the hose from. I have one on a different brand of car and the electrical connector came off and it would not idle when cold. As yours idled better when warm I’m wondering if it’s along the same lines.

[@Wizards_Sleeve]

Sorry if this sounds bleedin obvious Jeff, but if the fuel filter was that dirty whats the fuel pick up/sock/screen like in the tank ?? Or indeed the condition of the bottom of the fuel tank ? Sorry if I'm not remembering if you've already checked the tank/pick up.

[@excossack]

Given the crap in the fuel filter could some dirt have found its way down the pipes? If rubber have they degraded?

[@shaunclarke7396]

Don't really know my merc engines but aren't they timing chain setup? If so, could a stretched chain be the issue?

[@_Bram]

It idles fine when warm, could there be something wrong with the system that makes it run richer when cold? A temp sensor or an extra injector (if there is one.) Vacuum leaks or leaks in the gaskets from the intake are typically things that create these kind of rough idling issues, so that is something to check.

[@marcboriss187]

After the filter change with not the result u expected! I would have changed the fuel line as well. U never know whats in the lines and chocking up your injectors again. Unfortunately the ECU could also be the issue!

[@tamimahmed9061]

Check the throttle body wiring maybe the biodigradeable wire has gone bad .It is the wiring of throttle body that causes many problem of idle like high idle , rough idle, cruise control problem etc etc .After Rewiring it check maybe your problem gone . If not then 100% T/LRR module for idle control and cruise control . If you open and see any short circuit then repair it . If you can't then replace the module with good one . please Note and try my advice it will solve the rough idle 100% . I have done on mine 1995 E320 . I have had high idle issue about 1300Rpm at idle .

[@Stoney1985]

After watching this one, I'd just assumed previously you'd already done the basics when it comes to maintenance. Now I know you haven't, start with the basics. What fuel pressure is it? Test that Do a smoke test of the inlet to check for any vacuum leaks. What is the compression test results? These are also notorious for the engine bay wiring looms to degrade, as you have discovered, that they generally just replace the entire unit.

[@randycollett1746]

Is there an IAC (idle air control) solenoid in the system that could be malfunctioning?

[@arni780pl]

maybe you should check air leaking with steam generator? And after that check temperature sensor, in many cars ther are two sensors - one for ECu and second for dash indicator. I had that issiue in old mazda 626 - no idle and hard starting when cold. ECU thought that engine is always hot.

[@justinxabregas1611]

Have you checked the coil packs?

[@pisej5]

Can it be that the fuel tank breather valve doesn't let air into the fuel tank, resulting in a vacuum building up?

[@thefast100]

Just replace the whole wiring harness. That wiring will be a constant problem unless replaced. It looks like a new harness here in the US is around $400.

[@paulspeedy4704]

Having almost eliminated all the sensors that send data to the ECU, could it be the ECU itself? Only other thing I could think of would be the crank position sensor but your problems would be more evident

[@deankdx]

TPS was causing similar issues on a mates patrol

[@radekbiczak5304]

👋 If I were you I would change the ignition coil, it is a common fault with this engine 👍

[@brucebendall353]

Not familiar with this engine but does it have an idle control valve a la bmw m30? On that motor a duff ice gives very similar symptoms!

[@Kwozzie1968]

Does the car have a fuel pressure accumulator? They can fail and could be worth looking at

[@rickdacosta6041]

Hi Jeff, Just a thought… Could it be the coolant Temperature sensor( if equipped with it) If faulty, it would trick the computer into thinking the car is warm at cold start and starve it of fuel. Good luck trying to figure this out. Cheers

[@figjoy]

The fuel filter made the biggest change. Where did the crud in the filter come from? The tank? How about checking for an intank filter or flushing the tank.

[@Papa-Bogey]

I feel your pain … eco friendly wiring looms are not owner friendly. I’m no expert but it seems to keep pointing to a wiring issue. Good luck … LCS - Patreon for the win.

[@HomeBuiltByJeff]

It is looking a lot like that is the likely culprit.

[@inthenose9033]

Is there an idle control valve? They get dirty and don't control the idle well any more..

[@TechnoHippy]

plugs look a little lean, if it's turned into pot luck parts guessing you might as well change the lambda sensor see if that misreporting gases is making the ecu lean it out too far