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

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[@HomeBuiltByJeff]

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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

[@jimclarke1108]

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

[@middle-agedmtbhack8298]

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

[@SpankysHotRodsandCustoms]

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

[@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

[@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.

[@kcoertzen]

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

[@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!

[@brettpearce687]

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

[@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.

[@natalinowerty]

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

[@cameronmills8453]

I love dealing with idle issues. Good job though

[@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.

[@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.

[@mattscars]

Re the wiring loom... even though expensive I think it is worth buying so you can start from a solid base to trouble shoot and even if it turns out to not be the issue right now, it will give you headaches down then line :(

[@samramone84]

How much would a loom cost?

[@georgebettiol8338]

@@samramone84 About AUS$1k.

[@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 :)

[@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

[@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

[@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.

[@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.

[@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.

[@iainmcglynn833]

“ we’re close “🏴󠁧󠁢󠁳󠁣󠁴󠁿😎

[@scottwatson8648]

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

[@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.

[@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.

[@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

[@panpantz]

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

[@-MacCat-]

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

[@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.

[@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.

[@stevemundy3817]

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

[@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!

[@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".

[@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 ?

[@Goneforgood81]

Maybe a priest to give a blessing lol we never know

[@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.

[@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!

[@BrickDrifter-p2y]

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

[@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.

[@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.

[@samperras]

You must have some Greek in you? The way you wave your hands all over the place. I’m enjoying your content

[@chrisoo8998]

😂😂 haha tru

[@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.

[@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

[@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.

[@xanevans4472]

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

[@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.

[@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

[@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 😊😊😊

[@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.

[@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.

[@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

[@all-flat-engines]

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

[@jdjh38]

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

[@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

[@octane_matty]

We knew the merc was a bad idea from the start 😂 good to see it delivering 😂

[@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

[@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?

[@Kwozzie1968]

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

[@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.

[@csbpmg]

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

[@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

[@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

[@radekbiczak5304]

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

[@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.

[@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.

[@moderncoaches]

OVP relay! I forgot if you've tried it or not, but absolute next step is the OVP relay, and their very cheap considering.

[@HomeBuiltByJeff]

Last ep ;)

[@moderncoaches]

@HomeBuiltByJeff got it! Judging by your plugs then, it looks like fuel starvation, (white plugs mean lean burn).

[@Steve-jq4st]

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

[@haydenisaac3030]

Those parts were going to fail sooner or later anyway so it's not a waste to be replacing them now if you plan to keep thhe car

[@tomsrensen3906]

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

[@lotuselanplus2s]

You changed the sparkplugs, what about changing the sparkplug wires. They do break down and the high tension current can spark through the insulation to ground or even spark to each other.

[@user-ux9ix5vv8z]

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

[@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.

[@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!

[@glennarnold3970]

Jeff i would not trust the aftermarket air flow meter try unplugging the air flow meter and starting the car with it unplugged it should go into DEFAULT MODE if it idles then it will be the air flow meter then get a mercedes one have been down this road with nissans also try doing a smoke test to look for vac leaks cheers glenn

[@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.

[@shaunclarke7396]

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

[@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.

[@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

[@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?

[@justinxabregas1611]

Have you checked the coil packs?

[@_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.

[@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.

[@PedroFTeixeira]

hey.... Benny! Funny, these guy is literally on the other side of the world, but feels like a I know him! :) Jeff have you double checked the grounds?

[@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.

[@fernandoteles4080]

I have a diesel Mercedes with the same problem... everyone tells me it's the electronic accelerator pedal but mine turns off a few times a month and will continue... it's the car I use every day to go to work, to "beat" .. It's a Mercedes c220d sport sedan. It will continue to run and it will be fixed when it gets worse... taking the injection pump from the Mercedes 200 d w124 and "larger" injectors, and the electronic accelerator ends

[@huijskes]

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

[@deankdx]

TPS was causing similar issues on a mates patrol

[@georgs2057]

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

[@djambrosia]

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

[@excossack]

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

[@arcotaur]

Check the return fuel line to the tank.

[@randycollett1746]

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