No idle at all

[rcltrh]

Well, last weekend (9 days ago) I got the bright idea to rinse off the engine in my C220. Nothing high presssure, just sprayed with simple green and rinsed off. Afterwards the car wouldn't idle at all - start then immediately die. I figured probably water somewhere that needed to dry. It has been 9 days now and the symptom is still the same. There are no ODB2 codes at all, and if you hold your foot on the accelerator and drive it around town it feels fine and normal, but if you ever let your foot off the pedal at a stop sign it immediatly drops to zero RPMs and dies. You also have to kind of pump the accelerator right after it starts to keep it running, then rev it up a little before shifting into gear. It's as if whatever controls the idle is totally defunct. I have looked for vacuum hoses, electrical things, etc but see nothing out of the ordinary. Like I said, it runs fine going down the highway. Anyone with any ideas of what I might have gotten wet and killed that wouldn't set any kind of engine code?

[Proven Guilty]

even though you checked, it still sounds like a vacuum problem, or possibly the MAS was damaged from water.

[xvvvz]

Did you remove the top plate and make sure to check your spark plugs, wires and coils. Since you have a 96, does your car still have the original wiring harness?

[Proven Guilty]

Originally posted by xvvvz
Did you remove the top plate and make sure to check your spark plugs, wires and coils. Since you have a 96, does your car still have the original wiring harness?
the problematic wiring harness was mostly the old M104 inline 6 cylinder engines (280, 320, and C36)

[rcltrh]

It does still have the original wiring, but it looks fine. I think that was 95 and older maybe. I wonder if it is the idle air control motor. Is that the large black device on the back side of the intake? I just got back from totally reinspecting all vacuum hoses and sucking and blowing thru them all and they do not appear to have any breaks. I did take off the spark plug cover too and it was all dry inside. It doesn't miss at all when driving (except at stop signs if you dont hold your foot on the gas), it just starts up, then immediately dies unless you hold the gas down slightly. For the past few months, it always started kind of weird with the idle - would kind of surge up and down for a few seconds before stabilizing, so maybe it was just a coincidence that this happened after washing it and whatever it was, was ready to go out anyway. You would think if the idle air motor thing was out it would be showing the CEL or something though. Anyone want to come to Arkansas for a cheap C220? haha

[Proven Guilty]

give it time, nenad will chime in with the 1-click fix. :D

[rcltrh]

Heh heh, that's what I'm waiting for :beard:

[roundeler]

Fuel and spark are the first issues to check on an older car. Knowing your car isn't older, but still. I would consider you messed something up in the electrical system. When washing your engine, covering your alternator is the most important. After that the distributor is suspect.

Please check the grounds on the alternator and the condition of the Distributor.

I don't know much about the C220, just trying to troubleshoot.


-Mark

[rcltrh]

Well it doesn't have a distributor so to speak, just coils with 4 plug leads since it is electronic ignition, but it runs very smoothly if you hold it at idle or higher with your foot on the pedal, and it appears to be charging fine. It's like whatever controls the idle speed is simply turned off altogether. I wonder if there is a relay or fuse for whatever that part would be (idle air control motor or something maybe?)

[jnenad16]

check your MAS, have someone hold gas and keep engine running stable with the lowest rpm possible, but not more that 1000rpm. then unplug the MAS. if the rpm changes or becomes unstable, then MAS is most likely ok. if the rpms stay the same, MAS is definitely one of the problems. I would also change the spark plugs, even though everything dried off. last but not least, check the vacuum line at the back of the throttle body. the rubber union on it deteriorates rather quickly and all it takes is a little water or something else to disturb it, and it goes haywire.

nenad

[roundeler]

MAS are notorious for failing on so many cars over time. Also, does your car have OBDII? If so, is it running on an open or closed loop when warmed up? You would need a diagnostic tool to figure that out. -Mark

[rcltrh]

I'll check those things tomorrow in the light and report back. Didn't have time today to get to it before it got dark. Thanks for the tips!

[rcltrh]

Originally posted by rcltrh
I'll check those things tomorrow in the light and report back. Didn't have time today to get to it before it got dark. Thanks for the tips!

Ok, no luck with anything so far. If I unplug the MAS, the car freaks even worse then dies even with the gas being held. Reconnected it levels out and runs smoothly again as long as the pedal is held a little bit so it sounds like the MAS is ok. No vacuum hoses off anywhere. I checked very thoroughly. If I ever so slightly let off the gas pedal just a millimeter at a time until it is at idle position, it will drop to about 100 rpm, try to die, then run it up then run back then up then back down etc and then finally die, so it sounds like at least something is trying to recover the idle and you can hear and see the butterfly flipping back and forth a little bit and see the smaller lever clicking back and forth - which appears to be connected to the idle motor. If I just let off the pedal altogether from holding it at about 900 rpm it dies immediately. I am wondering if it might me crud in the EGR? About a month ago the CEL came on and was showing EGR code. I reset it and it has never come back on, but I have never cleaned it out either so it might be cruddy on the inside. Wouldn't a partially open EGR cause this symptom? I think I had it happen once on an Oldsmobile I had and I think the idle was the symptom way back then if I remember right. To remove the EGR is it just removing the single allen screw and disconnecting the metal pipe fitting? Still open to ideas.

[Proven Guilty]

if you're not throwing codes, i don't even know where else to help you since it's fuel injected and ECU controlled.

perhaps check your K40 relay by the ECU as it wouldn't throw a code. it might be complete coincidence that your car started dogging after you cleaned under the hood, and you have a dry socket that needs to be resoldered for the fuel pump relay (K40).

you might want to try cleaning out the EGR tube leading from the exhaust to the bottom side of the throttle body. nenad suggested it for me a while back when i was having similar problems and throwing a P0410, and it helped out a bit. just undo both ends, and hold a shop rag under the hole while spraying carb cleaner through the tube. you should have black/brown carbon deposits coming out in chunks if that was part of the problem.

[blink]

i think it's the fuel actuator or igniton coil.

[rcltrh]

Originally posted by blink
i think it's the fuel actuator or igniton coil.
Would it still run perfectly down the highway at any speed over idle (including 55-60 mph) if either of these were going out? It does run like it is supposed to at any speed but sitting in idle.

[jnenad16]

I cant help you much without seeing the car myself. Its hard trying to diangose the car online. For something like this I would have to take a look at it and test the various components, which sometimes takes hours. this is why shops take their time and charge a lot for diagnostics.
even though the CEL is off, sometimes the DTC can still be logged by the ECU. have it scanned anyways.

nenad

[rcltrh]

Ok, I'm about to give up on this stinking car. Its been cold and rainy here all week so I hadn't even looked at it again until today, and now today its got some other symptoms, but still no CEL or any codes with my ODBII reader. Today if you hold the pedal perfectly steady above idle (to keep it running) while the car is in neutral, the engine revs up and down and up and down really high really low, etc. - very erratic but kind of cyclical - and if you try to push the pedal in to rev it up even higher it dogs out - what would seem to be typical MAS symptoms. If you go ahead and put it in gear though, it does actually seem to run ok, but if you let off the pedal it dies like it has been doing. Can the MAS be bad and not throw a light or throw a code anywhere? I went ahead and replaced the plugs today - the old ones were pretty fouled looking but probably from all this dieing and crappy idling it has been doing, but now it does have good P4 plugs and that made no difference in symptoms. I also unplugged the battery for 10 minutes so everything would reset, but still no help. I have a good ODBII code reader/resetter and it says everything looks fine. Before I spend another $355 on a MAS and just start throwing parts at it does that sound like it could be the problem? I seriously am considering just putting it in the paper for sale as-is and see if there are any takers. I was going to give it to my daughter who turns 16 next month but I don't want to give her something that is going to turn into a nightmare to keep running. It's been a great car with just about zero problems up to now, but after this I don't know if I trust it enough to give it to her. Its about 100 miles to the nearest dealer and I won't have it towed that far.

[jnenad16]

is there any shop in your area that does MB's? have them take a look, and like I said, it might take them a few hours, but at least you know what it is.

nenad

[roundeler]

OK, You are a father and obviously well self-educated looking for solutions. My advice, as a father and a son. Get rid of the car, let your daughter crash a new safe car. The reality is that your daughter will probably get in accident. Maybe purchase a relatively new Saturn or Scion. Get rid of your headache, older cars can be this way, you have enough going on. Jokingly, ML's are a headache in a half, you have enough going on with that, your Lexus is probably serving you well. There may be a lot of people in a less affluent area happy to take this car of your hands. List it on craigslist.org or ebay for sale. Really there is a single part causing your problems, but tracking it down is a pain in the a$$. I wish you luck, haha, not with the car but with your daughter!

-Mark

[rcltrh]

Haha, yes that's kind of why I'd just as soon give her this to drive, that way if she wrecks it it will be 1. Safer than some cheapo thin sheet metal and plastic, and 2. Paid for. I went ahead and ordered a MAS tonight just to see if that's it. Everything else has been very well maintained and it has up to this point been relatively good as far as repairs go (everything minor and still driveable). This is really the first problem it has had that I haven't been able to just know what it is and fix it myself.

[Len013091]

On my 230k, I just unhooked the MAS, no code, no CEL, car didn't idle, but it ran normal above idle.

[rcltrh]

Well, the new MAS came in today. No change. Still won't idle. I guess throwing several hunded dollars at it at a time won't work. It is now up for sale if you're in the Arkansas area and want a 96 C220. Anyone have any ideas of any other money I could throw at it just for giggles?

[rcltrh]

Update. My mechanic has finally determined the idle problem to be the throttle actuator. Benzbin has one for $505 so I ordered it tonight. The new MAF I bought was defective - I tried to drive it after putting the new one in and I barely made it to the shop. We put the old one back in and it is back to running fine except the original no idle problem. We manually twisted the idle cable screw out nearly all the way and it now runs and idles ok but of course with the actuator out it doesnt compensate the idle for A/C, load, etc but is a temporary fix until the new part comes in this week. Will post again after it gets here. I will take the old one apart and see if it can be fixed and kept as a spare, but wanted a new one since my daughter will be driving it at her moms about 120 miles from here this summer.

[rcltrh]

Well it runs like a new one again with the new throttle actuator assembly. I was going to look at repairing the old one, but every single wire on the unit's cord has crumbled off all the insulation and is just a mass of naked wires inside. I'm thinking that must have been the problem. :rolleyes: The mechanic says the engine harness wires which connected to the part itself are starting to crack themselves, but not like the units own wires. We opened up several of the wiring runs and they are not as bad as he first thought. There are a couple injector wires that have cracked insulation right where they connect to the injectors. The plug to the sensor in the plastic air intake (thermometer?) has cracked right by the plug, but I taped it. Once you get further inside the wire looms they are not cracked, but that throttle actuator cord was just a mass of crumbled rubber. It must have been made with that very biodegradeable wire from the 94/95 era. Anyway, she now has a car. This coming weekend is her birthday so she will be very happy, and so will I since I don't have to run out and buy her a brand new Yaris this week as I had planned if this car wasn't repairable.

[jnenad16]

Im glad you found the problem and everything worked out great.

nenad