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Idle Problem That Fixed Itself.........almost.

4671 Views 141 Replies 6 Participants Last post by  LauraS
Today on my way into town I stopped at a stoplight which was red and the engine ideal wandered up rom about 500 to 750 RPM and seemed to have an ignition miss or something. I was a bit worried that it would stall but it didn't and once I accelerated the engine ran fine. This happened about 5 times when I had to wait for red lights. The temperature gauge read 90C and the ambient was about 22C. When I got to my destination I left the car for about 1 hour and when I returned the car sputtered but did start and settled into a nice 600RPM idle and from then on all of the way home it ran just fine? I have no idea what happened. Does anyone have any suggestions ? I would like to know of maybe the ICV might have been sticking or something else to look at.
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Thank you both. Today I inspected the wires and cap. Both are new within the last year as are the proper Bosch plugs. My neighbour removed the Idle valve and flushed it with Seafoam. All of the vacuum lines seem OK? The OVP is also new within the past two years and is the more expensive model. It will be interesting to see if this returns but for now I am driving my BMW 635CSi.
Dave, Thanks. I have a voltage monitor like you mentioned which is reassuring. If and more likely when the problem arises again I will clean the relay pins , grounds and replace the fuses as you advise. The fuses are practically all original and 30 years old!
Dave, Thanks. I have a voltage monitor like you mentioned (recommended by Dolucasi) which is reassuring. If and more likely when the problem arises again I will clean the relay pins , grounds and replace the fuses as you advise. The fuses are practically all original and 30 years old!
Well the idle problem started again while on a trip into town . The car started instantly in the garage with cold idle and then warm idle running perfectly but then as I pulled into a store parking lot the idle speed began wandering from about 400 to 750 with what seemed like an ignition miss and then suddenly almost stalled completed . The orange engine light didn't come on. Rather than return home I continued shopping and when I returned to the car it failed to start. it would sputter each time but not catch. Then the starter began to act up engaging and then not engaging. I didn't want to run the battery down or burn out the starter so I finally gave up and called CAA to tow the old gal home. When I got it home you put it on the battery charger and let the engine fool for about 4 hours. The car started up immediately as it usually does and settles into a nice steady idle. I guess will have to dig deeper into what may be the problem. I did remove and clean the ICV after the first event and the car ran perfectly for about the last 100km. I plan to check the coil and ignition components and the OVP(replaced two years ago or less) first since it does seem to be an electrical issue. Does that seem to be the best places to look. Would the crankshaft position sensor be a possibility? I do have a spare ignition module that I know is good also,
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Mr. Kost, Thank you for your advice. The battery is only about 2 years old and starts the car just fine. When trying to start the car multiple times in the parking lot I ran it down but not so that it was dead. I think it still had plenty of energy stored. I just didn't want to kill the starter or the battery. The alternator is working well according to the gauge I keep plugged into the cigar lighter socket . I only charged the battery after the car was towed home to ensure it was fully charged before another starting attempt.
The link that you posted opened to the cover page but when Intried to download the pdf file I was rejected. What are the cold and hot resistance values that I should be looking for when checking the CPS? I will be checking them this afternoon and also changing the ICM for a known good one. I recall how our 1952 DeHavilland Beaver would somtimes miss when it was running on one bad magneto. This reminded me of that.
I tested the CPS today. Ambient temp 29C
Engine cold CPS 850 ohms
Engine hot (90-100C) CPS 955
Voltage @ engine at idle 13.1 V
Engine idle speed smooth at about 700-750, no hesitation on acceleration.
All appears normal until the next time. I didn't do anything except pull the HT on coil and replace to ensure it was OK.
OK , We have DRL so on this car so all lights headlights and taillight etc are on at full luminance when ignition is on. I had the AC running and the fan at 3 so lots of load on a hot engine . It usually runs at higher voltage at first start uighur 13's. I so think its the alternator.
Its not the alternator IMO. I am still think a weak coil but how to test it?
Thanks but the problem that is happening is that the car does run fine some of the time but on two occasions so far the idle starts to miss a beat and the miss seem to possibly bounce the tachometer so that appears it is wandering idle. I don't know if it's actually wandering idle or the miss make sure it appear so. The car quite often does not have a smooth hot start but almost always start instantly when cold. It may indeed have a fuel delivery problem when hot but again not always. My main concern at the moment is locating the problem that makes the car miss and in this last episode almost stop the engine and not restart until it has cooled. I don't want to start spending money by guessing what it wrong and replace parts unnecessarily hence my query. So far nothing seems out of order so where to now? Thanks for all your guidance .It is very much appreciated by this old gal.
No Anayzer or scope etc but I do have a spare EZL somewhere. Once I find it in my cluttered garage I will replace the one in the car now. The spare is suppose to be good. I guess no way to tell except by trial and error?
i found the spare EZL but the white paste is pretty dried out. I guess that I will need to source some heat sink paste before I install the unit. i wonder of the heat sink dried out in my EZL and caused the problem. Maybe refresh of paste will restore it back to reliable operation since it seems to be heat related.
I removed the old EZL and the heat sink paste is pretty dry. i am hestant to install the spare EZL until I have it coated with heat sink paste which I will try to source next time I go to town. No sense in destroying a piece this valuable just to be in a hurry.
I sources two small packets of heat sink paste at an electronic store while in town yesterday. i applied it to the spare EZL according to instructions found on the W124 forum. The car started and idled fine both cold and warm but I havent taken it on the road yet. I hope this solves the problem but if it is the EZL I will try ty to find another spare!
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Well I am not sure the problem is fixed as it does seem to come and go. I did finally get a chance to take the car for a length drive today and the idle and acceleration seemed OK but it doesn't start so readily when cold or hot and on two occasions when accelerating from a stop sign the car engine stumbled a bit before smoothing out? I did put a bottle of Gumout Fuel System Cleaner with P.E.A so maybe it is doing something that is adversely affecting the fuel system. Anyway I am reasonably confident that the car won't let me down for the time being. I may have the cold start valve and fuel pressure tested when in town.
w201fan, The filter was installed less that 5000km (3000miles) ago. I only use premium gas (91octane). I live in a rural where all of my trips involve highway driving.
I have had good experience with certain additives in my vehicles, boats and aircraft.
ewee, The cap and rotor were changed not 3000 miles ago with Bosch parts. The hesitation only happened twice in a total of about a dozen starts.
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Well the stuff is in the tank now. My late husband was an air engineer as well as an airforce and commercial pilot and used gas additives in his aircraft and vehicles approved but not recommended by Transport Canada as I recall but honestly can't say which. We used Seafoam in our outboard engines for many years also. It might not have done any good but didn't seem to do any harm.
In any event it is a wait and see at this point since I am not going to syphon the gas from the tank. Thanks for your advice.
I am going to check the CSV and the Temp switch to see if I am getting a shot of gas at the cold start as it seems to be a lean mixture. This happened only after I switched the EZL module. Before the incident when the car wouldnt start the engine always fired up on the instantly.?
Well I did check the thermo switch today but could not get one of the 5mm hex bolts out with my neighbours help. I certainly did not want to strip that bolt!
The thermo switch read 2675 ohms at 18C which i ink it ok. With the ignition on it read 4.5 volts but being alone at time I could not read the voltage in start mode. the line to the CSV had pressurized gas so I think that is good. No I don't have any nylon pad between the EZL and the fender. If I remove this EZL I will lose the expensive heat sink paste.
It is odd that the old EZL seems to starting the car fine cold but rich when hot and this seems to be lean starting and hot. I may try to get hold of a fuel pressure gauge and see it that is OK. Thanks. Laura
I do have a strobe timing light in the garage somewhere. So what should I be looking for on the timing marks when at idle and at higher rpm. Do I hook up the wire to the number I cylinder spark plug wire. The issue at the moment seems to be a lean mixture not a rich one?
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