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.
Idle Problem That Fixed Itself.........almost.
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'84 Euro 500SE, '85 Euro 2.3-16, '51 Euro 170S, '97 Jeep Wrangler Sport, '15 G63 AMG
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Sputtering or hard starts after it was warm might be indication of either a leaking injector (or several) or a failing fuel accumulator unable to keep up the rest pressure in the fuel system.
Idle issues could range from a vacuum leak, dirty/faulty ICV, fuel mixture issue from the EHA, or the small microswitch at the throttle body. These cars didn't have the idle control modules like the bigger V8 cars had, so that's one electronic gizmo that you don't need to worry about. Could be a fouled plug, improperly gapped plug, bad plug wires, or buildup up the cap and rotor.
Although it solved itself, it's quite possible it will return again. There's just a host of things that could be responsible or contributing to the conditions your described. Check the basic things like plugs and wires, cap and rotor, then start looking visually at any vacuum lines or air hoses for obvious cracks and other damage. If all that checks out, then it may be time to dive deeper into the CIS system and measure things such as the duty cycle to make sure the fuel system is actually functioning properly.
Idle issues could range from a vacuum leak, dirty/faulty ICV, fuel mixture issue from the EHA, or the small microswitch at the throttle body. These cars didn't have the idle control modules like the bigger V8 cars had, so that's one electronic gizmo that you don't need to worry about. Could be a fouled plug, improperly gapped plug, bad plug wires, or buildup up the cap and rotor.
Although it solved itself, it's quite possible it will return again. There's just a host of things that could be responsible or contributing to the conditions your described. Check the basic things like plugs and wires, cap and rotor, then start looking visually at any vacuum lines or air hoses for obvious cracks and other damage. If all that checks out, then it may be time to dive deeper into the CIS system and measure things such as the duty cycle to make sure the fuel system is actually functioning properly.
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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Behavior as this are almost exclusively electrical in nature. And as Josh mentioned, if it happened once, you can bet it will happen again.
Sometimes it has to be persistent enough where it can be diagnosed.
One known component that does this is the OVP. If it is cutting in and out you will get that. Do us a favor and check the date code on your OVP.
It is the 1" x 1" x 3" relay that has fuses on top and is next to the FPR behind the battery compartment.
Sometimes it has to be persistent enough where it can be diagnosed.
One known component that does this is the OVP. If it is cutting in and out you will get that. Do us a favor and check the date code on your OVP.
It is the 1" x 1" x 3" relay that has fuses on top and is next to the FPR behind the battery compartment.
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.
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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It is quite likely that you will need to keep driving the car until it shows the behavior more frequently. Mine kept stalling randomly once a week for 6 months until it started doing more often (every other day) and we found the problem eventually. Not a stall since in 3 years. So some persistence may be required.
I would start by cleaning of of the grounds and replacing all the fuses with the ceramic copper ones. Also clean all the relay pins. I like a product called Deoxit. I know its a pain to do but it can save you aggravation down the road. There is a voltage gizmo that you can put in the Cigarette lighter plug that you can monitor running voltage, they are around $10.00 US.
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!
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,
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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I would eliminate the CPS as a possible culprit first. My understanding is that there is an expected range to the the CPS resistance (at the EZL).
If it is out of this range the ignition unit senses a fault and shuts off ignition.
Because the resistance is not constant between hot and cold if it is out of range either hot or cold the ignition will not fire.
Usually they are outside of range when hot and in that case the engine just shuts off and you have to wait till it cools down and falls in range again.
I would advise to disconnect the EZL end of that CPS sensor wiring and measure the resistance at cold engine and hot engine and see if it is getting too close to the limits.
Although that idle speed wandering does not sound like a CPS to me. As the CPS cut off is sudden and the engine will stall and not start again.
If it is out of this range the ignition unit senses a fault and shuts off ignition.
Because the resistance is not constant between hot and cold if it is out of range either hot or cold the ignition will not fire.
Usually they are outside of range when hot and in that case the engine just shuts off and you have to wait till it cools down and falls in range again.
I would advise to disconnect the EZL end of that CPS sensor wiring and measure the resistance at cold engine and hot engine and see if it is getting too close to the limits.
Although that idle speed wandering does not sound like a CPS to me. As the CPS cut off is sudden and the engine will stall and not start again.
Laura,
Sounds like a weak battery to me. Starter clicking- charging battery then the car runs good. How old is the battery? The voltage can read good but it will eventualy fail because it does not hold the capacity. Could be the alternator, (or voltage regulator) or a possibility the ground side of the charging circuit could be at fault. The alternator needs a clean path to ground to work effectively. Put your Meter to Ohms , one lead to to the alternator case and the other to the battery ground. Want does it read? Go have your battery load tested. If its older that 5-7 years I would replace it.
The ground side of the circuit is as important as the power side for all of your electrical components to work properly. That is why I recommend making sure all the ground and fuses are clean before the start testing and replacing components. Remember the ECU is working with millivolts controlling components.
Sounds like a weak battery to me. Starter clicking- charging battery then the car runs good. How old is the battery? The voltage can read good but it will eventualy fail because it does not hold the capacity. Could be the alternator, (or voltage regulator) or a possibility the ground side of the charging circuit could be at fault. The alternator needs a clean path to ground to work effectively. Put your Meter to Ohms , one lead to to the alternator case and the other to the battery ground. Want does it read? Go have your battery load tested. If its older that 5-7 years I would replace it.
The ground side of the circuit is as important as the power side for all of your electrical components to work properly. That is why I recommend making sure all the ground and fuses are clean before the start testing and replacing components. Remember the ECU is working with millivolts controlling components.
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.
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.
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.
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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I read on the forum that the spec for CPS is 780 ohms - 1200 ohms.
Yours is well within the limits so I would strike that for the culprit list.
My system voltage heavily depends on what is on.
If everything is on it will drop as low as 13.0V.
By everything, I mean:
Headlights
Aux Fans running (these realy use a lot of current)
AC, on with fan turn to position 2.
Otherwise if everything is off, it hovers around 13.5V once the engine warms up and the battery is charges. Starts out at 14.0V after cold start.
So when you measured 13.1V, what were the conditions?
Yours is well within the limits so I would strike that for the culprit list.
My system voltage heavily depends on what is on.
If everything is on it will drop as low as 13.0V.
By everything, I mean:
Headlights
Aux Fans running (these realy use a lot of current)
AC, on with fan turn to position 2.
Otherwise if everything is off, it hovers around 13.5V once the engine warms up and the battery is charges. Starts out at 14.0V after cold start.
So when you measured 13.1V, what were the conditions?
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.
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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Yours is similar to mine. The alternator/charging system in these cars s a bit on the weak side and your results are expected. I do not believe your issue is your alternator/regulator/battery.
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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I think you have to determine "is this is just an idle issue or a general running issue?". If the car runs fine driving around town I would say your ignition components are fine.
Then you have to look more into idle/starting issues.
Then you have to look more into idle/starting issues.
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.
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