Hey everyone, I am about at wits end with this car's idle issues. Last year in July my E30 caught fire because of the o-ring on my FPR leaked onto my intake manifold and exhaust headers. Luckily I had a fire extinguisher and got it put out within a couple minutes. Not too much damage really, had to get the hood repainted and I had wires melted together.. injector wires, thermostat housing sensor wires, alternator wires etc. I fixed all of the wiring issues myself in a very professional manor. My father is an electrician and walked me through the process so I am fairly confident that everything is right in that area. After everything was fixed replaced the car was running great and I had no problems for a while. One day my idle was a little jumpy so I decided to clean my ICV with carb cleaner. After doing that, my car developed a surging idle from 700-1500 very rhythmic with no change at all. Unplugging my ICV did change the pattern of the idle and revved it up to around 2000 and back down. So I assumed my ICV was at fault because my ICM was clearly working. I went ahead and purchased a used ICV from eBay. It didn't fix it, so I purchased a new rebuilt ICM from Programa and that didn't fix it. I have a working ICV now it buzzes when the ignition is on and clicks when 12v is hooked up and has been cleaned. Since then I have replaced my fuel pump in the tank, both regulators, fuel filter, injectors rebuilt and ultrasonically cleaned and flowed, in-line fuel pump, intake manifold gaskets, valve cover gasket, CAR HAS BEEN SMOKED TESTED SEVERAL TIMES WITH NO VACUUM LEAKS, all of the sensors on the thermostat housing have been replaced, TPS, CPS, TB was cleaned, throttle cable and TPS adjusted to proper spec, AFM was replaced with a remanufactured one, and all of the ignition system components. After doing all of that work on the car, the surging is gone I just now am experiencing a high idle WHEN WARM. It idles perfectly WHEN COLD but as the car warms up and I drive it.. the idle rises to 1200 and stays there steadily with no change at all. When I squeeze the hose going from the elbow to the ICV, the idle will settle down to 800. When I purchased the car, previous owner has some janky rigged up exhaust which is currently on the car. THERE IS NO O2 SENSOR. I have been told that it could very well be the ICM not getting that warm o2 sensor reference and throwing a fit when the car is warm but my question is, why did the car after a year just now decide to throw a fit because I'm not running an o2 sensor. I have plans for a full exhaust and o2 sensor bung but am not in a rush because I don't believe that is my problem. Please let me know if you guys have absolutely any suggestions or ideas of things I can try. Also let me know what you think about the o2 sensor issue and if that is likely the cause. I'd just like to mention again, the car has been smoke tested I don't have any vacuum leaks. (For the people who like to comment "vacuum leak" and scroll on to the next post) I have also tried the penny trick and yes it works, but without the ICV working the revs drop too low between shifts and I have to hold the throttle up on cold start until the car is warm. It just creates a lot of unnecessary annoyances that I don't have to deal with when this is most likely a very fixable problem. Let me know what you guys think, thanks
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What is the penny trick? Is the TPS adjusted properly? -
The TPS is adjusted properly via Bentley manual specifications. It is also a new TPS that was replaced recently. The penny trick is when you drill a hole into a penny and stick it on your idle control valve so that you can restrict the air going into the idle control valve via the size of the hole you made in the penny. The larger the hole, the higher the idle. The smaller the hole, the lower the idle.Comment
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i couldn't dig through the block of text but i thought icv / vacuum as well.Originally posted by hurryupcole View PostComment
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ICV is working properly, cars been smoke tested several timesOriginally posted by 82eye View PostComment
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Originally posted by hurryupcole View Post
there was something about no 02 sensor in there as well. first thing i would do is get the car back to stock.
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I'm sure your dad is a fine electrician so I do not want to challenge that out of respect. With that said, it is of the highest importance that all connections are repaired COPPER TO COPPER. I always overlap the copper strands attempting to weave them together, crimp a connector over the "patch," spray the connection with dialectic spray and shrink wrap. Many of the fuel injection circuits run on resistance values based on stock harness conductivity - one false repair and the data going to your ECU is wrong.Comment
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Understood, everything was spliced via soldering, all copper to copper connections were twisted together tightly, then soldered, and heat shrink to cover the splice and I promise you the car doesn't miss a beat. As per the injector side of the wiring harness, I had no injector pulse after the fire obviously because that's what happens when you have a short in that circuit. Well actually I had 4 sets of injector wires melted together so I ordered some late model BOSCH EV1 injector plugs to make for easy quick disconnect when I want to get them rebuilt, take the head or intake manifold off, etc. I also had alternator wires burnt together which is okay shouldn't effect anything with my ECU idle readings. That was also fixed as well though.. the battery light was lit up on the dash, after my electrical work it went out and the battery was charging again. That is interesting though now that I think about it, is there a way to test and see the that my ECU is getting the proper values from all of my sensors? I do have a Bentley manual I can reference to if the info is in there.Comment
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I am going to an exhaust shop this week to get a new system and bung for an o2 sensor installed into it. I already have a new o2 sensor waiting for the exhaust. I don't believe that is my problem because the car ran fine without it for a year. But I am still going to get it running how it is supposed to be. I guess this would affect my fuel economy as well.Originally posted by 82eye View PostComment
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it throws the car in to a closed loop. the ecu in motronic 1.1 won't change things by a lot, but it can't do much of anything without the 02 input. i would expect it to result in a poor warm running condition.Originally posted by hurryupcole View Post
you mention you have trouble right from start up though, so the missing 02 sensor may be only one part of the problem.Comment
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Also, if you are still running a cat, it is likely that you are just loading it up with unburned crud between idle and open road "cycles." The oxy sensor is key here.Comment
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you need to eliminate the yellow coolant temperature sensor. cut the ends off the connector and bridge the wires together. report back.'72 2002 pickup | '88 M5 | '89 330is | '89 M3 | '01 Z3M | '11 328xi-t
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What is the purpose? The coolant temp sensor changes the maps the ECU uses. Does this trick it to choose one particular temp for fuel mapping?Originally posted by e30austin View PostComment
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yellow temp sensor handles cold start to 20c. if that switch fails, it's always thinking it's in open loop. BMW no longer sells a correct switch as a replacement for the yellow one. the purple is a sender only, no switch involved. the "fix" is to eliminate it because it's absolutely pointless.'72 2002 pickup | '88 M5 | '89 330is | '89 M3 | '01 Z3M | '11 328xi-t
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Is this the one that also controls the cold start injector?Originally posted by e30austin View PostComment
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