Hi all, hopefully someone has had a similar problem I am having recently. I have searched and read many, many, threads and have not found a solution.
I am the original owner of a 91 325i daily driver with about 270k. About a year ago 9/2017, I has a small fuel leak from the return line from the FPR sprayed gas onto the area above the thermostat housing which burnt my wires and melted my CTS (Blue plug). Developed rough running when the engine is hot, stalling at lights,etc. and it threw a CEL was unable to do a stomp test. So I changed and adjusted the TPS, then I got a 1222 and 1223. So I also spliced in a new FI plug to the harness and replaced the CTS. I also replaced the ICV because the ohms between the terminals were off. The car ran fine for the past year through the winter of 2017 and spring,summer and fall of 2018 without a problem.
Almost 1 year later 9/2018 I get a CEL when I come to a stop after highway speeds, and when I pull away the CEL goes away. Stomp test = 1222, I check for vacuum leaks, my intake boot has a slight crack, so I change that. while it was out I also cleaned out the the ICV and the AFM and the throttle body. sprayed throttle body cleaner all over and also found a leak at the intake manifold. So I replaced the manifold gasket and also the six lower injector o-ring seals. Car runs fine for a few week when the outside temp is about 45f. No CEL code stomp test 1444.
But now its getting even colder outside low 30's to 20's. So when I start in the AM the first time. I get it to turn over without a problem, but I get a very rough idle / hesitation / misfire and sometimes stalling. It takes a few minutes and when the engine warms up a little it idles fine and settles down. I warm up the car for about another 5 to 10 minutes and the temp gauge reaches 1/4 to 1/2 point and I drive away and things are fine for a few minutes. As the cold outside air cools the engine down or flows into the engine bay at speed, it cools something down to the point where I get hesitation / misfire and rough a idle again. I can pull over and let it idle for a few minutes and then it settles down again. I drive away again and if its very cold outside it happens again after a few minutes at highway speeds. This does not happen if its cold outside and wgen i am in stop and go traffic. I believe that everytime I stop at a light it warms whatever the issue is and I do not get the hesitation / misfire etc... If its warm outside like in the 40's It will not happen and I can go from A to B without pulling over to allow whatever to warm up again.
So here is what I have done so far, no CEL Stomp test 1444
I pulled the DME connection and checked the resistance at points 24 and 45 for CTS and its within the normal values as per Bentley manual hot and cold. I redid the splice at the CTS / FI plug with solder. Checked the ICV resistance and it was all WNL
I had a 75c thermostat installed 5 years ago and though it might have been stuck open and as the car was going down the road it cooled the CTS down and caused a change in the open/closed loop of the DME control. I changed that to a 80c thermostat without any changes.
Tried a remanufactured AFM, installed a new FPR, new O2 sensor, six new bosch copper plugs gapped at .028, new valve cover gasket, new rotor, new distributor cap, new crackcase vent tube and a new fuel filter. Checked C191 and looks ok, wiggled all the wires that I could when the car is in the hesitation / misfire mode and nothing, no changes.
So I stress this is temperature related issue. When cold = hesistation / misfire
/ bad idle. Engine warms up and idles fine and purrs like a cat. drive away when its cold outside, engine cools down and hesitation / misfire returns. Pull over and let the engine warm up again for about 5 minutes and I am able to drive away without any problems untill it cools down again. Does not happen in stop and go traffic because of all the time stopped at lights and allowing engine to warm whatever up preventing hesitation / misfire.
Thanks in advance for all your input and help!!!!
I am the original owner of a 91 325i daily driver with about 270k. About a year ago 9/2017, I has a small fuel leak from the return line from the FPR sprayed gas onto the area above the thermostat housing which burnt my wires and melted my CTS (Blue plug). Developed rough running when the engine is hot, stalling at lights,etc. and it threw a CEL was unable to do a stomp test. So I changed and adjusted the TPS, then I got a 1222 and 1223. So I also spliced in a new FI plug to the harness and replaced the CTS. I also replaced the ICV because the ohms between the terminals were off. The car ran fine for the past year through the winter of 2017 and spring,summer and fall of 2018 without a problem.
Almost 1 year later 9/2018 I get a CEL when I come to a stop after highway speeds, and when I pull away the CEL goes away. Stomp test = 1222, I check for vacuum leaks, my intake boot has a slight crack, so I change that. while it was out I also cleaned out the the ICV and the AFM and the throttle body. sprayed throttle body cleaner all over and also found a leak at the intake manifold. So I replaced the manifold gasket and also the six lower injector o-ring seals. Car runs fine for a few week when the outside temp is about 45f. No CEL code stomp test 1444.
But now its getting even colder outside low 30's to 20's. So when I start in the AM the first time. I get it to turn over without a problem, but I get a very rough idle / hesitation / misfire and sometimes stalling. It takes a few minutes and when the engine warms up a little it idles fine and settles down. I warm up the car for about another 5 to 10 minutes and the temp gauge reaches 1/4 to 1/2 point and I drive away and things are fine for a few minutes. As the cold outside air cools the engine down or flows into the engine bay at speed, it cools something down to the point where I get hesitation / misfire and rough a idle again. I can pull over and let it idle for a few minutes and then it settles down again. I drive away again and if its very cold outside it happens again after a few minutes at highway speeds. This does not happen if its cold outside and wgen i am in stop and go traffic. I believe that everytime I stop at a light it warms whatever the issue is and I do not get the hesitation / misfire etc... If its warm outside like in the 40's It will not happen and I can go from A to B without pulling over to allow whatever to warm up again.
So here is what I have done so far, no CEL Stomp test 1444
I pulled the DME connection and checked the resistance at points 24 and 45 for CTS and its within the normal values as per Bentley manual hot and cold. I redid the splice at the CTS / FI plug with solder. Checked the ICV resistance and it was all WNL
I had a 75c thermostat installed 5 years ago and though it might have been stuck open and as the car was going down the road it cooled the CTS down and caused a change in the open/closed loop of the DME control. I changed that to a 80c thermostat without any changes.
Tried a remanufactured AFM, installed a new FPR, new O2 sensor, six new bosch copper plugs gapped at .028, new valve cover gasket, new rotor, new distributor cap, new crackcase vent tube and a new fuel filter. Checked C191 and looks ok, wiggled all the wires that I could when the car is in the hesitation / misfire mode and nothing, no changes.
So I stress this is temperature related issue. When cold = hesistation / misfire
/ bad idle. Engine warms up and idles fine and purrs like a cat. drive away when its cold outside, engine cools down and hesitation / misfire returns. Pull over and let the engine warm up again for about 5 minutes and I am able to drive away without any problems untill it cools down again. Does not happen in stop and go traffic because of all the time stopped at lights and allowing engine to warm whatever up preventing hesitation / misfire.
Thanks in advance for all your input and help!!!!
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