Hey r3v, My '86 es has developed a rough idle condition. When stone cold, it starts fine, and runs and idles beautifully for about 5-10 minutes. Then, as it begins to slowly warm, it develops what feels like a misfire or an air (vacuum) leak, and a slight rich exhaust smell. If the engine gets up to operating temp and is shut off, it will be harder to re-start (stumbles for a second or two) after sitting and cooling for an hour or more. Always starts fine when cold, though. I understand a smoke test is a great diagnostic tool to start with, but I'm not aware of any shops that offer that around here. Car is 100% stock, no mods at all....you know, for reliability....
A second, and hopefully related, problem is that the engine would shut off after driving about 30-45 minutes or so, sometimes sooner. At first, it would re-start right away, but now, it has to sit for a while before it will restart. Last time this happened, it was 3 hours before it fired up again. Initially, it was a rare occurrence. Now it is almost guaranteed to happen, without fail. Never happens in my garage, so I can test anything. I recently got my OBC working properly, I understand that can somehow cause rough idle??
Parts recently replaced:
in-line fuel pump
coolant temp sensor (connector can twist/spin when sensor tightened into
place--never seen that on any other CTS)
ignition coil, plugs, wires, distributor cap and rotor
water pump and timing belt (timing is set properly)
ignition speed sensor
intake boot and all rubber air/vacuum hoses on engine, and all are very tight
fuel pump and main relays
AFM seems to test fine, I recently adjusted the "wiper" to a less worn section of the track...no change. That worked great on my 533.
Spark plugs seemed to be fouled somewhat a week ago. Loose, too. Torqued them down to spec, no change.
I haven't fully checked out the ICV, and that's about all that's left, along with FPR and/or injector(s). O2 sensor could be replaced, too, but PO welded it into exhaust, rather than screw it into the bung.
I'm not sure where to go next at all, this really has me stumped. Whatever it is, I'm sure is simple and I'll feel stupid for overlooking it. I always do. Today I found myself looking at an E46 M3 in hopes of buying, and I felt like I was cheating on the E30. But this is to be a DD, and it's going to have to get sorted fast. Thanks to anyone who can point me in the right direction!
A second, and hopefully related, problem is that the engine would shut off after driving about 30-45 minutes or so, sometimes sooner. At first, it would re-start right away, but now, it has to sit for a while before it will restart. Last time this happened, it was 3 hours before it fired up again. Initially, it was a rare occurrence. Now it is almost guaranteed to happen, without fail. Never happens in my garage, so I can test anything. I recently got my OBC working properly, I understand that can somehow cause rough idle??
Parts recently replaced:
in-line fuel pump
coolant temp sensor (connector can twist/spin when sensor tightened into
place--never seen that on any other CTS)
ignition coil, plugs, wires, distributor cap and rotor
water pump and timing belt (timing is set properly)
ignition speed sensor
intake boot and all rubber air/vacuum hoses on engine, and all are very tight
fuel pump and main relays
AFM seems to test fine, I recently adjusted the "wiper" to a less worn section of the track...no change. That worked great on my 533.
Spark plugs seemed to be fouled somewhat a week ago. Loose, too. Torqued them down to spec, no change.
I haven't fully checked out the ICV, and that's about all that's left, along with FPR and/or injector(s). O2 sensor could be replaced, too, but PO welded it into exhaust, rather than screw it into the bung.
I'm not sure where to go next at all, this really has me stumped. Whatever it is, I'm sure is simple and I'll feel stupid for overlooking it. I always do. Today I found myself looking at an E46 M3 in hopes of buying, and I felt like I was cheating on the E30. But this is to be a DD, and it's going to have to get sorted fast. Thanks to anyone who can point me in the right direction!
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