Hi guys,
About a week ago I noticed that my car ( 1988 325is) would run a little rough and throw a CEL when pulling off the freeway to a stop, as soon as I gave it a little throttle the cel would go away. It’s always idled a little rough but this seems to have made it worse.
Yesterday while driving around town in traffic the car started to buck heavily and act like it had no power, I turned the car off and back on and it pulled like a freight train again. It ran fine until I pulled off the freeway 15 minutes later.... same bucking and no power, turned it off and back on again and it was fine again.
When I got home I stomp tested it, classic 1222 /1221 combo.
Things I’ve checked:
Plugs: all under 5k on them and they looked perfect with the exception of cylinder 1 which had just the tiniest amount of carbon fowling. ( very very slightly black around the base of the plug)
Ghetto smoke test with carb cleaner:
Sprayed around the intake elbow, ICV, throttle body, evap canister, fuel injectors etc. No change in idle speed.
Cleaned ICV: no changes, the rotor seems to move freely and the ICV buzzes when the key is on. When unplugged the idle changes a tiny bit but not much.
AFM: sparkly clean, door moves smoothly, when unplugged the engine dies instantly. ( car started throwing 1224 code after I did this a few times)
Valves:
Adjusted to spec within the last 10k, very slightly loud.
O2 sensor:
changed in the last 20k or so, unplugging doesn’t seem to do anything ( no change in idle)
Car pulls well when and has no problem climbing grades at 80mph, the bucking seems to mostly happen when the engine is hot.
Thanks for the help guys!
Edit: engine was rebuilt 20k ago, intake elbow, manifold gaskets, timing belt, C191 ( repinned into a heavy duty water and oil proof Audi/VW style gasketed plug), cap and rotor aren’t particularly old either.
About a week ago I noticed that my car ( 1988 325is) would run a little rough and throw a CEL when pulling off the freeway to a stop, as soon as I gave it a little throttle the cel would go away. It’s always idled a little rough but this seems to have made it worse.
Yesterday while driving around town in traffic the car started to buck heavily and act like it had no power, I turned the car off and back on and it pulled like a freight train again. It ran fine until I pulled off the freeway 15 minutes later.... same bucking and no power, turned it off and back on again and it was fine again.
When I got home I stomp tested it, classic 1222 /1221 combo.
Things I’ve checked:
Plugs: all under 5k on them and they looked perfect with the exception of cylinder 1 which had just the tiniest amount of carbon fowling. ( very very slightly black around the base of the plug)
Ghetto smoke test with carb cleaner:
Sprayed around the intake elbow, ICV, throttle body, evap canister, fuel injectors etc. No change in idle speed.
Cleaned ICV: no changes, the rotor seems to move freely and the ICV buzzes when the key is on. When unplugged the idle changes a tiny bit but not much.
AFM: sparkly clean, door moves smoothly, when unplugged the engine dies instantly. ( car started throwing 1224 code after I did this a few times)
Valves:
Adjusted to spec within the last 10k, very slightly loud.
O2 sensor:
changed in the last 20k or so, unplugging doesn’t seem to do anything ( no change in idle)
Car pulls well when and has no problem climbing grades at 80mph, the bucking seems to mostly happen when the engine is hot.
Thanks for the help guys!
Edit: engine was rebuilt 20k ago, intake elbow, manifold gaskets, timing belt, C191 ( repinned into a heavy duty water and oil proof Audi/VW style gasketed plug), cap and rotor aren’t particularly old either.
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