Just picked up a new to me 1984 240 GL auto trans with 90k miles on it. Having trouble with a high idle. It did idle around 1300 rpm in all drive gears as well as park before troubleshooting and now 1000rpm after.
Heres what ive done so far after much research.
1. bypass IAC with jumper wire which at first did nothing(more to this in step 4). No change in RPM
2. ohm out pins on IAC motor per another threads instructions. Ohms were within range but on the high side. Plug side had 12v with engine running middle pin.
3. Removed IAC. Cleaned. Disassembled. Cleaned some more even though the insides werent dirty. Just typical carbon buildup on the pintle side. Reassembled and reinstalled.
4. Started car and re tested jumper idle adjust port/plug. Almost died due to the adjusting wheel being turned all the way in. Adjusted to 750ish rpm per tach. when disconnected the idle went back up to 1000rpm and stayed there engine warm. Repeated test. same result.
5. Carb cleaner sprayed all over vacuum hoses, intake, manifold gasket area. No change in idle so no leaks.
So does this indicate a faulty IAC? Would hate to shell out the 300 dollars for a bosch replacement if theres something else i should check.
Thanks in advance
Heres what ive done so far after much research.
1. bypass IAC with jumper wire which at first did nothing(more to this in step 4). No change in RPM
2. ohm out pins on IAC motor per another threads instructions. Ohms were within range but on the high side. Plug side had 12v with engine running middle pin.
3. Removed IAC. Cleaned. Disassembled. Cleaned some more even though the insides werent dirty. Just typical carbon buildup on the pintle side. Reassembled and reinstalled.
4. Started car and re tested jumper idle adjust port/plug. Almost died due to the adjusting wheel being turned all the way in. Adjusted to 750ish rpm per tach. when disconnected the idle went back up to 1000rpm and stayed there engine warm. Repeated test. same result.
5. Carb cleaner sprayed all over vacuum hoses, intake, manifold gasket area. No change in idle so no leaks.
So does this indicate a faulty IAC? Would hate to shell out the 300 dollars for a bosch replacement if theres something else i should check.
Thanks in advance