1986 240 DL IAC

Post by **jimmy57** » 09 Feb 2015, 12:24

One power wire and two grounding wires. One grd is open pulse and the other is closed pulse. If the closed pulse is missing then the valve goes full or near full open. Go to RH kick panel insie forward of door opening and locate the LH ECU and then unplug it and spray the connectins with WD-40 and then plug it in and unplug it 3-4 times and then crank engine and see if the idle is normal speed.

ECT sensor issues cause high idle and throttle switch issues do too.

mhgreen · Post by **mhgreen** » 09 Feb 2015, 20:16

Bad ecu. Plugged in a good one (borrowed) and idle was fine

mhgreen · Post by **mhgreen** » 09 Feb 2015, 20:17

Cleaning ecu connection as discussed above - worth trying? Or is bad, bad?

93Regina · Post by **93Regina** » 09 Feb 2015, 21:13

mhgreen wrote:Cleaning ecu connection as discussed above - worth trying?

I would use electrical contact spray, and let it dry...I always disconnect battery when swapping.

On weathered connections, I slap some di-electric grease on them before plugging back in.

mhgreen · Post by **mhgreen** » 18 Feb 2015, 15:29

I replaced ECU with a working used part. I can now plug IAC in and all is well. Cleaning the terminals was a good idea anyway on the connector, so I went ahead and did that. I just hope this ECU doesn't burn up somehow - - especially considering I am not sure what caused the failure on the last one that was in there.

lummert · Post by **lummert** » 18 Feb 2015, 17:20

Now that the problem is solved, take the cover off the bad ECU and look for something gone wrong.

mhgreen · Post by **mhgreen** » 18 Feb 2015, 19:43

lummert wrote:Now that the problem is solved, take the cover off the bad ECU and look for something gone wrong.

I took it apart, but I am not even remotely sure of what to look for! There is a lot going on under there

93Regina · Post by **93Regina** » 19 Feb 2015, 22:46

mhgreen wrote:I am not even remotely sure of what to look for

Bad capacitors