928S MN

I have an 85 but have never experienced this problem. So asking this question in an effort to help out here.

Would a bad ground connection cause this problem?

When I did my upper refresh, I made doubly sure to clean all the grounds, including filing off the Powder Coating on the water bridge for the temp sensor.

Mrmerlin

if the idle doesnt change the computer has been damaged from a stuck ISV unit
Find another computer

Mrspencer

who out there rebuilds them on the west coast many thanks again , to all who have replied.

Mrmerlin

Not sure about that maybe John Speake?
Louie Ott?

davek9

Also before replacing ECU's make sure that the signals are getting to the ECU's, from the sensors and switches.
I recently had a bad connection from the TPS to the ECU's so the idle map never triggered, testing the switch it showed good.
However the jumper test also didn't work for me due to no connection back through the Firewall

Mrspencer

will check that also signal from sensors to each, have ECU out now looking for pin diagram, on what pins to check for ohm if their checks out then onto the wire harness., thought I saw that diagram in one of these post.

monkez

the diagrams have been uploaded before, but I had them handy on my laptop. Good luck!

-adam

Mrspencer

Mr Merlin thanks for the time and info, in the end it ended up being a bad maf, after talking to Kevin at injection labs, due to all the symptoms I told him I was having, so here is a check for all those having idle issues and you have no leaks and still have idle issues unplug the maf and start car idle smoothes out so sent my Maf out today , I can't believe 4 tear downs 3 isv valves 1not bosch , im kicking myself because i knew about unplugging the maf and starting the car and totally spaced about that quick check. So erratic idle and you dont know what else to do unplug the maf start car if the maf is bad your idle should improve if there are no other issues.cheers.

Mrmerlin

Spencer Thanks for filling in the rest of the story.
FWIW installing a rebuilt MAF is part of an intake refresh,
NOTE the MAF now needs to have the mixture set for your engine, that link I provided will tell you how to do it.
If this is not done then the idle mixture will be off.
NOTE a new factory O2 sensor should also be installed as well

NOTE If the computers idle circuit wont turn off,
then you should put your computers into another car and test them before getting another set.

Mrspencer

thanks again Merlin trying to source parts to make the blinker.to set the idle mixture.

Mrmerlin

you may have better luck asking for someone to send one to you to borrow

Mrspencer

update maf is out of adjustment it has gone to the lean, very low voltage side, i.e car thinks there is no air therefore less fuel except the car is getting the correct air it's just not being seen. Also injection labs says when I get the maf back it's plug and play for my year car no co adjustment needed. Whew, fingers crossed.

Mrspencer

Merlin got the maf back and installed from injections labs Thanks Kevin.so I installed the maf and the car wouldn't start or idle, unless I applied throttle, so I check the wiring harness to the maf,see pics, so replaced with new CONNECTOR from Roger now the car starts but idle is still hunting.