Craig Hobbs

Believe it's a wiring issue caused by owner after ecu wires got messed with, no code but engine is going up and down in RPM. Cold it's not as bad but as it gets warmer it does it even at idle. This is a ten plus year old build that now has a problem. Thanks

bheinen74

tps sensor

Craig Hobbs

Tps senor was tested and adjusted but thanks. Anyone know where I can find pinouts diag for pm7 or one that has same pinouts

jlicrx

most likely cause for fluctuating idle is EACV not working correctly - also could be a vacuum leak or faulty PCV valve

PM7 ECU pinouts are essentially the same as PM6 pinouts

any codes showing on the ECU?

Craig Hobbs

No codes, it fluctuating at all speeds after it warms up. Pcv checked , I'll check the eacv wiring to pinouts. We bought the car many years ago from a guy that had spent a lot of money on it but never could get it run properly, he had sent the harness to a company in CA to have it wired for this engine but he got frustrated and sold it to my son. I found the harness was made for a different swap and I had to redo it. The car ran very well but over time the wiring got bad at brain end and I believe my son resoldered them in the wrong place. We lost all of my notes and diagram that we had and the other sites with the information is now dead and for sale. Thanks much for the information as I thought the pm6 was the same pinouts but didn't want to make bigger problems.i will just have to trace all wire from one end to the other once again and eliminate a wiring problem and go from there. Thanks again

jlicrx

to check if the EACV is working properly, with the engine running unplug the connector to the EACV - the idle should drop down to around 500 rpm and remain steady - if it is still fluctuating, it is probably something else, possibly in the wiring or connectors switched - don't forget to reset the ECU after unplugging the EACV, and re-connecting it, since you will get a Check engine light with a code 14 - what was the model of the car originally?

the EACV wire colors are Blue with Yellow stripe which runs to ECU pin A11 and Black with Yellow stripe which is power

Tyson

its always been a vacuum leak or the throttle body idle screw needed adjustment.

its never been the TPS for me.

and while its not a bad thing to clean out the EACV and put a new gasket, thats been pretty reliable for me too.

and ive never found it necessary to do the unplugging and plugging of the EACV while setting idle. just close the screw until it barely runs then bring it back up. done.

Craig Hobbs

The car is a 91 Civic dx hatch back. Black and yellow pin what?

jlicrx

Black/Yellow doesn't run to ECU - it is 12v power which comes from the under dash fuse box, fuse 14

Craig Hobbs

Thanks I will check it out later today or tonight I should be able to check out all the pinouts now that I know for sure that pm6 has the same pinouts as 7. Thanks for the info and I will let you know what I find out.