NoNeck

Hey guys. I'm pretty clueless with the electronics in these things. I'm kind of a Chevelle guy. Anyhow, I recently got an 86 Tuned Port Iroc that had a completed T5 conversion from the original 700R4. I haven't driven it much and I know the car has sat for about 4 years prior to now. The motor is a .030 over 305 rebuilt, with a Crane cam #114122. It idles high, I'm assuming because the computer (ECM?) is telling it to idle high so when you drop it into Drive, the idle drops to the correct speed? How do I correct this. I read somewhere about having the ECM re-programmed or something? Can someone point me in the right direction? I'm used to carbs! In fact in looking at the wiring diagrams for these cars, I am astounded that they actually run at all! The check engine light is on, I'm going out now to jump out the pins and try to get the codes. MAybe that has something to do with the high idle? Thanks!

Pillsbry10

iTrader: (1)

more than likely the check engine light being on is the problem, check the code and go from there. when i did my t5 conversion the only problem i had was a jumping idle coming down to a stop

NoNeck

Thanks. I got the 32 and 36 codes. I did start the car once with the MAF sensor unplugged and it ran rough till I plugged it back in. That may be the 36 code. I disconnected the battery for a while to reset the ECM. The "new" trans goes in tommorow. Thanks for the help!

Drac0nic

The 32 is an EGR I believe. If it's been sitting for a while I would advise checking ALL vacuum hoses. There is a good chance it has a leak. Something else (even though in a way I doubt it) is that they may have had a higher idle for an auto because it's always loaded by the converter/pump compared to just spinning the flywheel with a manual except when it's in park. The last thing is it may have something to do with the cam and the tune being off too, or the previous owner somehow bumped the idle speed to compensate for the cam. It looks like a standard 204/214 cam which isn't huge but it's way bigger than what comes with stock.

RBob

iTrader: (1)

When the auto to T5 swap was done, there is a wire that goes to the ECM from the shifter. This is the P/N input to the ECM. Make sure that this wire is left open. For a T5 this is correct as it tells the ECM that it is in drive.

If grounded then the trans is in P/N, which is incorrect.

Wire color is orange w/blk stripe. Goes to B10 on the ECM.

The other thing to do is a minimum idle speed setting. This is where the throttle blade position is set along with adjusting the TPS. This is critical on the MAF TPI ECMs. See the tech articles here on TGO for the procedure.

RBob.

NoNeck

Thanks guys. I reset the computer and drove to my buddys house and the idle was normal and the SErvice Engine light stayed off. When I drove home the light was back on and the idle was at 2000+ rpm again. That orange with black stripe wire is just taped off after I cut the auto harness and wired the neutral switch together, so that is correct. As for the tune I guess it is the EGR code making the idle high. I'll have the check to see if it threw the MAF code again or not. I think that was probably related to me starting the car one day with the MAF unplugged.

BANDITSBC

i had a 2k plus high idle and swapped my injectors for my turbo build and it went away. i noticed that when i disconnected my injector wires while it was running that the idle only changed for half of them, i think they were sticking open

good luck

NoNeck

Interesting. Thanks . I think I may have gotten it dialed in. I did the procedure for TPI and TPS set up. I dropped the throttle stop down to as low as it would go which was like 1500 rpm. And I think the blades on the TPI were completely closed, which I think is wrong but that was the lowest I could get the idle with the TPS disconnnected. Then I connected the TPS and now it will idel high upon start up and then drop to 900 RPM. It does have a mild cam and also an exhaust restriction. (Someone crushed the pipe over the rear axle for some reason to about an inch and a half wide. So it's better, but not perfect. I also have an exhaust leak, I believe from the driver side header exh. gasket. (It has Edelbrock stainless HEaders as well....)I reset the comouter and now I just need to get some drive time on it. I don't know why but it seems slower than my other 86 with an auto trans and 105,000 miles. This is rebuilt (With like 2000 miles)with the cam and headers and a 5 speed and just seems slower for some reason. MAybe it needs a custom tune?