jonnyboyskate

3.1 camaro rs 1991
Okay first off I have been battling this for a month now,
Timing perfect, good fuel pump, good fuel pressure, no vaccume leaks, good compression, new ecu but wont.connnect to obd1 scanner for whatever reason, no codes, no blown fuses

New egr valve, fuel filter, tps, map, plugs, wires, dist cap, rotor, all 6 injectors, o2 sensor (only one on v6 upstream) ait filter, oil filter, ecu, fps, cata converter, timing chain and gears.

Wont idle under 1k rpm itll instantly.die, also dies in gear sometimes itll be no more.then 5 secs. Usually instantly though. Throttle position screw previously messed with before I had the car but thats not the problem, the iac engages closed when key turn to on position, and of course the fuel pump turns on for a few secs too. obviously wont do an idle relearn cause It wont run in gear even with throttle full but it should atleast crappy idle not just die. runs PERFECT at higher rpms. Rev engine and goes back perfect when throttle position set it 1-1.5k rpms idle will not run in gear even with throttle open. I am so in need of.my.car.

any ideas? I am officially stumped.

antares57

iTrader: (8)

Just to confirm you did disconnect the est connector for timing? Also your aren't bleeding vacuum when to step on the brakes through the brake booster?

jonnyboyskate

We papercliped it. Is that what you're talking about?
Actually we never disconnected that, do you disconnect the bypass located behind the ac canister? We used a timing light what affect would it have since we didnt use It? Car runs flawlessly in park above 1k rpms. And the vacuum ill check any suggestions on how to check with the brake booster?
Ill try to check but when in park I press on the brake and it doesnt lower the idle or do anything different.

willexoIX

If you dont disconnect the EST connector you are not reading base timing. Also if you try to set timing with it plugged in it wont have any affect because the computer will be compensating to correct the timing.

It has to be disconnected to check your timing.

jonnyboyskate

We put the ecu key into a+b doesnt that disconnect it?

jonnyboyskate

Making sure the service engine soon is constantly flashing right?

willexoIX

No, the connector that needs to be unplugged is the single black connector by the blower motor/ac canister. Disconnect it then start the car.

jonnyboyskate

Based on Mitchell its unplug connector or ground the aldl same affect either way

willexoIX

Ive never heard of doing it that way. Basically what that wire does is provide a 5v reference, which tells the computer to take over timing control. AFAIK grounding the ALDL doesnt interrupt that 5v signal, so the computer takes control of timing.

Though I have always done it by disconnecting the EST wire, because that is the procedure in both books I own. I have never had the need to ground the ALDL, so I do not know 100% whether or not that works. BUT I would rather do it the way the book says to do it. No harm in trying it the way I described and making sure that you still get the correct timing reading.

Also if you are talking about the michell book, books are known to have some things wrong, which is why I have a chiltons And hayes manual.

jonnyboyskate

Ill try that out what about it being a possible torque converter problem?

willexoIX

I honestly dont see how it could be the TCC. Its not locked in park or 1st gear. But if you want to rule it out, unplug the wired connector from the transmission, if you have the 700r4.

jonnyboyskate

Okay well let.me.make sure the timing is correct then ill get back to you. Any ideas if the timing is right?

willexoIX

Could be a vacuum leak somewhere. I have a feeling that since the idle was messed with previously that might have something to do with it. Is it a new IAC? If not that may be the next thing to look at. Maybe try cleaning the IAC passages first. Sounds like not enough airflow at idle, which could coincide with it running fine at the higher rpms.

Maybe the PO had the same problem and tried to compensate for it by messing with the idle screw, so the moment you can get it to run under 1000rpms, dont waste time with anything else but an idle relearn. We will try to help you out to get you there though.

jonnyboyskate

Well we replaced the iac with a known good one (85% sure) to test and we didnt have a different outcome but we are going to try to get it running and unplug it with it closed then try to lower the throttle positipn screw. Ill let you know when we test it

willexoIX

You may want to see if you can clean the IAC passages first. Also check for any leaking intake gaskets.

jonnyboyskate

Timing is perfect, fixed the wiring and the scanner finally connected the serial wire was frayed. Accoring the the Mitchell book throttle voltage should be 2.9v? But it stops at 5v. Still wont idle. lower then 1k rpms the scanner say the ecu wants to run at 800rmps. But it wont. Iac is working perfectly, perfect spark. Checking today for possible vacuum or gasket leakage. Any other things should I try?

willexoIX

If im not mistaken, tps should be from .55v to 5v. Sounds like the tps either needs to be adjusted or replaced. Try some carb cleaner around your vaccum lines and intake gaskets while running, youll hear when it comes across a leak.

jonnyboyskate

Ill check that out you thinkin intake gasket?

project89

iTrader: (1)

yes .45-.55v at idle and 4.60-5.00v for wot

jonnyboyskate

It stops at .4 something actually I had mistaken, and I just replaced the tps a day or two before I started this thread lol. Ill put it at .53 and adjust from there. Gunna be about 3-4 hours then ill be able to do some more work im hoping whatever is leaking someone nearby has in stock haha. Alright guys thank you sooo much ill let you know whats goin on.

jonnyboyskate

Okay it was the lower Pentium gasket huge leak. Checked the timing with the est Connector unplugged and fixed the timing. Now the computer keeps advancing the timing too far and forcing the car to misfire and shut off. I can drive around with the est unplugged, I did an idle relearn like 5 times. Still nothing. Itll rev up to 2.5k slowly go down then die at 1k. Ive even tryed dropping it into gear at 1.2k and died each time I retried the idle relearn I unplugged the battery and turned the key to drain all voltage for 10 seconds. It drives amazing with the est disconnected... my mechanic said the only down side to driving it disconnected is ill loose a little horse power. How can I fix this? Lol