Open Loop Problem

[86 IROC-Z]

Hey Guy's I am having a problem with my car and am suspecting I am running in open loop all the time. My plugs are black from running too rich. When I had the car warmed up and disconnected the O2 sensor to see if my SES light will come on it did not. I know the SES light works because I short out the A and B terminal on the ALDL and I get the code 12 reapeating, meaning all is ok.

I have an 86 Iroc 305 TPI, 4 speed auto, it has been converted to speed density. I am in Australia and have not found access to a scanner at all. I was told by a person that there is another way to check if the car is going into closed loop. Something to do with shorting out A and B on the ALDL when the car is started. Anyone know anything about this test??

I am also pretty sure that my torque converter is not locking up, which tells me I am definitely running in open loop.

Anyone have and advice or suggestions please?

Thanks Michael

[uk88gta]

As far as the testing for closed loop or open loop goes you can bridge terminal A & B with the engine running...make sure you start the car and THEN bridge the terminals otherwise you could be in TROUBLE...the "check engine" light will flash approximately 2& a half times a second for open loop...once per second for closed loop...
Hope this helps a bit....anything to help a fellow "long distance Thirdgen owner" !!

[86 IROC-Z]

Thnkas for the Info mate! I tried the test after the car was warmed up properly and it flashed 2.5 times per second meaning it is in bloody open loop. This really sucks as the mechanics are not that really familiar with these cars here. Of course there are people who will fix it but will charge and arm and a leg for it.

One other question I have is, does this put excessive stress on the trannie running in open loop all teh time. I heard that it stuff the trannie up because the torque converter is not locking up? And a to rebuild a 700R4 I will almost have to sell the house.

[marald]

Hi,

I live in holland and it's quite hard to get a scanner overhere aswell. I think my car is in open loop all the time and my torqueconv isn't locking up the way it should.
(still got a code 32) Can I use that ALDL trick on a carbed (Qjet) car aswell without damaging anything???

Greetings marald


------------------
1985 Firebird LG4 4BBL
replaced carb/no cat/ new muffler/rebuilt engine

[uk88gta]

Marald,
According to my Chilton manual the aldl test only works for fuel-injected cars so it won't work with yours I'm afraid....of course, I might be wrong...I'm sure someone will correct me if I am!.
You could also try www.thirdgen.org (http://www.thirdgen.org) to find an answer through their excellent technical message boards....unless someone else here can help some more??
Good luck!!
Jon.

[84FBODY]

As far as I know the ALDL (Assembly line Diagnostic Ling) works on all cars. easy to pull codes and the open loop and closed loop should work. just shrot it out AFTER the car is running. nothing bad will happen if it doesn't work. but it should

------------------
John- 1984 camaro, 350, Dynomax Cat-back, busted tranny.

Warrior Court Jester of the Not So Famous Cascade Crew.

http://www.vision2100.com/mt3.jpg

http://www.suempresaenlinea.com/drowned/images/iroc-gray.gif http://www.suempresaenlinea.com/drowned/images/iroc-front-gray.gif

If you can read this MY TRANSMISSION IS STILL BROKEN!

[Corey]

If the car has been converted to speed density maybe that is the problem. Dosen't the computer go into open loop if it dosen't get a signal from the maf/map sensor?



------------------
Corey
'88 T/A 305 TPI