Reading engine codes - Second Generation Forum

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Reading engine codes
Tuesday, November 29, 2005 6:26 AM
89 Sunbird GT 2.0 OHC Turbo

I know you can read them by jumping the A-B terminals. But for some reason I don't have any wires leading to the A-B location.

My setup - Only 3 wires go to the terminal.
_ _ _ _ _ _ _ _
1
_ _ _ _ _ _ _ _
2 3

I've tried ever combo to get the engine light to respond, but no luck.

I have access to an old OBD 1 scanner that understands the vehicle I'm trying to read, but it comes up with a message that a special adapter MAY be required due to the Turbo.

Problem with the car is: Rad fan turns on immediately with the key. RPM stays at 1,000 until it warms up and than it stays at 1,750. But what is wierd is my speedo works when it wants too and at first when speedo did work, engine light would go off. RMPs stayed at 1,750 though. Engine light still stays on even if the speedo works or not.

I just rebuilt this engine and had a 90 Sunbird Turbo as a donor. I didn't use any of the parts from the 90, but I have started to swap some sensors.

First- Both engine temp switch (in the head) and engine coolant sensor (in the fill neck).
Second- Bought a new VSpeedSensor (Didn't help)

I need to find this code so I can get the car emission tested.

The mechanic that has the car now thinks it may be the ECM, what do you think.

Any and all help would be greatly appreciated.
Thanks Allen


89 Sunbird GT Turbo (My new toy)
95 Camaro Z28 (My Baby)
97 Avenger (Wife's Baby)

Re: Reading engine codes
Wednesday, November 30, 2005 2:06 AM
Now that really doesn't make much sense. I have a '90 turbo, and it has the standard aldl in it. Is the car from another country by any chance?

Ohh, you wouldn't happen to have the guage cluster from the '90 would you? Mine messed up and I need a new. Hopefully one with around the same miles as mine has.
Re: Reading engine codes
Thursday, December 01, 2005 5:29 AM
Sorry Scott, donor car is gone.

The setup doesn't make sense to the mechanic thats working on it either and he works mainly on old domestic cars. We're waiting for a friend of his to go to his shop to check it out.

To give you an example of how GM can mess this stuff up, my 95 Camaro has an OBD2 hookup, but only reads OBD1 codes. I found a website that shows how to jump-wire the scanner to read the codes. My Camaro was throwing a code an other mechanic couldn't read, so I printed out the procedure. It actually worked and he gave me the test for free.

BTW, the car was bought brand new 5 mins from my house. I'm the 3rd owner and my nephew was the 2nd owner. I may live in Canada, but I don't think we are that foriegn. LOL




89 Sunbird GT Turbo (My new toy)
95 Camaro Z28 (My Baby)
97 Avenger (Wife's Baby)
Re: Reading engine codes
Saturday, December 03, 2005 3:17 PM
your Camaro is probably "OBD 1.5" the older 4th gens were like that...i forget the cutoff year but i know the '96 i just worked on was pure OBD 2.

this might help: http://www.v6z24.com/howto/codes



Re: Reading engine codes
Saturday, December 03, 2005 3:39 PM
infact, all gm cars and trucks at one point had an obd1.5 system. basicly, it was an obd2 plug and chip style (soldered to the board, not removable) but it was obd1 programming. a lot of car between 94-95 had this. 96 most went to full obd2.



Re: Reading engine codes
Sunday, December 04, 2005 7:19 AM
Thanks for the link Dave

BTW, nice f-body. check out my site. www.ccfbg.com

Good thing, the pic in step 2 shows exactly where my wires are.
Bad thing, I've tried that hookup and I still didn't get a code 12.

According to the mechanics friend, he thinks I may have grounded out the ECM where the wiring leads from under hood to inside car. I seems my extraordinary power washing (with some heavy grease cutters) while the engine was out allowed water to go into places it shouldn't have.

I don't know how, but he was able to get the code cleared long enough to pass the emission test.

The code did come back, so I'm going to order a new ECM and check this out when I get the car home.

Thanks guys


89 Sunbird GT Turbo (My new toy)
95 Camaro Z28 (My Baby)
97 Avenger (Wife's Baby)
Re: Reading engine codes
Tuesday, December 06, 2005 9:47 AM
I was going to suggest you might have a bad PROM. It sounds like you're in what's called "limp home mode" which is is a default "safety net" to allow you to drive home or to a garage till you can have the car repaired. Usually the fan stays on when the key is on, the idle goes up and the speedo doesn't work.
I know this because I've been trying to learn how to reprogram my PROM and when I have a bad connection at the ECM adaptor or I screw up the programming I've been in limp home mode and it sounds like what you have going on.
Take it for what it's worth. Good luck!

Tony


Tony
1987 Sunbird GT turbo convert
Ported intake, Fiero 53 MM TB, 52 lb inj, ported and flowed head, tube header, Mitsu TD06, ARP rod
bolts/head studs, adj cam sprocket, 4" x 12" x 31" FMIC, Paxton AFPR, modified 125 trans/LSD
unit/3.42's, custom chip tuning, Alky Control Methanol injection
13.61 ET at 101.44 mph, 262 WHP/350WTQ

2009 Pontiac Solstice GXP roadster, 2.0 turbo w/GMPP exh, CAI and turbo upgrade, 290 hp/325 ft lbs

1969 Olds 442 convert
400 Eng, 200-4R trans, 3.73 posi, power everything, OAI


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