I just changed the spark plugs on my 91 formula 5.7L to NGK plugs, gapped at .035 as it says on the sticker under my hood. I started the car afterwards and it seemed to run great. I took it out for a little test spin last night. A little ways down the road I jumped on it and it really ran great, the shift into second was so hard the wheels completely broke loose, not just barked like normal. Immediately after that the dreaded "service engine soon" light came on. I drove back home and it went off once, came back on, then went off and stayed off. This was 12midnight so I just went to bed (my wife doesnt appreciate revving the engine in the garage while shes trying to sleep). I wonder if I knocked of a sensor or something. Also I took off the EGR tubes on the driver side to be able to get to those plugs, but I put it back on as tight as it was (this is the four metal tubes that each screw into the exaust manifold, I think that is the EGR lines). I guess I will have to invest in a code reader to see whats going on. The car runs great and Im ready to change the distributor cap, rotor, and coil, but Im thinking I should wait to not complicate the matter further.

what do yall think?
Larry

 

stick a paper clip in the a-b terminals on the aldl connector to check the codes.
http://www.fiero.mn.org/Knowledge/Features/ECMcodes.htm

 

The "Diagnostic Terminal" is on the ECM in a 91 Formula? I read the link and that is for a Fiero. Anyway I have a Firebird shop manual so I guess I just look for the Diagnostic Terminal and follow the instructions. Oh yeah, I did disconnect the negative battery terminal during the changing of the plugs. Does this car have to "relearn" settings after disconnecting like that?

I will try this procedure tonight and see what code I get.
Thanks

 

the ALDL is on the bottom side of the dash, to the right of your steering column. Jump the A and B terminals, turn the key on, then count the "Service Engine" light flashes. It'll flash once, then twice, signalling a "12". It'll do that 3 times, followed by another number 3 times. That next number is your error code. After it flashes that one 3 times, it'll move to the next stored code. Once it flashes "12" again, you've gotten all of the codes.

 

Larry,


First, you'll need to acquire a GM OBD I ECM Diagnostic Trouble Code Retrieval Tool (commonly known as a paper clip to TGO members).

With the engine and ignition turned off, locate the ALDL connector under the dash, just to the right of the steering wheel in the driver's foot well area. There should be a small rectangular cover over the access hole in the lower dash trim.



Insert a tool as described above (paper clip) into the 'A' and 'B' terminals on the ALDL connector:



WITHOUT STARTING the engine, turn the ignition to the "RUN" position. Watch the Malfunction Indicator Lamp (MIL) and it will begin to flash. This is also commonly called the "Service Engine Soon" or "SES" lamp. The first code will flash three times, and will usually be a code '12'. This is encoded by one flash of the lamp, a brief pause, then two successive flashes of the lamp. Each code will repeat three times, so you should see a "Code 12" flash three times. Any other error codes will follow in numerical order, and each code should flash three times. After all codes have been displayed three times, the "Code 12" will again flash three times, then all other codes will follow as described earlier. This cycle will continue until the jumper is removed or the ignition is turned off.

After you have made a note of all error codes, turn off the ignition and remove the jumper immediately. If you forget to remove the jumper and attempt to start the engine with it in place, you could damage the ECM. For this reason you should remove it immediately.

Once you have a note of all error codes, check this file for the decoding:

GM Error Codes.pdf.

You'll need Adobe Acrobat Reader to open/print the file. (See link below.)

 

As text if you don't have the acrobat reader:

 

I really appreciate this info, it is very clear and concise. Once I know that code then I need to figure what to do about it. I forgot to disconnect the negative battery cable and I was change a plug near the starter from the bottom, I actually got some sparks briefly. I then disconnected the battery and finished the plugs. I hope I didn't short something out. This is the first time Ive got the warning light with this car, Ive had it about 3 months. It runs great still so Im hoping its nothing serious. This wouldn't happen just from disconnectingt the battery and then reconnecting would it? This is the first time Ive done that too.

Larry

 

another vader post that gets my printer going, are you married? lol

 

sure all the wires are on good and tight... and al lthe plugs still tight... my friend change the plugs in his Xploder... then after he went out and ran it for a while he checked them again... and 1 of them backed off some (became loose).. dunno if that would sned your little light on or what... well shoot i dont know

 

Havent checked the wires and plug tightness yet, that seems like a good idea. I ran the check with the paper clip deal this evening and I got a code 53, or System overvoltage, over 17.1 volts. It only happened when I jumped on it last night, tonight I changed the coil and the rotor and distributor then reset the codes by disconnecting the battery and took it out and ran great with no codes. Maybe it fixed itself (hahah). Any I going to watch it, at least i know how to check the codes now.

thanks again

 

LMFAO! "Xploder" Classic, man! I hope you don't mind if I use that one - great.

I like to call the longer, uglier version the "Extinction". And of course we all know the big, fat, slow-*** sedan is the "Drowned Clitoria", and it's Mercury sister is the "Grandma Key"

Xploder - gotta love it. That's why you're a Kuhl-man...



Larry,

As for your error code, I'm guessing you generated a really nice surge when you had your resistance welding episode with the starter and ratchet. I'll bet you won't see that error code again until the next plug change.

 

Uh oh. I got the code again tonight. Its the same one. I let it just run for a while in the drive way and I noticed that the voltage on the dash dial would jump up to about 17 and the lights would get brighter, then after a while it would go down to the middle (14 or so i think) and the lights would get dimmer (normal). This doesn't seem good. Im thinking I must of fried something, possible the voltage regulator, although I don't know enough about the electrical to tell. PLEASE HELP. Im actually thinking about having to take it to a mechanic (read $$$$$). How can I test the voltage regualtor? What else might it be, generator or alternator? I could certainly change these with my handy shop manual, but how can I tell what it is?

Thanks

 

Vader... haha yeah 3 of my good friends all have them Xploder's.... its like there own club... im the rebel of the group with a CAR!

my last name is Kuhlmann...

 

Gotcha. I'm wasn't sure how you pronounce it. It might be with a short "u", so I can see the misunderstanding. But if you were in Germany or Holland it would probably be "kool' man", so I took literary license and twisted it accordingly. Cool - Man!

I still like the "Xploder" thing...


BTW - Larry started a new thread on his electrical problem:

https://www.thirdgen.org/techbb2/sho...threadid=97314