OBD1 help

[85c10owner]

Does anyone know where I can get a obd1 code reader that will clear codes? Just bought this 85 GMC c1500 and did a complete tune up and now the check engine light comes on after running for a few seconds. I know I can use a paper clip to jump to 2 terminals and count the flashes but I need to clear them so I can smog this thing and get it in my name. Hopefully I just knocked something loose when I did the tune up. Sad thing is it really didnt run any better after the tune up and many plug wires were burned and the cap and rotor were the worst I`ve ever seen.

 

[RetroC10Sport]

Just unhook the battery for a few minutes.

 

[85c10owner]

Just unhook the battery for a few minutes.

Will that stop it from coming back?

 

[RetroC10Sport]

Not likely. It will likely come back until the problem is fixed. You should check the codes and see what is wrong.

 

[85c10owner]

Not likely. It will likely come back until the problem is fixed. You should check the codes and see what is wrong.

That's the plan. Hoping it's something simple. All I did was replace the cap, rotor, plugs and wires. Thinking maybe I unhooked something by mistake.

 

[RetroC10Sport]

Very possible. 1985 is fairly simple though so it shouldn't be too tough to diagnose and fix.

 

[85c10owner]

Very possible. 1985 is fairly simple though so it shouldn't be too tough to diagnose and fix.

I did notice the temp sensor wire was broken but covered in grime at the break so it's been that way. Would that have anything to do with it? I am going g to jumper the terminals and see what code flashes and pray it's a cheap easy fix. I really want to swap to a later engine with less smog crap but I'm not in a position to do that yet.

 

[RetroC10Sport]

If it's for the gauge, then no it will not make the light come on.

I don't think there were two temp sensor wires in 1985, one for the ECM and one for the gauge like later. I would have to look at the wiring diagrams to see.

If there were one for the ECM, then that one would most certainly cause the light to come on.

[edit]Seems they did have a CTS like the TBI engines. 2 wires, yellow and black.

 

[85c10owner]

I need to get a book on this thing. The wire I found goes to a sensor on the driver side head. The gauge did read before and now it doesn't so I don't know. It doesn't seem to be butchered but was certainly neglected a bit. I don't even know where that wire feeds to so I can fix it. I need a wire diagram I suppose.

 

[RetroC10Sport]

Okay, that wouldn't turn on the CES light.

Are you on a computer or have access? I can send you links to the wiring diagram to download. I do not have a service manual for a 1985 but do for a 1986 which is pretty much the same.

I take that back, I think I do have 1985 service manual.

 

[85c10owner]

Okay, that wouldn't turn on the CES light.

Are you on a computer or have access? I can send you links to the wiring diagram to download. I do not have a service manual for a 1985 but do for a 1986 which is pretty much the same.

I take that back, I think I do have 1985 service manual.

Sent you a pm with my email addrss. Thanks

 

[85c10owner]

Ok, had code 23, 34 and 54. Disconnected the battery after checking all of the hoses and lines and seems I still have code 54 but then the check engine light starting flickering and I couldnt check it. Guess I should just buy a code ready. Also seems like I have a slight miss that wasnt there before. I need to check the firing order but I`m pretty sure its right. Dont it more than a couple times in the last 25 yrs but could be wrong. Idles fine though. Also idles very low, lower than before the tune up. Guess I should have just left the damn thing alone. I really shouldnt have bought it but no sense in crying over spilled milk.

 

[Georgeb]

Just a thought....
http://www.gmsquarebody.com/forum/showthread.php?t=13194

Having this helped me alot.

 

[85c10owner]

Just a thought....
http://www.gmsquarebody.com/forum/showthread.php?t=13194

Having this helped me alot.

Will that work on a carb set up?

 

[Georgeb]

Will that work on a carb set up?

Um...... Not sure. I assumed fuel injected when I saw OBD1. That would require more research. I'm a ******* somtimes.