Looking for a shop in Sacramento, CA-Smog Related

[68c10owner]

Not sure if this belongs here or in the drivetrain section so mods feel free to move it.

Im looking for a shop that has experience doing smog repairs on these older trucks. My 85 GMC has a CEL and the last time I checked the code was code 54. I dont have any smog experience and Ive looked it up online and such but I dont have the patience to actually track down the issue and repair it. This truck has fought me since day one and I the more I try to fix it the shorter my patience gets. So Im looking for a shop that can handle the job. Most places around here only work on newer stuff and I need a old school shop that knows how to work on these things.

[storm9c1]

No advice on a repair shop. Sorry.

But if you are willing (patience aside), maybe we can help you? I've seen code 54 happen when the truck stalls on its own. But it may not have anything to do with the stalling (I'll explain later).

Does it ever stall?
Do you have good oil pressure when it is running?

The reason I ask these questions is if something stalls the truck (like an ignition problem, fuel problem, etc), the oil pressure switch will open when the oil pressure drops out, shutting off power to the fuel pump. If the key is on when this happens, it will sometimes set code 54 because power is suddenly removed from the fuel pump circuit. But the cause is usually something unrelated to that code.

[68c10owner]

Oil psi gauge doesn't work. It's got a electronic qjet so it has a mechanical fuel pump. Truck runs strong, does not flood over or run super rich. Just can't get rid of the light. Been messing with it since September. I've had enough. It's someone else's turn who knows this smog crap because I dont. It's either someone else fixes it or I get rid of the truck.

[storm9c1]

I didn't think code 54 was used on carb'ed engines... Hmmm. Need to refresh my memory.

OK, on pre-86, it means mixture control solenoid or circuit. Remember something new everyday.
"The mixture control solenoid voltage is high at the ECM because of a shorted M/C solenoid circuit and/or faulty ECM."

I'll let someone else chime in since I either know carbs or fuel injection but know very little about these electronic carbs. I kinda ignore the fact that they ever existed. In fact, I ignore the fact that the 80s ever existed.

Have you done any testing on that circuit? Looking for a bad solenoid (shorted, open, etc)? Unplug it and apply power directly to it -- does it click?

Lacking that ability, yeah, you might need a mechanic who knows those electronic carbs. Good luck. Hopefully someone else will reply.

[68c10owner]

Originally Posted by storm9c1

I didn't think code 54 was used on carb'ed engines... Hmmm. Need to refresh my memory.

OK, on pre-86, it means mixture control solenoid or circuit. Remember something new everyday.

Correct, mixture control solenoid. I have the flow charts to diagnosis it as well but like I said. My patients have run thin. I've never had to mess with anything smog related in my 27yrs of wrenching and I'm just lost. I know my limitations. It's someone else's turn

[Nitis]

pm sent