Possible Wiring Problems?

[drjeckles]

I just bought this car and recently changed the spark plugs and spark plug wires and my check engine soon light comes on and the engine runs rough. My car is a 1994 Buick Century 3.1 liter V-6 engine. It ran perfectly before I changed the plug and wires, sigh.

My brother has a spark tester/analyzer and that checks out OK. I got Pep Boys to do a scan for $20 so did not have to buy a tool or pay GM $85 for it.

The error codes are:
P0321 24X Reference Circuit
P0342 Cam signal Circuit (loss of cam pulses)
P1640 QDM "A" Circuit
P1650 QDM "B" Circuit
P0740 TCC Circuit

I had to remove the Coil pack and some vacuum hoses along with a few connections to the coild pack to get to the plugs and wires.

Many of the vacuum hoses are/were questionable and I have been repairing replacing many. The wiring in areas looks like there have been problems before and there is actually a new wire outside the harness to make the AC switch on.

So far I have been unable to find any poor connections, loose wires, or vaccum connections, but I suspect that the problem is wiring related. I am very open to suggestions/advice/similar experiences.

1. Would a wiring harness connector with bad connections (corroded or broken where I cannot see them) explain these problems?
2. Would you suggest buying a new universal harness, a new OEM harness, Used harness from salvage, running idustrial grade shielded wiring to the critical sensors and bypassing the possibly bad sections, or something else?

My budget is only a few hundred so I don't think the GM shop could help that cheaply. This probably rules out a completely new OEM wiring harness too.

PS
I have access to AllData diagrams and troubleshooting for this vehicle.

[drjeckles]

Found problem!
There is difficult to find group of inline fuses that can only be accessed by removing the glove compartment and fuse block. Even with diagrams and a photo from the shop manual (which showed the old style round fuses instead of the bayonet type that were in the car), I went back and forth the diagrams and car 3 times before finally locating the blown 10 A fuse. It turns out that that fuse supplies power to the crank sensor and will cause all these errors. When I reset the computer, all the error codes disappeared.

Alas, I also had one bad AC/Delco sparkplug, which I found much to my disappointment when the car still ran rough.

I then cleaned up the mess left by the last shop that tried to troubleshoot the problem before I bought the car and all is well (with the wiring anyway, grin).

[wilkie_5]

well, hopefully your problem is also my own. i have the same car with the same situation... wish me luck.

[BNaylor]

Originally Posted by wilkie_5

well, hopefully your problem is also my own. i have the same car with the same situation... wish me luck.

Good luck.

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