Hello all,
Well for those of you that remember I posted a few topics on turbocharging 3.4 DOHC, and 4.3L V-6's. Come to find out it would cost lots of money and create the need for lots of fabrication that as much as I like to do I don't have time. So anyways I ended up finding a 3.1 in the junkyard with 110k miles on it. It failed to leak down test with flying colors. Turns out it just neede a valve job... done. So car, engine, accessories, machine work, and misc parts and I'm out a wopping $750. Once I get everything working.... let the turbocharging begin!

Here's the problem. I got the engine installed, the guys that pulled the original engine did their best not to butcher the MPFI wiring, and they did an okay job for a couple red-necks. I can crank the engine over with the computer disconnected, but once I hook up the computer the engine won't crank. The fuel pump does turn on and pumps plenty of funny colored fuel (cars been sitting for a while). I'm having a hell of a time trying to figure out whats going on here. The only thing that isn't hooked up, and this is because I can't find the wire is the oil sensor on the oil filter boss. I just rebuilt the steering column because some ape apparrently thought it was supposed tilt from side to side and when it didn't thought he'd try to fix it. So I took the guts out of a steering column I had from an '89 IROC and rebuilt the '91 column with it. I used the lock cylinder with the VATS sensor, and the turn signal switch from the '91. I haven't connected the wiring from the column to the car except for the igintion and airbag. I don't think that the cruise, turn signal, hazard, or brightness switch have anything to do with this.

Ok, so I'm pretty sure I mentioned everything, if anyone has some insight as to why it'll crank with the computer disconnected but not with it connected please let me know. Also if anyone happens to have an A/C compressor bracket for a 91 RS they want to get rid of let me know too .

 

sounds like vats....

 

Wait.. what electronics did you put in the car? Did you change the whole wiring harness over to speed density? Or did you put the 3.1 block in and reused all of the wires (and computer) from the 2.8?

 

The car already had all the stock electronics in it. All I did was put the hard parts for the EFI (intake, runners, plenum, tb, etc.) from another '91 3.1L MPFI Camaro in. The only difference between the two cars is that the other one was blue. All of the wiring is stock and has been untouched (other than disconnected). I don't believe it to be VATS because VATS just keeps the injectors from firing it doesn't kill the starter. I looked for an aftermarket alarm and there isn't one. As far as I can tell everything gets power, but as long as the computer is hooked up it just won't crank. I thought the battery was dead at first and charged it and noticed it wasn't drawing any amps from the charger. Plus when I disconnected the computer it spins over just fine with no slow down. I must have missed something when I was hooking everything up, but I've gone over it 4 times in 2 days to be sure and can't find it. The car was already speed density the computer is a 730 so its a speed density computer. All the wiring and electronics are stock. There is nothing aftermarket or non-factory replacement on the whole car except for a K&N Air Filter.

All in favor of a carb. say "I"....

Brian

 

OH, okay, I get it... by your name, I thought you were talking about an '87. What threw me off is that you couldn't find an oil pressure switch connector; early 2.8's had two oil pressure switches, later model 2.8's and the 3.1's just had one "combination" switch (did dual-duty of fuel pump and gauge/idiot light).

I can look at my '86 2.8 GM Service Manual tonight, but you'd be best off finding someone with a 3.1 Service Manual (or buying your own from http://www.helminc.com ); wiring might've changed.

 

What are you looking for out of the service manual? I have a 1990 Camaro Service manual, the 3.1L is in it. Lemmie know what you need and I'll try and do what I can.

 

He'd probably need from the electrical section; all the wires for the starter motor from the key down to the starter solenoid. There's gotta be somewhere that the computer's involved in that circuit. For the life of me I can't remember how the starter solenoid connects to the ignition key! I know it somehow connects thru the clutch pedal (manual) or park/neutral switch (automatic), but that's all I can picture.

I could tell you how to remove/reinstall a starter, though. But that's not much help!!

 

LOL thanks Tom but I figured out how to remove/install the starter. I don't think its the neutral safety switch because its in park first of all and why would it crank with the computer disconencted. My 87 SC wouldn't crank even with the computer disconnected if it wasn't in neutral or park. I was told by a friend that it could be because the oil sensor isn't hooked up and it won't crank because the computer doens't see oil pressure. Well how can the engine make oil pressure if it doesn't crank? Maybe the computer just needs to see the sensor? I dunno....

 

check the cable from the shifter to the column. check that the metal rod is in the right place under the column. move the sifter and see if anything is moving under there. see if you can manualy move the switch under the column to park. i made this mistake when i replaced my column, but i never tried to start it without the computer.

 

Well here is what I turned up, there is another page following that gives a step by step thing, if you need that also, let me know.

Did I ever mention that I hate 1-way cable modem service??? This upload near KILLED ME! lol

 

Ok well, I broke down and bought a subscription to the Alldata DIY site. I think it is VATS, I thought the VATS only cut off fuel but it cuts off both fuel injectors and starter operation. I know I have the right key and I hooked up the wire for the VATS.... AAARRGGGHH!!!