The bird had been stalling and finally one morning it wouldnt start at all. It seemed to try but wouldn't run for more than hlaf a second.

Fuel pressure was nonexistant, so got a new fuel pump, sending unit, and filter. All that put inand it still wouldnt really fire, but the spark was weak so I got a good used ignition module, which made the spark noticeably stronger.

After all this the car will fire once then shut down. That is, the fuel shot in on the prime gets burned in each cylender but no more is injected. It gets spark all the time so the problem must be in the fuel getting there. Pressure is good at the valve on the rail. and the ignition system must be OK since it'll turn the engine that one time.

One thing I found that may be of help is that, key on, not trying to start the car, both wires going to the injectors are hot (a test light will light if touching either wire). Is this normal?

MAP sensor is good, coil is good, plugs are new, EGR is good, all vacume lines are hooked up. What else is there? ANY ideas are helpfull, I'm really stuck now.

 

My guess is a bad FPR, injectors, harness, or possibly a fuse, have you tried throttling it to keep it going? Could also be CSI if you have one, I never did figure out why but after I had my 2.8 running it kept stalling, but if I throttled it long enough it would run on its own after a bit. Hopefully that issue doesn't follow over to the 3.4...
If you have one, hit the schrader valve on your fuel rail, just be careful cause if it has the pressure it should that stuff will shoot out some force.

 

Check for both a shorted fuel injector and then a code 46, since you have VATS.

And no, the 90-92 cars didn't have the cold start injector...

 

Unhooked the vacume from the FPR, dnt know if that could possably have made a difference but it didn't..
Giving throttle doesn't make a difference, still shuts down as soon as it starts. Always good pressure at the valve since the new pump was put in.

 

Could this possably be an issue with the anti theft system? Because it's not like the car dies or stalls, something is stopping the injectors from injecting gas into the cylenders, best I can tell.

 

I believe vats systems disable the engine even turning over, so assuming that is the anti theft system you have, then no.

 

Its supposed to disable the fuel injectors also. I really have no ideas anymore on what could be causing this, and apparently neither does anyone else...

SOMETHING is not firing the injectors or not allowing gas into the engine after the prime. There's plenty of pressure on the rail after the car shuts down, ans spark isnt being interupted. It's not stalling or dying, its just not letting itself run..

 

VATS has 2 functions when it finds that the proper resistor key has been inserted or a resistor put in place of the key: 1. It switches a relay to enable the ignition switch to control the starter, and 2. It provides a 30Hz signal to a pin on the ECM which tells the MEMCAL to enable the fuel injectors. If the dark blue signal wire is somehow damaged, the ECM will disable the fuel injectors and:

Check for a code 46, as I said above.

 

So it's got at least 1 injector that's shorting out and it looks like that's the problem.. Will 2.8 injectors work on the 3.1. Like these ones:
http://cgi.ebay.com/ebaymotors/ws/eB...MakeTrack=true

 

Work, probably but they probably have less lb/hr rating, which probably won't be too big a deal if you have a stock motor, but I wouldn't mix and match them, and imo just get 3.1 ones...

 

The injectors depend on the year of the engine that they are meant for. For at least 2 years, the 2.8 had a choice of either the 2.8 or the 3.1 injectors. There isn't that much of a difference (not like throwing 305 injectors on one side and leaving the others) as there is only a .7 lb/hr difference in the ratings (14.7 vs 15.4).

Since the ones in that link are half the price of any other full reman set, I'd jump on them, real quick.

 

Found some of the newer Multec's being sold by the same place, so I bopught these.
http://cgi.ebay.com/ebaymotors/ws/eB...=STRK:MEWNX:IT
$90 for 6 reman injectors is pretty good.