On my 95' Trans Am, I recently did a lot of interior wiring work, went to test fire the car, which hasn't ran since June-July of last year, nothing has changed mechanically under the hood except for the removal of the AC and all heater core lines and accessories.
I've had the car on a battery tender for the past few days, and the starts are relatively quick and full of power. I added fresh gasoline, and I've tried to prime the fuel lines before I start by turning on the key for a few seconds, and switching it on and off.
What have you done vats wise? It could just need to relearn idle, can you coax it to run a little more if you apply throttle or is it a start/quick idle/die no matter what?
What have you done vats wise? It could just need to relearn idle, can you coax it to run a little more if you apply throttle or is it a start/quick idle/die no matter what?
VAT's is questionable, I did nothing to the actual VATS system, I removed the stereo, all the power wires to it, heat & air bags. I even pulled the fuses for those accessories. VAT's in my computer should be tuned out, but there is a manual kill switch which I had to ground before it started running.
Even if I apply gas/throttle it still only runs for that duration and sputters out the same way. I was thinking of disconnecting the battery again, and try it without the mass air flow? All guesses at this point.
Maf shouldn't start applying corrections until closed loop. You are going to have to figure out what the car is losing causing the stall. Probably the simplest thing would be to spray carb cleaner into the throttle body. If it continues to run, you are losing fuel. If not, you may still be losing fuel but also losing spark. If you have a fuel pressure gauge, check your readings key on for the prime and while it briefly runs. Should be around 41-47 psi primed and 3-10 psi less while idling.
If you can rent/borrow/buy/make, a noid light will be helpful to know if the injectors are firing. You disconnect one injector, insert the light into the connector, and fire it off. It should blink while running. If it stops blinking AND THEN the car stalls, there is an issue with them receiving a signal.
Finally, you can remove a plug wire and use your preferred method for checking spark during the stall.
Things that could be going on are opti signal, vats, fuel pressure, injector signal, icm, and on and on. First thing first, find out what the car is losing to cause your stall!
Is the fuel pump running while the car is running? That sounds a lot like the pump is priming, then shutting down and not pumping again when running.
Maybe try jumpering the relay to force the pump 'on' and testing again? If it continues to run with the relay jumped, then you need to figure out why the fuel pump isn't staying on.
"If a trouble code is present (ex. DTC 46 or P1626), the computer is not receiving the fuel enable signal from the TDM[BCM]. This could be a wiring/connection issue or module failure (not a common problem as stated above). Your engine would crank, but not stay running as fuel to the injectors will be cut off. Aside from using a schematic to narrow down the problem, a bypass is also available (see below)."
I guess I need to get under the dash and check the wiring? This is a little out of my area of expertise. Maybe the car is confused, with a manual VATS bypass and a tuned computer?
I checked under the dash, my wires are still connected just like the photo, but I traced the wires to the passenger side, it looks like a 4 pin connector (if these are the same wires) but my big bag of wires just got thrown out last night without my knowledge. Will wiring in a resistor work? What kind of resistor? This is out of my league, I'm willing to pay with beer if someone could come and help me out. I've just about had enough with this project.
You can jump the fpr on the passenger strut tower.
Vats can definitely be the issue. It has to be both tuned out in the pcm as it sends a 50 hertz enable signal and the resistor needs to be bypassed. There are a couple ways to accomplish it, just want to see what is going on first before we start creating more potential issues.
When I had the car with the original engine and PCM I had the VATS tuned out of the computer. That took out the TDM.
One day I got stranded because of the starter engagement issue, which is related to the TDR- the relay. I replaced the relay thinking it might fix the issue, but it didn't work. The switch was there to ground out the TDR if I needed some extra security (from what I remember).
When I had the car with the original engine and PCM I had the VATS tuned out of the computer. That took out the TDM.
One day I got stranded because of the starter engagement issue, which is related to the TDR- the relay. I replaced the relay thinking it might fix the issue, but it didn't work. The switch was there to ground out the TDR if I needed some extra security (from what I remember).
The theft deterrent module sends the ground signal to the td relay once it sees the correct key resistance. This may be your issue.
I thought mine was to the left of the glove box but it has been a while. This shows it to the right. There should be a small gauge yellow/black wire. This goes to the TDM. If you simply ground this wire, probably to the metal dash structure, the key portion of VATS is bypassed. The purple wire goes to the starter. The yellow wires should be a large and a small. One comes from the ignition switch, the other from the 3 amp crank fuse through the neutral/clutch safety switch and powers the relay. Basically ground that wire and forget the rest
So, as long as vats is tuned out and you bypass the relay, your car has no VATS. If the Security light is still working in cluster, it will be lit. You can simply remove the bulb or wait for it to burn out
I thought mine was to the left of the glove box but it has been a while. This shows it to the right. There should be a small gauge yellow/black wire. This goes to the TDM. If you simply ground this wire, probably to the metal dash structure, the key portion of VATS is bypassed. The purple wire goes to the starter. The yellow wires should be a large and a small. One comes from the ignition switch, the other from the 3 amp crank fuse through the neutral/clutch safety switch and powers the relay. Basically ground that wire and forget the rest
So, as long as vats is tuned out and you bypass the relay, your car has no VATS. If the Security light is still working in cluster, it will be lit. You can simply remove the bulb or wait for it to burn out
To be honest this is all a foreign language to me, I'm having a really hard time comprehending. Its clear I removed something I shouldn't have, but if I gather what your saying, and I've attached pics: this yellow/black line is currently grounded with an inline switch already. The second photo shows what I think is the other end of the connection from under the drivers side, It must have been connected to something that I removed by accident and threw away.
I tested my key with a multi-meter, and determined what resistance was in the chip, and went to my local electronic store and built the correct resistor for that numerical value, but i've seen two different write ups place the resister in two different spots. I've tried both and there has been no change.
This is the TDM? The switch is in a temporary grounded position, and its spliced exactly where everyone says, but theres something missing to this puzzle.
mystery connection:
If I'm correct I tracked the two wires from the VATS harness on the drivers side, a Purple with White Line & a Off White with Thin Black Line to this connector, I have no idea what it went to.
Prepare to kick yourself in the ass. That second pic is supposed to plug into the Theft Deterrent Module!
Awesome sketch I know. It should be to the left of the glove box and right of console. Black box that I think has the same color female connector on it. I am going to say that vats is NOT tuned out of the pcm, too.
The first pic is the theft deterrent relay. This controls the starter. I am not crazy about the whole wiring it has but if it works, it works. Flipping the switch should prevent the starter from engaging. If you like it, leave it. Just tuck it into the dash and find a good clean ground to attach it to.
So I think your two options are find your module and plug it in or have someone disable vats in the pcm. You could try getting a used module but then you need the proper resistance for that module to work. I may have one, I'm not sure if my key matches it though. I know I had vats tuned out of the pcm though. Follow me?
