gld77

I put my 97 lt1 in my 94z it will start but shuts of quickly this not the original pcm it from a 95z.My question is can I get thepcm reprogramed or what. Or is this my problem.

Injuneer

VATS is not in the PCM. Its in a separate module (or in the BCM for 96/97). That module send a signal to the PCM to tell it to run the fuel pump.

Look over Shoebox's writeup on PASS-KEY/VATS problems:

http://shbox.com/1/pass_key.html

I would seem that once the VATS system allows the engine to start, it wouldn't shut if down. That could be dangerous.

bobdec

Correct Vats prevents starting, but will not stop the engine after it starts. You have a '97 engine, in a '94Z with a '95 PCM. What year is the harness, and what type of ignition/coil setup are you using on the '97 engine to feed the PCM. The '95 PCM needs Opti pulses to keep the fuel pump picked. Do you have a fuel pressure tester to see if you are loosing fuel pressure. Also on the '95 OBD1 PCM an Opti or ICM DTC will kill the injectors, do you have any way to scan it ?

shoebox

VATS may stop the engine just a few seconds after startup if the fuel enable signal is not seen. It won't stop the engine while going down the road.

gld77

My car turns over starts but wont stay running.Can this be a VAT problem also .My car is a 1994z with a 98z engine.

RamAir95TA

You have an LS1 motor in a 94Z? If that's the case, try the LS1 Based Engine Tech forum.

gld77

I did change the coil because of different connectors.Ialso had to change the ends of the coil wire because the 97s was smaller.Ijust changed the tip to fit the larger prong on the 94 coil.As far the fuel pressure Ihave not checked it yet.Im trying to figure this vats. crap out first.Seems to me if the key is not recognized the car would turn over.

gld77

Im using the 94 z wiring harness nothing was changed there.

gld77

Im sorry I meant a 97z it an LT1 engine

SCNGENNFTHGEN

I'm struggling with a nagging starts, but won't run long enough to idle issue myself. Fresh motor, new rings, bearings, the heads were cleaned up, and had a valve job. It has the cc503 cam. I had fuel issues but I have that sorted out now. It's killing me because it sounds healthier than it ever did, but just will not stay running? I've done the vats ignition on both my Z's before. The security light came on with both of them I replaced the switches with the phone wires through the column and both ran after the repair. I haven't found my code scanner yet so I haven't done that. I was wondering if something with my bcm is telling the pcm or something not to stay running? Is this possible with my 94? It seems mice ate some wires on what appears to be the bcm under my passenger footwell. All I could see was some heater wires and my power windows don't work now, so I figured it was just that and would get to it once I got it running. Is there anything in the bcm that could tell it not to stay running? If so, what colors would the wires be? Any help on this will be greatly appreciated. I'm riding in the rain, and it's getting colder. I need this car back on street duty. Or even any ideas on what else it could be from here on it. We're stumped other than it has to be something only giving power enough to start, but not stay on long enough to run? It's got fresh brand new 93 octane sunoco after we pumped the tank of all the nearly one year old gas.

shoebox

Better do some other searching and get the scanner. A 1994 does not have a BCM.

SCNGENNFTHGEN

I saw where it said the 94 doesn't have a bcm, but what else could that little black box be? I haven't found it in my manual yet. It's right behind the passenger footwell plactics, and says TRW on it. I'm at work now, on my lunch I'm doing some reading on it. I have the next 2 days off, so I'll be working on it. It's just frustrating, that the thing sounds incredibly healthy, but won't stay running. I had some injectors not firing, so I made the injector cleaning apparatis that was on the board. Worked awesome, also checked with the noid light. All is good with that now. I'm hoping to find a wiring diagram of what's coming off of this box, so I can trace them around the car, but I can't find anything as of yet. Let me just say your tech page on LT1's is absolutely awesomehelp . Has helped me many times. When I get in a better financial position, I will certainly donate some $ to help out. at this time though I'm struggling. Thanks again for any help, and all the help in the past.

Injuneer

Sounds like the remote keyless entry receiver.

From Shoebox:

http://shbox.com/1/keyless_entry.jpg

shoebox

Indeed.

SCNGENNFTHGEN

That's it. Yall are awesome, thanks guys! I've got a couple of wires to fix in that, but I still don't think that's it. I have some help from some great friends from LS1tech. J&J Motorsports, seems to think it's my vats, so I went ahead and had them order me a vats eliminator. Everytime I've done the vats ignition cylinder, my security light came on, and I don't remember wether or not it would still crank. Here is what I have, and it worked for a long time. I lost my keys a while back, so I went and got a plain old lock cylinder and put that in the column. I had the cylinder from my patriot red Z, since I just put it in prior to the accident. So I plugged it in with the chip key and shoved it under the dash. It was working beautiful, but the car sat for almost a year. It was a mouse condo..lol! Not anymore, she's all cleaned out and ready to rip again. Thanks again for responding folks.