So I have been having an issue with a '97 RS. When it was cold it would start fine, but if you shut it off when it was warm it would crank but not start. I have good fuel pressure at the rail, but I don't think the injectors are firing.

Spaying some starting fluid into it and it fires right up and runs until it burns that up, but dies.

Now it won't even cold start.

So I'm thinking it's the VATs, the "Security" light is on on the dash, has been what little time I've own the car.

So I'm thinking the BMC is not sending the 50Hz signal to the PMC( Pin #50 ?? ). to enable the signal to the fuel injectors.

Odd thing is it will crank, but if the VATs is not working, should it not also have a no crank condition?

I tested the resistor on the key and it reads 9.47k ohms, so I guess that is a #14 VATs key. I found the two wires that come out of the bottom of the steering column, that I think are the VATs wires from the ignition. Tho it's two white wires coming out of an orange wrapping, and it has a black connector connecting to two brown looking wires( two pins in the connector ).

I tried to read the ohms of the two wires coming out of the column with the key in the ignition and there is no resistance what so ever. So I'm assuming the ignition key cylinder pickups for the VAT is bad or I'm testing the wrong wires?

I know I can connect a 9.xx k ohm resistor and bypass the key, but maybe someone already installed one that I don't see or programed it out of the PCM. Or I could just buy a VATs bypass for that.

But the issue with the crank but no start won't be fixed by that, as I guess the Body Control Module is not sending the 50Hz signal to the PCM to enable the injectors. So I know I can buy a bypass for that.

Here is the issue, I can't figure out what wire I need to connect the 50Hz output of the bypass module to?

I only know it's pin 50 of the PCM, or so I read, but I can't find that in any wiring diagram.

Is there a wire under the dash I need to connect to, or do I need to run a wire all the way to the BCM or PCM?

What color is it and where do I find it?

Anyone have a wiring diagram that shows that wire and what color it is?

All the videos I see are not for a '97 with a BCM.

4th Gen LT1 F-Body Tech-PassKey/VATS

 

if you haven't yet download the factory service manual here, http://www.mediafire.com/?40mfgeoe4ctti 96svcman should be same as yours. either that buy a hard copy for your year on ebabe. I have found them to be very helpful after figuring out the way the books are set up.

 

I'm still having an issue with this, just not getting fuel but it is intermittent.

Every time I think I have it sorted, the next time I go to start the car it is back.

If I spay some fuel to it is starts and runs until the fuel runs out.

I replaced the lock cylinder, the old one had the two wire leads under the steering wheel cut because they got in a bind on some sharp electrical leads.

I got a Passkey II system because I like the antitheft to actually work correct the way it did from the factory.

I got the correct key blanks( 14.5k ohms ), now it seems work correct when it wants to.

For some reason with the old lock cylinder with the cut wires, the starter would engage, and sometime when the car was cold it would start. This should not be, the security light was on the whole time.

With the new lock cylinder installed, the keys that came with the cylinder won't engage the stater, I just hear the click from the starter rely as I should.

So I just can't figure this, if the rely was bypassed, and I can't see that it was, it would still crank with the non-passkey keys.

Anyway, I'm fairly sure for some unknown reason the BCM is not sending the 50Hz signal to the PCM when it will crank and not start. I just can't figure why?

I can't seem to figure what wire it is( I think it is a blue wire but there are a few of them ). Can someone help me find the correct wire so I can test it and trace it from the BCM to the PCM, please?

I'll upload some good pictures of both ends if someone can help.

I don't have a multimeter that can read Hz, but I can get one, it's just all the instructions I can find for using them are for AC systems and not DC systems, so before I go out and buy an expensive new multimeter can anyone tell me how to check this wire for the 50Hz signal?

I did pull the BCM and check the circuity, there is nothing I could see that is an issue. The PCM did have some corrosion on the pins and I cleaned all that up and added some circuitry lube.

For a while, shaking the tow connectors at the PCM would fix the issue, before I cleaned and tightened them, but that doesn't work anymore. Next I was leaking a little fuel from the fuel rail schrader valve, and pushing that in and sealing it back would fix the no start issue.

Now neither one of these things works.

So it could be an issue with the fuel pressure regulator?

Would a faulty regulator shut off fuel flow?

No liquid gas in the vacuum line, but I do taste gas if I suck on the vacuum line.

So it's one or the other or both. Either I'm not getting the 50Hz signal to the PCM to enable the injectors or the fuel pressure regulator is faulty????

 

So I spoke too soon, I have no spark!

Looks like a new issue:

I have no pulses the 3X CKP Signal from Crankshaft Position Sensor is not being received. Without this Signal the ICM will not spark the Coils. The Crankshaft Position Sensor is bad. Replace it.

https://www.gmforum.com/trouble-shoo...m-test-299761/