lt1z2897

I have a 97 z28. My car suddenly lost signal to my fuel pump an coil/injectors my bcm chimes wen i touch it. Even I changed everything im suppose too. #opti #icm #coil #ignition switch #optiharness #pcm #vats. Im lost. Can U TELL ME IF THE BCM WILL STOP MY FUEL PUMP SIGNAL????? PLEASE

shoebox

The BCM supplies the fuel enable signal to the PCM. If the BCM is bad or there is a VATS isssue (part of the BCM), then the PCM will not allow the injectors to operate. If VATS is programmed out of the PCM, then the BCM is not at fault regarding fuel delivery.

Injuneer

Have you scanned it for codes?

GaryDoug

The BCM (or VATS) module (depending on the year) will not stop the fuel pump from running, but it can stop the injectors from operating via the PCM.

Here is what happens if there is no "VATS" 50Hz signal input to the PCM: The fuel pump will run normally at ignition key ON time for about 2 seconds. When the engine starts cranking, each fuel injector will pulse at the correct rate 6 times or for about a second and then stop. The engine may fire briefly, but will not run.

But if the engine is already running when the "VATS" signal is lost, there is no effect.

lt1z2897

I bypassed my VATS. Still nothing.. my security is fine. Its the problem with my fuel pump signal.. i primed it an it works. My BCM chimes wen i touch it. With no key in the ignition.. when i first bought the car a few days later. I turned it off from the key. An it STAYED RUNNING???? CHANGED THE IGNITION SWITCH ALSO

lt1z2897

No i havent scanned it.. an i also tried a NEW PCM. AN STILL NOTHING.. every morning i open the door an touch the bcm. An it chimes. 2 -3times . I hold it still so the wires wont move. So ino my wires are good... im confused.. my car ran perfect

GaryDoug

Have you replaced the fuel pump relay? Inspected the relay socket?

shoebox

What did you do to bypass the VATS? If you only did the key resistor bypass, then it is not fully bypassed. The BCM is still in play to provide the fuel enable signal to the PCM. The PCM has to be reprogrammed to bypass the need of this signal from the VATS (or use a bypass module). If the BCM reacts when you touch it, then I would say you have a BCM or connection problem. BCM issues are common. GaryDoug even has a write-up dealing with repair.

lt1z2897

I bypassed my security . The orange Vats. With resistors. The bypassed worked cause i got a new key with no chip.. also i swapped my pcm. Still nothing. An yes the bcm chimes randomly.. i checked the relay also.. im not even getting spark too my coil

lt1z2897

My security light goes off after 3-4 seconds. But b4 the bypass it was blinking.. #why DO MY CAR KEEP RUNNING? AFTER I TURN IGNITION OFF??

shoebox

Your VATS is not totally bypassed (explained in post #8), only the key is.

It is possible your ignition switch was not adjusted properly at install. There is a special sequence to do it.

lt1z2897

So u saying its not my bcm??? An how sure are u. That my vats not bypassed right? An yes the ignitiom switch is correct. Double checked it.. so u still dont no why my car will stay running after the key is out??????

Injuneer

People are trying to help you by offering suggestions and asking questions. You may want to be less critical and accusatory. No need to get annoyed with them.

shoebox

I can't be sure of anything with what is written in this thread. I am somewhat confident that you bypassed the key pellet, but I am not sure you understand what the BCM does and how VATS and fuel enable actually works.

I am trying to throw out suggestions. If the car will not shut off, then things are getting power when they are not supposed to. Either you have some serious wiring issues or as I suggested, the ignition switch is not adjusted correctly (which you don't seem to see as a possibility). You can't demand that I tell you why your car keeps running, because I don't know. I am not there to troubleshoot it.

lt1z2897

so what more do I have to do to bypass my vats