GTS346

iTrader: (1)

Can somebody explain to me how the VATS works, as its supposedly been deleted, well I asked to when tuned.

I have starter motor cranking, 12Volts at the coils but 0Volts at the fuel pump.

Any ideas? Does it sound like part PCM problem?

All fuses and relays are fine.

70 LS1

iTrader: (1)

Could be a VATS problem. I know Vats will disable the injectors and I believe it disables the fuel pump relay.

GTS346

iTrader: (1)

do you know what else it disables?

Speartech

iTrader: (14)

It ONLY disables injector pulses.

In the original vehicle it also went to a relay to interupt the starter, but that part doesn't carry over in a swap.

If the fuel pump relay doesn't work it's usually improper wiring or a bad relay.

GTS346

iTrader: (1)

Relay seems fine, hopefully it isnt bad wiring, had a shop here set it up. Ouch.
So what your saying is even if VATS isnt disabled the fuel pump will still work or have its 12Volts but the injectors wont pulse?

G-Body

iTrader: (4)

The fuel pump should run for 2 seconds everytime you turn the key to run, even if the VATS has not been disabled. Is the fuel pump relay a standard bosch style realy? with 4 or five terminals. If it is you can jump it out and see if the problem is wiring related, or computer, relay related. Most relays have a diagram right on the side, if it is a standard type relay it will look like the pic. Terminal 85 and 86 are to energize the relay, one of them will be a ground, the other will be +12V whenever the computer wants the fuel pump to run. (there should be voltage here for 2 seconds after you turn the key to run) There should be a constant +12V at either terminal 30 or 87, If you put in a jumper between 30 and 87 in the relay socket the fuel pump should run.

GTS346

iTrader: (1)

The fuel pump runs constantly if I bridge the terminals, but engine only runs for 2-3 seconds?

Is this my VATS symptoms?

70 LS1

iTrader: (1)

Could be. When I first built me VATS module I made it for the old 30Hz Passkey II system and it would only run for about 2 seconds and die.

Slo_240sx

iTrader: (17)

If you jumped the terminals and have constant fuel, VATS is cutting out your injector ground through the PCM if the engine WILL run only for 2-3 seconds. Give the computer back to the guy that supposidly disabled it and have him show you while hes doing it.

GTS346

iTrader: (1)

Thanks all, I just wanted to tripple check it was the PCM setup with VATS not disabled that was causing the grief, will bring it back when shop opens.

Merry Xmas all.

dynosmith

iTrader: (1)

70LS1, I saw your vats module on your web site but as a novice I would need further details to make my own. Is this something that you would be willing to provide me? Can you recommend any alternatives besides flashing the computer - I really like your idea for added security.

thanks for any help...

crewchef

iTrader: (6)

I just went through the same problem because I had a bad vats module. Injectors would pulse twice and then shut off. Just get it programmed out or if that becomes an issue try this website www.lt1350.com. It's an inexpensive solution that's easy to install and seems to work well.