K Guys I know we've had this discussion many times so I hope this is the last time lol. Anyways I recentley pulled my 305 TPI out of my 88 GTA. The frame was gone before I pulled motor tried to gert car running in that chassis and had Vats kick in and No start no fuel pump and No power to trigger wire.Now with this car over 10 yrs ago I bought a bypass switch for the Vats its a toggle switch with 3 positions on it and for the life of me I can't remember the procedure once I hooked it up BUT fast forward to this week I pulled motor put into another 88 chassis and tonight go to turn key and Again Vats seems to have kicked in again all kinds of power but dead to starter and no fuel pump sound.So I installed bypass box into harness and tried and nothing but when trying to start the Security light is Not on when switch is on the resistance toggle once I click switch to other setting security light comes on again on both settings I get nothing this box is over 10 yrs old so who knows if its still working Please guys help with this prob its driving me CRAZY am I better to just get a new key?? I'd hate to spend the Cash on chipped key and I doesn't work I've seen all the bypassing and tried most of the ways and I'm just not getting anywhere with this Vats Thanks in advance!!!

Tom

 

For starters ,
VATS doesn't affect the fuel pump so if the pump not running you have other elec problems
Are you using the same VATS module ( in car) .
Bypass resistor is coded ( one of 15 different values ) to the VATS modulein the car ; not the ECM ; one size does not fix all

Or do you have the bypass unit that supplies the fuel enable signal to the ECM ( which requires the starter relay to be bypassed manually )

 

Bypass module.... its easier to put a resistor in the plug going yo the key lick that matches the resistance value your current module is looking for unless .. your current module doesn't work

 

Unless you don't know the correct resistance. I too am having VATS issues on my 92. Bought a module off ebay for some change. Installed all woppin 3 wires correctly even threw 50hz at it just for &^%4 of it. Nothing. Are these modules supposed to flash the LED i hit up the vendor but no reply yet. Not sure if its faulty. Starter relay bypass is complete. No fuel pump prime. NOID light test failed. Could this be a faulty ECM/ECU if so how should I efficiently go about troubleshooting. Have only got to check the fusible link underhood and checked good. ECM warm to the touch with ignition on for some time.

 

You have other problems as well
Pump prime is not a VATS function

 

[QUOTE=Could this be a faulty ECM/ECU if so how should I efficiently go about troubleshooting. [/QUOTE]
Yeah I kinda figured it went beyond VATS. I have power to the fuel pump relay and verified operation via jumper wire, relay seems to be good to the shake, no excessive rattling. I know the ECM operates this relay.

 

Also no diagnostic flashing check engine soon light when jumpering diagnostic and ground on the connector under dash. Checked for power at the bulb and good. All wiring to the connector is in tack. Freakin ECM's man. Guess I can't expect more from a 10 yr old beast uh?

 

there are 15 different variances to test for vats with your module... do you have the original key to the ignition...? if so take a digital volt meter and put a lead on either side of the chip. That should show you the resistance you should place into your vats system. If you dont have the key get a variable resister and test each of the 15 variables one at a time leaving 15 mins between test to reset the security light...

 

Will give this a shot. Was not really impressed with the module. I know there's 15 different resistances GM threw out there. What is the most typical? If any?

 

Oh and no original key. Bought it with resistors already in place. 839 ohms was in place and operated just fine until valve seal leakage occured into cylinders consuming oil. Had to pull the heads and get the valve job done and resurfaced. Put her all back together and what do you know let her sit for a while and this.

 

my first column was running 2.5 and the original key runs around 1.1. Most of the ones i come in contact with are in that range... Like i said the variable resistor is the way to go when it comes to it because you wont have to buy 15 resisters just one thats tuneable. However once you find the correct value i would put a permanent resister in place it sucks if you accidentally bump the variable one and it changes.... trust me... I keep a voltmeter in that car...

 

if your resistor in place is working replace it with the same value and then test your fuel pump relay and starter relay... prob something amiss there...

 

Alright I'll give it shot man. And thanks for the reply will get back to this thread.

 

no prb us texas boys gotta stick together lol

 

OK here's the skinny. Fuel pump prime prob. solved. Couple good taps with a wrench to the relay, or maybe that just made me feel better.
No one in town sells variable resistors, so I opted for the same resistance that was already in the car. Security light comes on when key is turned to accessory then turns off. Crank the engine via starter relay bypass security light returns when ignition released. VATS Bypass module is inoperational AT BOTH 30 & 50 HZ with intermitant wait times to allow ECM cycling. Got it hooked up to the blue wire coming from VATS PIN B6. Its all hooked up according to spec. Does the ECM provide signal to fuel pump relay havn't got a chance to trace wiring diagrams?

 

oh and still no start.

 

Key on. :ECM runs pump relay for 2 sec to prime fuel rails
ECM does not operate relay again until it sees the ref pulses from the dist showing that engine is being cranked over
I suspect your bypass module is faulty

 

Yeah you were right. I opted for removal of bypass module. Threw some different resistances into the connector under the dash and wala injector pulse. Pulled the NOID light from injector connector, reinstalled connector. Fired her up and sputter, sputter, backfire. Didn't install distributor correctly after valve job. Gonna reattempt install. Question.
Do the connectors on the distributor face directly forward so that 1 & 8 are centered facing forward or is it sideways towards driverside? Can't remember, will look for some pics.