hey guys i got a 89 t/a swapped the 305 for a 350 tpi fired and run good the first time, tried to start it again turns over fine but have now lost injector pluse, have good spark and fuel pressure any ideas?its got a .510 lift cam, headders and a hypertech chip everything else is stock

 

No injector pulse is a very typical of a problem with the vats system. Its also not the first time ive dealt with a car starting only once with a new ECM or a swapped set up and never again as result of a VATS system fault. Havnt figured out why only once yet but never cared enough to look into it because i dont have VATS. Ide give your VATS system a good checking over.

 

possible ignition module.

 

thanks guys i been changin sensors and the ignition module today (got the hook up at advance auto parts LOL!) whats triggering the vats and what can i do to fix the problem or can i bypass it all together?

 

Well as you already know the VATS modual looks for a particular key resistance to say ok the cars ok to start. Now because it cranks i imagin you have no security light because the vats system will dissable the starter. Now for the injector pulse enable the VATS modual sinks a 30 or 50 HZ square wave signal from the ECM. This is how the ECM knows to enable the injector pulse. In your case i think one of 2 things is happening. 1 a bad connection from the VATS modual to the ECM or 2 remeber how i said a 30 or 50 HZ signal your current VATS modual may be trying to sink a 30 HZ signal while your ECM is looking for a 50 hz signal or vice versa and because its not seeing the signal it expects it will not enable the injector pulse. For more info refer to the link below. Very detailed on the inner workings of the VATS system. Also its kinda hard to bypass it can be done but i think it would be easier to fix in your case as i dont think a simple resistor will do it for you.

https://www.thirdgen.org/vats_passkey_system

 

well guys im stumped again finally got hold of a good snap-on scanner and my problem is i have lost the +12v to the computer it will pull the codes but it tells me i have no diagnostics communication with the ecm so im gonna take a day off from it tomorrow and start hunting the little gremlin the next day any input would be greatly appreciated!