Okay to cut to the chase my 91 305 TPI T5 Z28 will not start. The motor will crank with the key (meaning that it is not VATs or the neutral safety) but the engine will not fire. I have checked all of the following things and need help!

Cap and rotor - replaced
Distributor - replaced (also tested ignition module and pickup coil)
Coil was tested
Tested for spark
Fuel Filter - replaced
Fuel Pump - replaced
Fuel Injectors were flow tested as well as tested for resistance
Fuel Rail is getting fuel
ECM was tested
Tested power going to fuel injectors
Tested ground continiuity from ECM to Injectors

Spraying carb cleaner straight down into the TB will get the car to fire up and start however it will not run long even with it WOT. I think that it is a fuel problem, hence the reason I replaced so much of the fuel system. I have a feeling that the injectors are not pulsing, however since they are getting power and their resistance is good and I had them flow tested, right in front of me on Saturday I cannot figure out why the car will not start!

Please help!

TIA

 

bump

 

Get a noid lite from autozone.

For like 3.99 you can find out of your injectors are pulsing or not.

If u have spark at the plug, odds are distiributor related stuff is ok.

Could be a VATS failure still. The starter enable is just a regular relay for the vats and that could be bad either way.(I have seen them crank and have no injector pulse)

Find out if you have injector pulse, if u verified power and grd, something is causing it not to fire.

Go that route first and see what u get(noid lite) then let us know what u find

later
Jeremy

 

Thank you for the suggestions (please keep them coming) I am planning on getting a noid light tonight to test the pulse on the injectors. I just had to replace the VATs well the key clyinder earlier in the week, but when it went out the key would turn but do nothing. In this case the pump is primed and the key cranks. But you say it could still be the VATs module itself right?

Thanks again

 

I have a Helms manual for my 88 but of course tracing back the wires doesn't work so well for my 91 considering the ECM/wiring differences. Does anyone know of a good link to a wiring diagram for a 91/92 TPI Car? Thanks again

 

Bottom of the page:

http://www.diy-efi.org/gmecm/ecm_info/1227730/

RBob.

 

Thanks

 

this may be a long shot... but did you happen to check for any wires that might be frayed, melted, or grounding on the block or body??

i had a similar problem with mine Randy.. and it happened to be some stupid relay in the kick panel on the driverside.. there are 2 big thick green wires there.. and i removed the relay and just attached the 2 wires together and it started.. not sure if this info helps...

if it doesnt then i'll shut up..

 

I am definitely up for all suggestions I will look it over and make sure I didn't miss any melted or frayed wiring. I was concerned about an aftermarket alarm that might have had a kill switch for it, but I couldn't find any alarm devices at all. It looks like at some point one might have been installed but someone did an okay job removing it.

 

I just went through this....https://www.thirdgen.org/techbb2/sho...=303895....try your ignition module

 

The ignition module was fine, because I had it tested and tried a different distributor.

For those that are curious for the resolution. Well the noid light indicated that the injectors were indeed pulsing. A fuel pressure test indicated the pressure was around 80lbs. Obviously a bit high, so back down to the fuel rail I went. The return line was clogged, we I removed it from the fuel rail it appeared that a nice crystaline structure had blocked the return line coming from the regulator, kind of like as if someone had put sugar into my gas tank Anyways once that was cleaned and everything was bolted back on the car fired right up - thanks again everyone

 

Basically the high pressure created a hydralock on the injectors preventing them from firing - sweet huh