Hey everyone. My name is Thomas and I'm new to the forum. I joined because I have a third gen Firebird that has been sitting for two years because I can't figure out whats wrong with it. Here's the deal:

I have a 91 Firebird Formula with a 5.7 TPI engine. The engine will turn over but will not fire up. I have got fuel pressure ( have a gauge on the fuel rail), I have spark at the plugs, and the ignition cylinder and the keys were replaced about two years before this issue began. The only code that is being tripped is the EGR valve code (43 I think), and I have changed the EGR valve multiple times with no success. I have been told by a couple guys that I probably have a VATS issue. I have been working on small block chevys for years but theses electronics are really kicking my butt. Has anyone ran across this problem before? I would really appreciate any insight on this issue. Thanks!

 

If its a spin - no start, I would say its not a VATS issue. If everything is intact and in good shape you should only need 3 things. Air, Fuel and fire. You have to be missing one???? Have you tried starting fluid to see if it will fire over? May just have a blown fuse for injector pulse???

 

Well there are times when I can go outside and try to crank it and it will just spin and spin until the battery is dead. Other times it will spin for 15 to 30 seconds and fire up and run rough for a few minutes and eventually shut off. But like I said, every time I mess with it I have fire at the plugs and pressure on the fuel rail.

 

sitting two years?? Bad fuel??? clogging injectors?? Fuel tank smell of varnish??

 

I have had issues with bad fuel before. But when this issue began the car had only been sitting up for about a month. I have to assume fuel has a longer shelf life than a month? On a side note, all 8 injectors have been replaced and the fuel rail has been refurbished in the not too distant past.

 

How much pressure ?

Depending on it's past life it is possible for a PO to have bypassed the starter part of VATS ( so it cranks over ) but the injector cutoff function is still working
Need to confirm the code you have up to see if it is VATS related

Need to get a noid light on the injectors to see if they are being pulsed to spray

 

The fuel pressure peaks out at about 35 psi. But what do you mean by PO? And could anyone recommend a noid light that works well with the TPI setup so that I could check the injector pulses?

 

PO stands for "previous owner"

any noid light set will work, unless you're looking to become a mechanic, I'd just see if you could rent it from AutoZone or someplace.

As a side note, "spins over" and "cranks" are describing the same thing. I suspect you mean it cranks but won't start.

As others have said, VATS disables cranking so since it cranks over, it is probably not VATS. I say probably, because there is always a chance someone bypassed the VATS relay. Try spraying some carb cleaner into the throttle body while you have a friend crank the engine. This will confirm that the problem is fuel delivery.

 

PO, duh! I should have guessed that. I actually am a mechanic that owns a shop. But I specialize in suspension and braking systems. We're basically an alignment shop. So dropping 20$ on a noid light isn't a big deal if it points me in the right direction. But I will give it a shot this weekend and see what happens. I really appreciate all the advice because I really miss driving this car. I'm also planning on breaking in the new small block in my 1970 Nova too, so hopefully I can get it all done. More soon...

 

Awesome! Be sure to fill out your profile also. Always good to know we have people "in the biz" on the forums. Posting your location, along with your car specs, could help us and help you too. Welcome to TGO!


Edit to add the link for how to update your profile:

https://www.thirdgen.org/forums/tech...formation.html

 

Pressure is on the low side ; should be 43 psi



The enable relay as shown below can cause problems with age so some bypass it instead of replacing it and still have anti theft because of the VATS injector cut off

 

Well the rains really slowed me down over the weekend. However I got clear skies long enough to charge the battery and attempt to start the car. To my surprise, after cranking it for about 10-15 seconds it fired up. The car was skipping horribly as it seems that more than one of the cylinders had a dead miss. I didn't have my test light handy to check which cylinders weren't firing. The fuel pressure held steady at around 45 psi the entire time it was running. However, after letting it run for about 20 minutes the car started to detonate (spark knock) really badly. And it got worse the longer it ran. After about 30 minutes I finally shut it off. Immediately after shutting it off I tried to start the car again but the engine just spun and spun but wouldn't fire up. The "Service Engine Soon" light never came on while the car was running. But I am more confused than ever as to what is going on with the car because many times the car won't even start. It definitely seems that I have an intermittent problem going on here. BTW, had to order the noid light set, should be here one day this week. Got it for about $14 from Summit.

I don't know if any of this information will assist anyone in helping me diagnose my problems. But since everyone was so quick with responses I wanted to let you guys know what I got accomplished over the weekend. If I get a free night this week I am going to crank it up again and check the cylinders with a test light to see which ones aren't firing and then go from there on trying to correct it. More soon...

 

All vacuum lines good? especially to EGR and MAP? Cap and rotor in good shape? Just some thoughts...