I have a 91 Camaro 5.7 TPI. I set the timing to 6* BTDC with the EST wire disconnected. Now the problem is whenever I connect the EST wire the engine starts up, but has a bad idle, shakes, also I can hear it backfire through the exhaust when I step on the gas, then eventually the engine dies within seconds of being started. Now with the EST wire disconnected the car runs great like a champ. I checked every single fuse, sensor, all vacuum lines, put in reman distributor, new spark plugs, pretty much everything I can think of. Found a couple of threads with the same problem but no one has been able to figure it out. Any help will be greatly appreciated.

 

what does the timing do once you plug in the est? what condition is the plug that goes to your ignition module under the cap.?

 

When i plug the est wire timing advances to about 12* or 14* BTDC and the idle goes up and down then the engine dies. The plug looks pretty good, theres no burn marks or any kind of wear.

 

So as soon as the computer takes control of spark advance you have problems.
Any codes showing?

 

Yes as soon as the computer takes control of the advance thats when i have problems. Nope, no codes show up. Only when i disconnect the EST, the code for that shows. Everything else is ok.

 

The timing is too low when EST wire is disconnected. Turn the distributor clockwise some to get the engine to speed up then try to disconnect the EST wire. If it keeps stalling give it a little gas while disconneting the EST wire. If none of this works that you may have a bad ignition module in side the distributor. Make sure it's an AC delco part.

 

Are you sure that the timing advances? When did the issue start to occur?

RBob.

 

I went throught the exact symptoms and it turned out to be and exhaust leak at the manifold to y-pipe connection on the drivers side. Just check it out even though you cant really relate the two.

 

My brothers decided to swap out the reman distributor we bought a week ago from summit racing. They ended up putting back the original distributor that came with the car when we bought it. As soon as they dropped it in and plugged the EST wire the car fired up and is now roaring haha. Thanks to everybody who helped us along the way, all the info you guys provided helped out. The only problem now is that the idle kinda goes up and down not really to noticable, and it seems like it only does it when the engine is still cold. Once its warmed up the idle stays steady. Any thoughts what might be causing the rpms to go up and down? Already checked for vacuum leaks.

 

Turn the fuel pressure up while it's idling.

 

How do i turn the fuel pressure up while its idling? Can you list some steps on how to adjust it?

 

Do you have an adjustable fuel pressure regulator?

 

No its still the stock regulator that came with the car. Is there a way i can still adjust it or will i have to purchase an adjustable fuel pressure regulator?

 

You need it. It's helps out alot when you make mods.