Hey Guys, I've visited the site multiple times already but finally decided to join, tons of info on here!!!

So I've got a 92 RS with a 305 TBI. It broke down on me about a week ago and the only way to keep it running was to unplug the EST Bypass (tan and black wire), like when you time the engine. I finally thought it was the distributor that was the issue and replaced it, which it ran better after I did but when I plug the EST back in, it still starts to run for like half a sec and then dies spitting fuel back up through the throttle body.

Ive tried replacing the MAP, IAC is newer, cap, rotor, dist., spark plugs, computer, etc...
Tried unplugging the battery and let the computer reset then see what codes it will pull with the EST plugged in but it wont run long enough to pull any codes. Any ideas?

I'm going to readjust the IAC tomorrow but other than that the only thing I can think of is a vacuum leak or maybe a ground not connected properly?

 

There are people on here that will have better advice than me in this subject, but when that EST wire is plugged in the computer is controlling the timing. The computer reads what all the sensors are telling it and controls the timing from there. With it unplugged its not using the computer, its just at the base timing. It sounds to me like your knock sensor is retarding timing to the point of stalling out the engine,and this could also explain the fuel spit-out at the TB. If your knock sensor has failed or is operating correctly is unknown so far, it could be working fine but sensing detonation so its retarding timing. It could also (as already stated) be shot and thats causing the issue.

As ive said tho, there are others who will be able to help you too.

The knock sensor is on the passengers side of the block, by the cts(i believe) it looks like a round sensor. It can be tested with a multi-meter, you will have to look into how this is done though.

Good luck!