Been having some problems with a 95 tahoe with the TBI. I know its not a 3rd gen but it is TBI and I know there are some very smart people on this board. The problem the truck is having is it will run fine sometimes then randomly die. Sometimes it will start back up and some times it wont. We replaced the distributor with a new module and pickup coil. Still has the same problem. The TPS shows .6 volts at idle and has no flat spots in it. The truck always has spark even when it wont start, It will fire with starting fluid but wont stay runnning. You can hear the fuel pump prime everytime but the injectors arent pulsating. Also we took the ECM out of my truck and put it into his and the same problems are present. Any ideas??

Thanks

 

oops I was thinking of something else. Do a search this has been covered before.

 

I had the same issue with my 91 RS 305 TBI. Tried everything, dist module, oil pressure sensor, fuel filter, relays, etc.. Turned out to be the Fuel Pump in the tank. Then once it we got the new fuel pump in it turned out the Fuel pump relay fried also due to the original fuel pump shorting out. Replacing the pump and relay and never had the issue again. Check the relay first since its cheap and quick to replace. Mine was one of the two on drivers side firewall in my car. May be different for you.

 

In order to pinpoint the problem you need to know if the injectors are triggering or not. This can be done with a test light or a noid light. They are not going to look like they are pulsing unless you have fuel pressure so make sure that you have fuel in the tank and that you indeed have pressure. I think when you figure that out you should have an idea of where to look next.

 

Does the fuel pump run the whole time your cranking when it has the issue, or does it only run for 2 secs and shut off?

 

I am assuming that you switched ECMs with someone and your truck still won't start at times?

Are the injectors getting +12VDC when the problem occurs? The ECM needs 3 basic things to pulse the injectors. Power, Tach (EST) Signal, and Ground. Nothing more, it could care less if the MAP, TPS, IAC, CTS, etc are connected, it will still pulse the fuel injectors(not acurately though).

 

Another thing you may try is checking for codes. That may point you in the right direction. I know mine was throwing the fuel pump circuit code when I my fuel pump issue.