So i happened across this 88 Jimmy for $200, and ive known the guy for a while so i decided to buy it. Its pretty rough on all fronts but the main problem is the engine which is rebuilt with about 8k miles on it. It is a 88 2.8 L V6 throttle body injectors of an 86. When i start it starts fine rune fine for about 2 minutes then it starts to sound like its gonna die then it goes for about another 30 seconds then it does dies. Long story short what could cause it to do this ive changed a few plugs and am going to do a general tune up this weekend. Any answers would be greatly appreciated.

 

It could be a problem with the timing. The PCM uses the ECT (engine coolant temperature) sensor to determine what the engine temperature is. Based on this information, it modifies the spark curve. If the ECT is stuck on cold, it could cause it to stick in the cold start cycle and not advance the spark to keep it running properly.

If the 2.5 minutes runtime is consistent regardless of engine temperature, then it may be a fuel supply problem. While you are doing your tune up, make sure to change the fuel filter. If you can, get a fuel pressure gauge (you will need a TBI adapter) and install it. Monitor the fuel pressure, especially when it gets close to stalling. If it drops below 8psi at any point, you have a fuel pump problem.

 

Thanks for the info. It still does run pretty rich i was wondering how would i adjust the flow to the engine.

 

You cannot adjust the flow of fuel to the engine. The ECU is supposed to do that. What you can do is make sure that there is no additional fuel getting to the engine from a leak in the throttle body anywhere.

How does the spray from the injectors look?

 

Well the i have gotten the fuel flow problem fixed, but now the engine is cutting out on me. I know this truck is kinda a p.o.s but i hope before to long i am gonna try and get a 4.3 for it.