95 350TBI, intermittently fails to start, frustrating

[Laid GP]

My 95 with 350 TBI has recently started having trouble starting on occasion. At first I thought it was a bad battery which I replaced, and it acted OK for a while. Then it died on me on a short errand and left me stranded, and would not start again. Had it towed home and replaced the fuel filter, as a stopgap before replacing the fuel pump. After replacing the filter it did start 3-4 times consecutively and seemed to run OK. I did not drive it out of the driveway for fear of getting stuck again, but I held it at a constant RPM with the truck in neutral and it seemed to be OK. Then, today I decided to try it again and it failed to crank. At this point I am assuming it is the fuel pump but I am not sure. Before I yank the bed off, can anyone tell me what else I can try out to see what it might be?

 

[SkyHighColorado]

if it failed to crank I would say its starter or the wires going from the +terminal to the starter. I had this problem once and it turned out to be the starter solenoid was worn out and when it heated up it wouldn't make contact, when it cooled down it would most of the time.

 

[Laid GP]

The starter goes and goes it just never fires up.

 

[SkyHighColorado]

next I would remove the intake and watch the injectors and see if your getting fuel. Then I would unplug a plug wire and ground it when someone cranks the engine and see if you have spark. When you turn the key to ignition 2 listen for the fuel pump humming in the tank and see if it continues to buzz or if it build pressure and stops like it is supposed to. If you have someone crank your truck you will see fuel spraying from the 2 injectors.

 

[SkyHighColorado]

if you pump is dead. get a rubber dead blow and give the tank a solid hit right under the front of the tank and try starting. If it starts up it will probably run fine until you turn it off again and then you will have to give the tank another hit to get started again. Just so you know, you do not need to go get the entire assembly for the pump. just get a new acdelco/Delphi pump for $40 and see if you get a strainer sock filter thing in the box or not. if no filter in the box just get any brand filter sock. Its very easy to replace.

 

[98_k1500]

Sounds more ignition related with it being intermittent, may wanna pull your dizzy cap and pull your ignition module out and have it tested (repeatedly back to back to get it hot like its in the truck working). Coil could also be heating up and not firing.

 

[Laid GP]

I started the truck today and it did crank and run like it should. I pulled the air cleaner off to look while I was doing it and there is definitely fuel going in there (not surprising since it ran!). When it cranks, it runs fine, so I am thinking maybe it might be the distributor or the ignition module going bad. Not sure where I would take the ignition module to have it tested though. I did get some new spark plugs today to put in just to see if that makes any difference.

 

[Laid GP]

I changed the plugs today and the old ones were in really rough shape. 5 of them were very oily so I am guessing that means I've got some bad piston rings or something similar? For what it's worth the truck did fire right up and run pretty well right after that.

I have a 5.3 LM7 to swap in at some point, but hoping I can baby this one and get another several months out of it.

 

[whatif3387]

I'm willing to bet its the ignition control module.

 

[Laid GP]

Back to the same problem again. I guess I will swap out the ignition module and go from there. Any other suggestions would be greatly appreciated!