Won't start

I have a 1996 3/4 ton 2 wheel drive 6.5 turbo. I have 205,000 miles and replaced my FSD about 6,000 miles ago. The truck won't start. I replaced my lift pump, fuel filter and have swapped in / out various FSD's and the truck still won't start. My glow plugs are working. It seems like the truck initially gets fuel when I activate the starter because it fires up for about a second then dies. My batteries and connections seem to be OK as well.

Any suggestions out there? Bad electrical connections? Or dead ECM?

Do you hear the lift pump working? If not, OPS might be your culprit.

Verify fuel is being pumped by LP. Then check if fuel is coming out of IP: loosen a fuel line at injector and see if it weeps fuel after cranking it for a while. If no fuel feel for the fuel shut off solenoid operation.

Any codes? You said batteries are clean and connections look good make sure they are; side posts can be decieving especially passanger pos post take it apart and clean. Check the grounds and other end of battery cables. Also all fuses.

Other thing you could do is plug in block heater to make sure its warm enough to start too. Batteries should turn over pretty quick too. Recharge them if possible.

I used engine degreaser and rinsed the engine with water. There was some diesel in the engine compartment from injector inpection. Now my truck started right up and runs like a champ. It did this a few weeks ago as well then died on me again. The majority of the wiring and many connections are routed directly behind the fuel filter. Is it possible that diesel / grime is interfering with some electrical connections?

On your first post,Eng would not start. Had you just washed the Eng?

Unfortunetly, electrical connections are always an area to investigate but hard to pinpoint unless you can make problem come and go. FYI: I think GM later said when replacing IP they also replaced a section of wiring harness that goes to FSD. Communication between the FSD and ECM must be good and ECM must like what the FSD is doing or ECM cuts off fuel at shut off solenoid. Your test FSD's may not have ever communicated with ECM????

Explain the washing part again and occurances of the no starts.

How did it crank up. Were you testing fuel out of IP (loose fuel line at injector) and it started up with no apparent real fix? Then seems A OK? If no codes that does sound like a bad communication or other electrical gremlin not sensed by OBD.

I read about this earlier on this site, if your truck is an automatic, you can put the truck in drive, then turn the key to the start/crank position, if your lift pump runs when you do this OPS is working, the ops turns on lift pump when cranking and running(with oil pressure...) if you don't here lift pump, check power to it...you can also do this after changing fuel filter, crack the drain valve and use the lift pump to purge the air/fill the fuel filter cannister...

Thanks everyone for your help. I ordered a new FSD and cooling kit from SS Diesel. I installed it today and so far everything seems to be OK. My current FSD only had about 7K on it so it was hard for me to believe that could be the problem. Meanwhile I'll be saving my pennies for a truck without a 6.5. This truck would be great if I didn't have to rely on it to actually run.