Sporadic no start issue on drag truck

BOSS450 · Oct 19, 2015

S475
Midwest dual fuel
150% nozzles
Gh tuning
4r100

Truck has a sporadic no start issue dealing with hpf

9psi to both pumps
One second it will start. The next it will spike when you first crank to 150psi fuel pressure then drop to 40 or 50psi and stay steady
Wait 10 minutes and it will crank up. I've wiggled every wire and checked ever connection multiple times. No bent pins in any connector and all are all the way on.

Not throwing and codes pertaining to this problem.

For instance pulled up to staging lanes and cut truck off. Went to crank no start. 5 mins later started right up no problem. Ran a 6.72 fuel only. Parked truck back in staging lanes. Would not start back and had to pull it back to trailer with a strap. And hour later it cranked right up and pulled it up in trailer. Now it will not build pressure. Any guesses? Or things to check.

6.4 Stroker · Oct 19, 2015

Try a rail pressure sensor yet?

Rubenk · Oct 19, 2015

Is it cranking and not starting? Or not cranking?

BOSS450 · Oct 19, 2015

No it was brand new 3 months ago when motor went together. When motor fires it reads fine. So doubting its that sensor

BOSS450 · Oct 19, 2015

It will crank fine any time. Just a sporadic no start

6.4 Stroker · Oct 19, 2015

Gotta love intermittent electrical problems.
Perhaps try unplugging one of the K16s, and see if it will start with one or the other.
After that I'd break out the multimeter, and start checking voltages.
Without Codes, it's gonna be alot tougher to track down.
Good Luck.

BOSS450 · Oct 19, 2015

6.4 Stroker said:
Gotta love intermittent electrical problems.
Perhaps try unplugging one of the K16s, and see if it will start with one or the other.
After that I'd break out the multimeter, and start checking voltages.
Without Codes, it's gonna be alot tougher to track down.
Good Luck.

That's another part of the problem. Truck is at twisted getting the transmission rebuilt

SEABEE08FX4 · Oct 20, 2015

A buddy of mines was doing the same thing, I'd watch the rail pressure as it was cranking an it would go from 17-23 psi sometimes 50-55 psi then climb real fast to 1200-1500 psi and fire up. It would only run for a few seconds then die, ended yo the pump was leaking from one of the control valves. His oil was all sludgy and looked like guacamole.