Cold start problems

[ChrisB]

1992 6.5L, injection pump was changed(twice), all rebuilt injectors put in, the head gasket was recently changed, a new cold advance switch was put in the vehicle, fuel system was pressure tested all fuel lines were checked for kinks, a new lift pump was installed and a new sending unit. All new glow plugs were installed and subsequently individually tested, a new glow plug controller was also attempted. This vehicle was at the dealer for 2 months and it still has a cold start problem, even plugged in all night it will have trouble starting in the morning, do you have any ideas on what this problem could be? The glow plugs only seem to stay on for 10 sec or less no matter what the temp. Sorry so long but alot has been done to this truck and still not fixed. Help.

[CleviteKid]

Have you run through every step on the online TroubleShooting Guide? Seems like you have hit most of them.

There is a fusible link (or two) in the glow plug circuit, so you may want to use a voltmeter to be sure voltage is actually getting to the glow plugs.

Badly worn rings and cylinders will lower the compression and make cold starts challenging. Had the compression been checked?

Has the dealer drained the fuel tank and put some fresh diesel in it? And how about the fuel filter and the lift pump - new filter, functional lift pump? You reported that the lift pump is new, but is it getting power through the starting circuit that bypasses the oil-pressure switch? Try hot-wiring the lift pump directly to the battery.

Has the engine been able to run long enough - like 1/2 hour straight, to purge all the air from the high-pressure side of the system? With the engine running, you or the mechanic could back off each fuel line nut at the injectors about 3/4 turn, for a minute each, to help bleed any trapped air.

My suggestions are not exhaustive, and I hope other members will join in with their ideas, as well.

Dr. Lee :cool:

[ChrisB]

everything that you mentioned has been attempted.
Recently I pulled the coolant temp sensor wires and it fired right up, but on subsequent attempts this failed to work, I'm suspecting electrical problems but cannot find them. What I want to do now is hook up a cab mounted switch to actuate the glow plugs to allow them to cycle longer as this does allow for an easier start, nothing else seems to work, however I will check the fusible links you mentioned they may be intermittenly losing contact.