Engine/Transmission (1994 - 1998) sometimes it starts, sometimes it just cranks

[Beast2B]

OK, my son's truck is a 96 12v with 200k on the clock. when you go to start the truck (hot or cold engine, warm or cold ambient temps) it either cranks and cranks or it starts right up. no pattern, but it has never started after cranking for a while. if it cranks more than a couple times you know it ain't lighting off! is there a relay or solenoid or something that is involved in getting fuel flowing when cranking? we jumped the truck to my truck to make sure it had plenty of battery just in case, but it was no different... .

any ideas?

 

[ewcmr2]

Fuel shutdown solenoid or it's relay. When the truck doesn't start leave the key in the "on" position, then check if the solenoid is in the "up" position. If it's down, lift it up and the truck will start, if it's already up you have a problem elsewhere.



The Solenoid is in between the brake master cylinder and the AFC housing on the P7100 injection pump. The lever you need to pull up on is on the bottom of the solenoid.

 

[Beast2B]

thanks ew2cmr2, I'll be home in a couple hours to start checking it out!

 

[Missouri Mule]

It seems to be your fuel shut off solenoid relay which hangs on the cowl on drivers side (one closest to the fender). Usually if it is the solenoid it just quits but the relay will work sometimes and at other times it won't.



As ewcmr2 stated turn key to "start" look at solenoid rod to see if it goes up, if it doesn't it is probalby the relay.

The shut off solenoid has two coils one to hold up the rod up (powered by ignitoin switch in "run" postion) the other to pull the rod up(powered by the fuel shut off solenoid relay when key is turned to "start"). The solenoid relay is activated by the starter relay. You should have blue wire with fusible link at batteryside supplying power to solenoid relay.

 

[Beast2B]

OK, got a few minutes to play with it. The rod does not lift when the key is turned on. I can manually lift the rod and it stays up. Truck starts fine after that. I swapped relays with the other 96 truck, but that changed nothing. It was cold and dark, so I didn't go any further (no rush, thank goodness). So, does the same relay control both coils in the solenoid? If the solenoid will hold the rod, does that confirm the fusible link's integrity? It has been suggested that I pull the solenoid and clean it up since they can get sticky, and we did just fix several oil leaks... . Thanks again, just trying to learn me some 12v !

 

[Skydiver]

These solenoids have two coils. One to get it moving which does not stay on and the other keeps it up which uses much less current. If you have a VOM check the resistance. With 200k it's about time for a new one.

 

[GAmes]

With 200k it's about time for a new one.

Totally disagree. The solenoid is a very heavy duty component. Disassembly and cleaning will keep it working for a very long time. Mine is the original, but the boot deteriorated and was removed years ago.



The plunger will not lift just by turning the key on. As someone has already stated you need to go to the start position first to get it to lift. Once you have done that leaving the key on will keep it up.

 

[hsmith]

Let me say that the small blue wire at the driver's battery positive terminal is a ofter overlooked problem child. Remove it completely, clean, and make sure the wire is not broken just up from the crimp at the insulation. As Gary said, the solenoids are durable unless starter contacts have stuck and caused the solenoid coil to overheat.