canu49

I own a 93 T100 that I bought new. It's got 256K miles on it now. For the last 3 or 4 years it's had a problem that no one's been able to pin down yet. About once a year, the truck will not start. It's usually after the engine has warmed up and the truck turned off. I wait about 30 minutes and it cranks and runs fine. It's done this about 4 times, usually a year apart. Also, when I start the truck it will crank, then lope for a couple of seconds then catch up and run fine. Also, if I run up to about 45 and let off the gas, it will bump. I only drive the truck about 10 miles round trip, 5 days a week and rarely on weekends. I don't get a check engine light when the problems occur. I've changed fuel filters, cleaned throttle body and replaced plugs, distributor cap and rotor. This really has me stumped.

maachine

could be your starter relay or your starter with the no start issue. and the "bump" you are talking about, could be slack in the drive line. like bad u joints or slack in the rear differential gears

DanBates2002

Hey I've got this same problem, but more frequently. Say, I drive to work, 8 hrs later it will start fine and bring me home. However if I drive to a restaurant and stay for about an one and a half it will not start for another few hours. I'd love if we could get to the bottom of this!

Stats: 94 t100 sr-5 auto trans 4x4, 226000 miles

j2the-e

Happens once a year is pretty much impossible to diagnose. My suspicion would be the temp sensor for the ecu. Engine has 2 temp sensors, one for the gauge and one for the ecu. So make sure you get the right one if you do it. Another possibility is a leaky injector, but that would be more likely to be more frequent.

canu49

I'm changing the temp sensor this weekend. I'll let you know.

maachine

i misread your first post, sounds like the starter turns but the engine wont start right?

brianh699

There is a third temp sensor, but it's actually a switch for the cold start injector, if it's out of spec the cold start injector can fire on a warm engine flooding it.

canu49

not an intermittent problem anymore. Won't start at all now. Had a temp sensor so I changed it and no help. Did some troubleshooting and looks like the fuel pump is dead. I jumpered B+ to FP in the test connector with the key on and it didn't make a sound.

maachine

check all your fuses first before you start buying parts

canu49

I checked voltage at B+ before I jumpered it. According to the schematic, I was putting 12 volts directly to the pump and bypassing all relays also. Checked fuses earlier.

DanBates2002

Dang, it sounds like this issue is really get out of hand! I'm on the verge of having a local shop drop a new engine in. Like most, I depend on my truck!