captain chaos
Well-Known Member
So I bought a 2000 Expy to clean up and make a daily driver and it's giving me some serious headaches.
It's a 2000 EB 4wd w/ the 5.4, just for reference.
Occasionally, but not always, it will crank but not start. It seems to mostly do it when it's sat for a long period but it's hard to say for sure if that's a contributing factor.
I've been all over this thing and have narrowed it down a bit.
-The fuel pump works fine.
-Fuel pump relay is good, as is the fuse
-There are no stored or pending trouble codes
-"Theft" light blinks normally w/ key off (though faintly) and at key on it comes on solid for a few seconds and then goes off
Checking the fuel pump relay has revealed some oddities though.
When its acting up (no start) the PCM is not grounding the relay. There is power to the 2 legs that get power (30 for the high current and 85 for low current switch) however, the PCM does not ground the relay (86) and thus the truck is dead in the water.
If I remove the relay and add a jumper between 30 and 87 the pump comes on and it starts/runs just fine.
This thing is really getting on my nerves as I'm trying to get it road worthy but I need to be able to trust that it'll start every time.
I've kinda narrowed it down to some kind of issue with the PATS system or possibly an intermittent PCM failure.
Any ideas anyone???
It's a 2000 EB 4wd w/ the 5.4, just for reference.
Occasionally, but not always, it will crank but not start. It seems to mostly do it when it's sat for a long period but it's hard to say for sure if that's a contributing factor.
I've been all over this thing and have narrowed it down a bit.
-The fuel pump works fine.
-Fuel pump relay is good, as is the fuse
-There are no stored or pending trouble codes
-"Theft" light blinks normally w/ key off (though faintly) and at key on it comes on solid for a few seconds and then goes off
Checking the fuel pump relay has revealed some oddities though.
When its acting up (no start) the PCM is not grounding the relay. There is power to the 2 legs that get power (30 for the high current and 85 for low current switch) however, the PCM does not ground the relay (86) and thus the truck is dead in the water.
If I remove the relay and add a jumper between 30 and 87 the pump comes on and it starts/runs just fine.
This thing is really getting on my nerves as I'm trying to get it road worthy but I need to be able to trust that it'll start every time.
I've kinda narrowed it down to some kind of issue with the PATS system or possibly an intermittent PCM failure.
Any ideas anyone???