The truck cranks but refuses to start. i have narrowed it down to the ASD relay circuit and cant figure out whats tripping it. i have replaced the pcm, ignition coil, cam pos sensor, crank pos sensor, fuel pump, swapped the relays, fixed the splice under the PDC, and the distributor cap /w/ rotor... im not sure what else could be tripping the ASD relay any advice would be appreciated

 

PCM will engage ASD relay for a few seconds at initial key on, then, it will only engage it afterwards if it sees the engine turning. (via crank sensor.) Does the fuel pump prime when you first turn the key on?

 

it does not prime. but i do hear a click like a relay is engaging. i can manually prime it with a jumper

 

How about the ignition switch itself?

Check the voltage at the ASD; see if there's voltage on terminal A with the ignition switch on. B should have 12V all the time. If you jump B to D on both the fuel pump and the ASD relays, do you get fire then? And if a friend cranks it, do you get a ground on pin C of either relay?

There's also instructions on testing the crank position sensor in case the new one is defective in the factory service manual; the 1995 FSM can be downloaded from a link in the FAQ (about 40% of the way down in the message).

Grab the parts list also for your reference.

RwP

 

terminal A did have voltage when i turned the key on, terminal b did have +12 volts all the time but terminal c was open once i turned the key from from off to on, and when i tried to start it, it would still be an open circuit. i did jump both the fuelpump relay and asd relay then cranked it but still no fire

 

Is the PCM getting power??

 

I believe so... How would I check for power just in case
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When you say "terminal c was open", how did you test it? Test light from it to 12V? Or to ground? Since it's open, but driven to ground to turn it on, if you weren't comparing to 12V, it won't turn a test light on.

RwP

 

12V on the DLC connector under the hood.

Does the CHK ENG light come on when you turn the key to ON? (Not coming on doesn't mean the ECU isn't powered or running; at this age, the bulb may be burned out! But still, it's a quick test.)

RwP

 

The check engine light does not come on, I also do not get any codes when I do the key turn method