No start no spark

DOUG JORGENSEN

MEMBER
1999 CHEVROLET TRUCK
7.4L
V8
4WD
AUTOMATIC
320,000 MILES

My truck is the k3500 model. It will not start. I replaced fuel pump. I am getting 55 psi at crank. I also replaced crank sensor, cam sensor, distributor, cap and rotor, coil, ICM, and PCM and had that reprogram. Also replaced wires and spark plugs. Still no spark. The crank sensor is getting power and ground but the output wire is constant twelve volts. This wire should be intermittent with 0 to 5 volts? Is this wire hooked up to the ECM fuse. When I pull this fuse I have no power. Could this wire be going to the fuse box and be connected to another wire by being fused together or shorting out somehow or does this wire go directly to the PCM and if so what connector does it go to white, black, blue or red to the PCM? Side note, I have had three different professional mechanics come out and charge me and still no luck on getting it to start.

1 Reply

HMAC300

MECHANIC
48,601 POSTS

First try another key as it may be security problem not a new key. As it would have to be programmed to your truck you should have 55 psi key on only and hold for at least five minutes after turning key off. Check all fuses under hood then if still not starting.