[klockdoc]

Laredo, 4.0 auto, Problem with not starting. NO fuel at the rail. Had fuel pump replaced. Car starts now intermittently. When it doesn't start, there isn't any fuel at the rail. on't think pump was the problem though.

Bypassed the fuel relay and pump runs. Changed fuel filter. Thought that was problem Ran a couple of times, then stopped.

Changed the Crank Positioning sensor. Car started immediately, then quit again after several runs.

Every time it stops, there isn't fuel at the rail.

Thought it might be the ECM, tried another from the junk yard, (from a friend) and it still didn't start. Not sure of exact replacement because it has been replaced before. I think some will work and some will not. Is this correct?

Will check for spark again tomorrow as it is not running or even trying to start now.

Any ideas? I am going nuts.

[StellaTheZJ]

Here's a possibility:

If the factory alarm is not disabled properly, it turns off the fuel. There are threads about the wire (purple/yellow) that rusts or falls off the lock cylinder in the door. Also, after a million openings and closings, the wires can break near the door hinges, so your truck thinks the alarm has not been turned off. Search a bunch for this, and try locking and unlocking the door next time it stalls. In fact, use your key in the passenger door too.

Some aftermarket alarms will access this wire too. Do you have more than the OEM alarm?

Good luck!

[klockdoc]

Originally Posted by StellaTheZJ

Here's a possibility:

If the factory alarm is not disabled properly, it turns off the fuel. There are threads about the wire (purple/yellow) that rusts or falls off the lock cylinder in the door. Also, after a million openings and closings, the wires can break near the door hinges, so your truck thinks the alarm has not been turned off. Search a bunch for this, and try locking and unlocking the door next time it stalls. In fact, use your key in the passenger door too.

Some aftermarket alarms will access this wire too. Do you have more than the OEM alarm?

Good luck!

Yes, have an alarm system that was installed by Best Buy. It operates the alarm for the car. However, the door lock/unlock operates under the factory alarm. Guess it is connected with a relay.

Doors still lock and unlock and alarm goes off/on with remote.

Does the purple/yellow wire operate any of the door locks?

[ZeeJay1997]

Have you used a meter to check the ground to the fuel pump? It goes all the way under the front drivers seat before it attaches to ground. Then there are these grounding terminals that just spike through the paint in the floorboard. Not a good setup. If you check it and read anything over 1 ohm from the ground pin at the harness connector to a good chassis ground, that could be your problem.

[klockdoc]

Car wouldn't start for 2 days. Checked tonight. Had spark at the distributor. Tried to start.

Started right up. Drove it home. Ran great on the way home.

Tried to start again after sitting for a while. Car started right up, then choked out.

Checked fuel at the rail. Lots of pressure. Checked spark. Good spark.

It would start, but wouldn't run over several hundred RPM. Ran like it was choking out .....flooded. Pushing the gas pedal to the floor did not increase the RPM's at all. Just kept putting. When put into drive, the motor would die.

Could the TPS or the Idle control cause this problem?

I am going crazy with this problem.