No start a new engine 7.4 Vortec

[Saab84mw]

I have been fighting with this thing for about a week now trying to get it started.

It will start up and then shut off almost immediately fuel pressure is at 55 psi it will run for a couple of seconds long enough to pull almost 15 vacuum.

I have checked all the fuses replaced the TPS sensor it’s working. I have an OBD II code reader that says I have a TPS signal MAF sensor is working others are working I will attach a video that shows what it’s doing.

I’m about ready to start it with a stick of dynamite.

Any help would be much appreciated.

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[Bear 77]

Noticed your security light is staying on. May need to do a key relearn. Hope that helps


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[Saab84mw]

Noticed your security light is staying on. May need to do a key relearn. Hope that helps


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Tried that already and it has never had chipped key it uses a regular style key and the doesn’t flash it just stays on.

 

[df2x4]

Tried that already and it has never had chipped key it uses a regular style key and the doesn’t flash it just stays on.

These trucks never used a chipped key, even the '98+ ones with PassLock.

This looks like a textbook PassLock failure.

 

[df2x4]

If I were you I would find someone with HPTuners (or contact Black Bear Performance) and disable the PassLock system entirely. I've never heard of it actually preventing a truck from being stolen, but I regularly read horror stories of how it creates headaches for the owners of the trucks. There are other (more hack) ways to bypass the system, but disabling it entirely in the PCM tune is the best way to go.

 

[Bear 77]

May be one other thing to check but it’s going to sound weird. I had the same thing happen to mine as well. I didn’t find out about it until after I sold it though. From what I was told, there’s a wire that burnt up behind the instruments cluster that wouldn’t allow it to start. I’d check there. This was from the same person I sold it to. Hope this helps with the problem! Agin, I know how weird it sounds, but he drove it back to my house and told me!


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[Saab84mw]

If I were you I would find someone with HPTuners (or contact Black Bear Performance) and disable the PassLock system entirely. I've never heard of it actually preventing a truck from being stolen, but I regularly read horror stories of how it creates headaches for the owners of the trucks. There are other (more hack) ways to bypass the system, but disabling it entirely in the PCM tune is the best way to go.

Could this been activated because I towed the truck and trailer it back to my house from an engine failure?

 

[1998crewcab]

Battery looks very low
See if you can start with a fully charged battery
Disconnect maf and try and restart
Will go into limp mode

 

[Saab84mw]

Battery looks very low
See if you can start with a fully charged battery
Disconnect maf and try and restart
Will go into limp mode

I started with a fully charged battery that was near the end when I couldn’t get it to start.

I’m going to try this afternoon to get it past the PassLock feature I had to buy a battery charger because it keeps running the battery down while trying to reset the PassLock

 

[df2x4]

Could this been activated because I towed the truck and trailer it back to my house from an engine failure?

I wouldn't think so unless you had to mess with the ignition somehow in the process.