99 Tahoe 383/4L80E 0411 troubles

[chevyracer8262]

I have a 99 Tahoe with a custom built vortec style 383 stroker in it which I have converted to run on the 0411 Gen 3 PCM and I had that thing running ok driving it around tuning it when I noticed the coolant temp was reading 57deg f after over 30 minutes of driving then the engine died. Since then I replaced the ECT with a new one from autozone only to habe this thing act like the VATS system is engaged when I know I shut ot off in hptuners, any suggestions on what to check? It has new Accel header plugs, MSD 8.5 custom wires, new cap/rotor, new dephi crank, cam pos sensors, new delphi ignition module and coil and a remanned PCM (because the ignition driver died in the other one)

[Alvin]

It could be anything. A log of it trying to start and scanning codes would be a good start.

[chevyracer8262]

The only DTCs it has is the MAF fail which I habe disabled for SD tuning, I'll try to crank it over and upload that log file tonight

[chevyracer8262]

Cranking datalog

[edcmat-l1]

Post the tune file.

Need to check the fuel pressure with a mechanical gauge also.

[Alvin]

Cranking datalog

Something is up with the map sensor/wiring etc.

Its reading 25kpa which is super low. It should be around 101 kPa for sea level. 5000 ft elevation will be about 85 kPa for reference.

This is the issue.

[chevyracer8262]

Something is up with the map sensor/wiring etc.

Its reading 25kpa which is super low. It should be around 101 kPa for sea level. 5000 ft elevation will be about 85 kPa for reference.

This is the issue.

I'll check that but i reflashed it with an earlier calibration file that ran pretty decent and now it starts and runs again

[chevyracer8262]

Post the tune file.

Need to check the fuel pressure with a mechanical gauge also.

I already did I have an autometer gauge permenty mounted in the aftermarket fuel rail

[gtstorey]

I already did I have an autometer gauge permenty mounted in the aftermarket fuel rail

The experienced diagnostic technicians on here would tell you those can't be trusted.

[Alvin]

I'll check that but i reflashed it with an earlier calibration file that ran pretty decent and now it starts and runs again

a reflash will not fix how that Map sensor is reading.

[SiriusC1024]

The experienced diagnostic technicians on here would tell you those can't be trusted.

Why? That's like saying use a meat thermometer because the ECT can't be trusted.

[gtstorey]

Why? That's like saying use a meat thermometer because the ECT can't be trusted.

You've seen the discussions. Just passing on that he might want to confirm with a separate gauge. Maybe he has a remote electronic sensor but I read that as a under hood gauge.

[gtstorey]

You've seen the discussions. Just passing on that he might want to confirm with a separate gauge. Maybe he has a remote electronic sensor but I read that as a under hood gauge.

And if edcmat-l1 told me the coolant temp was off, I would at least hit the thermostat housing with a infrared thermometer.

[edcmat-l1]

Something is up with the map sensor/wiring etc.

Its reading 25kpa which is super low. It should be around 101 kPa for sea level. 5000 ft elevation will be about 85 kPa for reference.

This is the issue.

Totally missed that but yeah, looks like he's on the moon LOL

[SiriusC1024]

You've seen the discussions. Just passing on that he might want to confirm with a separate gauge. Maybe he has a remote electronic sensor but I read that as a under hood gauge.

Oh gotcha. Yeah, underhood gauges are worthless. I took autometer to mean that it's a pressure transducer in the rail and an electronic gauge in the cabin.

[chevyracer8262]

I checked out the map sensor reading and noticed what was said about it should be reading around 100kpa when I compared it to my daily drive avalanche which has the same map so I replaced the map with a new one and instead of installing it in my custom machined remote mount I hooked it up using a 1/4" id hose straight off a vacuumed port off the intake plenum and now it reads 100kpa when not running so I just drive it around and datalogged for about 45 min and looks like everything's working as it should now. Thanks for the input, if anyone's curious or would like to see one of the latest dataloggs I can post one here in a bit