07 6.0 starts and immediately dies

webb06 · Jun 26, 2025

Will start and run 1-2 seconds, if that, and immediately dies like key is shut off. Will restart and immediately die. Found a post on another forum about a pcm/tcm issue causing similar symptoms so I unplugged trans harness and started engine with starter jumper wire and engine will stay running. Ran it over 30 minutes idling today. Plug trans harness back into pcm and stalls within seconds. Swapped pcm with another. No change. Unplugged trans main connector on trans case and reconnected at pcm. Will idle all day. Swapped ficm as well because voltage did occasionally drop below 40v. No change. Anybody ever dealt with this? I can’t imagine anything inside the trans causing any issue like this…help

6.0 Tech · Jun 27, 2025

Try unplugging the fan and see if it stays running. It does seem like it’s something in the trans though, do you have something to monitor pids with? Almost wonder if your lock up solenoid is weak or something and being over powered, and the converter is locking at ifle

webb06 · Jun 27, 2025

Ya we tried unplugging fan. No change. Have IDS

DEEZUZ · Jun 27, 2025

Hold throttle on start.

Remember that 6.4 I had... Maybe, maybe it's a tps issue.

6.0 Tech · Jun 27, 2025

Also, is the maf plugged in? There is one strategy that requires it to run. Had a similar one, thought it was an aftermarket alarm issue. We had test fit a compound kit in it, and I half ass threw it back together to just drive it out of the shop, and it wouldn’t run more than 5-10 seconds. Eventually we sold it, so I had to figure it out, as it ran when we brought it in the shop, pulled the alarm, no change, then boss told me to quit wasting time? Threw it all the way together, and ran no problem. I had still had the air box out while testing stuff, and lo and behold had to have the maf plugged in

webb06 · Jun 30, 2025

This one will run without maf plugged in. What’s strange is the warmer it seems to get the less it wants to act up. We let it idle with trans unplugged for awhile and then tried again with trans connected and it would actually stay running. Throttle it up hard and after coming back down to idle it will die though.

YODA · Jun 30, 2025

I hate to say this, but carefully watch your dash oil pressure gauge the instant it starts. If the oil pressure drops the truck will shut down. The gauge is watching the normal truck oil pressure. If it is going to zero either that pump had failed or more likely the high pressure pump that drives the injectors has failed. Either way its an expensive fix. One other thing is during the repair the will be messing with the wiring harness the runs over the top of the engine. Be very careful not to damage that harness as it is no longer available.

DEEZUZ · Jun 30, 2025

6.0 Tech · Jun 30, 2025

What’s fuel pressure?

webb06 · Jul 5, 2025

Honestly haven’t checked. It seems like it’s gotta be something electrical. Because if the trans harness is unplugged it will fire and run. We have also swapped ipr valve.

bismic · Jul 5, 2025

Have you scanned for codes?
Sounds like an issue with the Transmission Range Sensor. One failure mode of that sensor is that it can drag down the PCM power (voltage) - similar to what a fan clutch short can do.