2004 Tahoe Engine Stall

[SteveMA]

Loss of power.  Engine stopped.  Started again on 3rd recrank.  Got home.  Amp draw on fuse on PCM reads 8.8 amps.  Is this an indication of a bad fuel pump?  2004 Tahoe 5.3 Z71.  Had3/4 tank fresh fuel.  If not fuel pump than possibly what?

[Supreme Pizza]

If your getting an 8.8 amp draw from the PCM, with the keys out of the ignition, then I would assume there is an electrical issue of some sort. Perhaps the PCM did not power something down properly. If it caused the truck to stall, then perhaps the PCM itself is failing. I would check for any OBD2 trouble codes. You could try disconnecting the battery, and then the PCM, and then re-connecting the PCM, then reconnect the battery. They will reset everything as much as possible without special tools, and it will also check the connections on those items.

[Jsdirt]

Probably the all too common failing ground on the left side of the block behind the p/s pump. Causes no spark, and a dead battery from parasitic draw. Sucks to diagnose when intermittent - you have to see it losing spark during a test. 9 times out of 10 spark will come back leading you down the wrong path. 

 

If it dies for an extended period, stick a T-pin (or any small pin) in the ground wire in the gray plug on the center of the valve cover, then get a jump wire and connect the T-pin to any good ground within the jump wire's reach. If it now starts and runs, that's your problem.

 

See if you have any codes for mode master input mismatch, or comm codes, or both together. Sometimes this happens ... sometimes not.

Edited December 18, 2021 by Jsdirt

[SteveMA]

Engine was running during the amp test.  There has been no check engine light or trouble codes.

[Jsdirt]

Engine running I'd say that's probably normal.  

 

If I remember right, the fuel pump doesn't get power through the PCM. Should be a completely separate circuit for that. 8-10 Amps is normal for a CPI setup, but a little on the high side for multiport.

Edited December 19, 2021 by Jsdirt