5.7 hemi crank but no start.

[MonkeyMadness]

08 hemi 5.7 with 6.1 topend. Hotwire harness and Bouchillon performance ecu and sensors.
I got crank, spark, and can hear the fuel pump prime, and throttle movement. But no start. Every once in a while I'll get a pop fire out the header.

Alittle frustrated, not sure what to check.

 

[DionR]

Might look into the start signal. Going off memory here, but seems like some PCM’s need to control the starter relay and the start signal needs to go to the PCM rather than the relay. Not sure if there is a change to the tune to turn it off or not.

The other issue can be power to the PCM being interrupted when the key returns to the run position. PCM has to see power at all times. Might try jumping power to the PCM and see if it starts then.

Just some ideas.

 

[DARTGAME]

Injectors opening? Will the engine fire if you put some starting fluid through the throttle body

 

[MonkeyMadness]

Might look into the start signal. Going off memory here, but seems like some PCM’s need to control the starter relay and the start signal needs to go to the PCM rather than the relay. Not sure if there is a change to the tune to turn it off or not.

The other issue can be power to the PCM being interrupted when the key returns to the run position. PCM has to see power at all times. Might try jumping power to the PCM and see if it starts then.

Just some ideas.

I will check this tomorrow

Injectors opening? Will the engine fire if you put some starting fluid through the throttle body

This was my next step to try. I didn't have any starting fluid today but my plan was to grab some on the way home from work..

 

[MonkeyMadness]

Starting fluid didn't do much, got a few more popping but no real light or fire. So I'll pull the power leads to the harness/ ecu and run a jumper to them to see if I get anything...

 

[racerjoe]

Might look into the start signal. Going off memory here, but seems like some PCM’s need to control the starter relay and the start signal needs to go to the PCM rather than the relay. Not sure if there is a change to the tune to turn it off or not.

The other issue can be power to the PCM being interrupted when the key returns to the run position. PCM has to see power at all times. Might try jumping power to the PCM and see if it starts then.

Just some ideas.

Dion is correct. If you didn't make modifications to your factory start/run circuit, it won't start. Common problem when people install EFI on old Mopars.