LT1 trouble shooting help

[MikeP99Z]

Pcm?

[Trublu]

Check the float bowl levels

[liquidroam]

Check the float bowl levels

????? Float bowls... we are not talking carbs here. Maybe I about to look really dumb but I did not think I had float bowls with EFI.

[Trublu]

????? Float bowls... we are not talking carbs here. Maybe I about to look really dumb but I did not think I had float bowls with EFI.

They are hard to find....

[liquidroam]

They are hard to find....

Touche

[Sook]

Were the dead cylinder's exhaust tubes getting hot? I've been fooled by the injector test before.

Disassemble the whole intake path, I had a MAF clogged with rubber at cresson. How are the O2 sensors? Maybe lost a sensor and is in limp mode?

Skipped timing chain??

[Sook]

The LT1 beat me last year. Once they start acting up it's hard to figure out the problem (within CMC rules). I was always finding broken things but they would never solve the problem.

[Pranav]

Lift the Fuel rail above the intake with the injectors and lines still attached, disconnect the coil connector (the control/thin wires, not the plug wire) to stop spark, and see if all of your injectors are spraying correctly while cranking the motor over with the ignition on. Keep all ignition sources away from the engine bay so put the vape and cigarettes away and make sure all of your spark plug wires are still connected with the coil disabled by disconnecting small low voltage connector.

If you see an injector that is not firing, it is either clogged or not getting a signal to fire; swap it to another position to verify the issue.

Autozone also has a Noid light set on loan a tool that you can plug into each injector connector to verify it is getting voltage to the injector (can't check with a voltmeter because it is a PWM signal).


I know clogged injectors were an issue for you in the past from your donor motor, but if you used the old/donor fuel rail with your good injectors from your original motor, the old fuel rail WILL shed varnish and clog up the good injectors.

All post-filter fuel injector/rail/hose parts need to be cleaned if they came off a non running car. This was an issue for me in the past as I even did my injectors and rail, but the supply hose kept shedding varnish and clogging my injectors.

[liquidroam]

Were the dead cylinder's exhaust tubes getting hot? I've been fooled by the injector test before.

Disassemble the whole intake path, I had a MAF clogged with rubber at cresson. How are the O2 sensors? Maybe lost a sensor and is in limp mode?

Skipped timing chain??

Got it... ya there may be a sensor issue. I am hoping codes can point me in the right direction. If that is the case. I did not even think about the timing chain but that could make sense.

[marshall_mosty]

Check the float bowl levels

Isn't that something that's only legal to do in Colorado at the moment??