LT1 trouble shooting help

[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]

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.

Ya, good call on the fuel rail. Man that just sounds like an accident waiting to happen. Lol.....

[Pranav]

Lol you can take some baggies or something and cover up the injectors so the fuel doesnt go everywhere.

[liquidroam]

Lol you can take some baggies or something and cover up the injectors so the fuel doesnt go everywhere.

Ah great now I am building a weak compression chamber. Boom!!! See ya'll on the other side.

[Fbody383]

Sean reminded me we had a similar issue at Houston in January. Before we started swinging parts we borrowed Casey's laptop and his scanning software. We found that the PCM engine temp signal was sketchy - you could wiggle it and see it drop out. I think we changed pigtail and sender.

[39PitCrew]

Sean reminded me we had a similar issue at Houston in January. Before we started swinging parts we borrowed Casey's laptop and his scanning software. We found that the PCM engine temp signal was sketchy - you could wiggle it and see it drop out. I think we changed pigtail and sender.

Yep. That's what we did. Computer was jumping back and forth between open loop and closed loop because the
temp it was seeing was jumping between -40F and ~210F which really messed with the timing. Turned out to
be a damaged wire a couple inches from the factory connector. The insulation had been cut and the wire was
all corroded about an inch in each direction. Eventually the wire had broken inside the insulation.

[liquidroam]

Was hoping to be able to hook it up today but nice, waiting the cable. Should know being in Wednesday or Thursday, will know more then.

[liquidroam]

Lol you can take some baggies or something and cover up the injectors so the fuel doesnt go everywhere.

Pranav clear your inbox, it won't let me PM you.

Below is what I was trying to send

Do you have someone that you know and trust for cleaning injectors/ fuel rails?

I have found a ton of people that do and most are $17 -$19 a piece. Not bad high or low but it feals like a reasonable ball park.

[Pranav]

Yeah injector RX has done mine.

I still have my clean rail and injectors for sale if you want.

I ran mine full of sta-bil before pulling them.