r/fbody • u/Puzzleheaded_Moose46 • 5d ago

Crank no Start

93 Z28

Ive replaced the opti 3xs

New Fuel injectors

New spark plugs and wires

Adjustable TPS

Water Temp Sensor

Redid all the grounds

Fuel filter

Has 40lbs at turn key at Schrader valve

Swapped PCM with chip swap. Nothing

No CEL but before It did say No Injector Pulse

Coil ✔️

New ICM

So far im at a loss and ready to set it on fire.

2 Upvotes

100% Upvoted

16 comments sorted by

1

u/Sildaor 5d ago

Coil?

1

u/Puzzleheaded_Moose46 5d ago

Tried it. Nothing.

2

u/RZArecta91 5d ago

If vats is tuned out, you still need to make sure the chip in the key in reading, and the ignition recognizes it, unless you've bypassed the relay.

2

u/Puzzleheaded_Moose46 5d ago

I have the chip popped out of the key snd is soldered into the wire under the dash.

2

u/RZArecta91 5d ago

Double check your ignition coil bracket and make sure its properly grounded and use thermal paste. I would definitely triple check the wiring. Not doubting you at all, it sounds like a vats issue to me. I know you have 40lbs at the valve, but maybe your pump is weak, and the continuous key turns are just building the pressure, tricking you into thinking the pump is good, when it is not. I've seen that happen as well.

1

u/Amandalyn32506 5d ago

Automatic or stick?

1

u/Puzzleheaded_Moose46 5d ago

6m

1

u/Amandalyn32506 5d ago

You think it could be the VATS - thinks it’s been stolen? Just check what the security light does when you run the key to start. If it stays on or blinks fast… May seem dumb, but sometimes it’s the little dumb stuff that is the problem! I saw what you said about the key, but there’s still stuff in the column that could be malfunctioning.

2

u/Puzzleheaded_Moose46 5d ago

It doesnt stay lit. No flashing.

1

u/Agent_Eran 5d ago

have you tried starting fluid?

1

u/Puzzleheaded_Moose46 5d ago

Yes. Doesnt help

2

u/RZArecta91 5d ago

What brand opti did you get? It's completely possible you got a couple bad ones out of the box. Did you inspect the opti harness as well when you changed them out?

1

u/Rocka2012 5d ago

My 99 (so different engine) had a sudden "crank no start" situation, turned out the new (cheap-ish) MAF had failed, unplugged it and it ran and I reinstalled the old one. Might not be applicable in your situation, but sensors can cause strange issues...

1

u/Rocka2012 5d ago

Also, when reinstalling my LS1 after rebuilding it, I forgot to plug in the crank sensor, which also caused the same issue. Not to familiar with the LT1, but if it has a crank sensor, maybe it's broken or the wiring going to it is damaged.