Sudden No Start Issue, Please Help!

[LS1Formulation]

I just got my new Stage 4 T-56 installed in my Formula yesterday and was driving it around to get some mileage on the break in when I stopped at the gas station for a drink. I was in the store maybe 2 minutes and when I came back out, the car would not start. It's getting fuel for sure, I checked twice. It's just not getting spark. Previous to this, the car would randomly not start every so often, but if you left the key on for a minute, it would start right up. Well, this time it would not. I tried everything. Disconnecting the battery, removing the PCM fuses - nothing worked and I had to have it towed. The only two things I could think it might be are a malfunctioning VATS system, or the crankshaft position sensor failed. If anyone has any other ideas OR if they know a way I can diagnose this without a scan tool, please let me know. I have been without this car for a YEAR now and I really want to drive it before the snow flies. Thanks.

[Derek]

this may seem totally stupid but have you thought about the starter? or is it turning over just not starting? Otherwise i dunno, I just figured check the most common stuff first because if it started before it seems like something simple must have went out.

[LS1Formulation]

It turns over perfectly. Just has no spark.

[TSTONE]

is the security lamp staying on?

[MP81]

Leaving the key on would sound to be like more of a fuel problem (letting the fuel pump prime up longer to build up more pressure), but you said it's not fuel so, it's not that.

Maybe the flux capacitor has to build up charge?

Seriously, I don't know. Did you check all the coils?

[meissen]

Going with Todd on this one, if it were VATS the security light would come on in the gauge cluster.

[ITSSLOW]

I've witnessed this happen before on Patrick's car. The car cranks and gets plenty of fuel. There is just no spark. I think that key has been in and out so many times the key (and resistor) and/or ignition cylinder are wore out.

[meissen]

If the resistor in the key is wore out and the VATS module can't measure the resistance through the chip, though, the security light will display on his dash so it should be a really easy troubleshoot to see if the light turns on or not. If it is the VATS, you could simply look up which two wires are going to the VATS module from the tumbler, disconnect them from the tumbler, and place a resistor across those two wires. I think there's onlly 12 combinations of resistors for VATS, but just grab a multimeter and measure what the resistance is going across the chip and then get a resistor that matches. We had to do something similar to disable VATS for remote start, but in our case we used a relay that would only use the resistor when we used the remote start specifically.

[LS1Formulation]

All I have to say is Sean at Cars is the MAN! I called him up and he had my problem diagnosed and fixed in ten seconds. Bad ignition relay. Car is running again! I do believe this was the cause of my intermittent no start problems as well.

[lozanoa11]

its not the vats b/c it would not turn over. i had that problem with mine. and yes the security light would be on. check for a signal from the crank or cam sensor.