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Fuel, no spark

1591 Views 7 Replies 3 Participants Last post by  steveo
1994 LT1 with LT4 Goodies

Car turns over, but there is no spark, only fuel.

With the weather here in Chicago, it's possible condensation built up in the opti not allowing it to fire (it's 55 degrees today, it was 22 on Sunday, and will be 17 degrees on thursday, Stupid Chicago weather.

Anyways, I figure it's the opti or the Security key feature. Is there an easy way to tell a difference as both will cause a non-spark issue? I have had really good luck with this stock opti unit (120k) so would assume that it would need replacing soonish, but I think it's weird that car started and ran fine, and then sat for the weather change and no will not fire at all.

Thanks for any and all info forthcoming!

or any other ideas it could be.
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Put a grounded spark plug and the output wire of the coil ..if it sparks u got it there and its opti.
Thank you, never even thought of that, I guess it would be a good idea to try that before ordering 500 dollars worth of parts :)

Will have to wait until tomorrow, garage has another vehicle in it and it's raining, on a 55 degree day, in January, In Chicago........
VATS security system disables fuel, so it's not that.

could be ICM, coil, opti high voltage side, or wiring

if you get no fire from the coil, check with a test light to see if the ICM is grounding the coil

and remember just 'cause the coil is firing doesn't mean its strong enough to jump the rotor AND spark plug gap. make sure its a really hot spark
Thank you,

personally I am just hoping for no spark from the coil. Since my garage has a vehicle in it until Sat, tomorrow I guess I will pull out my timing light and put the clamp on the coil wire and see if I get anything.

I was really hoping the car would have no problems until spring when I planned on doing all the maintanence, (the basic, replace the heater hoses, power steering hoses, water pump, opti and upper/lower radiator hoses.)
its really common for this stuff to happen in the winter -- moisture is the enemy of ignition stuff, you should use dielectric grease on every connector, it helps a lot

Thanks for all the help and info, it's the opti. Luckily it's frozen here in chicagoland again, thus, no condesation in the distributor, thus, car now runs again! Hopefully will be able to stretch this out until spring again until I have the time and funds to do everything that I want to do.

And if anyone reads this, Would I be better off with a new billet opti instead of just a cap and rotor change? (I am thinking yes, but always open to other opinions)

if you have moisture intrusion, you're better off with a complete opti. your optical section will be on borrowed time..

on your car since yours isnt' vented already i'd go for an msd 8381, since they are vented. installing the vent system isnt a huge deal. it'll help a lot.

open it first and loctite the rotor screws though
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