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TrailblazerSS
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Discussion Starter #1
Hey I have a 1996 chevy caprice with the LT1 in it....parked it last night and it was fine and then it would not start today...nothing changed. So did some tests and we have plenty of fuel getting to the engine, and we replaced the icm, but now we still don't seem to have any power in or out of the coil. It just keeps cranking and will not start. Does anybody have any ideas?? It also has had an aftermarket tach for a while that someone said could possibly be causing a problem if a wire rubbed through??
 

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2008 SilverStone 2WD
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503 Posts
Could be the VATS (pass key) is malfunctioning. Do you have a different key to try?
Go to impalassforum.com and do a search.
 

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TrailblazerSS
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Discussion Starter #4
Not getting any power to the coil and fuse is good...also it takes the old style gm key so no pass key problems and if it was a pass key problem it would not even engage the starter so this is why im really stumped??
 

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07 TBSS 1SS AWD
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TrailblazerSS
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Discussion Starter #6
the tach would act a little strange now and then while driving it but I just checked and it was tapped into a wire at the ecm not down by the coil but I unplugged it anyway to rule it out and it still does not start. Have not messed with any of the wiring on it lately, I drove it the night before and parked it and it was fine, now she will just crank all day and never kick.
 

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TrailblazerSS
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Discussion Starter #8
we were checking the plug wires next to the plug on the coil with a test light.
 

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TrailblazerSS
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Discussion Starter #9
also, could the wire just break overnight sitting there?
 

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mixmaster
TrailblazerSS
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828 Posts
Pull the plug off of the coil and stick it next to a uncapped spark plug or manifold/header - see if you see an arc jump. If I had to guess probably the opti went bad, how many miles?
 

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2007 TBSS AWD
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31,503 Posts
WAIT...

your checking plug wires.. or your checking the wires in the plastic plug that connects to the coil?

if your getting power to the end of the plug that connects to the coil.. and your getting nothing out of the coil...

well... thats a pretty simple diagnosis...
:iamwithstupid:
 

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TrailblazerSS
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Discussion Starter #13
I'm checking the plug that goes into the coil and we don't seem to get anything. I was thinking that it was the optispark that went bad but the motor is rebuilt and only has like 30 or 40k on the rebuild and it looks like they put a new optispark on it when they did it, it doesn't look like its drenched or anything, it looks pretty clean. Is there a way to test the optispark itself and narrow it down to that without pulling the water pump and everything else??
 

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TrailblazerSS
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I got a 95 z28 and mine did that and it ended up being the distributor. Good luck. Hope you get it figured out.
 

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TrailBlazer SS AWD
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Optispark Is Probably Your Issue. When I Was Researching Buy An Impala SS And What Problems They Commonly Had The Biggest Issue Was The Optispark Units Behind The Water Pump.
 

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'07 awd
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I had a 94 Caprice with an LT1, and never needed an optispark, the Caprices/Impalas all had vented opti's, and didn't fail as often as 94 and earlier non vented f body and vette optis, unless the water pump let go and drenched them with coolant. I did have a coil go bad though, the terminal got all corroded. And for what it's worth those b-bodies did have a theft det. key. They used the little external chip toward the base of the key.
 

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mixmaster
TrailblazerSS
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828 Posts
I'm checking the plug that goes into the coil and we don't seem to get anything. I was thinking that it was the optispark that went bad but the motor is rebuilt and only has like 30 or 40k on the rebuild and it looks like they put a new optispark on it when they did it, it doesn't look like its drenched or anything, it looks pretty clean. Is there a way to test the optispark itself and narrow it down to that without pulling the water pump and everything else??
dude i cant tell you how much trouble i had with optis, i tried just about everything (coil packs, msd opti, ect). it was one of the reasons i got rid of my TA. anyway

check this out: http://shbox.com/1/4th_gen_tech2.html#opti_test
 

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TrailblazerSS
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Sounds like Opti, being I had 2 Impala SS's(94 & 96) stock and stroker/modded car the opti seems like your issue. If you replace I would suggest some red silicone ontop the plug to it, this is commonly where the opti gets oil and especially coolant from the waterpump be it from the hose,where its on the block, or its failing and the weep hole is letting it out. Reman water pumps are dirt cheap.
My #1 piece of advice is if you replace the Optispark buy ACDELCO, the other brands and parts stores are junk or chinese garbage. This is from experience, other's too, and from expert opinions such as my engine builder and well known builders/members on the impalassforum I had belonged to since 2002.
 

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TrailblazerSS
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Discussion Starter #19
Thanks for the info guys...it sounds like I'm probably going to be doing the optispark this weekend....:wtf:
 
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