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View Full Version : LT1 won't idle

spina74
08-18-2008, 11:15 PM
I have a 94 trans am GT that is cammed out and other top end mods. My car doesn't keep and idle it tries to stay on but constantly stalls out. When i hold down the gas pedal it backfires and pops out of the intake. I do have an MSD opti spark on there and i had a nasty coolant leak that spilled tons of coolant all over the opti, and also I was told that my valves might be too tight. I have not checked them yet but due to the coolant leak is it possible the opti is shot?
JSPERFORMANCE
08-19-2008, 06:37 AM
Both options are possibilities you need to put a vacuum gauge on there to see if it is ignition or a tight valve.
LTb1ow
08-19-2008, 06:39 AM
Also, did you get an aftermarket TB? If so, check your TPS voltage. Fuel pressure, IAC sensor acting up etc.
Pampered-Z
08-19-2008, 07:55 AM
Sure sounds like the Opti or valves, is the car throwing codes? Is this happening right after the cam was installed? If so then you want to double check your plug wires. The car will semi-run if two wires are crossed.

What are the specs on the cam? And you didn't mention if you have had it tuned?

A cam like the Hotcam or 305 will run with the stock tune, but if you have something larger it will have issues.
JerzLT1
08-19-2008, 09:15 AM
sounds like my cousins LT1 car when he installed the cam 180 degrees out.
spina74
08-19-2008, 08:58 PM
There is an aftermarket TB on there and I replaced the IAC, I have a custom cam in there its a .570/.550 and the computer was tuned for everything I had done to the motor and as for the cam I did not install it myself I had the machine shop install it for me after the engine was rebuilt. And the engine isn't throwing any codes.
LTb1ow
08-19-2008, 09:00 PM
Def check the TPS voltage then.
http://www.golenengineservice.com/html/tps.html
sweetbmxrider
08-19-2008, 09:10 PM
a bad tps wouldn't really cause the car to backfire and pop out of the intake. i'd double check the wire routings and plug gaps but it seems that the opti died from the coolant.
LTb1ow
08-19-2008, 09:33 PM
A bad TPS would def cause a horrible idle... but I agree, the opti could also be at fault.
sweetbmxrider
08-20-2008, 04:57 PM
A bad TPS would def cause a horrible idle... but I agree, the opti could also be at fault.

yeah it deff would but he says when its revved it pops and backfires and crap.