402 having trouble idling
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From: Port Tobacco, MD
402 having trouble idling A local guy had a LS2 402 installed in his Z06, tuner had issues getting it tuned so now I get the car. Its a pretty standard setup, 402, Stage 2 heads, 90mm/LS2 TB. When I got the car it would crank but no start. Went through the tune and got it set where I think it should fire. Still no fire. So I start checking some things. I'm not sure if the previous mechanic swapped the cam wires so I swapped them.
Now the car starts but runs very rough and needs pedal to keep idling and noticed the MAP sensor is dead. Raised the RAF which usually fixes it and find the MAP sensor is broken in 1/2 and the end is cracked. Replaced the MAP and the car starts with 15% pedal and will not idle without using 10-15% on the gas pedal. RAF is up to 20-22 in the normal engine temp area. Timing is 22-24 degs. Still not sure why it won't idle without keeping your foot on the pedal.
Now the car starts but runs very rough and needs pedal to keep idling and noticed the MAP sensor is dead. Raised the RAF which usually fixes it and find the MAP sensor is broken in 1/2 and the end is cracked. Replaced the MAP and the car starts with 15% pedal and will not idle without using 10-15% on the gas pedal. RAF is up to 20-22 in the normal engine temp area. Timing is 22-24 degs. Still not sure why it won't idle without keeping your foot on the pedal.
Thread Starter
7 Second Club
iTrader: (11)
Joined: Jul 2002
Posts: 8,758
Likes: 9
From: Port Tobacco, MD
Man, I've had a headache with the car....
1) The mechanic that put the engine in, installed the engine complete and jacked the engine up far enough to crack the map sensor in 1/2 and break the nipple off
2) The mechanic pulled one of the wires loose in the LS2 adapter harness
3) The oil pan was not installed correctly leaving a HUGE oil leak.
The loose wire in the LS2 harness was causing the problem.
1) The mechanic that put the engine in, installed the engine complete and jacked the engine up far enough to crack the map sensor in 1/2 and break the nipple off
2) The mechanic pulled one of the wires loose in the LS2 adapter harness
3) The oil pan was not installed correctly leaving a HUGE oil leak.
The loose wire in the LS2 harness was causing the problem.
