cant get my 408 to idle
Thread Starter
Teching In
Joined: Oct 2006
Posts: 27
Likes: 0
From: Bossier City,Louisiana
cant get my 408 to idle i cant seem to get it to idle. it has a 248/254 622/612 camshaft, 90mmfast/90nw, stage 3 6.0L heads, 11.3 to 1 and 42# injectors. I have tried to unplug the tps and turn the idle screw up. ive messed with timing, for some reason when it does halfass idle around 1000 rpms the iac counts are 0. i cant get them to 40 were they belong. it surges up and down and dies. and it wont start on its own, i have to give it gas while cranking for it to start. im new at tuning and am lost! please help!! i have read the tuning document and have tried everything except drilling the throttle blade. I dont want to do this unless there is no other way! any help would be awsome!
First, turn the idle screw (throttle blade screw) on your NW90 open far enough to keep the car running. Once you have the idle high enough to stay running, you can log what the car is doing in order to make changes. It will be almost impossible for you to get started if the car dies every few seconds. You will most likely have to drop your idle VE tables a bit with a cam that size. Also, you may have to increase idle spark. Once you get in the ballpark, you can adjust expected idle airflow, as well as other tables. Hopefully someone with more NA monster cam experience will chime in. I mostly mess with baby cam FI stuff.
I agree with the above. First make sure timing is set.Then I would check the IAC count and get them around 30 at full temp.Then make sure the fuelling is right.Then it keeps going with idle tables.
If you have EFIlive,send me the file and I'll adjust it for you.
If you have EFIlive,send me the file and I'll adjust it for you.
TECH Enthusiast
Joined: Sep 2004
Posts: 564
Likes: 0
From: Omaha, NE
If your fuel is way off, you will have this problem. Make sure your closed loop is turned off, go to the maf table for your idle range and start decreasing it 10% at a time and see if it improves, if not, start increasing it 10% the same way. I recently had a 408 that, due to some head/header exh leaks drove the vehicle's 02s, our wide band and the tuner crazy.
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Teching In
Joined: Oct 2006
Posts: 27
Likes: 0
From: Bossier City,Louisiana
I have used the injector calc. to set the injectors. I am using HP tuners. It pops out of the exhaust as it is trying to idle, not sure what timing I need. I opened the tps up 5% and reset it back to 0 by unpluging it, and it still wont idle. I scaled the cranking VE table down 80% also.
Thread Starter
Teching In
Joined: Oct 2006
Posts: 27
Likes: 0
From: Bossier City,Louisiana
talked to jason at texas speed. He pointed me in the right direction. gonna try his suggestions and shoud be in the ballpark. it seems timing and fuel are my problems. going to try it tonight. thanks for everyones help.
