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minytrker
March 12th, 2007, 09:45 AM
I have a 408 with a fast 90/90 setup and a good size cam. I can't get the car to start without giving it gas. I can't get it to idle either. I have tuned 402's before and never had a problem. The IAC is really high on also. I have added to the ve from 1200 on down,I have tried subtracting from the ve with no luck. Im lost.
Rhino79
March 12th, 2007, 10:01 AM
Try setting B4604 to something similar to:
275.000000
275.000000
275.000000
275.000000
240.039063
205.078125
175.000000
150.000000
150.000000
150.000000

Between that, and desired airflow, that should get it starting pretty good, at least it worked for me on the last 408 I did which had a Victor Jr. and Edelbrock 4bbl.TB.
minytrker
March 12th, 2007, 10:58 AM
That helped some. The IAC is at 175 at around 1000 rpm. There is something also weird going on with the TPS. I can move the gas pedal a petty good ways before it the tps changes. It seems slow to respond. I have messed with the idle screw also.
oztracktuning
March 12th, 2007, 12:53 PM
Maybe reset your TPS sensor for a start. Disconnect it and key on (dont start the car) and then wait and reconnect it. This might help the slow to respond issue.
minytrker
March 15th, 2007, 04:40 AM
Found one problem, bad tps. Just put a new one on will mess with it tommorrow. Being the 90TB blade has been messed with so much, by the owner and then by me can I set the new one up to factory specs by voltage? I dont have it in front of me, but isnt it supposed to read live .55 volts or something at 0% throttle?
Bruce Melton
March 15th, 2007, 05:17 AM
This does't have a LS2 cam sensor does it?
minytrker
March 15th, 2007, 06:20 AM
This does't have a LS2 cam sensor does it?

Not that I know of, but I will check tonight, Im 99% sure its ls1.
Bruce Melton
March 15th, 2007, 06:38 AM
It makes sense that it is LS1 but the way it is running is similar to the common reversed cam sensor lead on LS2s.
slowhawk
March 20th, 2007, 10:23 AM
If the iac is at 170 then open the TB alot more via the screw. You can set the idle limit to 2% or so.
minytrker
March 20th, 2007, 04:20 PM
If the iac is at 170 then open the TB alot more via the screw. You can set the idle limit to 2% or so.

If I open it more then the car will start but it idles at 1500rpms and wont go down. I have not tried this since I installed the new tps sensor however.
slowhawk
March 20th, 2007, 11:38 PM
If I open it more then the car will start but it idles at 1500rpms and wont go down. I have not tried this since I installed the new tps sensor however.

First try a TPS reset.
2nd you change the idle table to 2% throttle(it idles high because it is in a load table.)
3rd,you slightly port around the throttle blade.