Custom prom and Throtlebody sizing question...
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Custom prom and Throtlebody sizing question...
I've found that when I disconnect the battery on the Sled (Superram, 383, yadda yadda), the ECU and custom programmed chip take awhile to 'relearn' the parameters that make the car perform well off the line and at part throttle. Thinking that it might have been a flaw in the programming, I was making a mental note to see what parameters it WAS using and have them burned in as the default values.
Then I thought about it a bit longer and wondered if the problem was that 48mm throttlebody I still have, instead of the 58mm throttlebody I specified in the custom chip order form. It was a logical choice as I'm planning on swapping out the TB pretty soon and didn't want to have an additional chip burnt (at $350+ shipping a pop.)
I'm also having a minor cold start issue where the motor doesn't light off immediately, making the exhaust REALLY rich...oh yeah, and the motor hunts at idle...think they're related too?
Then I thought about it a bit longer and wondered if the problem was that 48mm throttlebody I still have, instead of the 58mm throttlebody I specified in the custom chip order form. It was a logical choice as I'm planning on swapping out the TB pretty soon and didn't want to have an additional chip burnt (at $350+ shipping a pop.)
I'm also having a minor cold start issue where the motor doesn't light off immediately, making the exhaust REALLY rich...oh yeah, and the motor hunts at idle...think they're related too?
Safety Car
Joined: Dec 1999
Posts: 4,691
Likes: 1
From: Framingham MA
Re: Custom prom and Throtlebody sizing question... (RocketSled)
I've found that when I disconnect the battery on the Sled (Superram, 383, yadda yadda), the ECU and custom programmed chip take awhile to 'relearn' the parameters that make the car perform well off the line and at part throttle. Thinking that it might have been a flaw in the programming, I was making a mental note to see what parameters it WAS using and have them burned in as the default values.
If you car doesn't run that well initially the initial calibration is probably off a little and the computer need to learn to compensate. I don't know if the TB will help unless I was looking at your BLM's. I would assume the larger TB would lean out your mixture. If you current BLM are indicating the base line BLM are rich (BLM would be below 128) it could help the problem.
As for the idle did you reset the IAC to register minimum air?
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Re: Custom prom and Throtlebody sizing question... (dgoodhue)
Have done so now.
Previously, I'd turned in the minimum air screw a full turn when I found it evend out the idle a little. (Ya, I know it's not an idle screw, and that it affects the TPS, but it worked.) After adjusting it back out and performing the, rather simple, IAC adjustment procedure, It idled pretty crappy. Turned it back in a little and everything evened out.
TPS is showing .50v, I've got a TPS and an IAC on order...what the hell, they were the last part from the stock motor anyway.
Previously, I'd turned in the minimum air screw a full turn when I found it evend out the idle a little. (Ya, I know it's not an idle screw, and that it affects the TPS, but it worked.) After adjusting it back out and performing the, rather simple, IAC adjustment procedure, It idled pretty crappy. Turned it back in a little and everything evened out.
TPS is showing .50v, I've got a TPS and an IAC on order...what the hell, they were the last part from the stock motor anyway.
