Cam surge on cold/warm startup's, but fine while driving, help???
06-12-2005, 10:16 AM
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Cam surge on cold/warm startup's, but fine while driving, help??? Ok well I recently swapped my cam out from a TR224/.563/112 cam to a F13 (230/232 .595/.585 112) cam along with Stage 3 LS1 heads, LS6 intake and ASP underdrive crank pulley only and I am having idling problems only on start ups. When I start the car when the engine is cold, it surges some, then idles at about 600 for almost a minute, then shoots up to 1000, which is what it's set at for cold idling. On warm start ups, it surges a few times, then idles at 900 where I have it set at. Ok now here's where I am confused, while I'm driving, car runs awesome, when I come up to stop lights, car doesn't stall or surge at all, no "cruise control" effect either, when I cut on the AC, doesn't hesitate a bit. I fixed my cam surge problem with my TR cam by using a method I read on another board, and I used this file on my car with the new cam and it's still surging, where do I start to tune this. I have read numerous threads about cam surging and how to fix it, but it seems that people are having trouble while driving also, and I am not, which is why I am posting this. BTW, tuning is with HP Tuners, I have a stock untouched MAF, and a stock untouched/drilled TB and I am pretty new to tuning so talk to me like I'm an idiot 
Thanks
Thanks
06-13-2005, 02:12 AM
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OK you idiot...
Ok when you cold start or even hot start for that matter, you run in open loop. Hot starts will only keep you there for few seconds, but cold starts will keep you running in open loop till ~145 degrees, when it switches to closed loop. Chances are your Open Loop A/F multipliers are commanding fairly rich on startup and bogging the motor down. The fix: lean out those tables
The better fix: Learn about VE tuning since and make sure all that is cleared out of the way before you start leaning things out. This will give you control as you will know what A/F you are requesting and producing on startup
Ok when you cold start or even hot start for that matter, you run in open loop. Hot starts will only keep you there for few seconds, but cold starts will keep you running in open loop till ~145 degrees, when it switches to closed loop. Chances are your Open Loop A/F multipliers are commanding fairly rich on startup and bogging the motor down. The fix: lean out those tables
The better fix: Learn about VE tuning since and make sure all that is cleared out of the way before you start leaning things out. This will give you control as you will know what A/F you are requesting and producing on startup
06-13-2005, 02:41 PM
#5
Originally Posted by txhorns281
Ok when you cold start or even hot start for that matter, you run in open loop. Hot starts will only keep you there for few seconds, but cold starts will keep you running in open loop till ~145 degrees, when it switches to closed loop. Chances are your Open Loop A/F multipliers are commanding fairly rich on startup and bogging the motor down. The fix: lean out those tables
06-13-2005, 05:10 PM
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well I just went out and started it cold, with it about 90* outside, my wideband was reading between 14.7-14.9 so I'm guessing that my AFR is on, I didn't get a chance to read my MAF readings, any other ideas? Thanks for the all the help so far guys.
