Power FC Idle and 850 primaries
10-22-17, 09:41 PM
#1
Idle and 850 primaries
A quick search turned up that it's hell trying to get 850 primaries to start and idle, but it is possible.
My setup: PFC, stock port, fresh motor, single 8374 IWG turbo, 850/1680s, supra pump. New motor was just built, tuner worked for hours on the starting and idle but it still sucks. He even went so far as to reinstall the accelerated warmup system on my throttle body to try to smooth out the idle till it warms up. Starts ok cold, revs to about 1500 and kind of hangs there, but runs super rough if you try to drive before 80deg C or so. If you start the car warm it lopes up and down and sometimes settles to 1000 rpm, or sometimes goes back to 1500 and hangs there until you blip the throttle. Lots of hesitation in city driving from stop lights and stop signs. Stumbles every time 1st to second shift under low to moderate load. All this normal for 850s, or can it be tuned out? Or easiest/most economical to just ditch the 850s and get some 550s and tune from there, as I think 550/1680s would be more than sufficient for my 15psi setup as my current injector duty cycle is only maxing at 65% or so under boost.
My setup: PFC, stock port, fresh motor, single 8374 IWG turbo, 850/1680s, supra pump. New motor was just built, tuner worked for hours on the starting and idle but it still sucks. He even went so far as to reinstall the accelerated warmup system on my throttle body to try to smooth out the idle till it warms up. Starts ok cold, revs to about 1500 and kind of hangs there, but runs super rough if you try to drive before 80deg C or so. If you start the car warm it lopes up and down and sometimes settles to 1000 rpm, or sometimes goes back to 1500 and hangs there until you blip the throttle. Lots of hesitation in city driving from stop lights and stop signs. Stumbles every time 1st to second shift under low to moderate load. All this normal for 850s, or can it be tuned out? Or easiest/most economical to just ditch the 850s and get some 550s and tune from there, as I think 550/1680s would be more than sufficient for my 15psi setup as my current injector duty cycle is only maxing at 65% or so under boost.
10-23-17, 12:32 PM
#4
As far as the cold idle goes, I had to keep my foot on the gas and hold the revs until the temp showed ~60c then it would idle on its own but just barely. It was pretty rough. Once it got to operating temp, it was perfect. Your problem with coming from a stop light can definitely be tuned out. That problem, I did not have. It drove perfect once it was to operating temp. What are your parameters in the settings 5 tab and how old are your injectors? I got mine cleaned and flow tested before getting the car tuned. My idle was was in the mid to high 12s at 1000rpm. Stable as can be
10-26-17, 08:19 PM
#5
As far as the cold idle goes, I had to keep my foot on the gas and hold the revs until the temp showed ~60c then it would idle on its own but just barely. It was pretty rough. Once it got to operating temp, it was perfect. Your problem with coming from a stop light can definitely be tuned out. That problem, I did not have. It drove perfect once it was to operating temp. What are your parameters in the settings 5 tab and how old are your injectors? I got mine cleaned and flow tested before getting the car tuned. My idle was was in the mid to high 12s at 1000rpm. Stable as can be
Settings of the pfc, I don't know, I'm working on getting a datalogit as we speak so I can work on the tune myself. Injector age unknown, never cleaned/flow tested. What should my af/r be at idle? I'll take another vid asap of a warm start and show my wideband if that helps.
10-27-17, 06:52 PM
#7
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Maybe you should try adjusting the SETTINGS 2 Water Temp Correction table. It adds more warm up fuel for a cold engine as gas does not evaporate well in a cold engine.
Left column is for idle or low loades. Right column is for higher loads.
Left column is for idle or low loades. Right column is for higher loads.