W0LF

iTrader: (3)

I hate to have to start another cold start thread but I just can't seem to have any luck trying the suggestions I've found across the numerous of threads reviewed. As others, I'm experiencing an infamous cold start issue while running Tephra V7 9417.

For the most part, my issue seems to be isolated after throttle input. If I start the car, I'm able to get decent AFR on start up (ignore rich startup on this rom) and after a minute or so, it hovers near stoich. The problem is if you give it throttle input to say back out of a driveway, it runs fine/etc but the moment you let off the throttle, and let it drop back down to idle, idle gets choppy and the AFR goes real lean before re-stabilizing. If you repeat by pressing the clutch and engaging first gear for a foot or so and then push in the clutch pedal again, it repeats. This continues to be an issue until you start driving for a few minutes and the engine heats up. Once the engine is at operating temp, it's fine. I've tried numerous "fixes/suggestions" to no avail. It seems like no matter what I do I can't seem to figure out what exactly the problem is. I've attached a Datalog, video, and a test tune file (base ROM that still has all the changes I've tried applied to it) for assistance with troubleshooting. Does any of the tuning gurus or more experienced users have any ideas on what could be the prob? I thought it might have to do with the Post Prime Enrichment or Decay but haven't had the best results. I did notice the LTFT Low being a little screwy which is something I'm also looking into. The air temp during the attached log is around 79F

Symptoms:
AFR go lean for a few seconds and idle gets choppy
idle appears to drop slightly before raising back to desired idle as this occurs
Depending on severity/choppiness, vac gauge may drop down from 15 in/hg to 10 in/hg
Only occurs during warm up and more prevalent after a touch of throttle
Seems to also occur between 32-38 load

Mods:
04 Evo GSR
3" Turboback w/test pipe
Evo 9-20G Turbo
Stock Intake/MAF with Buschur Cone filter
Stock Injectors w/Walbro 255lph
Buschur UIC w/race core FMIC
9 recirculated BPV
264 HKS Cams
EGR Delete (issue present prior to EGR delete)
Exedy Twin Carbon

**7.7.16 CUR Tune file attached which is the most recent testing of new settings. Seems to be a little better but issue is still present.**

lancerrally45

iTrader: (22)

You forgot to list your injector and injector settings. I will guess....Fic, low impedence?

W0LF

iTrader: (3)

Actually using the stock injectors with stock settings. Only have a Wally 255 HP pump to maintain consistent fuel pressure. This problem has been present before the Walbro upgrade.

lancerrally45

iTrader: (22)

Sounds like a boost leak.

W0LF

iTrader: (3)

The only leak I could find before the TB was the BPV leaking after 25psi. Otherwise pressure held good. Any other suggestions? Can't do a leak down just yet. My only confusion is that the issue vanishes after the first minute of driving. It's literally only on first start up. I did notice that when this happens, the rpms drop to like 1k-1100rpm and the vac drops to around 10 in/hg on the boost gauge. Then once it recovers, vac increases back to near 15 in/hg and the rpm increases back to around 1300rpm before it drops as it warms up.

lancerrally45

iTrader: (22)

Sounds like its something in open loop then. Force your car into open loop and see if it continues to do it. Good starting point anyways..

W0LF

iTrader: (3)

Forcing full time open loop causes the car not to have the problem however it does get real lopey (you can hear the cams a lot more prevalent). I still feel like this is something with the cold start/warm up settings but just can't put my finger on it.

todd6027

iTrader: (10)

try zero out "Warm up ignition retard map " or whatever they are calling it these days , "low coolant temp timing trim map" or something similar

W0LF

iTrader: (3)

Already done. Issue still present. Gonna try a suggestion that was given to me.

merlin.oz

The table at address 36EA, this needs to be set to hex 80, ie 128 which will multiply the warmup function by 1.000.

There is also something funky going on with this rom and the Warmup Spark Retard map, I think both these tables play into this lean condition.

W0LF

iTrader: (3)

I'm lost on this one. I don't see any table defined in the xml as address 36EA? Also what is hex 80? I'm assuming that's the percent 128 option.
Which table is the warmup spark retard? I'd assume it's the ow coolant temp timing trim which is zerod at due to not having a cat (running test pipe).

Any clarification would be appreciated.

edsct9a

iTrader: (5)

What fuel are you using? From what I read it sounds like I have the same problem. When I start the car after it's been sitting awhile and drive off without warning up it goes lean, I have to slip the clutch more then usual and step on the gas more for it to actually move without shutting off on me. After a few minutes it drives fine. For some reason I think it has to do with running e85 but I haven't used regular fuel for awhile to verify. Also on cold start my idle is very loppy for the first minute and sometimes makes p0300 come up.

W0LF

iTrader: (3)

I'm actually running 93 pump. Idle is only showing major lope in full time open loop mode. If I turn that off then closed loop hides the lope more.

W0LF

iTrader: (3)

Has anyone been able to figure out what the 36EA table is that Merlin is speaking of? I'd like to take a look at it

W0LF

iTrader: (3)

After trying Full Time Open Loop enabled, the car is very lopey since the idle seems to slightly fluctuate. I also noticed that as it is doing this, the car is bouncing back n forth between 13.4afr to 16afr. Since I was seeing this, I decided to try to trouble shoot. I added a few full points of fuel at idle and got it to idle at around 12.8afr. idle was pretty steady..... Decided to gradually increase the Fuel map value and observe the changes. Since it idled better with more fuel, i got to thinking that maybe it was an issue with my cone filter causing too much air to pass through resulting in a lean condition (considering after a few seconds the idle will re-stabilize in CL op). I decided to go ahead and and multiply my MAF Scaling from 19-50hz cells by 1.09. This actually caused the car to idle around 14.5afr without any idle fluctation! Looks like i may have finally figured out the nuisance.