Cold Startup issue
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- civic4g
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Cold Startup issue
Well let me see if I can explain the problem and make it clear to all of you. I've only noticed this problem about a month ago so i think that it may be related to some modification in the rom code. I've tuned the duty cycle of the IACV to -68% (I have a OBD2 engine and IACV) since the beginning and never had issues, now when I cold startup the engine it takes to much time to reach cold idle rpm (1500rpm) and rpm keeps going up and down almost stalling the engine. To try to understand what was causing this i've set the DC correction of the IACV back to 0% and it starts perfectly. Anyone else has experienced this problem? I think only OBD2 engines will experience this because they don't have FICV. I don't think I can find a Duty Cycle correction value that will suit both situations (coldstart and idle after warm). Is it possible to have a IACV DC value for coldstartup and other value for \"normal operation\"? or disable IACV DC correction for first x seconds? I think this would solve my problem but if there is another way to correct this issue let me know. Datalog files below:
- Attachments
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- eCt.base273.cal
- Calibration
- (8.18 KiB) Downloaded 433 times
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- IACV DC @ -68%.elf
- Cold Startup with IACV DC correction set to -68%
- (84.18 KiB) Downloaded 429 times
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- IACV DC @ 0%.elf
- Cold Startup with no IACV DC correction
- (51.6 KiB) Downloaded 435 times
Last edited by civic4g on Sat Nov 29, 2008 3:24 pm, edited 1 time in total.
i cant view the cal on this computer but what are your fuel cut settings? I know that i made a mistake in that area once and it wouldnt get to the cold start RPM's and it would also bounce for a second while cold.
eCtune Authorized Tuner Blake Barr Pensacola, FL XXX Performance - In House DynoJet 850-457-DYNO
Re: Cold Startup issue
My engine is OBD2, and it has both IACV and FITV.civic4g wrote:I think only OBD2 engines will experience this because they don't have FICV.
99 Prelude Base 5spd JRSC ~7 psi
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- <font color=green>eCtune Authorized Tuner</font>
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The best way to do it is actually a DC->RPM table with a CLT modifier. You can usually get away with skipping the CLT modifier. So basically if the ECU determines the engine is -5 and sets a target idle RPM of 1500 then it looks up 1500 and knows that it requires approx 68% DC to achieve that so that's it's starting point and any PID control it has is applied after that to fine tune and achieve the actual target. -Michael
eCtune Team eCtune Authorized Tuner Location: Ottawa/Gatineau, Canada
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Way back, a few years ago, it was decided that the OBD2 IACV behaved differently than the OBD1. My engine is obd2 with the obd1 IACV, no fitv, no coolant lines to anything. Only problem I have is when it's real cold and the oil is thick, I have to give a little throttle to keep the rpm at a reasonable level right after crank. Within a minute everything is self sustaining and stable.
I dont get as cold as you do up there being in Florida, but i am running an s2k throttle body (no FITV) and it idles perfect.hackish wrote:I have an H22 with the fast idle valve bypassed and it does exactly the same thing as yours. A little annoying... -Michael
eCtune Authorized Tuner Blake Barr Pensacola, FL XXX Performance - In House DynoJet 850-457-DYNO
- Gaskleppie
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Are the base settings for the idle control ok? I mean, when the engine is warm you must be able to unplug the IACV valve and the engine must fall down to about 500rpm at idle. If it stalls, open up the idle screw till it keeps running at 500rpm, if it runs higher than 600rpm, close it a bit to get it around 500rpm. When the base idle is ok, plug the IACV in, reset the error code and try again.
Regards, eCtune Team eCtune Authorized Tuner Location: The Netherlands
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This sound pretty good, but is impossible with S2000 throttle body (no idle screw) Mine is running pretty good when cold with the S2000 throttle body if i let it run few minutes without toutching the gaz pedal. Here in Canada is wery colt in winter. Lots of people is running OBD2 engine without FITV and eCtune. It is possible for Calvin to code someting for that pleaseGaskleppie wrote:Are the base settings for the idle control ok? I mean, when the engine is warm you must be able to unplug the IACV valve and the engine must fall down to about 500rpm at idle. If it stalls, open up the idle screw till it keeps running at 500rpm, if it runs higher than 600rpm, close it a bit to get it around 500rpm. When the base idle is ok, plug the IACV in, reset the error code and try again.
- Gaskleppie
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I also run an S2k throttle body. You still have to do what I wrote. If you dont have an idle screw, you have to adjust the min throttle screw to get some air through and to get it running at 500rpm with a warm engine with the loose IACV plug.
Regards, eCtune Team eCtune Authorized Tuner Location: The Netherlands