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hot start, post start lean problems

Posted: Wed Apr 04, 2007 12:12 pm
by Gigi
Hello,

I have a problem with hot start. Everything is good in the cold start AFR in the 12s/13s then warmed up after hours of tunning, it's in the way around 14.7 wenn cruising but wenn I stop the car (warmed up) then direct after re-start, the AFR at idle goes from 13s to say 16.1.... then wenn I drive little again there is no problem. I try to fix it with playing post start trim since monday but no good results. I m runing open loop.

Here is a 3 different datalog from this kind of problem: the first is direct 3 sec after stopped the engine and restart. The 2nd is after 5min stopped the engine. then the 3rd is with 20% afterstart post fuel trim, the fours is without the 20% afterstart post fuel trim.

Thanks a lot for your help!

Posted: Wed Apr 04, 2007 12:45 pm
by 92hb_hb
i'm in the same boat too.. I bet its a glitch in the software or something.. Never happened on my s200 and if its happening to 2 or more people i'm suspecting it isn't an isolated incident..

I tried playing w/ the cranknig fuel trim too w/ no sucess..

Posted: Wed Apr 04, 2007 1:41 pm
by Spunkster
Post your calibration. If you notice your car has heat soaked while sitting and the intake temps are higher at startup when it is the leanest and it richens up as the iat temps come down. You may need to adjust the IAT fuel compensation tables.

I run s300s on all 3 of my cars, one with 550's, one with 440's and the other with stock injectors and they all have no problems with hot starts or cold starts. It is usually best to not touch the compansations at all.

Posted: Wed Apr 04, 2007 2:26 pm
by 92hb_hb
I moved my IAT sensor from the IM to my charge piping, IT helped a little, but the problem still persisted..

Its more noticable when the weather is warm.. right now its like 30 degrees here, so i"ll have to try it again when it gets around 60 or so..

Posted: Wed Apr 04, 2007 3:38 pm
by Spunkster
The best location for the iat sensor is in the intake manifold as it is on Integra manifolds.

Posted: Thu Apr 05, 2007 10:35 am
by Gigi
Here is my calibration.

I have explored all the possibilities but it's very strange...

Thanks for your help.

Posted: Wed Apr 11, 2007 10:47 am
by Gigi
Hello Spunkster

Any idee about my this problem? Last sunday I tried in closed loop thinking that could be better so. But it's not.

It's very strange. Do you think it could be a problem that I use the temperature in degree Celsus instead of Farenheit??

Thanks a lot for your help.

Posted: Wed Apr 11, 2007 3:02 pm
by Spunkster
Temperatures units have nothign to do with this as that is somethign only the software looks at and not the ecu. Try zeroing your IAT fuel comepnsation tables. There is a known bugt that makes the last 2 colums the same value, but that should not be the cause of your problem and will be fixed in a release of Smanager. In this case try making those both 0 to see if the hot start is any better. You can see that it is directly related to IAT temps as it does get richer as the intake temps cool down.

Posted: Wed Apr 18, 2007 8:21 pm
by 92hb_hb
K.

Here's mine I just logged again.. LMK what you get out of it..

thanks..

Posted: Mon Apr 30, 2007 11:18 am
by 92hb_hb
gigi,

did you ever figure this problem out??

Posted: Mon Apr 30, 2007 11:43 am
by Gigi
Hello,

I m doing some tests. I find out that it's seams to have a problem with Celcus translation. I was alway at 3% IAT? correction and then, in F? at the normal temparature, there was 0% correction... (I'm from Europe and here we use C? instead of F?)

I took everything in F? but the problem is still there. I run 440 RC injectors, I thought also it was comming from the higher fuel pressure (tested with stock injetors and 55PSi. It's maybe comming from the Skunk2 cams pro 2, they are so big that maybe come from there... I m really lost with this problem. While I tryed to zeroing the n?gative value to test it but it's still running too lean. (17 AFR) and there is no correction IAT?... so I think it's come from another thing. I will try some other test to see in closed loop if the ECU makes the job to correct it.

What cams type have you? are you in C? or F???

Posted: Mon Apr 30, 2007 11:50 am
by 92hb_hb
i have stock GSR cams and am running in F degrees..

My LM1 wideband is permenantly hooked up and the Analog1 output goes to d14, while analog2 goes to d12.. the analog ground is spliced into the ECu ground wire as well..

WHen hot starting the car, the engine doesn't go lean until the wideband warms up and begins to register the AFR readings.. At that point it goes from high 17's to as high as 20, and even stalls out once in a while.. IT takes about 20-30 seconds for the AFR's do drop back down to normal or if i give it a little gas..

I"m suprised no one else is experiencing this but us 2.

Posted: Tue May 01, 2007 11:38 pm
by SpadeMotorsports
I have had the same problem since s300 came out. I also have a problem with hondata retarding ignition even if all compensations are set to 0. Hopefully someone can figure this one out.

Posted: Wed May 02, 2007 9:31 am
by Spunkster
92hb_hb wrote:i have stock GSR cams and am running in F degrees..

My LM1 wideband is permenantly hooked up and the Analog1 output goes to d14, while analog2 goes to d12.. the analog ground is spliced into the ECu ground wire as well..

WHen hot starting the car, the engine doesn't go lean until the wideband warms up and begins to register the AFR readings.. At that point it goes from high 17's to as high as 20, and even stalls out once in a while.. IT takes about 20-30 seconds for the AFR's do drop back down to normal or if i give it a little gas..

I"m suprised no one else is experiencing this but us 2.
Have you tried disconnecting the input to the O2 (D14) and just using a stock o2 sensor? To me this sounds lik ea problem with the signal that the LM1 is outputting.

Posted: Tue May 08, 2007 12:18 pm
by Gigi
Hello,

I made some tests and here are my result. F? compensation table seems to work better than C?. But the problem is still there. I tried zeroing the IAT compensation from 110? to the end of the table. It's a little better (around -1% comp) but still 16,5 AFR at around 148? IAT. (hote start) but it's not so hot I think. (the Idle is at around 14,2AFR)

I tried to compensate with +8 at 168? in the IAT compensation table. It correct it good but too much in cruising! (so the closed loop will must compensate...)

Then I tried to get the Idle under 850rpm and surprised, I couldn't get the idle under 850rpm... even with the idle set at 400, the idle couldn't go down... I think with the PRO2+ Skunk2 cams, it's impossible to gi under 850. (already very good with so bigs cams)

What do you think Spunkster? Is that possible that come from the cams? I think yes (reversion) But 92hb_hb seems to have the same problem with stock cams??

I attach my hot start and as we can see, there is 16.6AFR at 148? with 1% IAT compensation (tried to ad 8% at 168IAT Idle compensation table) but thenn, with the same inj pulse and IAT comp the AFR goes down to 15 but still with 144IAT...

Please Help, the sommer come... (with the hot) :x