ECMlink ISC Deceleration Question

[Devilsfutbol17]

When I am just cruising or even in the upper range of rpms and I disengage the clutch, my rpms will drop and be caught by the ISC aournd 1.2k and slowly make thier way down to ~850rpms like normal. My problem is, about 80% of the time lately whenever I engine brake for any time over a second, then disengage the clutch, my rpms will drop low and it will almost and sometimes does, stall.

I have been watching my ISC position via ecmlink and noticed as soon as I engine break, the ISC position drops from upper 70's to like 40 and sometimes lower. I'm wondering if I need to make some adjustments or something to prevent my ISC from closing so much when I decelerate. It idles fine right around 850rpms with the ISC around 30.

I haven't checked the resistance on the ISC for a few months though and I also replaced my own ISC drivers a few months ago, but this issue just came up within the last two weeks.

Thanks

 

[98spydereugene]

Are you simulating idle switch in link??Or still using it

edit: not saying thats your problem, just a starting question..here's a good link http://www.dsmisc.com/dsmweb-dw/faqs.html

 

[Devilsfutbol17]

I was still using the actual switch, but I just adjusted my TPS from the ecmlink tuturial and switched to simulated idle switch this morning.

 

[98spydereugene]

And still did it I'm guessing??

Got a log to post while this is happening???and maybe an initial idle log as well?

If you haven't got it either in the next week, I'll be coming through there to go fish the columbia, I could bring my good ISC and see if it works????

 

[Devilsfutbol17]

Oh didn't even realize how close you were. I have atleast one spare ISC that I can try for sure, and my buddy has atleast three throttlebodies at his place that all have the ISC in it, so I think I can try different some other ones.

Yeah after setting the TPS and the simulate idle switch the problem persists

 

[LiquidX]

It's your flywheel, I have the same problem. If I set my idle too low and then then throw it in neutral it'll sometimes drop too fast and the ECU will have a hard time catching it.

Your ICS numbers are where they are supposed to be for adjustment and I would assume it's working fine. If you want to test for a bad coil do so, but I doubt it will show anything for you. Try raising your idle (properly) to 900rpm and see if it does the same thing. You can also add about 100 to the coast offset value.

 

[Devilsfutbol17]

Ok I will up my idle to 900. I was curious about what that coast offset parameter is used for. Currently it is set at 0, but I see in the ecmtuning wiki to set it to your idle minus 900. I will try to post up a log of it happening today.

I heard about the flywheel possibly causing this, but I don't understand how my ecu can catch it when I push the clutch in from 5k rpms but not when I engine break from 5k to say 2.5k then push the clutch in it will almost stall.

 

[gofer]

Add AvgAirVolPerRevY and AvgAirVolPerRevW to your log and go for a drive making it do whatever you described above, then post the log.

I'm moving this to the Log File Advice forum.

 

[AlaskanDsm]

Ok I will up my idle to 900. I was curious about what that coast offset parameter is used for. Currently it is set at 0, but I see in the ecmtuning wiki to set it to your idle minus 900. I will try to post up a log of it happening today.

I heard about the flywheel possibly causing this, but I don't understand how my ecu can catch it when I push the clutch in from 5k rpms but not when I engine break from 5k to say 2.5k then push the clutch in it will almost stall.

More time to react possibly, even though its really not all that much different?

 

[Devilsfutbol17]

Ok I changed my idle to 900rpms, but I didn't do it properly I guess because I didn't adjust my BISS so my ISC position was at 30 at idle. After chaning it the ISC position was like 35 or 36. I also changed my coast offset to 90.

The first log is when I pulled off the highway, the other two are just driving on the streets. It's easy to find where I almost stall because both rpms(obviously) and battery voltage take a dip together. Oh and I went to the captured values and it showed those two parameters as being measured but they were not displayable I believe.

 

[gofer]

Connect with link and go to your Idle Air tab, then click the enable box and go for another drive. Log the results and post them, it shouldn't try to die now on decel.

 

[97eclipseNT]

I just posted this same answer to a similar question but you could try cleaning your throttle body out. I had similar problems and after thoroughly cleaning it out it idles perfect.

 

[Devilsfutbol17]

Ok I will click the Enable idle air clamp and go for a drive. I just put some chicken on the Foreman grill so I will have to wait a few minutes. Yeah I had my throttle body out twice within the last 6 months but I never got around to giving it a deep clean. I should probably do that.

Ok I just went for another drive but it didn't seem to behave any differently.

The car is almost stalling more often now. Just driving through town it will want to stall when I down shift to turn. I think it's either the flywheel or the ISC system.

If it's my flywheel, are their anyways in ECMlink to counterack the loss of momentum?

My idle is pretty good I think, so I'm not leaning toward my ISC being the cause. I included an idle log.

 

[Devilsfutbol17]

I know this isn't the proper way to fix my problem, but I am going to give it a shot for a while. First I went out today and rose my idle to 950rpms in link. Then I went out and opened the BISS screw just to the point where the ISCpos was 0. I did this in hope that one, it would keep my idle up because of how open the BISS screw was, and two, because I'm hoping if the ISC does open up when I'm disengaging the clutch to turn or come to a stop, it will manage to catch my rpms higher than the 500-600rpms that it was doing.

I took a drive and I was unable to get the rpms to drop below 800 under any conditions, so it appears to be working well right now. The ISC is now between 0 and 5 when I'm idling, is this going to cause any problems since it's suppose to be at approximately 30 at idle?

 

[98GSXtacy]

Not sure, but the coasting fuel cut that our cars use may be part of it too. Iirc, the motor cuts fuel when there is not tps but speed is there and rpms are over 1200. Now in my mind, I would think that with it engine breaking with fuel cut then when you push the clutch in, the fuel may not be getting to the engine fast enough to kick up combustion again. Not to mention that, with the lightened flywheel your rpm's probably go down alot faster than what the engine is used to as well. Just a thought.

 

[UofACATS]

If it's my flywheel, are their anyways in ECMlink to counterack the loss of momentum?

Yes, under RPM/TPS > Coasting FC offset:

Coasting FC offset is used to raise the rpm above which fuel cut takes place when the idle switch is closed.


What value do you have there currently?

As a rule of thumb, any RPM set over 900 rpm should get added to the Coasting FC offset value.

 

[Devilsfutbol17]

If its from the coasting fuel cut, should I try and increase this value? Currently it set at 90 because my idle is set for 950.

4am this morning on my way to work it went back to its old self 3 times. I didn't let my car warm up at all though and its about 10 minutes to work with about 3 minutes of highway driving, plenty of time to get up to operating temperature. On the way home from work I let it warm up before I took off and it didn't almost stall once, it was a perfect drive home.