Where is that located?

 

 

thanks

 

Seriously? C'mon man. You are being freaking spoon fed here. At least try and figure some of this out, it is painful to see some of these guys try like hell to help you out and you just sit there and can't even figure out where the ISC is....

edit: that came out a little harsh, sorry. If you honestly want to tune your car yourself, you need to do a little harder researching on stuff yourself before posting 17 new threads about various little things. This ISC thing is just silly, it could surely be your problem. It takes 10 mins to take off and look.

 

I knew it was on the tb but I didn't know where or what it looked like. Never really took a close look at the TB on the evo.

Well, it turns out that the Buschur hardpipe makes my car's airflow read too high and that makes the ECU use the LTFT mid for idle instead of LTFT lo. I swapped the stocker back in. I was thinking though...I'm pretty sure that's why everything I logged doesn't make sense. I need to figure out a way to make the higher airflow reading fall into the LTFT lo area...in other words, change something so the LTFT lo uses the higher airflow reading instead of having the mid use it.

I'm not sure if that is possible with the ecu.

edit: the ICS is working properly.

 

Well, I don't know if anyone has found it in disassembly, but there are switchover points on where the LTFTs switch over. I'm sure it could be configured if we found the tables.

Also, there is a way to log what LTFT the ECU is using, but I don't think that request has been found for the Evo either. This was an option using DSMLink on the DSM ECU.

If we were able to log this 'selected LTFT' value, then you can know for sure whether LTFT Lo or LTFT Mid was being used at idle in your case. If LTFT Mid is being used, which it appears it is from your logs, then if someone can find the switchover parameters, maybe adjusting them could help.


I think I may make another new patch request thread, though. Your sympton of stalling when free revving or clutching-in/coasting to a stop is actually very common when upgrading intake pipes, bigger bb turbos, even bigger ICs sometimes. The basic issue is that the MAF overreads after the throttle lift. There has been a thread on the DSMLink forums for a couple years now and the creators are adding code to V3 to fix this. There are other hardware boxes out on the market that do this (I think HKS has one, but I forgot it's name), but basically all we need to do is have a maf clamp (set value for Hz and possibly load) for certain conditions, like when the throttle is < 15% and RPM is above a certain value or decreasing, etc.

I can probably think of the correct conditions, but solving this stalling issue with a patch may be the best route and one of the most wanted patches for anyone running the stock MAF with aftermarket inakes and turbos. Actually I am reviewing a log I got in a PM from someone else with this same exact problem and his log is nearly identical to redlanevo's log and other logs I have seen with this issue.

I actually had this same exact issue with my DSM and resolved it completely by installing a GM MAF in blow-through. I think we can stick with the stock MAF though, as long as we can get a patch to do what we need.

I'll make a new thread explaining this in detail and see what tephra, mrfred, and others say about it.


Eric

 

Ok, makes sense. You are a true help to us all.

 

Well, I'll tell you...I swapped the Buschur for an AEM and all the issues associated with the Buschur went away. I was then able to scale the MAF myself. Fuel trims are in check and no stumbling of any sort. I guess the Buschur didn't work for me. Thanks guys who helped me out!

 

Glad to see you got it worked out. That pipe was just causing too much disturbance to the MAF reading in your case.

Maybe someday the patch I requested can be written to help with the problem, but in the meantime, it's good that you found a pipe that works well.


Eric

 

One more thing I just found out today...

I used the Buschur intake hardpipe again and instead of using Buschur's air filter(open top) than came with it, I used the AEM filter(closed top) and it worked flawlessly! Better than the AEM pipe! The AEM pipe would sometimes(very rarely) want to stumble coming to a stop. I am very surprised...
So Buschur pipe with AEM filter works for me with no issues.

 

That's interesting RedLanEVO.

I found the same issue with the EVO X and open vs closed top filters. Car would run like **** and be down in power with a open top, put a closed top one on and it worked perfectly and was up on power.

You can read about it here:

https://www.evolutionm.net/forums/sh...d.php?t=341608

 

^ Very interesting.

I'm running the full Buschur intake with hardly an issue like the OP had... do you think I would stand to gain anything by switching to the flat-top type filter?

 

Just thought I'd put it out there for those who are having problems. You can try switching filters and see if it gets better...

I did log the airflow of the AEM full intake kit and the Buschur hardpipe with the AEM filter. Airflow reading was exactly the same but with the Buschur pipe with the Buschur filter, airflow was high...which probably threw the car into using cruise trims even at idle.

 

Hmmmm reviving this thread a little because I'm researching MAF scaling etc. This sound suprisingly similar to issues some motorcycle guys have when they add individual filters ontop of their indivdual carbs. Basically the problem most find is that the air flow is too turbulent with the filter sitting right on the carb because it is coming straight from the filters right through the throat. The solution was/is to add a small length (2"-3") of pipe between the carb and the filter. This lets the air flow settle down and "streamline" (read: become less turbulent) so that the carb can accuratly meter the fuel.

So why do I think this applies? Well most aftermarket filters that I've seen for the evo (unlike a lot of the DSM ones, but not all) sit right on the MAF. That gives little time for the air flow to straighten out and settle down. Worse yet, the cone filters with open tops tend to lend themselves to creating a lot of turbulance as the air entering from the sides interacts with the air entering from the top.

The solution would seem to be to get the filter further away from the MAF to allow the air flow to settle down much like the bike guys running indivudual filters on their carbs. Using a filter set-up that allows for smoother air flow would help too but I know we're also trying to increase filter area for flow reasons. Then again, turbulent flow hurts flow rate, so I really wonder if an open top filter, under real-world conditions (read: not on a constant flow-rate flow bench) actually out flows a non-open top [shrug].

Just a thought given the evidence as presented here coupled with things I've read / learned elsewhere.

 

Oh yeah easy test too for those without a filter to swap ... put tape over the top of the filter to block flow. I plan on doing that during my next tuning session to see if it changes / improves anything. I too have a bit of an idle issue, hence my research on MAF scaling. Adjusting my BISS a la triggering the actuator in EvoScan has helped a lot but it isn't perfect, and behavior is still a bit "off" so perhaps this is my problem. But I also have the stock pipe but with an open top filter (inherited when I bought the car, I never would have bought it myself).