So I swapped in a ps pump with the sensor, that didn't fix the issue. I guess I'm gonna play with the dv and try to loosen it up and see if that fixes anything until the new biss screw gets here.

 

With all due respect that isn't necessarily true depending on what mods you have. I was having an issue where under light load highway driving my afr's would swing rich all the time with no change in tps value at all. I have fic 1100 high z with walbro 255 that has a 14 volt rewire and Mr Fred told me to get an afpr and it fixed the problem instantly. Just saying..... I know you run your monster Evo on a stock fpr but mine wasn't cutting it. I probably could have got another NEW stock fpr and it would have fixed the issue too but what's the fun in that?

 

What intakes do you guys have? I'm starting to think my custom intake might be messing with my maf readings and just got an ets intake. Will update after install.

 

I have an AEM, I'm starting to think mine is in the tune. I replaced the biss, and have been watching the rpms closely lately and have been noticing that mine only does it after I push the car hard with high load (namely going up the hill to my house). When I'm just cruising around town and driving it like a Honda the rpms catch themselves right at 900-1000 rpm.

 

Weirdest thing about my situation is if I leave the port c of synapse dv not hook up to boost line it doesn't do it at all. But if I have it hooked up properly it has idle dips. It sucks in traffic it happens to me a lot on and off the clutch in first gear.

 

what throttle body are you using?

 

Oem

 

I also have oem tb.

 

I think there is never a definitive answer to this problem is because it's usually caused by multiple things. In my case I had leaking intercooler couplers, leaking throttle body shaft seals, and a bad IAC valve. Also my turbo boost gauge was leaking by the FPR T-connector. My theory is the IAC eventually fries itself trying to control idle with lots of leaks. Unless you have really good ears a pressurized leak test will only work with soapy water. Don't trust your ears. Good luck but my money is on a leak somewhere.

 

Any custom intake would need the MAF rescaled otherwise you WILL have rich issues and idle dipping. I had a JM Fab intake that was causing a lot of issues for me. I finally got fed up and put the stock intake back on and it fixed almost eveything. If you're having idle dip issues with a stock intake though try raising your idle stepper look up table in ecuflash. The 3.9 row change all the 10's to 15 and the 7.8 row change all the 20's to 22 or so. If 22 doesnt help enough go up to 24. I wouldn't change the 3.9 row any higher then 15 though because your idle will swing up and down from 900 to 1200 all the time. It fixed my dip but I feel like its a bandaid solution and something else is really going on and this is patching the problem rather then fixing it. Maybe a bad cam sensor or a bad mivec gear? I'm still trying to sort my idle dip issue but it is fixed right now for the most part.

 

Thanks for a great tip, jrainwater.

Mine is EVO 8 with 94170715 Tephra Mod V7, and mine didn't have rpm dipping problem so far until I installed Cusco intake hard pipe from stock rubber one.

I do have partial VTA GFB BOV, and Tomei 270 cams, but it was fine when on stock rubber hose.

I was lowering "Desired ISCV initial step position when A/C off-Neutral" to fight against rpm hovering up when coming to a stop after hard pipe change. (It was 30 before) Then this infamous rpm dip problem started.

But it seems 94170715 ISCV related definition was not updated when I searched last time (back in 2012), it seems that table is actually, "ISCV Demand CTS Adder #1", and basically I was bumping up the demand % to get higher stepper position.

So according to your suggestion, I need to lower the previous adjusted table back to 3.9% and 5.9% (which is same as 88590715), then adjust the actual lookup table as you suggested.

I know there has been some discussion that this problem can only solved to delete MAF and go SD, but if it becomes ok with band-aid fix, I will be happy.

 

Yeah personally I would move those tables back to 3.9 and such. Then go into the actual steeper table so that when the ecu references the 3.9 it is going to "step" more for that value. Right now I have my 3.9 row set to 14 and all the other rows I left alone and it stopped idle dipping like 99% of the time. I have noticed if I am turning the steering wheel that it will still dip sometimes so like Buschur suggested I'm going to trace the power steering wire and make sure there are no shorts in it or that it isn't messed up somewhere. It could also just be an old power steering pump putting too much drag on the engine too I suppose.

 

The issue i have with my car is, when i run a Evo 9 dv i get idle dips and when i run a Forge i get none of the problems just flutter haha.