9!'clipseDOHC

iTrader: (7)

Background, I have an Evo V with an Evo VIII ECU. ECU is running a Tephra V7 ROM. I was having an issue where the idle was very low on cold starts (700rpms) and very high when it warmed up (2000rpms). I tried using the idle adjustment feature in evoscan to properly set the BISS but it had no effect on the idle (it is supposed to remove ecu control so you can properly set the mechanical idle). I did a boost leak and fixed some minor leaks on some vacuum lines but it had no effect on the idle. I then replaced the FIAV, ISCV, BISS screw, and physically cleaned all the ports on the throttle body.

I just got the car going again and at first the idle was beautiful. I entered the idle speed adjustment mode using evoscan and got the idle perfect at 800rpms. However as the car warmed up the idle kept climbing. After driving the car to adjust my fuel trims it was idling at 3,000rpms. I tried activating the idle adjustment mode in evoscan but it had no effect, idle stayed at 3,000. Any ideas? Are there any issues which the VIII ECU's control over the V's ISCV?

9!'clipseDOHC

iTrader: (7)

I did some research into the TPS sensor and mine was showing 19% on evoscan. That seemed a bit high so I adjusted it down to 12.5% on EvoScan (which is .67 volts on the actual TPS, confirmed with a DMM). I started the car and it began idle surging from about 2,250-2,700rpms. This is a change because before it was just steady at 3,000, no surging. I again tried activating the idle speed adjustment in evoscan but it had no effect.

9!'clipseDOHC

iTrader: (7)

I did some boost leak testing today, figuring there has to be air getting past the TB. I found a small pin hole leak on a vac line going to the SAS and a larger leak on the wastegate actuator, where the rod comes out of the housing. I don't think it's a leak causing my idle issue.

I just started it again and the idle jumped straight to 2700rpms. I tried activating the idle set screw feature in Evoscan with no luck. I unplugged the ISCV, no effect. I screwed the BISS screw all the way in and it only dropped to 2500rpms. I'm at a loss here.

Honestly it seems like i have two issues, first the ISCV not working at all (possible wiring issue) and second too much air getting past the throttle body. I just don't know how or why!

9!'clipseDOHC

iTrader: (7)

I did some work to the car over the past week including installing GSC S1 cams, springs, valve stem seals, head gasket, ARP head studs, full timing belt job, and new water pump. My idle is still super high and I really want to figure this out. I just did and idle log and have some specific numbers as to what is going on.

Throttle postion is reading 15.2, so its at idle.
RPM is 2,300 RPMs, Stupid high, but not surging.
MAF Hz is 66.6, from what I have read this should be around 35 or so. Could this have something to do with using the V MAF and VIII ECU? Any way to adjust for this?
Timing is 33* advanced, which corresponds on the timing map because the RPM's are so high.
ISC steps are 0, which means the ISCV as hard as it can to lower the idle. BISS is also all the way screwed in.
Coolant temp was 192 during the above readings so normal operating temp.

Speed Adjustment Screw setting in EvoScan still has zero effect. Evo V ISCV.

Anyone?

Bladey

I believe that evo 5-9 maf's are the same are you sure you wired in the evo 5 ecu correctly? cause when i put an evo 7 ecu into my friends 4 there are one or two wires to change even more if its an RS ecu

9!'clipseDOHC

iTrader: (7)

I had it confirmed on another thread that the V MAF reads the same (or at least close enough to not make any difference) as the VIII. So the MAF is off the list.

The ECU is wired correctly. I swapped pins 8 and 22 (fuel pump and AC), disconnected pin 87 (ACD), disconnected pin 91 (IC sprayer), and rewired the fans (which work correctly). Everything else is the same as far as the ECU pinouts go.

9!'clipseDOHC

iTrader: (7)

I lowered the timing in the 1500 and 2250 RPM columns from 10-40 load down to 8* from 33*. Afterwards I started the car and it was idling at 1600 RPMs. I took he car for a drive and came back and it was still idling right at 1600 RPMs. It's still high but at the same time that's a good 1000 RPM drop! Progress!

Also even with the lower timing and this RPM, my MAF Hz is still right around 60. I have read that this should be around 35 at idle. Anyway to change that? I am running a metal intake pipe with a K&N filter, which I guess could be elevating it.

roni4g63

iTrader: (1)

wait why was the timing in the low load range so advanced? I wonder what the car that the ECU came off of had as far as cams go. did you ever fully fix your issue?