When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
EVO IX fuel cut at 4800RPM consistently regardless of boost level.
Please Help
Description of problem: Car is hitting a fuel cut(IDC's will randomly go to 0 @ 4800RPM. AFR's go to 12 initially, richen up, and then lean out in parallel with/just before the cut.. This happens regardless of boost my tuner adjusts for (from 16# to 24#.) It feels like the car is hitting a brickwall. Car runs perfectly below that and makes boost fine. I did a boost leak test and only issue I found were the Throttle Body shaft seals which i replaced and the leak was fixed. I've checked the factory grounds and cleaned them all.
Car history prior to: Car was tuned in washington state about 2 years ago and since I have moved to South Carolina. Car started to do the boost cut around 4800 rpm after the move but i had another vehicle to daily so i wasn't super concerned and i wanted to do some mods to it. I went ahead and replaced my ghetto UICP with a nice short route UICP from VR-Speed. I knew i'd need a tune either way and attributed the boost cut to the change in elevation as well as the humidity and general climate of the area. I still drove with the car but kept out of boost for the most part except a couple pulls to see if the issue was consistent or not. The car continued to do so and the AFR's would go to about 12ish and richen up like the ECU was controlling Fueling as appropriate as boost built but then the car would lean out and it would hit the fuel/boost cut. The car (even today) continues to do this and even with the boost cut turned off the car continues to have this issue. The tuner adjusted fueling and boost with no luck today..
Car details (performance and electrical wise):
'06 EVO 9, stock bottom end.
Buitl head with Jun 272 cams
UICP and Short Route UICP, VR speed 3" intercooler, and a 4" SD Intake.
Walbro 450 -> FIC 2150's. Currently running stock fuel rail and FPR (I just ordered a FIC rail, FPR, Fuel Press gage, as well as a new injector O-ring set incase the fueling setup is the culprit. I also have a spare Walbro 450 i was saving for once i built the bottom end and did a double pumper but i can toss it in to try out if need be)<br />E-85 only (Zeitronix ECA for indications)
stock throttle body and intake manifold but I do have an EGR delete.
FP Black with ported compressor housing with a Turbosmart wastegate actuator. Grimmspeed 3 port EBCS.
Spoolin up COP with OEM equivalent NGK plus gapped to 23 thousandths but they do have a slight amount of carbon buildup from running rich down. (I went ahead and ordered a set of 1step colder and intend on gapping to 18 thousandths.)
tuned on speed density
AEM Boost, Voltage, and Wideband gauges for indications. Wideband is hooked to ECU but was only done a couple days ago (way after this issue started occuring) and is only for logging purposes via the rear O2 sensor input.
factory ground wires but I plan on going to a car audio shop or radioshack equivalent and upgrading to 4gage wires and doing some additional ground points as recommended in some of the how-to's in that part of the forums.
Battery is relocated to the trunk and I was told by the tuner that it can impact the car depending on how the car grounds are. I've gone ahead and ordered an ETS minibattery and tray just to rule it out. Worst case i'll sell one of them later.
so to reiterate my upcoming troubleshooting:
-1 step colder plugs gapped to 18 thou
-4ga ground wires and additional ground wire runs
-replace fuel rail, FPR, and install a fuel pressure gage to ruel out a fuel supply issue<br />-remove battery from trunk and install ETS mini battery in engine bay for much shorter hot and ground wire runs
What do you guys recommend I do? I'm lost after the above and really don't even know where to look next. I've attached logs from the runs on the dyno today. Thank you for any help, it is greatly appreciated.
I
pulled the plugs and replaced then with NGK R7437-8's gapped to 18thousandths. These are the old plugs gapped to 22-23 thousandths based on feeler gauges. Car starts significantly better(first crank vice 3-5 seconds of cranking) but it may just be from the warmer weather. I have new tires on order so I'm waiting to try more pulls until the rubber is replaced.
To the top. Issue still ongoing after plug swap. I'm looking into disabling launch control in case car isn't registering being driven and attempting to cut fuel for launch control.
Yep, part of Tephra. Up towards the top, IIRC. Second or third list of options, I think. I'll screen shot my laptop next time I'm on it.
Found valet mode. It's not on. I went ahead and unplugged the clutch safety switch and the clutch switch for launch control.
I also changed stationary rev limit to 7500rpm and same for valet mode rpm's.
Made 2 pulls and she still exhibits same problem of going lean and cutting fuel at 4800rpm as evident by IDC going to 0.
Last edited by theonlyherb; Apr 14, 2019 at 05:03 PM.
Found valet mode. It's not on. I went ahead and unplugged the clutch safety switch and the clutch switch for launch control. Made 2 pulls and she still exhibits same problem of going lean and cutting fuel at 4800rpm as evident by IDC going to 0.
If memory serves me, unplugging the switch makes the ECU think the clutch is being pressed, which if you are setup for NLTS then that could be triggering. I would try tuning off NLTS if its enabled and also try raising the stationary rev limiter to say 7k and see how that goes.
Mar 2, 2019, 10:13 PM
EVO IX fuel cut at 4800RPM consistently regardless of boost level.
