First off, here is the car and associated mods for reference.

2006 GG IX
Stock Block
Tomeii 260 Cams
ARP Head Studs
Hallman MBC
AMS Intercooler
AMS LICP
Crushed 9 BOV
Stock UICP
3" TBE
Precision 1200CC
Walbro 255
AEM Wideband
TBolt Clamps everywhere
Kuniiizzzeee Dial In Tune (Road Tune)
E-85 Fuel
QM Twin (EDIT* Exxedy Hyper 4 Puck Single*)
Problem -

Car was tuned by AMS on pump gas originally at 23psi. Car ran great.

Car was road tuned on E*85 next and ran great but I had boost leaks. It would not make it past 24psi. Boost leaks fixed and retuned.

Car was then touched up at 30psi. Car runs fantastic at WOT. Starts great. Idles solid at 1K rpm. Everything about the tune is spot on except for one thing.

THROTTLE HANG! More specifically, when shifiting gears over 4K rpm in mild to slightly aggresive boost, the throttle jumps 1K rpm after pressing the clutch in. The clutch is not slipping. It grabs crazy good. The problem makes the car not enjoyable at all. It appears that I can not drive. In fact, It even made me second guess myself, "am I really removing my foot all the way from the gas pedal" etc....

Any help you guys can share from personal experience with this problem would be much appreciated. Thanks guys.

 

i read a post like this a while ago..and i think the guy was infact leaving his foot on the gas slightly..but idk bro..

if you completely have ur foot off the pedal whatsoever..and clutch in...and it doesn't do it..than you must be still on the gas when it does it...

drive in socks

 

Ha ha. I wish it were that simple man. I made a point to completely pull my right foot away from the pedal before shifting and it still does it. It is almost like the throttle plate is being forced open or the spring tension is not enough to return it closed intially. I dont know, that is why I am so frustrated.

But I do know it is not me leaving my foot on the pedal. I have ruled that out.

 

This is a common problem, I'm figting it on mine too. I have gotten mine a LOT better but it still happens on occasion. The problem is high load, part throttle, above 3500rpm. The more weight you have in your car the worse the problem is too (because it puts more load on the engine at lower threasholds). So I thought I had mine fixed, and last weekend I loaded my car up with coolers and people to go to the Indy race. On the way there in traffic, part throttle, boost builds, high loadcells hit, let off throttle and "vroom" throttle hang. I have logged my car every day every single time it has run for the past two months (yes, tons of logs)...

Anyhow the way I helped mine was to play with the ICSV stepper tables and the DecelFuel tables. Seems this problem is only evident on 05 and 06 Evo's. Since that's the case I got roms from 03 and 04 cars and compaired them to mine, those two tables were VASTLY different. I made those two tables match the 04 tables and that's what helped (almost fixed) mine. I still have it though, so there's something else going on.

 

Yes. The problem does get worse with another person in car but it does it when I am by myself as well.

My tuner says it is the IAC doing its job too well and that it is a common problem with Evo's. I just cant by that. The problem takes away the enjoyment of the vehicle to me. Hope there is something else going on that can be easily corrected.

Any other high boost E85 stock turbos guys want to chime in here?

 

Happens to me too. I notice it mostly when I get on the gas kinda hard to 4-5k, throw in the clutch and the RPM's just hang around 3-4k RPM for several seconds. If I tap the gas while it is hanging it goes away.

 

mine goes away if i tap the clutch..i have another iac that i'm gonna put in though

 

this happen to me before and it actually stopped when i got a different bov and mounted it on the uicp because it released the air out faster then it would if it was in stock position and thats why throttle hangs a lil because it go to travel more. not sure if i sed that rite but thats wat i was told and it wokred mb try chanign bov.

 

check out mrfreds iscv routine in this thread... there are 3 tables to combat throttle hang! the (2) rpm adders, and the moderated by baro and iat map.

https://www.evolutionm.net/forums/ec...sassembly.html

 

Check for a Vac leak that's usally it.

 

Thanks guys - I have some work to do.

1. I might uncrush by stock 9 bov a bit.

2. I will check for vac leaks. But if I am not leaking boost anywhere probably not leaking vac right?

3. Tuner when he gets a chance will look at tables.

Any other ideas you all can throw out there.

 

Yeah, same problem for me under high throttle. My fix was to just use NLTS when I am WOT and going through gears (problem solved), or leave the car in gear if I am just doing a 1 gear pull. I am going to check out those icsv tables now though.

 

had the same prob my throttle body seals were leaking sooo bad it wasent funny and your tuner was right the iac valve is working to hard to compinsate for the leal so u get the " throttle hang" its the throttle body shaft seals, do a leak test bet u there leaking, very easy to fix too !

if thats not it someone said a clogged pcv valve

 

I have the works TB seals, I will throw those in. On a boost leak test I dont here anything leaking from there all the way to 32 psi and I am only boosting 30psi. Who knows. Ill add that to my list of things to do.

Tks for the heads up. Ill report back after I am done.

 

+ 1 for vac leak check all the little houses and zip tie all vac lines