dodaddy

I've been having this issue for ahwile whenever I go on cruises on the freeway. After about an hour of driving 60-70 mph, my car starts to stutter while trying to hit boost, or past vacuum, or get above 4,000 rpm.

I have been calling around and a lot of tuners say the car is going into "Limp Mode" which means the car starts running extremely rich because the ECU gets triggered because of something, and the place that tuned my car advised me that this happens to WRX's alot as well when boost is turned up. They explained the only solution is to disconnect the battery and let the ECU reset. I haven't tried it yet, but the car has been reading 10:1 air fuel on my AEM wideband gauge whenever this "limp mode" occurs, and smells extremely rich too.

I'm not 100% convinced that this method is the only way that will fix my car. It's scary when the car is fully shaking while trying to hit boost, then hitting boost fine once it's passed vacuum.

I need help, I'm considering retuning my car but with methanol, or just retuning it as it is.

My current setup:

2006 Scion tC
5 speed transmission
Greddy Emanage Ultimate w/440cc injectors
Greddy Bolt-On Turbo Kit
Greddy Downpipe
NGK Spark Plugs (1 step cooler than stock)
HKS SSQV Blowoff Valve
HKS Axelback Exhaust
Megan Racing Midpipe
Megan Racing S-Pipe
Agency Power Lightweight Crank Pully
Currently Tuned @ 6psi
255 whp/251 torque


Please please any input will definitely be appreciated!!!!!!

rhythmnsmoke

How long did you have it tuned before this happened? Don't recall ever having this problem myself. Wonder if it's your fuel trims getting out of whack.

dodaddy

It was tuned for about 6 months when it happned, I got it tuned last spring, then summer is when it happened.

BlackKnight

I know this isn’t directly related to your problem but this is an example of my car having an issue when running the Greddy Ultimate cause of the stock ecu. I was doing a burnout at the track to race the tuner raised my rev limiter which I ask him not to do and found out during my burnout. RPM’s climbed passed 6250 and went to 6500 so I let off the throttle (this caused the oem ecu to have full control over car again) stock fuel cut took away fuel. When this happened the Greddy tripped a fault and caused my car to run rich 10:1 the entire run the only way that I could fix my problem after I got off the track was to turn the car off for a few minutes to allow the Greddy to be reset and then restart the car without any issues. Standalone will not have the issues fighting with the oem ecu. Try disconnecting your batter for 10 min, reconnect, start the car and let idle for 10 with everything off so the oem ecu can re-learn. Overtime the fuel trim could have gone too far out of wack and caused and the issue. The factory ecu constantly trims fuel and since your boosted if I remember correctly your short term fuel trim will show positive reading and long term will show a negative reading (like I said if I remember correctly). I bet your long term fuel trim finally has gotten too far out of wack and caused your issue.

dodaddy

^^ that definitely sounds likes ome great advice. So aside from a standalone, is this possible to fix if I retuned?

rhythmnsmoke

Hate to say it too Nick, but I also don't think it was setup right when the redline was increased. You have to tune the car when you bump the redline as well. It has to know what to do when it passes that fuel cut point. I don't think that was done, or done properly.

ValenciaS

hey guys i think im having the same problem , I just installed my turbo kit and im running the greddy ultimate. My car at first was pulling so hard. now its not pulling at , im at work right now im going to try what you guys were saying.

BlackKnight

ZPI did it so he was the one who tuned it. Piggy backs only have 100% control at wide open throttle. While I was WOT it was fine the minute I took my foot off the pedal the oem ecu has control over it again which is what happen.

ValenciaS

Also to metion i can smell gas so I must be running rich, so just disconnect the battery for 10 minutes and then reconnect and let it idle for 10 without nothing on. Also is it required to unplug the ECU harness while the battery is off ?

BlackKnight

Just disconnect the negative cable and make sure it is not touching the negative terminal for 10 minutes this will give the system enough time to drain down completely you will not have to disconnect your ecu.


Biggest thing to realize you need a tuner that knows the system you are running and understands it inside and out.

ValenciaS

I understand, I thought my clutch was slipping but it cant be , i only have 7,xxx miles on my tc and its running at 7.5 psi, all of a sudden the car started to run alot slower then it was it dosnt even pull any more

dodaddy

Yeah I can definitely smell gas too, now that I think about it, I think it only happens after I have done like a freeway pull where i almost hit rev limiter either going onto an onramp or racing a friend. Man this is frustrating, I know there is a fix, maybe it's time for a retune another $150 an hour I'll have to pay lol

rhythmnsmoke

Yea I know. I dont think it might have been done right. Just going off of PTuning's accomplishments.

BlackKnight

That is very possible. I have learned the tuner needs to definitely know the system in and out. I have went to a lot of different tuners over the years and learned just because someone says they can tune it doesn’t mean they are proficient in doing so.

I want to know how Ptuning did it considering this is a piggy back and it will be fighting with the oem ecu.

rhythmnsmoke

There is also the solution of disconnecting the factory wb (primary) sensor. This will stop the ECU from overriding/fighting with the tune. It's a bit cumbersome seeing as how the slightest change in weather, and you will have to adjust your tune. In the event of emissions testing, you can plug it back in for that. I also noticed that in the Ultimate's software, you have a table that is designed to force the ECU into Open Loop in cell area's that were otherwise closed loop (ecu controlled). Can't wait to play around with that portion more as well. You know I keep you posted on what's going on Nick...hehee.

BlackKnight

Don't think like that immediately. If I where you cause the car ran that rich these are things I would do. Start by disconnecting the battery, change your oil, and change your spark plugs. Then reconnect your battery start the car and let idle 10 minutes for the ecu to relearn with everything turned off. See how this does. I bet if you pulled your oil dipstick you will smell more than oil and I wouldn't take a chance with the plugs either just change them.

dodaddy

I've changed the plugs already, and I've had the oil changed recently, it's still the same. I think it's the tune still, but I am still researching on the solution, cause I agree with you there could definitely be more issues.

BlackKnight

Have you disconnected the battery yet? Do this the emanage will not loose its tune by doing so it is flashed in a memory chip so you have nothing to worry about.

op07tc

iTrader: (1)

Just throwing this out there, I have the same problem on my car with the F/IC. I aggree with you, I think it's the tune. Past 4000rpm in 5th gear, espically when trying to set cruise control, the car is not stable at all. It will try to go into boost, but then I let off the throttle a tiny bit and it falls out, then I attempt to correct and it goes back into boost again. Emailed Paul Dezod on this issue and he said that sounds about right, and the only way to correct it that he knows of is some precise tuning in that specific area. It's just another reason why piggybacks < standalones lol. Good luck dude.

dodaddy

damn, that is bad news haha, but yes I have tried disconnecting the battery, that works temporarily until it happens again. SOmetimes i even get a check engine light saying bank 3 or bank 1 running to lean, but my air fuel gauge says its 10:1