Hope someone here has some insight as I have just about tore every hair from my head. Happens only after UTEC is in. When you touch the throttle slightly, ie 2-5%, the car runs very lean, ie 25.1! But if you give it more throttle, it goes away and back to normal. When it is running lean area, it hesistates. I can reproduce this during idle when I blip the throttle but worse underload. Some times I would have to rev it up just to get it moving. But once it is on throttle, everything is okay. I already tried replacing the factory FPR since I thought it wasing hold fuel pressure to no luck.

Its just part driveability that I having problems with. Full throttle is fine.

Thanks again!

Alfred

 

Post up some logs

 

Did you put in larger injectors?
Did you make any changes to the 0% load column?

 

I wish I can, somehow I misplaced my floppy drive for my laptop so I cannot save files. I have to get a new laptop or at least a new drive....

Alfred

 

Buy a USB thumb drive. Very effective and cost efficient That's what I use and eliminated the floppy completely.

 

Nope, stock injectors, and yes I did change the 0% column but all that does is make it richer at idle but right when I press the gass pedal a hair, it runs lean, then rich again. Its lip the tip in throttle adjustment is adjusted so it runs lean right when you tap the pedal. But I know the UTEC has no tip in adjustment.

This also happens in others gears, ie 5th gear where you are crusing and blip the throttle a little bit, causes it to run lean, but if you continue to give it gas, it will run normal again.

Also, I noticed today that I found another problem. Sometimes when I hope the throttle steady on 5th gear, the car runs SUPER rich, ie 9.6 AFR's. This is before open loop since it is under 20%. I tired ajusting the 0% colums in that area to no luck since it only sometimes does it. If I give it more gas, ie go into open loop, AFR's are normal again. Gosh, so many problems with UTEC.

I just hope I dont have a faulty unit.

Alfred

Oh BTW here are my engine mods, if it helps.

Walbro Fuel pump
Buschur Intercooler
Buschur Hardpiping
Agency fuel rail
HKS 280 cams
Perrin short ram intake
UTEC, ofcourse
O2 housing thru catback all 3 inch.

 

Did you buy the UTEC new?

 

Nope used.

Alfred

 

Did you completely reset it (reflash the firmware) before you used it? Its possible some of the settings are leftover from the previous owner..

 

Yes, complete reflashed twice. Used stage one and two maps with a little customization. Funny thing is, car runs great when on 100 throttle, almost perfect AFR's. Just part throttle is driving me crazy.

Alfred

 

Is it possible that your stock O2 sensor is bad that the ECU uses to adjust fuel? Are you throwing any CEL codes right now? I know from experiance when I was running really rich or really lean for any amount of time it throws the O2 sensor not responding error on my car. Make sure your CEL isnt disabled in the UTEC and see if anyone has made changes to the Stock Injector and Scaling settings in the Open Loop Fueling options under parameters for your map. They should both be at 550 right now since you are running stock.

Good to see another Pacific NW guy online!!

 

Yes, constantly get the PO172 ( car running to rich code). Have a OBDII tester to clear it. Cel disable DOESNT work on my UTEC. I tried it before but it never disables the check engine light so I just clear it if I dont want to see it there. Yes, fuel injector settings are correct at 550. It seems like I never meet much of the crew here in Seattle. It will be fun to meet them sometime.

Thanks again for your ideas.


Alfred

 

Well, I've seen what your describing at idle, however I noticed that my idle fuel trims were way off (25% LTFT) and it would swing back and forth periodically, barely running..

What is the MAF input, and output MAF HZ at idle? Thats usually a dead giveaway.. also, look at the OBD-II scanner and see what your Airflow is at idle, it should tell you if something is up (with and without the UTEC)

On a stock turbo car, with stock sized injectors, idle MAF reading the ECU expects is about 30hz-38hz, with injectors, or cams with alot of overlap, you usually have to raise it or lower it to get it back into range. Cams with alot of overlap tend to have low vacuum and can lower the maf reading significantly because of it, which can cause your idle and off-idle tip-in to become really lean until it catches up.

A very leaky BOV at idle can also cause a very lean tip-in. Ive seen some of this with my blowthrough sensor, whenever the airflow lags severely behind the throttle input changes (especially at idle) it will run lean until the airflow catches up.

What concerns me is that you say its not a problem without the UTEC installed, so you need an OBD-II Scanner that can view all the relevent sensor data, and view it with the UTEC installed, and without.. Look at your Air flow, coolant temp, air temp, O2 sensor readings.. see if they all look the same.. Also make sure at idle the car is runing closed loop..

Sometimes I find if I start my car immediately, it doesnt give the UTEC time to initialize all the sensors (the MAF) and then passes a bad signal to the ECU, which in turn runs open loop and idle is poor, tip-in is lean, and part throttle driving ends up being really rich..

So next time you start the engine, turn the key, wait three seconds, then crank it.. see if that helps..

 

Oh and if the CEL disable doesn't work, then there may be something wrong with your UTEC.. If its enabled, it should turn that light off, it doesnt eliminate codes, just turn off the light.

In all honesty, people who own UTEC's usually don't sell them for no reason.. and I've seen many used UTECs go to new owners that are defective or damaged in some way. So don't rule that out. I love the UTEC, but don't have alot of confidence in how used electronics are handled by the previous owners. The good news is TurboXS can check it out for you and repair it.. They have very good service.

 

The BOV thing is very true, I changed my to an APS and tip-in is very smooth. Also do what MJ said and wait 3 sec before you start the car, this make a huge difference expecially with my car. If I wait my MAF hz is at 38 and if I dont it's 48-50.