My tuner tried to tune my utec a few days ago, and couldnt because the utec would just dump fuel as soon as the MAF sensor was maxed out no matter what the RPM. The utec does have a MAP sensor hooked up but for some reason once in boost the utec will not totally switch over to the MAP readings. So, my tuner called Jermaine at turboxs and he said that the crank angle sensor needed to be shimmed out because it was giving false readings due to my ats light weight flywheel. My question is has anyone had this issue, and if so how big of a shim did you put in to resolve the problem ?

 

Bump ! Anyone out there ?

 

I have tuned UTEC's with an ATS flywheel/Clutch,and didnt have an issue. Are you getting an unusual timing readings in your datalogger?

Also, the UTEC has a tendancy to read ahead a little bit. At what RPM is the UTEC dumping fuel?

 

According to my tuner and jermaine which he e mailed the maps to all of the values for fuel and timing look perfect. It dumps at all different rpm's depending on throttle position causing the maf sensor to max out. So when he mashed the gas it dumped at lower rpm, and when he only went about 40 % throttle it dumped in higher rpm's. Hope that makes sense.

 

Interesting. Keep us posted on what you find out.

 

Will do.

 

I'm tuning this car. I've left Jermaine at TurboXS a few messages asking for the thickness of the shim he wants us to use, or the contact info of anyone who has performed this fix, so we'll see what happens. If anyone knows this info please let Dave or I know! We're not going to throw washers in there and see what happens.

According to Jermaine the fact that the MAF maxes right when the car dumps fuel is purely a coincidence.

-Mike

 

We tested another UTEC in this car with the exact same result.

 

Inn-Tune, at WOT, at what RPM does the UTEC dump fuel? What load column are are you in?

 

40% load (around 7-8psi with our settings). boost cut is set at 14 psi.
4000-4500 rpm

-Mike

 

Try doing this.

For instance, lets say in the 40% load column, you have 13ms of duration at 4000rpm. Copy the 40% column values all the way out to the 100% column. Sometimes, the UTEC will read ahead on the fuel table, and if you have some high pulse widths in areas that you arent theoretically reaching, it can cause the UTEC to dump fuel.

Let me know if that works.

 

Already thought of that and tested it. None of the values in the whole fuel table are near as high as the car jumps to.

 

Is the car going pig rich, or is the power abruptly cutting out (like a fuel cut)

 

I know it's going pig rich because in the log when the car freaks out it's because the UTEC prescribes a pulsewidth around 19.5 ms. I'm sure it just chokes on fuel for a second.

Everything else in the log is normal.

-Mike

edit: In the fuel map the pulsewidth in that region is in the ballpark of 11-12 ms, so jumping to 19.5 would surely bog the car out.

 

Well, I am stumped. So the highest IPW you have in your map...anywhere...is much less than 19.5ms?

What injectors are you running?

 

My injectors are 750 cc rc's.

 

I am still stumped. Having tuned dozens of 350Z UTEC's I have never experienced this before. Since your tuner swaped UTEC's, I can only assume it is not related to the UTEC. Wish I could offer more help.

 

Thanks for all the responces. Yea it is definately stumping us too. I wanna assume it is something in the car, but the car worked perfectly fine 2 days before the utec went in when it was tuned on an e manage. Well as soon as we figure it out I will be sure to post results for anyone else that might be having this problem ( I can think of 2 others off hand ).

 

This is very similar to an issue we're having on a APS ST w/ cams and UTEC. Another event we're having is low fuel pressure at idle and under boost. After the car warms up, we see only 45psi at the fuel rail. Under full load and 8 psi boost, we're only seeing 56-59 psi fuel pressure. According to APS, this number should be 66 psi. So we're 7 psi low on the fuel pressure.

Check your fuel pressure. It may be related. At this point, I'm just throwing darts at it. Maybe this, maybe that. The UTEC is very new for the VQ's. Maybe there is some type of sensitivity issue on some cars.

I'm stumped! I'm changing out the bosch regulator first with a SARD unit. The SARD is small and adjustable. It should fit in the same area as the bosch unit.

Our car in question is an 04 G35 6MT coupe.

 

Thanks for the suggestion, I will also check this, anything to get the car up and running good !