Ok so the car is bolt-ons, 272's, hta35r, and so on. Anyway its tuned through aem ems and it just was dyno tuned 2 days ago. It was at a A/F of about 11.8's at 26.5psi. The car was running great with no problems up until tonight when I got in it and was having trouble.

My problem is now that the car is "hesitating" "studdering" when under WOT at full boost. I looked at my uego and it was showing an A/F ratio in the 17's. I lost my serial to usb adaptor so I cant log anything.

I was thinking ohh its because its so cold out, so I look at the temp and its 30 degrees outside. The car was tuned when it was about 35-40 out so I dont think that should play a huge role like this in the way the car is running.

Anyone have any ideas of why my car might be having this problem out of nowhere?

Here a links to a video of it before this problem occured
This was not the best pull but the only one that shows A/F's and some other info.
http://s220.photobucket.com/albums/d...Picture239.flv

 

check your plugs?

 

I put brand new NGK8ES in the same day as the tune because the 7's cause to much knock. But I will look at them again tom in the A.M. just to make sure.

Thanks, John

 

Bump,

Anyone know what could cause the car to get so lean. I didnt touch the tune and added no boost or nothing.

 

1) pre-turbo/post MAF air leak--have seen this personally do exactly what you said.

2) FPR/injectors/fuel pump/sump filter

any other simple things?

 

The car is proabably NOT going that lean

What is Prob going on is that a miss fire is going on and the lack of complete combustion is throwing off the a.f reading

Often when a car jumps from dyno to road and the temps change these kind of situations can result

try gapping your plugs significantly tighter and see if it helps

 

Thanks, I will try gapping my plugs closer. Would it be miss firing every time i get on it? once full boost hits my a/f readings go off the gauge ha, so I am affraid to get on it. It does it the worst in 1st and 2nd then 3rd and 4th are in the 15's. Boost levels are still the same I checked that.

 

Im running a map sensor not stock maf.

No FPR but the injectors are brand new along with the double pumper setup that ws installed before the tunning just 2 days ago.

 

Ok so I fixed the gap even smaller and its still showing up being way to lean. I finally was able to get the serial to usb adaptor.

Could someone please help me connect it to my ems. I had it connected but it was not reading rmps and a couple of other things. This is my first time connecting my laptop to my ems. I would like to log some 1-3rd gear pulls to show you guys whats going on.

 

car is freshly tuned. just go back to the tuner/should be something simple. i would not poke at it too much so the tuner can discern and fix quickly what happened.

i would guess the second pump is not kicking in or some other fuel flow issue. also could be a baro/temp issue, but you said the temps outside were close which makes me wanna stray from that.

lol your plug gaps are fine is you're putting down that much power on the dyno.

EDIT: you can check the fuel pump stuff/verify voltages/relays/etc.

EDIT2: verify the fpr vacume hose/solenoid setup etc. this would make sure the fuel pressure is rising appropriately with boost pressure. would be good to get a fuel pressure gauge at this point. i would stop there and take it back/i know the feeling of missing a sunday race day as my LSD is at the post office which is closed and i have to wait till next week for the install/etc.

 

I plan on taking it back, Just wanted to know if there was some quick fix or something I was over looking. The shops not open until monday but im just going to take it back. There are very helpful and fix a small idel issue i had already.

 

well...let us know what happened after its back up!

 

Ok I will let people know what the problems were. That was good info on the fuel pressure sending unit and 2nd fuel pump.

 

So they tested everything. They put in new fuels pumps, injectors, swapped out the FPR, FPSU, checked all the vac lines, loaded the map back on it.

The car was running good on the dyno earlier that day and said to pick the car up. I pick it up and this problem is still occuring. At this point we believe its something wrong with the ECU. They are sending it back to get checked out, so I hope the is the problem and I can have my car running again soon.

Ill post here again once the ecu returns.

 

We just got word back from the injector manufactur (sent in the old 1200's). They said the injectors were clogged with a thin metal wire? We are looking more into this, and at all my fuel filters and hopefully can get to the bottom of this set-back