Running lean while in boost

So I just installed the racer X FMIC kit onto the car and sent over a couple log files to the tuner just to make sure everything was still good tune wise and I get an email back saying that something doesn't look right and I might have a fuel system issue. He saying that it's running lean while in boost. This is my first turbo car and I'm trying to learn as much as I can. The car hesitates IF I have the BPV fully open, but with it fully closed the car seems to run fine. Current mods are catless UP, catless DP, Cobb sf intake, full catback exhaust, GFB respons BPV and the racer X FMIC and as I stated before it is e-tuned. I have attached one log that I had sent over to the tuner. If anyone of you tuning experts could have a look and tell me what it is he sees. Thanks for any and all help

datalog7.csv

Your car is running lean and knocking badly. IDC is around 80% which is ok.

AF Learning D is almost -8% which is probably why it is running so lean (that -8% is carried into boost). Who tuned the car? Has the AFR always been like this except now it's a little worse?

Here's an example.

Say your AF Learning D is 0% with target AFR of 12.0 at peak torque.

Now it's -8% so that AFR is nearly 13.0 instead.

 

The AFR gets richer with higher RPM while load remains about constant. not a fueling issue.

Eric with torqued performance is doing the e-tuning. If it's not fueling and I'm hitting target boost, which I assume means there's no boost leaks, what else could it be?

Could be a small vacuum leak or the MAF scaling was slightly off before so the intercooler causing 3-4% change on top of it resulted in fueling being too far off from target.

Your tuner should try making an adjustment to the MAF scaling and see if that helps.

Make sure all your hose clamps are nice and tight on the turbo inlet and intercooler connections and throttle body.

 

If I tuned the car and the IAM dropped to 0.3, your car would be in limp mode right now so it would not be causing damage. So, don't take this situation lightly and only boost as needed to troubleshoot. Get a revision to the MAF scaling and at least try to get the AFR in line.

Ditch the GFB. Most shops wont even tune your car if you have a GFB they are terrible and all have issues.

IME, Eric is a very talented and careful tuner. I will look over your log later but if he has asked you to check on hardware issues that's what I'd do.

your pull at time 95s has learned -2.45 knock and your dam is at .38. DONT DO ANYMORE PULLS LIKE THIS until you get whatever wrong fixed.

Could be a small vacuum leak or the MAF scaling was slightly off before so the intercooler causing 3-4% change on top of it resulted in fueling being too far off from target.

Your tuner should try making an adjustment to the MAF scaling and see if that helps.

Make sure all your hose clamps are nice and tight on the turbo inlet and intercooler connections and throttle body.

 

If I tuned the car and the IAM dropped to 0.3, your car would be in limp mode right now so it would not be causing damage. So, don't take this situation lightly and only boost as needed to troubleshoot. Get a revision to the MAF scaling and at least try to get the AFR in line.

 

Here's his response when I asked him to look at the MAF scaling..

 

"there is nothing wrong with the maf scale. The engine load numbers are proper meaning the maf scale is correct. The problem is 100% with the fuel system."

Thanks everyone for all your help and recommendations. I will be taking off the BPV this weekend and will also be looking over the engine for any obvious signs of any damaged hoses or what not.

So I was giving the car a little look over to see if I could see anything obvious and I found the throttle body hose was backed out, clamp was loose, pushed hose back on, tighten the clamp and while I was in there I put the stock BPV on. How much of my issue would be affected by this? Once again, I appreciate all the help with this as I'm still trying to learn as much as I can.

So I was giving the car a little look over to see if I could see anything obvious and I found the throttle body hose was backed out, clamp was loose, pushed hose back on, tighten the clamp and while I was in there I put the stock BPV on. How much of my issue would be affected by this? Once again, I appreciate all the help with this as I'm still trying to learn as much as I can.

 

 

 

Post-turbo leaks make you run lean in vacuum and rich in boost.

A pre turbo leak can cause lean condition under boost so check all the turbo inlet connections and hose clamps. Maybe you bumped something loose during the install.

Actually, visualizing this in a graph helps. I've seen this behavior before with a failing fuel pump or a fuel pump which did not have a good seal. Do you have an aftermarket fuel pump?

A pre turbo leak can cause lean condition under boost so check all the turbo inlet connections and hose clamps. Maybe you bumped something loose during the install.

Actually, visualizing this in a graph helps. I've seen this behavior before with a failing fuel pump or a fuel pump which did not have a good seal. Do you have an aftermarket fuel pump?

 

Stock fuel pump. I know the previous owner had something done to the fuel system I just have to go over the service records again.

i have attached another log file that i did after adjusting the throttle body hose and clamp and swapping out the BPV for the stock unit.

datalog13.csv

can you also log final fueling target or commanded fuel final? I forget what's called off the top of my head on the AP.

I'm with Th3Franz on this.

 

I've run into this exact issue before, to a lesser degree. I was having fuel issues under maximal pump demand, which only became worse with time. Then one day, I noticed the pump sounded as if it was cavitating whilst priming.... Turns out the canister filter in the pump housing was clogged and thus causing cavitation and subsequent overheating on the pump itself. I replaced the filter with new OEM and the pump with a DW65 and all was better.

 

However, when this happened to me my fuel trims were pegged positive in the C and D ranges. I'm not sure why your ECU is pulling fuel. It could've been from that boost leak. In actuality, how comfortable are you with the mechanical integrity of your GT? As in, if that's less than 100% you need to give the whole thing a fine toothed comb looking over before you continue with the E-tuning process. I only say that because an E-tune is based upon your car being 100% functional and mechanically sound. When that isn't the case... you run into all sorts of funky "pull-out-your-hair" issues.

I'm with Th3Franz on this.

 

I've run into this exact issue before, to a lesser degree. I was having fuel issues under maximal pump demand, which only became worse with time. Then one day, I noticed the pump sounded as if it was cavitating whilst priming.... Turns out the canister filter in the pump housing was clogged and thus causing cavitation and subsequent overheating on the pump itself. I replaced the filter with new OEM and the pump with a DW65 and all was better.

 

However, when this happened to me my fuel trims were pegged positive in the C and D ranges. I'm not sure why your ECU is pulling fuel. It could've been from that boost leak. In actuality, how comfortable are you with the mechanical integrity of your GT? As in, if that's less than 100% you need to give the whole thing a fine toothed comb looking over before you continue with the E-tuning process. I only say that because an E-tune is based upon your car being 100% functional and mechanically sound. When that isn't the case... you run into all sorts of funky "pull-out-your-hair" issues.

 

I bought the car used with 79000 miles and the previous owner had a pretty good service record folder. From the beginning I planned to perform all the preventative repairs but the car was running "good" and the mod bug hit me quick. Now the issues are slowing showing up. car seemed to be performing fine up until i installed the front mount. and also, the tuner never mentioned anything was out of the norm until after i sent in the log file for him to give a once over after installing the front mount. hopefully with the little adjustment to that throttle body hose and clamp it took care of the issue.

can you also log final fueling target or commanded fuel final? I forget what's called off the top of my head on the AP.

 

is this what youre looking for?

datalog16.csv

if you think you fixed the issue, reflash the map so your learning will reset

Fellas. I THINK I might have found the problem. I was reviEwing the hose routing diagram for the fuel system and noticed that the hose that goes from the intake manifold to the fuel pressure regulator was missing. I can't find it so I'm going to have to buy a replacement hose. Hopefully this is the issue.

Yeah that makes sense. Vacuum/ pressure reference for the fpr is really important

Fingers crossed.. just bought the line from my local subaru dealer, installed, reflashed the car and just got back from doing some logs.. let's see what he thinks!!

That was the problem fellas... thanks for all the help, it was greatly appreciated. Now the etuning can continue. Eric likes what he sees now!!

Where did you find the diagram? I'm having a similar problem. I keep going stage 2 from Cobb and I'm running really lean under wot. Only making around 10lbs of boost and my af ratio is around 17/18 only on wot.

 

Stock the car runs great. I've looked over everything and that diagram would help me

 

 

Sent from my iPhone using Tapatalk

Where did you find the diagram? I'm having a similar problem. I keep going stage 2 from Cobb and I'm running really lean under wot. Only making around 10lbs of boost and my af ratio is around 17/18 only on wot.

 

Stock the car runs great. I've looked over everything and that diagram would help me

 

 

Sent from my iPhone using Tapatalk

 

Yikes do no boost! you have a big leak. What did you do?

 

Plug the intake, and blow into the BPV return hose and close with ur finger and you'll hear the leak, although this sounds like a big leak so it may not even pressurize.