Values for Long & Short Term Fuel % Trim? - 07 GT

3390 Views 6 Replies 3 Participants Last post by Heller, Mar 21, 2015

Heller

Discussion Starter · Mar 16, 2015

Hi together!
Could anybody give me the values I should be able to read for the Long & Short Term Fuel % Trim?

The story behind:
My 07 GT has been throwing the lean codes three times within the past 100km of driving. It's not my DD, so I can't tell if the CEL would come on daily, but it is frequent.
The first time it happened about a month back. This time P0171 & P0174 popped while I was accelerating, speed close to 140 Km/h and just on top of a short hill. I couldn't feel any power loss nor unusual behavior.

According to the readings, about 50km and two weeks later, the same codes at the exact same location come on again. Scary, as it was really the exact same position.

Cleared the codes again and now today, 25km later ONLY the P0171 popped up. Again no power loss nor unusual behavior. Actually I didn't realize it in first place, just when I was close to home...

I took some screenshots of the code, freeze frame and live data. Could someone with a knowledge have a look on it and tell me if these values are acceptable.
Don't want to replace the Injectors if there is enough fuel coming through...

For your information, I have a non tune required Spectre CAI (Tube insert) installed for more than a year. Never had problems until now, so I actually don't expect it to be the CAI.
It's possible that the Filter is clogged, as we had a few sandstorms the last weeks, but in this case it wouldn't run lean. Would it?
At my new place here, I'm able to drive about 20km/h faster than before and with every km/h faster I recognize the hood flattering a lot more at the position of the air intake. Might this be a reason? Maybe a combination of the speed and hood pumping creating turbulences... just an Idea...

Sorry for writing books ... and thanks for your help!

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Bullitt95

· #2 · Mar 17, 2015

A clogged air filter won't make the engine run lean, but you might wanna check for any vacuum leaks in the lines coming from the intake manifold, and make sure the intake tube hasn't come loose from the throttle body allowing unmetered air to enter the engine.
Sine you live in Dubai, you might wanna contact Louie at L&R Performance in Dubai Investment Park 2 for further advice. He;s akso the administrator and founder of the Emirates Mustang Club (EMC) where you could join as a member (if you haven't already).

Emirates Mustang Club

I live 130km from you in Al Ain and we're planning an EMC drive to RAK this Friday if you wanna join in. Meet at Ace Hardware Festival City at 09:30.

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Heller

Discussion Starter · #3 · Mar 18, 2015

Bullitt95 said:
A clogged air filter won't make the engine run lean, but you might wanna check for any vacuum leaks in the lines coming from the intake manifold, and make sure the intake tube hasn't come loose from the throttle body allowing unmetered air to enter the engine.
Sine you live in Dubai, you might wanna contact Louie at L&R Performance in Dubai Investment Park 2 for further advice. He;s akso the administrator and founder of the Emirates Mustang Club (EMC) where you could join as a member (if you haven't already).

Emirates Mustang Club

I live 130km from you in Al Ain and we're planning an EMC drive to RAK this Friday if you wanna join in. Meet at Ace Hardware Festival City at 09:30.

Thanks a lot for your reply and information, Bullit95.
I appreciate your details about L&R Performance, as I just relocated to DXB 3 month ago and still searching for the "Places to be" and a mechanic to trust... Already the import and registration of my Stang was a struggle... Now it continues with the parts.
May not join this weekend, as we are having visitors, but its nice to know that there is a nice community with activities over here.

Back to the actual topic,
I already checked every connection of the CAI System, without noticing any leaks. But I will take it apart the next days, to really check in detail.
I´ve noticed some cracks (not deep - only surface) on the rubber of the cone filter. I´ll investigate from here, as I have read about Mustangs running lean even with just having a bigger filter and more air infront of the MAF.
Maybe these cracks are deeper than expected... It´s just a thin straw I´m holding on to right now.
Next step will be a Fuel System / Injectors cleaning and fuel filter replacement. Did it a few month back, but since I´m not driving frequently, you never know what is sitting there in the tank, clogging the filter & Injectors.

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Bullitt95

· #4 · Mar 18, 2015

A new fuel filter and some fuel system cleaner definitely won't do any harm and might even help.
I'd definitely recommend you get in contact with Louie at L&R Performance.

Contact Us : L&R Performance

He's the man when it comes to Mustang servicing and upgrades. I'm taking my own car to him this Sunday to have some upgrades installed (McLeod RXT clutch & billet flywheel, Ford Racing braided steel clutch line, Barton shifter, Powerslot front rotors, Hawk ceramic front pads, and Ford Racing cut n' clamp X-pipe).

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nicholasa631

· #5 · Mar 21, 2015

Just curious with your CAI have you recently cleaned your air filter and recharged it? I only ask this because I had recently had someone bring in a car with nearly the same issue and the cause of the issue was he had recently recharged his air filter and either sprayed too much oil on the filter or put the filter on while it was still absorbing the oil and the MAF sensor had some oil on it. If you can clean the MAF and the air filter, check everything is fully connected and has a good seal and then go from there

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Bullitt95

· #6 · Mar 21, 2015

I'd highly recommend cleaning the inside of the throttle body at least once/year, preferably twice. If you have an aftermarket CAI and a more aggressive throttle response than stock, even a small amount of dirt inside the drive-by-wire throttle body can cause the idle speed to become erratic, at times too low, and in extreme cases cause the engine to stall. If your engine doesn't idle at a steady 750rpm, clean the throttle body.

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Heller

Discussion Starter · #7 · Mar 21, 2015

nicholasa631 said:
Just curious with your CAI have you recently cleaned your air filter and recharged it? I only ask this because I had recently had someone bring in a car with nearly the same issue and the cause of the issue was he had recently recharged his air filter and either sprayed too much oil on the filter or put the filter on while it was still absorbing the oil and the MAF sensor had some oil on it. If you can clean the MAF and the air filter, check everything is fully connected and has a good seal and then go from there

Bullitt95 said:
I'd highly recommend cleaning the inside of the throttle body at least once/year, preferably twice. If you have an aftermarket CAI and a more aggressive throttle response than stock, even a small amount of dirt inside the drive-by-wire throttle body can cause the idle speed to become erratic, at times too low, and in extreme cases cause the engine to stall. If your engine doesn't idle at a steady 750rpm, clean the throttle body.

Hey guys,
unfortunately not. I haven't cleaned the CAI Filter yet, but I'm frequently cleaning the throttle body as well as the MAF sensor. Minimum twice a year when I do my full maintenance and change all the fluids...

Have checked the system again for vacuum leaks, but everything is tight and well connected. Idle is and stays stable!

Don't get the lean codes with every run. Thursday I didn't get it at all as I was just cruising, no hard acceleration. It seems it has something to do with the load.

Well, as previous mentioned, I'll prepare everything to clean the Fuel System, change the Filter and hope it will sort it out.

Further, I'm planing on removing the tube insert of the CAI and Re-Tune my Stang....

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Values for Long & Short Term Fuel % Trim? - 07 GT

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