running lean
running lean I am having problems with my L-terms. They max out at +25 while at idle. Bought the car used and since then I have been getting P0171 and P0174. It's an '01 and I left it with MTI for a month and they could not figure it out. Am I losing power due to the problem or should I just ignore it? Starting is also a problem, the idle bounces up and down until it finds a sweet spot, but I have to leave my foot on the gas to keep it on. I would really appreciate some help. MTI did the tuning.
Re: running lean Well that's their cam so I'm surprised they couldn't tune it; must have a sensor that went bad. You need to hook up EFILive and log everything on a variety of driving conditions, then play it back slow with the "chart inspector" and see if you can spot the problem.
Re: running lean I do not have access to EFILive5. People have told me just to buy a MAFT and that might fix the problem. The problems been there since before any mods.
Re: running lean Both banks lean.
If your LTerms go to +25 while the car is at idle, but quickly drop to around -10 to +10 once you get on the gas, then you have a small vacuum leak OR your MAF needs to be replaced.
Slap a different stock MAF on and see if the problem goes away. If the problem persists, then check all of your PCV connections. Make sure that the block is under vacuum (the oil cap should make a sucking sound when removed).
If you can't find any PCV problems, cap your PCV system going into the intake and throttle body. Open your oil cap to allow your block to vent. See if the problem goes away. If it does, then you have air entering your block somewhere and getting sucked into the intake via the PCV.
The hard start problem is from the vacuum leak as well. A car that has unmetered air (not measured by the MAF) will have a tendency to surge and not want to stay running.
Good Luck
If your LTerms go to +25 while the car is at idle, but quickly drop to around -10 to +10 once you get on the gas, then you have a small vacuum leak OR your MAF needs to be replaced.
Slap a different stock MAF on and see if the problem goes away. If the problem persists, then check all of your PCV connections. Make sure that the block is under vacuum (the oil cap should make a sucking sound when removed).
If you can't find any PCV problems, cap your PCV system going into the intake and throttle body. Open your oil cap to allow your block to vent. See if the problem goes away. If it does, then you have air entering your block somewhere and getting sucked into the intake via the PCV.
The hard start problem is from the vacuum leak as well. A car that has unmetered air (not measured by the MAF) will have a tendency to surge and not want to stay running.
Good Luck
Re: running lean Check your brake booster hose as well
Check you intake manifold alignment atop the heads.
Ask MTI how much the heads have been milled. A stock intake will not seat properly on heads that have been excessivly milled. If the heads have been done more than 30 thousands it would probably be worth your time to remove the intake and blue your intake to head seals.
Check you intake manifold alignment atop the heads.
Ask MTI how much the heads have been milled. A stock intake will not seat properly on heads that have been excessivly milled. If the heads have been done more than 30 thousands it would probably be worth your time to remove the intake and blue your intake to head seals.
Re: running lean I have another question man, MTI told me they do not mess with Lterms. But everyone I have talked to said they recieved plenty of performance by doing so. Also are these codes causing the Lterms to be maxed out. MTI has retuned my car twice, they could not get it to idle. Do you do computer tuning and if so how much.
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Re: running lean Man they had my car for a month, nothing got fixed. They told that not to many cars can beat them, but mine did. I am almost begging for help. The car runs good, its just getting it to start. Also after I do the burnout it shuts off unless I pedal it. Also when they dynoed it they told me it was missing about 20 horses.
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Verdad Gallardo Re: running lean We do computer tuning for 550. Includes dyno time, two free reflashes (when you change something on your engine), and our guarantee.
We will be holding a special coming up this Monday for two weeks.
400$ will get you everthing that I mentioned above.
We will be holding a special coming up this Monday for two weeks.
400$ will get you everthing that I mentioned above.
Re: running lean That sounds great but I am from South Texas. Making it to your dyno would near impossible. How good would you be at mail order. Last night I tried everything. I checked all vacuum hoses, swapped MAF, swapped complete Throttle body, and changed O2's. While on A-tap the terms starting going up and down. The car had never done this. this morning it started up fine, but drove like crap. After a shot at WOT, the power came back, like a loose connection or the PCM is out of wack. I am already begging for help.
TECH Resident
Joined: Jan 2002
Posts: 754
Likes: 0
From: USA
Re: running lean IMHO, if I were you I would go back there and demand you either get a full tune or your monehy back.
Half *** tune on a chassis dyno with a few pulls with less then a few minutes run time us useless and does not even allow most of the normal fuel trims to be used and calibrated nor does it allow to see what happens in the real world when trims average out when all 23 cells are used, shifting of gears, etc.
Fuel trims have to be calibrated because one cell effects the next cell within the engine KPA and RPM range.
Consider on a dyno the PCM only uses about 6 or less of all the trim cells and 1 to 2 hours after a dyno tune all the other trim cells used cause total calibration to change.
To get good PE or WOT the part throttle has to be good to get you there.
Those not wanting to properly tune ALL trim cells either want to bang the car out quickly for profit or do not know how to tune each trim cell so that they all are within a few % of zero.
It is tuning like that, that makes the rest of us tuners look like lazy bums so I do get P.O'd when I read posts like this.
Half *** tune on a chassis dyno with a few pulls with less then a few minutes run time us useless and does not even allow most of the normal fuel trims to be used and calibrated nor does it allow to see what happens in the real world when trims average out when all 23 cells are used, shifting of gears, etc.
Fuel trims have to be calibrated because one cell effects the next cell within the engine KPA and RPM range.
Consider on a dyno the PCM only uses about 6 or less of all the trim cells and 1 to 2 hours after a dyno tune all the other trim cells used cause total calibration to change.
To get good PE or WOT the part throttle has to be good to get you there.
Those not wanting to properly tune ALL trim cells either want to bang the car out quickly for profit or do not know how to tune each trim cell so that they all are within a few % of zero.
It is tuning like that, that makes the rest of us tuners look like lazy bums so I do get P.O'd when I read posts like this.
I have another question man, MTI told me they do not mess with Lterms. But everyone I have talked to said they recieved plenty of performance by doing so. Also are these codes causing the Lterms to be maxed out. MTI has retuned my car twice, they could not get it to idle. Do you do computer tuning and if so how much.
Re: running lean I have tried plenty of times with these guys man and I just cannot get them to do a good job. I live in deep south Texas, and they are the closest tuners I know. I am not sure how good mail order tuning is. They first thought my problem was a broken intake, so they took it off and tested it. Of course that was not the problem. I know car has some power left over but if I cannot get tuned properly, what the hell am I supposed to do. I ordered a MAFT, to see if that would fix the problem. Give me some kind of suggestion.I checked everything on the damn car, and the Lterms are still maxed out at 25%.
TECH Resident
Joined: Jan 2002
Posts: 754
Likes: 0
From: USA
Re: running lean Are you using a modified MAF or T.B ?
Check for leaks in exhaust system ?
Using Cutouts ?
Were O2s tested and were their wires sliced or extented ?
Was fuel rail pressure tested for around 58 lbs ?
Were injectors tested ?
Check for leaks in exhaust system ?
Using Cutouts ?
Were O2s tested and were their wires sliced or extented ?
Was fuel rail pressure tested for around 58 lbs ?
Were injectors tested ?
