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Lean Condition

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bogies87

Active Member
Joined
Apr 13, 2004
Messages
590
So I am still fighting a lean condition. Scanmaster numbers show BLM to be around 115, o2 are a little low too 750ish. Car runs ok but get knock under boost anywhere from .2 to 8.9. I have pulled all the spark plugs and they are whiter then they were when purchased. The exhaust side of the turbo is white also. I have tried turning up the fuel pressure and it makes no difference. I ohmed my injectors and they are all good, Maf maxes at 255 (stock), I have checked, rechecked and over checked for vacuum leaks. Kinda at a loss. I am leaning toward the mass air flow sensor or all my injectors took a crap at the same time (I actually had this happen before, long story but they started failing the exact same way car ran lean and no matter what I did nothing changed that until I changed injectors.) I need some help on this one.
 
Tried adding fuel through the chip? Any idea what your injector duty cycle is...those are smallish injectors.
 
I had the same problem one time. Come to find out, the 36 lb injectors that I bought, were not 36 lb injectors. I ended up buying some 42 lb injectors and one of Eric's chips for them and the car ran perfect! Good Luck!
 
So I am still fighting a lean condition. Scanmaster numbers show BLM to be around 115, o2 are a little low too 750ish. Car runs ok but get knock under boost anywhere from .2 to 8.9. I have pulled all the spark plugs and they are whiter then they were when purchased. The exhaust side of the turbo is white also. I have tried turning up the fuel pressure and it makes no difference. I ohmed my injectors and they are all good, Maf maxes at 255 (stock), I have checked, rechecked and over checked for vacuum leaks. Kinda at a loss. I am leaning toward the mass air flow sensor or all my injectors took a crap at the same time (I actually had this happen before, long story but they started failing the exact same way car ran lean and no matter what I did nothing changed that until I changed injectors.) I need some help on this one.
You have the ability to add fuel because of your chip. Add 8% and see what happens. It'll probably run good with o2 readings in the 840-860 range.
 
How old is the fuel pump/filter? Have you checked that your fuel pressure is rising one to one with boost?
 
If BLMs are 115,is that not a rich condition and the chip is pulling fuel???I am not a great tuner but this is my understanding.

Kevin
 
I tried adding fuel through the chip. Still no dice. Not sure how old the fuel pump is but yes, fuel is increasing 1lb for 1lb. I have changed the o2 sensor twice and nothing changes. The blm of 115 would not be a huge, huge concern for me but the fact that the computer is seeing a condition where it needs to pull fuel for what ever reason and I cant change its mind.
 
BLM's have no baring on WOT. Use o2 millivolts for WOT. Should be 780-800mv.

If you can't get enough WOT fuel, it could be one of two things. Injectors are at the end of the line or fuel pump is not keeping up. To know for sure you would need to data log injector duty cycle and fuel pressure.

If you don't know how old the fuel pump is, I think it would be money well spent.

Good luck

RL
 
Whats your fuel psi at Idle line on and off. And at WOT. Should be additive......line off is your chip s says set for 43 psi and you are running 20 PSI then WOT fuel psi should be.............63.
 
I have verified fuel is rising 1lb of pressure for 1lb of boost. I have no way of logging duty cycle but with pretty much a stock setup I would not thing 30lbers are maxing out. This has not been a problem until recently. I have not changed anything in my comboto increase horsepower lately. I am running a stock turbo, unported stock heads. Heck I am not even running that much boost about 13lbs to be exact.
 
How about posting those scanmaster numbers at idle/op temp? Gotta start with values at idle. We aren't splitting atoms here...
 
ALmost sounds like a vac leak or a boost leak. May consider psi'ingf teh intake tract and look for leaks
 
I fought the same or similar issue a while back. Mine was a bad MAF. I went with the LT 1 and the GEN II. I figured it out by putting in a known good MAF. Can you do that?
 
How much boost are you trying to run? What fuel? The narrowband O2 numbers mean little to me. I was running 10.4 AFR (rich) on the wideband, and my scanmaster was reading .730. Going from 10.4 to 11.7 on the wideband on a friends car still showed .710 to .770 on the narrowband.
 
Not trying to run massive amounts of boost. Just trying to get it tuned so I can start upgrading. The numbers do not mean much to me either just the fact that I get knock at 13 psi and have added fuel and it does not change anything. I mean I can not get it to run any richer. My plugs show a very lean condition no matter how much fuel I add. I have tried adding through the chip and through the regulator. After adding fuel I should be able to see my plugs change color. Plus I should see my scanmaster numbers change. I agree it has to either be injectors or the MAF..... but was trying to figure which one before I spend the money. As far as a known good MAF.... I do not have access to one. I may have access to a set of injectors, I am in the process of finding out if he has a chip for the injectors.
 
Like I said, scan numbers at warm idle would help figure out your problem. It could be numerous things at this point, some info would help eliminate some guess work.
 
BLM's have no baring on WOT. Use o2 millivolts for WOT. Should be 780-800mv.

If you can't get enough WOT fuel, it could be one of two things. Injectors are at the end of the line or fuel pump is not keeping up. To know for sure you would need to data log injector duty cycle and fuel pressure.

If you don't know how old the fuel pump is, I think it would be money well spent.

Good luck

RL

BLM in cell 15 is a trim for P/E fuel flow unless there is a patch in the chip to bypass that part of the stock programming. On a stock chip and a lot of older chips out there if your BLM in cell 15 is less than 128 the computer will lean out the P/E fuel flow. I suspect Eric's chips don't do this but it can be a problem.

Neal
 
I fought the same or similar issue a while back. Mine was a bad MAF. I went with the LT 1 and the GEN II. I figured it out by putting in a known good MAF. Can you do that?
Yup...the loaner MAF I have right now behaves this way....can't add enough fuel or alky....

I borrowed this MAF to get me on the road becasue my OE MAF took a real dump.

With the loaner, I have the chip maxed out and the alky all the ay up...even took a few lbs of boost out...but at WOT the O2's stay in the mid to low 700's and I see KR of 3-5 at WOT...it's a remanufactured MAF and something about the calibration keeps it from signaling for enough fuel at WOT. Mine is the third GN this loaner has acted this way on....so it's definitely the MAF.

I'll be putting MAft Pro on (whenever Full Throttle finally ships it to me....ordered it last Thurs and still not shipped) and an LT1 MAF I already have waiting....but for now...I can't go WOT....driving me nuttssssssssssssssss.....
 
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