TXCAMSS

iTrader: (60)

My car is down on ET and MPH in the 1/4. It runs and idles fine. ATAP shows the O2s on Bank 1 to be consistently lower than Bank 2.

I have no codes stored and it feels strong, but something has changed. I swapped out both O2 sensors to confirm the readings and nothing changed. Any help would be appreciated.


James

GrapeApe

i would guess its something simple-- My best guess are these--fuel filter/o2sensor "clean them " sometimes a exhaust leak by the o2 bung will do that as well --crummy gas if its a injector you would of thrown a code --try runnin atap without a air filter and see if that does anything --how much of a loss in e/t ?

TXCAMSS

iTrader: (60)

I did change both the fuel filter and both O2 sensors today and I still have lower readings on B1 than B2. The O2 sensors were new and the double sealing washers gave a good sealing crush.

If the injector failing, then I could see a code being thrown, but what if it was just restricted or plugged?

I am down 1.5 tenths and 3 mph in the same air (DA) conditions.

I have played with the tuning (richer and leaner) and the car responds , but I end up back where I new the ideal A/F ratio needed to be.

Thanks!

GrapeApe

damn --hmmmm --well i guess its not hard to take the fuel rails off and peek at them
The only other thing i could think of would be the usual plugs ect. Do you have sims?
i've had a sim go bad before --and i had a K&N filter get oil on my maf "so i went back to paper" when you do a WOT run with atap --are you getting any knock retard?
Well I'm all out of ideas
if ya figure it out Pm me "So I can note it in my trouble shooting folder"
Well good luck

TXCAMSS

iTrader: (60)

Thanks for the reply Grapeape. I have the rear O2s deleted and I am not getting any KR. I did get oil on the MAF..(it's a long story). I'll clean it again and see what happens. I'll keep you posted. Thanks again!

My next step will be to pull the rails if I can't find anything.


James

Phate

iTrader: (2)

If you have access to a Tech2 then you can pulse the injectors using that and see if the fuel pressure drop is slower on the clogged injector.

Scott

Pro Stock John

iTrader: (34)

Unequal Ltrims is sometimes a sign that an intake manifold is not sealed on one side.

TXCAMSS

iTrader: (60)

I cleaned the MAF and the O2s are still off from side to side so I will move to the next possiblity

Well, the Ltrms look great. They are even (0-3) at cruise. Tonight I pulled the fuel rails and all the injectors. I cleaned them for insurance , but no obvious signs of a problem. I did swap the injectors that were on B1 and put them on B2 and visa versa. I hope this either swaps the lean or myseriously corrects the problem.

I sprayed water all along the intake while the car was running to se if there were any vacuum leaks. All is well there.

Could the fuel pressure regulator cause this?

Keep the suggestions coming. I'll keep you posted on my findings.

Thanks!

TXCAMSS

iTrader: (60)

Well, I scanned the car for B1/B2 O2 balance after the injector swap and they are much closer than before. They are still a bit lower on B1 instead of the reversed effects like I had expected.

I also track tested the car and it is still low on MPH and ET in like DA conditions for some reason. I'll keep chasing the gremlin until I find it. Thanks for all the input. I'll let ya know what I find...if I find it.

Cheatin' Chad

iTrader: (3)

You can put a screwdriver or something similar up to the injectors to listen to them pulse. Listen to them all and see if you hear a difference between them.

samz28

efilive v6 pro can do similar tasks. find a friend who has it. It's likely you'll see misfires and damaged/ashy/white plugs on a bad injector cylinder.

Of course what works at 800rpm idle, maybe not work at 6500 rpm's when the injectors are nice and hot from running static

TXCAMSS

iTrader: (60)

Well I dyno'd the car today at MTI and that confirmed the loss in ET/MPH. I am down about 13 rwhp from a month or so ago. Everything checks out though. No misfires, no banging out smooth solid power band , but it's consistently lower all the way across. I have Atap. Are there any programs that might detect a weak plug, wire or injector?

I even did an upper engine sea Foam flush hoping the intake may have been oil saturated.

I am lost. My next step will be a leak down test I guess.

Thanks!

TXCAMSS

iTrader: (60)

Well here is an update on the culprit.

First off I do appreciate all of the help that was offered here. I truely try to offer more help than I receive. It just keeps me from feeling guilty I guess. A special thanks to Grape Ape and Kevin (NO GO) for being so patient. I know you guys stay very busy. This was a tough one.

I performed a leak down and a compression test on the car and everything checked out great. While I was in the digging mode, I also checked the preload on the lifters since there has recently been some concerns about the preload on the Comp R lifters that I also happen to have. I found that I had .055 preload and the Comp spec is .002-.010. After redynoing the car produced additional RWHP and 12 Ft lbs of tq. I have not had the chance to get an ET confirmation , but the car feels good and the Valve train sound is back where it should be. This was an over site on my part and I have to thank the guys at MTI for working with me to get the issue handled. Corrected track times will soon follow.

Take care,

James

Pro Stock John

iTrader: (34)

Thanks for the updates.