Lean mixture

[MACADO1]

Last evening I tried to get a Dynotune for my '11 Charger R/T. No mater how much fuel the tuning guy tried to add, the car ran lean at high rpms. He said there could be a fuel pump problem. Has anyone heard of this? I'm off to the dealer to check this out.

[sharkcohen]

What was the a/f? Can you post some graphs?

[mikel]

Last evening I tried to get a Dynotune for my '11 Charger R/T. No mater how much fuel the tuning guy tried to add, the car ran lean at high rpms. He said there could be a fuel pump problem. Has anyone heard of this? I'm off to the dealer to check this out.

any mods?

how lean is lean?

[MACADO1]

Mikel. He said my r/a ratio was 13 to 1 . at 5400 rpm. The only mod is a Frankentake IV CAI. He was trying to install a custom tune. He also said it was lean with the stock tune. Possible fuel pump? Dealer will check tomorrow. The tech at the dealer said a lean condition should flash a eng. light.

[mastuning]

i have never seen an intake only cause such a lean mixture, try the stock file it will run fine.

the tuner is probably changing tables he shouldnt, if you fuel pump is dead your car will not run.

also check if in the device itself you did not make an lean adjustments which can cause lean conditions.

[mikel]

Well, if it was lean like that on the stock tune as well, there may be an issue somewhere...

[MACADO1]

Mikel. Perhaps I'm being snookered. First of all the car checked normal at the dealer. I ran a F/A run with the Diablo Tuner hooked up. At low rpms my readings were about 14.8, which is normal for idle. It goes to about 11.51 or so at about 5200 rpm. Right before second to third shift. Is this too lean, for a Hemi 5.7? This occurred with a stock tune.

[mikel]

11.5:1 is not lean at all....

[MACADO1]

Mikel. Thanks for the answers so far. But, how lean, is too lean?

[mikel]

these things like to be at 12.3-12.5:1 at WOT. Any leaner, and you're likely losing power.

[MACADO1]

Mikel. I had the car to the dealer, they said nothing was wrong. (See first post) I ran a F/A check with the Trinity tuner, and got something like 11.5 to 1 readings. The tuner guy said that those readings are what the computer is wanting, not actual. What's going on there?

[mikel]

Mikel. I had the car to the dealer, they said nothing was wrong. (See first post) I ran a F/A check with the Trinity tuner, and got something like 11.5 to 1 readings. The tuner guy said that those readings are what the computer is wanting, not actual. What's going on there?

correct,the PCM does not monitor AFR, it just shows what the PCM is commanding. I wonder if maybe there was an issue with the wideband or if it blew out of the exhaust at the end of the pull to go lean like that....

[MACADO1]

I am wondering the same. Is my tuner dishonest? Is there any way to check the A/F ratio with the Trinity?

[mikel]

No, you need a wideband to see actual AFR.

Next time you go to a dyno, make sure they can provide a printout of the dyno run, it can be very helpful

[MACADO1]

At what point(A/F ratio) would the car pull timing, and about how much? I would think that if my A/F ratio was as high as he says it is,( 13.7 to 1 @ 5000+ RPM.) I would be getting some long term knock, or a lot of short term knock. More than 2 to 2.5 deg. I'm getting.