Today's dyno session...

[Shaker1]

This is my JLT/EVO tune. Seems the A/f is lean. Also, LT fuel trim is at .88 both banks at cruise RPM (2000-3000). Any comments?

Should I add fuel at WOT with my Xcal3 to alleviate the lean condition at WOT? How much? 5-8%?

Adding fuel would be a temporary fix as I will be going back for a custom tune with a pulley soon.


EDIT:I'm pulling down the dyno, cuz I don't want to cause any problems for the shop and this took an unexpected turn.

 

[heffs03mach1]

a/f a bit high eh. wish i was a tuner so could tell you what to do but i wouldnt get on that car cuz it might burn it up.

 

[Bdubbs]

Why didn't they fix the a/f after seeing that?

 

[me32]

send EVO the data log and dyno sheet so they can tweek the tune some

 

[Shaker1]

send EVO the data log and dyno sheet so they can tweek the tune some

You think they'd still do that? I bought the tuner from JLT with the Evo tune in it over 2 years ago. In any case, I will go back ASAP and get a custom tune with pulley.

Makes ya wonder how many cars are running around like this! I've been driving it this way a couple summers already.

 

[Shaker1]

Why didn't they fix the a/f after seeing that?

I did not originally go for a tune (I went with my neighbor to get his 68 coupe with a 5.0 tuned), and I did not have my Xcal3 with me. I just asked (spur of the moment) for a few pulls to check A/F.

No one can comment if adding some fuel at WOT might be a bad idea?

 

[me32]

You think they'd still do that? I bought the tuner from JLT with the Evo tune in it over 2 years ago. In any case, I will go back ASAP and get a custom tune with pulley.

Makes ya wonder how many cars are running around like this! I've been driving it this way a couple summers already. So much for a mail order tune.

well your better off with a true dyno tune

 

[Red Turtle]

What did they use to measure the a/f? If I am correct, the tailpipe sniffer usually shows leaner conditions by about .3-.5.

 

[mixxer]

Do you have cats? Was it a/f with a tail pipe sniffer?

 

[Leonard 95]

It won't hurt adding 4-6% fuel, you actually need it. I am running around with 4% added on mine just for safety.

 

[Shaker1]

Yes, it has cats and yes it was a tailpipe sniffer. I asked about that too. Given my A/F numbers where does that put me? Safe? Add Fuel? How much?

 

[mixxer]

There is your answer. The tune is fine, in order to get true a/f there needs to be a bung welded in between manifolds and cats on drivers side. The cats clean up exhaust so it would appear to be lean.Also tail pipe sniffers are not real accurate to begine with.

 

[Van@RevanRacing]

This is my JLT/EVO tune. Seems the A/f is lean. Also, LT fuel trim is at .88 both banks at cruise RPM (2000-3000). Any comments?

Should I add fuel at WOT with my Xcal3 to alleviate the lean condition at WOT? How much? 5-8%?

Adding fuel would be a temporary fix as I will be going back for a custom tune with a pulley soon.

First and foremost, any dyno operator that would take a GT500 and do two WOT pulls with A/F exceeding 12.0 - 13.0 on both runs!!! Not good. And the car would have shown obvious pinging and detonation.

Once a dyno operator see's 12.0 on a set up such as yours they immediately should lift and try to identify the problem. He ran the car to over 13.0 A/F! That's ridiculous.

If that were your actual A/F which I don't think it is, the engine would have mostly liked jumped off of the motor mounts and run out of that shop.

His A/F meter needs to be replaced. GT500's typically run anywhere from 11.3 to 11.8 A/F safely. If you took your car to a different dyno you would likely see a different A/F measurement because this is simply inaccurate.

You should ask him when he last changed his A/F meter and/or had it calibrated.

I would also find another shop based on the fact he ran the car over 6,000 RPM twice with A/F bouncing around 13.0!!! That's the most basic principal with these cars, if you see 12.0 A/F on a dyno pull, lift.

 

[Leonard 95]

Again I would add 4-6% if I where you and recheck it again, have them put the wideband in the O2 bung this time for more accurate reading.

 

[Zeke0123]

I just had my mail order tune dynoed with the the meter in the bung and it tickled and passed 12 a few times ill be taking it easy and letting him tune it...didn't know 12 was such a red flag...and anyone care to comment on the "LT trim at 88% for cruise RPM ??" Ive experienced some ping at that rpm that's what got me worried in the first place.

 

[Shaker1]

Thanks for all input. I have never heard any pinging ever. And it runs great. I did add 6% fuel at WOT, as a temporary measure until I had a better idea what was going on.

I data logged lt trim today on a 20 mile drive and it stayed around .965-1.00. He said it was an indication that the ECM was pulling fuel when it goes below 1.00. I did see the same .88 after a 90 minute drive while datalogging in my driveway yesterday. And today the datalogging was done after adding the 6%, so it may have zeroed KAM?

 

[Van@RevanRacing]

I just had my mail order tune dynoed with the the meter in the bung and it tickled and passed 12 a few times ill be taking it easy and letting him tune it...didn't know 12 was such a red flag...and anyone care to comment on the "LT trim at 88% for cruise RPM ??" Ive experienced some ping at that rpm that's what got me worried in the first place.

West Coast Winterized 91 Octane Sucks and they are probably still pumping it. Get some octane in the car. Ping will go away with some octane, add a can of Torco. Did you buy your tune direct from Jon? Have you sent him any datalog's of your car since you noticed the problem?

 

[black99lightnin]

I learned this the hardway one day after spending about 5-6 hours getting my L tuned. Seemed that no matter how much fuel he added we stayed around 13-14 a/f. By the time a bung was welded in front of the cats the truck would barely run due to all the fuel being added to the tune. A sniffer will only give a realistic reading if you have no cats to clean up the fuel.:beer:

 

[Zeke0123]

West Coast Winterized 91 Octane Sucks and they are probably still pumping it. Get some octane in the car. Ping will go away with some octane, add a can of Torco. Did you buy your tune direct from Jon? Have you sent him any datalog's of your car since you noticed the problem?

I've added torco still has a problem at low rpm..I tried calling him once he didn't get back to me I'm sure he is a busy guy and I'll just let the shop tune it.

 

[Van@RevanRacing]

I've added torco still has a problem at low rpm..I tried calling him once he didn't get back to me I'm sure he is a busy guy and I'll just let the shop tune it.

There are so many levels within a tune that a data log with the properly selected PIDS can reveal to whomever is tuning the car.

Tip in spark, transient fuel blah blah blah, timing, commanded fuel at RPM the list is endless. I don't know who is tuning your car but I highly recommend patience and working with those that know what the heck they are doing. There are plenty that say they know what they are doing and they don't. Case in point, the dyno sheet from the original post in this thread. That A/F is ridiculous and I would have lifted at throttle tip in to WOT.

Good luck and go fast!

Van