proper adjustments

[jake3336]

hey , my ltft is at 25.00% any suggestion on best tune.

[06MonteSS]

wow!

you've got an air leak somewhere, or your O2's are shot....

no way would they ever be that high unless there's something physically wrong with the vehicle...

need to check for air leaks - exhaust leaks, header leaks, all clamps TIGHT from air filter/CAI all the way back to the throttle body... etc etc...

[rmck490]

Mine were like that when I first started this adventure. Like Lew says above, you may have an air leak. In my case it turned out to be my MAF but that took me a long time to figure out.

I tightened everything from the CAI to my downstream O2 sensor. Sprayed starter fluid every where in the air intake system that air could get in. And, replaced my intake gaskets and throttle body gasket. All this gained a little bit but was still high; about +20. I'm fortunate to have a snap on to view all the sensor outputs and test the components with so I also went through that exercise of checking all the sensors. Still, couldn't figure out the problem. My O2 sensors were only a year old. So, I replaced the MAF even though it checked out to be okay and the problem was solved. They went to +8 after that.

This may not be your problem but a bad sensor in the closed loop system could also contribute to this.

[seanst]

Lew made shorter log can you help with adjustments?

[06MonteSS]

yeah, make sure you don't have an aftermarket MAF on there at all...

you want the stock MAF with the screen still in it...

[06MonteSS]

Lew made shorter log can you help with adjustments?

go +5% on your injector slope setting...

[seanst]

ok...thanks.was that log better for you?..I think I finally understand how to use it...what a good application.

[06MonteSS]

yep, that log was better

[jake3336]

yeah i do have a aftermarket MAF sensorand intake. i did another log and got it to +13

[06MonteSS]

yeah i do have a aftermarket MAF sensorand intake. i did another log and got it to +13

a-HA!!!

get rid of that aftermarket MAF sensor man... THAT'S what's screwing you up...

the aftermarket MAF doesn't gain you anything, and only messes things up... by tricking the pcm into false airflow readings...

put the stock MAF sensor back on... and it if had a screen in it originally, make sure the screen is still in it.

[05silvycrew]

quick question to piggy back off what has been discussed here. it's been a while since I've posted anything on the Diablosport forum.

my LTFTs have always ranged in the +6 to +7% since I've owned the Predator. right now I'm running an adjustment of -7% on the injector slope. during a ride today the predator was calling for another -1 to -2% adjustment.

my question is, how far is too far to adjust the injector slope? Am I ok in the range I'm running?

my truck: 2005 silverado iron block, 5.3L, u7193 old revision can't data-log, 93,000 miles. only mods are airaid drop in filter, airaid MIT tub, replaced stock muffler with a Magnaflow. my o2's have been replaced and the airaid filter serviced about 6 months ago. new plugs and wires last summer. I've checked for exhaust leaks and double checked all intake clamps, everything's tight.

[06MonteSS]

I would go another -1% and that's it... cuz once the weather warms up and gets hotter out, your ltft's will go down anyway due to the warmer/hotter less dense air...