Engine Rev Limiter at 3K

[mmandley]

Hey guys been a while since i was here. Enjoyed all last summer with our new boat and the new Gryphon. Man what a great tuner thanks Bill for all your hard work when we got this first installed.

It ran great all summer pulling my boat. 21.5ft Moomba LSV Wakeboard boat.

I recently have noticed something strange maybe you can help me out.

Problem: Performance mode. Just the truck no boat. 87 Octane. JLT Ram AIr kit. Flowmaster 3inch duel exhaust.

Truck ran perfect till recently, happens at 3K or 4.3K RPM

If im at a slow speed and stomp the gas, right around 3K in first gear it will act as if i hit the rev limiter and kill the engine for a split second. Then the power comes back and it goes right to read line.

If im going say 20mph and hit the gas hard it will do this same action around 4.3

I am wondering if im hitting a lean condition?

No Engine codes not at least that i can see. Passed the emission test last month with there computer they plug in.
No smoke
No other issues.

Act's just like a rev limiter kicking in.

It will do this in tow mode two but i hate mashing my throttle in tow mode as it lights up my 285/65/18s and at 1500 bucks i don't like wasting rubber.

Any ideas you guys can give me to look at?
Running the truck with out a tune is not an option as Bill said my Ram Air intake will run really lean and damage my engine. Right now i just baby the truck in first and keep her under 3K.

One last thing, i can baby her all the way to red line, this is a WOT throttle problem. As in it only happens at WOT

Thanks guys.

[Longshot270]

You can check and see what it is set at by going to [Power Programming]>Pick whichever tune you are experiencing this problem in>[Yes] when it asks for custom options> Go straight to [Upload Previous Settings] down at the bottom. Check the WOT shifts and compare to your rev limiter. Another thing you might want to check is WOT fuel, that should be around 1.3-1.4. Then just hit menu when your done until you get to the home screen.

[mmandley]

Thanks for the tips, ill check that out tomorrow and see what it says.

Please don't confuse my explanation, the truck isnt hitting a Rev limiter thats the effect of what its doing but it only does it for a second then power returns and it goes to Red Line.

[jmt0645]

How many miles? Possible clutch slip in the tranny?

[mmandley]

You can check and see what it is set at by going to [Power Programming]>Pick whichever tune you are experiencing this problem in>[Yes] when it asks for custom options> Go straight to [Upload Previous Settings] down at the bottom. Check the WOT shifts and compare to your rev limiter. Another thing you might want to check is WOT fuel, that should be around 1.3-1.4. Then just hit menu when your done until you get to the home screen.

This is what i saw different
WOT is at 1.3
Shift points at WOT are 5300
Red Line is set to 5600
Tire size i bought new tires not to long ago and there slightly bigger i think.
Stock was 265/65/18 read as 2442mm in the programmer
NEW 285/65/18

Code P0148 Fuel Delivery Error

Does this help at all?

I didnt change any setting but when i backed out it caused the programmer to reload the tune. I hope this is normal and it doesn't cause more issues.


When i put the truck in Tow mode i dont have this issue and thats a Richer fuel ratio. Could it be Bill needs to add more Fuel for the 2800 to 3500 Rev range?

[mmandley]

How many miles? Possible clutch slip in the tranny?

The truck only has 37K on it 370034 to be exact.

Id think if the trans was slipping i would see it pulling the boat even more and when in Tow mode and the boat hooked up i can red line it with no problems. Though i don't like doing that as its a lot of unneeded strain on my drive train.

[Jackpine]

I think the P-code is giving the reason for your problem. My advice is to try replacing the fuel filter. P0148 means at least one bank is severely lean at WOT, which is pretty much what your symptom could be caused by.

- Jack

[88Racing]

Hopefully you didn't run the intake to long before you got your custom tunes and you didn't burn any valves.
Try the fuel filter first. Then if it continues you are going to have to get it compression tested.
JMHO

[mmandley]

OK cool thanks guys i been meaning to get new spark plugs due to my mileage being so bad, 13 in town and it used to get 15 or so. Also with my intake, i didn't install it until the Programmer was working last year. I wanted to make sure of that exact thing, i didn't damage my engine. I don't go WOT very often, mostly just when i am showing a buddy what she can do with this set up. I generally always keep her under 3K.

Leaving today for 2 weeks with the wifes car for vacation. Ill do the fuel filter and plugs when i return and let ya know how it goes. For now i reset the programmer and cleared that engine code and haven't been at WOT so she is acting pretty normal.

[mmandley]

Hi guys wanted to give you an update. I replaced the plugs, filter and still intermittantly the truck has the same rev problem in performance mode.

When i run the truck in Tow mode it runs great no issues.

I also noticed i actualy get better milage in tow mode when not towing then i do in performance mode. I think the truck might be running a little lean when in performance and maybe this is due to the winter additives and last summer i didnt have this issue.

Thanks for your help as for now i think ill keep it in Tow mode.

[Jackpine]

Sounds a good idea to keep it in tow.

Since you kind of "fixed" everything else, I'd say Bill probably needs to do something with your performance tune. It almost has to be an interaction with your intake and the tune. I wonder if the knock sensor is pulling timing on you at WOT in those RPM ranges? You MIGHT try reducing the timing in the Custom Options menu while in that tune. I'd probably try -1 degree. But, this "reduced" timing will become part of your "previous settings" when you go back to the tow tune, so you'll have to remember to manually change it.

If this works, you could advance it a bit, say to -0.5 and see if things are still good, then to -0.25 if possible.

If this is indeed a fix, Bill could change the timing in your custom tune so you would not have to muck with it.

- Jack