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RainMaker44
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Post subject: 3.9L performance decrease at full throttle - Tune issue?  Posted: Thu Jul 26, 2012 9:57 am |
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Joined: Thu Jul 05, 2012 8:31 pm
Posts: 6
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2002 Dodge Dakota two wheel drive, 3.9L V6 with a 3.92 rear end. The only change aside from the FlashPaq 3865 is a K&N drop in air filter. Truck has 97,000 miles on it and runs good.
Running the tow tune using 91 octane when towing or not if throttle is at about 3/4 to 7/8 it'll continue to gain speed going up hills. If I put it all the way to the floor (but not far enough for it to downshift) it loses acceleration. You can actually feel it get sluggish and watch the speed decrease looking at the speedometer. It's not a huge decrease but when towing and going uphill I have to let back off of the gas to continue at the same speed.
Could this be the tune programming, lack of air at full throttle or something else known with these engines?
Thanks,
Mike
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RON @ SUPERCHIPS
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Post subject: Re: 3.9L performance decrease at full throttle - Tune issue? Posted: Thu Jul 26, 2012 12:42 pm |
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Joined: Tue Jul 25, 2006 9:41 am
Posts: 18302
Location: SUPERCHIPS
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I would use the tuner to read the diagnostic codes in the advanced features, to see if there are any codes.
Does it do this on the stock program? Now?
Ron
_________________ RRAPP@SUPERCHIPS.COM 1-888-227-2447 8-5 EST. Email me directly if your having ANY trouble with the forum. Not able to LOGIN, email me with your Username that you registered with.
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RainMaker44
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Post subject: Re: 3.9L performance decrease at full throttle - Tune issue? Posted: Fri Jul 27, 2012 4:36 pm |
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Joined: Thu Jul 05, 2012 8:31 pm
Posts: 6
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There are no codes and I haven't noticed this with the stock in the past. I'll have to check it out and see.
It runs so much better with the tow tune that I've been leaving there all the time wether towing or not.
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RainMaker44
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Post subject: Re: 3.9L performance decrease at full throttle - Tune issue? Posted: Wed Aug 01, 2012 9:29 am |
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Joined: Thu Jul 05, 2012 8:31 pm
Posts: 6
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It looks like this initial problem is solved. Found a vacuum leak and changed the MAP sensor and TPSmfor good measure. Had a 20% off coupon so am looking at it like tuneup parts.
What I am seeing now though is running down the highway at 65 to 70 MPH in tow mode without towing anything the things stays in OL-Drive mode more than CL watching my ODBII reader. In stock mode it does not do this. Is this by design to increase fuel flow? If so, what's the overall effect on mileage going to be?
Another thing is that if I try to use the FlashPaq to read live data I get a J1850 (hope i remembered the number correctly) error if I'm in tow mode. If I'm in stock mode I can read live data. I've checked wire connections, etc. This is repeatable so is this a problem with the device or the program?
Note: it runs much better in tow mode even when not towing. Going back to stock for testing is painful.
Thanks!
Mike
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RON @ SUPERCHIPS
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Post subject: Re: 3.9L performance decrease at full throttle - Tune issue? Posted: Wed Aug 01, 2012 12:57 pm |
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Joined: Tue Jul 25, 2006 9:41 am
Posts: 18302
Location: SUPERCHIPS
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It is staying in OD becasue of the extra power. Unless the engine starts to lug, this a good thing.
The J1850 computers are not something that DAQ will work on. They are hit or miss, on communications. These comptuers can't do to many things at once.
Ron
_________________ RRAPP@SUPERCHIPS.COM 1-888-227-2447 8-5 EST. Email me directly if your having ANY trouble with the forum. Not able to LOGIN, email me with your Username that you registered with.
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RainMaker44
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Post subject: Re: 3.9L performance decrease at full throttle - Tune issue? Posted: Wed Aug 01, 2012 1:22 pm |
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Joined: Thu Jul 05, 2012 8:31 pm
Posts: 6
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Seems odd that my scan tool will pull live data from all sensors at once and the Superchips cannot. Is it something to do with how the acquisition works with the FlashPaq?
I can live with that but had hoped to be able to do acquisition as well as tuning when I bought so I didn't need both devices when tuning or checking.
Thanks.
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