sounds like a bad TPS or MAP sensor. Disconnect the MAF sensor and see how it runs when it runs off the open loop base tune. It may be nothing more than a dirty MAF sensor. The map could also be defective or plugged.
sounds like a bad TPS or MAP sensor. Disconnect the MAF sensor and see how it runs when it runs off the open loop base tune. It may be nothing more than a dirty MAF sensor. The map could also be defective or plugged.
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
id have to agree with greg, check the little things, hows the fueling on the gauge when giving it gas? like when you punch it? are ya'll logging during start up then sending tunes by mail? or is the tuner kinda somewhat guessing with the info youre giving him? that could be a nightmare for the tuner!
man that setup would be a beast with some nice 243 heads ( i take it thats the FAST truck intake? ) a nicer size cam!!!
Simple: 408 on steroids!
single digits coming soon!
Yes we are logging and sending it to Vince, he has sent us 3 revisions, and it seems to be getting better the more we try things. It is the FAST truck intake manifold, my dad doesn't want too big of a cam or heads because it is his daily driver and hes pushing 60 :p. He just wants some nice bottom end TQ.Originally Posted by skeet
Yeah, also I really wouldn't do too much WOT with that stock pump. Who knows how lean it'll get.
1969 Chevy RCLB C10 350/TH400 SOLD
2007 Chevy RCSB 4.8 4x4 LS SOLD
2008 Chevy RCSB 5.3 4x4 LT SOLD
2010 Chevy CCSB 6.2 4x4 LT SOLD
2005 GMC CCLB DRW 6.6 Duramax 4x4 191,000 and counting
2013 FORD CCSB F350 6.7 Powerstroke 4x4
We havn't gone WOT at all, we will stab it for like a millesecond then let off, we are babying it quite a bit.
Thanks for the quick responce, I unplugged the MAF, at first it didn't want to idle, after a few restarts it I let it idle, one thing it did fix was the hesitation when I stabbed the gas for a sec, it went away, I then turned it back off, plugged in the MAF, and the hesitation was back. Do you also think that the stock MAF is a big restriction with all the mods I have listed?
The stock MAF is fine. It's probably either dirty or bad. See if you can get another one to try out of a different truck. Also, try cleaning that one carefully.
1969 Chevy RCLB C10 350/TH400 SOLD
2007 Chevy RCSB 4.8 4x4 LS SOLD
2008 Chevy RCSB 5.3 4x4 LT SOLD
2010 Chevy CCSB 6.2 4x4 LT SOLD
2005 GMC CCLB DRW 6.6 Duramax 4x4 191,000 and counting
2013 FORD CCSB F350 6.7 Powerstroke 4x4
Ok, we will clean it first and see how that works, thanks for the help guys, I will report back, and if anyone else has suggestions let me know, thanks a bunch!
One weird thing is though it never did this with the 5.3, and it's the same MAF from the 5.3. But the MAF did sit around for quite a bit before we got the motor in the truck so it could be quite dirty, guess we will find out tomorrow.
Since the hesitation went away when pulling disabling the maf, might be a dirty maf or the PCM thinks there is a lean condition or there is one.
A map sensor doesn't respond the same way to a vac leak.
What are the ltrims showing when the ma is plugged in?
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'94 Chevy Truck: 8.9 et, 408 twins
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