Powermax dead spot

Rob D

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Anybody else have a pretty bad dead spot around 45-50mph, light throttle (slow moving traffic for example) when the truck goes into OD? Mine is pretty annoying, either have to tap the brake to lock up the coverter or put her in tow/haul....or put the pedal almost to the ground before it decides to downshift, then I am left blacking out the highway and rapid acceleration - neither of which I want for that type of driving condition. If I try rolling into the pedal to get it to pick up, truck just sounds like its sucking a bunch of air and not going anywhere. Have the same problem on different tunes by different tune writers....just wondering if this is the powermax's achilles heel or if I just need to spend more time tuning the thing.

Truck has 190s - 75 over
 

Wojo

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I have the exact same problem but with my factory charger and sticks. It wont unlock the tq converter unless doing the above mentioned things. That's on erics extreme street tune. It sucks.
 

windrunner408

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It seems to me that most folks I run into with this problem is because the stock injectors are not large enough and larger ones are what is needed to get rid of the dead spot. I could be wrong but that is what seems to be the culprit.
 

windrunner408

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Sorry I just saw that you have larger injectors. So please disregard my previous post. I am not really sure why the PM does that now.
 

Rob D

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Matt,

On yours, and Dougs. I tried adjusting the revs per mile as you said. Toyos website says 593 for the 35x12.5s. Doug says its more like 575 when he calculated it due to rim width being only 8" stock making the tire taller or whatever the correction factor is. I tried everything from 575-610, 610 was a little better, not much though.
 

Mdub707

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Correct. I've had similar issues before and found a chaffed wire harness going to my EPB sensor. It's on the drivers side coming out of the exhaust manifold. You could pop the sensor off at least and look at that and see how gummed up it looks.
 

Mdub707

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Or if you have access to a scanner you can watch all of that too... that's actually how I narrowed mine down to the EPB sensor, I had no check engine light or anything. Once I got up to cruising speed my boost would fall to 0. Backpressure would skyrocket and black smoke would roll for miles...
 

Gearhead

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i can always just make it downshift sooner if the turbo isn't going to be happy down there. depending on strategy it may not care about the EBP anyway.
 

Rob D

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Was your fuel mileage crappy due to this too? I don't think mine is quite as bad as yours sounds...I am not rolling coal at all when this happens unless I try to give it gas without unlocking converter.
 

Mdub707

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I didn't really notice mileage to be honest, it was the least of my concern at that point. The truck drove completely fine until I got into OD, and RPM went down a bit, then the boost fell to 0 and the exhaust not changed (vanes moved on the turbo). It didn't smoke until I rolled into the throttle to accelerate. If I matted it, it would downshift, turbo would light and it would go just fine. Only if I rolled into it would it just leave a cloud for miles, until I either floored it, or let off.
 

Rob D

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I didn't really notice mileage to be honest, it was the least of my concern at that point. The truck drove completely fine until I got into OD, and RPM went down a bit, then the boost fell to 0 and the exhaust not changed (vanes moved on the turbo). It didn't smoke until I rolled into the throttle to accelerate. If I matted it, it would downshift, turbo would light and it would go just fine. Only if I rolled into it would it just leave a cloud for miles, until I either floored it, or let off.

Hmmm that sounds a lot like mine - I will check it out for sure
 

Rob D

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i can always just make it downshift sooner if the turbo isn't going to be happy down there. depending on strategy it may not care about the EBP anyway.

Matt,

I just figured you and other tuners have had plenty of experience writing files for us guys with the powermax and injectors and I hadn't heard of anybody else having the dead spot so I was curious if guys just weren't really posting up about it, or if mine is an isolated behavior. If other guys don't have the issue with similar setups and what should be similar tuning I am at a loss for why my truck is acting this way. My fuel mileage is horrible too - I am lucky to get 14 on the highway, probably closer to 12 mpg.
 

Gearhead

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Matt,

I just figured you and other tuners have had plenty of experience writing files for us guys with the powermax and injectors and I hadn't heard of anybody else having the dead spot so I was curious if guys just weren't really posting up about it, or if mine is an isolated behavior. If other guys don't have the issue with similar setups and what should be similar tuning I am at a loss for why my truck is acting this way. My fuel mileage is horrible too - I am lucky to get 14 on the highway, probably closer to 12 mpg.

what are your temps rolling down the road and how old are your files?
 

java

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I have had the same dead spot at 45-55 with the factory turbo, EDEs VGT-SS, and the 03 turbo thats on the truck right now. I had innovative tunes with the factory turbo and the vgt-ss and now have gearhead tunes with the 03 turbo.

Matt can you redo my current tune to help this issue?
 

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