Why won't my truck dyno good?

Sense you guys are on the map sensor subject I have always ran my truck with the map unpluged for more low end ( supposedly ) would that be the same thing as a bad map if I ever dyno my truck ? hopefully you understand what I am getting at .
 
Nah, unplugging the MAP, makes the fuel box add fuel based on throttle position rather than boost when you do that...
 
so you are saying unplugging the map and a bad map are two different things right ?
 
dieseldork said:
so you are saying unplugging the map and a bad map are two different things right ?
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Yea... , one means you unplug the sensor and the other means the sensor is bad.
 
UM.....Lary was in Special Ops........just saying..........:hehe: :hehe: :hehe: :hehe:
 
dieseldork said:
Ok then couldn't BgBlDodge just unplug his map to dyno ?
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If I had a comp I could but it won't work with a TST since it does it's fueling based solely off of boost.
 
You have your wastegate set too low for top HP on the dyno. I also don't think you're getting enough fueling, egt's are too low. I would find someone with a TST to switch boxes. Sounds like the box isn't fueling.
 
Egt's hit 1300* with smarty and injectors only at 37psi of boost. With tst on level 2 the egt's were pegged at 1600*. I flipped the tst on today while maintaing a steady 20psi of boost and it instantly shot up to 35psi and started accelerating so I'm pretty sure the box is working. At 40psi of boost my drive pressures are 1:1.
 
BgBlDodge said:
If I had a comp I could but it won't work with a TST since it does it's fueling based solely off of boost.
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gotcha I thought a tst and comp worked the same way so now I understand.:thankyou2:
 
My bad, I thought it was 1300 with the tst. I still think you have your wastegate set too low. What are your drive pressures at when you go 45-48 psi?
 
Not quite sure. The POS gauge that I had was bouncing between 40 and 120psi so fast you couldn't hardly see the needle. I'll check it this weekend with a better gauge and let ya know.
 
Hate to even say it or bring it up......BUT have you had your compression check again since the whole injector fiasco you had?

I know you had a lot of diesel that got into your crank case…..im just wondering if you damaged something in the wake of loosing compression to the point where power is not 100%.

ALSO…valve springs….about the ONLY thing you haven’t replaced (Except the cam). Could these be getting weak? You have subjected them to a life of high boost for a few years now. Maybe that gauge is not lying to you....those spikes could be compression leaking……
 
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BgBlDodge said:
Not quite sure. The POS gauge that I had was bouncing between 40 and 120psi so fast you couldn't hardly see the needle. I'll check it this weekend with a better gauge and let ya know.
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I think Diesel Dan is on to something.

My back pressure gauge does not pulsate that much. Its more steady like the boost gauge.
 
This wasn't spikes. It was vibrating so fast you couldn't see the needle at all. It was a $2 tire pressure gauge from harbor freight and I ran it straight off of the manifold with 6' of copper line. And that was before the fuel in oil fiasco. None the less, that thought has crossed my mind that I did do some internal motor damage. Hopefully I didn't but ya never know. I just wish I knew where I could get a hold of a compression tester for cheap.
 
BgBlDodge said:
This wasn't spikes. It was vibrating so fast you couldn't see the needle at all. It was a $2 tire pressure gauge from harbor freight and I ran it straight off of the manifold with 6' of copper line. And that was before the fuel in oil fiasco. None the less, that thought has crossed my mind that I did do some internal motor damage. Hopefully I didn't but ya never know. I just wish I knew where I could get a hold of a compression tester for cheap.
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WELL....Keep in mind that 1 RPM equals 6 Combustions and 6 Exhaust strokes At 700RPM Idle this happens 70 times a second.... (140 times a second if you include the exhaust stroke.....Man i want a Detroit 4-71 for my Ford!).

I think any gauge would be buzzing on that one! haha....BUT, yes....still check with a better gauge.....
 
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