Hey Smokem

RSWORDS · #1 12-06-2009, 09:13 PM

Quick question for you weston. When I get on my truck real hard and then let off it quick I get a little puff of smoke when I let off. What is it from? You can see it here in this video in the 2nd and 3rd dyno pull.

YouTube - 89 1st Gen Cummins On The Dyno

A couple peopel have seen the same from there trucks... Any idea?

TTipsword · #2 12-06-2009, 09:22 PM

I would think it is because you are pushing so much soot through the pipe and engine that when you let off the pedal it is the excess soot getting blown through the exaust pipe. I notice this too.

BC847 · #3 12-06-2009, 10:07 PM

I think your IP throttle index is off a little, such that you're actually going a little past fuel throttle when mashing the pedal to the floor. Mine did that when I modified my 3200 governor spring recently.

- Ultimately I moved the throttle linkage back to it's original location on the IP's throttle bell-crank in addition to fine-tuning the indexing.

Drive it around on a back road and get on it full throttle. As the engine winds up through the gears, back off the throttle a little bit to see if you can feel additional pull in the seat of the pants. I did.

**seandonato73** · #4 12-06-2009, 10:13 PM

my truck does that every time i race a buddy, never seemed to hurt it thoe, an i dont hav a clue what it is.

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Originally Posted by BC847

I think your IP throttle index is off a little, such that you're actually going a little past fuel throttle when mashing the pedal to the floor. Mine did that when I modified my 3200 governor spring recently.

- I moved the throttle linkage back to it's original location on the IP's throttle bell-crank.

Drive it around on a back road and get on it full throttle. As the engine winds up through the gears, back off the throttle a little bit to see if you can feel additional pull in the seat of the pants. I did.

i never reindexed my throttle so why does mine do it? only when i'm beaten the crap out of it

Richie O · #5 12-06-2009, 10:30 PM

Excess boost with no where to go causing the turbo to slow down and trap smoke for a second???? Kinda like a bark with out the noise??? My best guess.

BC847 · #6 12-06-2009, 10:37 PM

Originally Posted by seandonato73

i never reindexed my throttle so why does mine do it? only when i'm beaten the crap out of it

Perhaps because you never re-indexed the throttle when you installed the 3200 governor spring.

I'm not saying it happens all the time, I'm saying we need to start looking a little harder at the index when we do goof around inside the IP.

tower_ofpower · #7 12-07-2009, 12:55 AM

ehh indexing doesnt seem to hurt too bad. i've had the truck started w/o the bracket on to figure out the indexing where the truck would start and run... i've got my truck indexed one tooth from it bottoming out internally. i've never noticed mine do this tho. only thing i can think of is chattering of the injectors... just enough pressure to open but not correctly atomize? mine are still stock and both bobby and sean are running aftermarket injectors. i dont believe it has anything to do with the pump. last i knew i was 1/2 turn from run away. i know once you free spin it to 1500 it starts to climb in rpm's by itself and as stated b4 i've never noticed this. i do believe smokem is the man to talk to tho

but injectors would be my hunch. plus VE's do a funny little thing; ya nail the throttle; once it returns to idle it drops below and picks right back up with a grunt, so it may also be fueling characteristics of the VE

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or maybe i just have a governor spring that's been stretched wayyy out

RSWORDS · #8 12-07-2009, 11:26 AM

Originally Posted by BC847

Perhaps because you never re-indexed the throttle when you installed the 3200 governor spring.

I'm not saying it happens all the time, I'm saying we need to start looking a little harder at the index when we do goof around inside the IP.

hmm.... You could be on to something. I did gain quite a bit of extra fuel when I did this

Getting Full Throttle Out of Your VE Pump

But I might have gone a little to far

... I'll need to play with that some. Thanks David!

Benjamin · #9 12-07-2009, 11:27 AM

it could be your truck's way of telling you it wants a P-pump....

RSWORDS · #10 12-07-2009, 11:30 AM

Originally Posted by Benjamin

it could be your truck's way of telling you it wants a P-pump....

Probably...

Smokem · #11 12-07-2009, 12:13 PM

Excessive case pressure being expelled after the throttle is lifted. With a VE you will get smoke, with a VP44 the truck often dies. The return side is too restricted, switched to an A1000 and bypass regulator, problem fixed.

BC847 · #12 12-07-2009, 01:48 PM

It's my understanding the factory/OEM fuel return orifice is sized to work in conjunction with the case pressure regulator.

Are we talking about the resulting case pressure spike as the regulator backs off with side-stepping the throttle after a high RPM run?

Bobby, your incoming fuel pressure is regulated isn't it?

Smokem · #13 12-07-2009, 01:57 PM

Originally Posted by BC847

It's my understanding the factory/OEM fuel return orifice is sized to work in conjunction with the case pressure regulator.

But, we are not talking about a factory or OEM quantity of fuel.

Originally Posted by BC847

Are we talking about the resulting case pressure spike as the regulator backs off with side-stepping the throttle after a high RPM run?

Yes. If you were to remove the KSB completely, use an open return fitting with the bypass regulator on the return side to control pressure, this would not be the case.

BC847 · #14 12-07-2009, 02:27 PM

Got'cha.

(Folks still need to keep up with the throttle index though).

RSWORDS · #15 12-07-2009, 04:46 PM

Originally Posted by Smokem

Excessive case pressure being expelled after the throttle is lifted. With a VE you will get smoke, with a VP44 the truck often dies. The return side is too restricted, switched to an A1000 and bypass regulator, problem fixed.

Originally Posted by BC847

It's my understanding the factory/OEM fuel return orifice is sized to work in conjunction with the case pressure regulator. Are we talking about the resulting case pressure spike as the regulator backs off with side-stepping the throttle after a high RPM run? Bobby, your incoming fuel pressure is regulated isn't it?

Read more: http://www.dieselbombers.com/newrepl...#ixzz0Z2eDSPJF

Yep, I have a aftermarket pump with a bypass reguator, 15psi. Never watched the gauge when letting off to see if it jumps though.

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