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DS4 pump mods

Turbine Doc said:
IIRC that was a DB4 mechanical, DS4 gives plenty of fuel depending how far you want to go with it, like 158 at Bonneville :) that said the electronics on a DS4 can be a PITA, but a remoted FSD cures a lot of that.
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I recall them saying that the DB4 wouldnt be a good pump to run on the street cause it would be too jumpy at light throttle acceleration. Thats why they said they could build a bigger DS4. Plus we all know Heath ran 150+ but I am pretty shure I am not getting the king of fuel to my motor he is. If I was I would be installing my HX35 and a big intercooler and go out racing duramaxes.
 
My point was the "king of fuel" I think you meant "kind of fuel" :D is same capability from any DS4 if it's asked for, I'm still testing that one, Bill is running a stock DS4 IP I asked him if there was a higher output IP or mech one, "If it was available, I'd be running it" Bill & Matt @ Peninsular are pretty hooked up with each other so if they could build a "h/o DS4" I think Bill would have it on the LSR already.

Bill did share with me that a h/o IP would be the next milestone, and sort of indicated it would not be based on the DS4, but would not share beyond that.

I just got another tune for my PCM yesterday that if I wanna smokes the highway similar to a wicked up notch 1/notch 2 Dmax now, it has shown good drive-ability thus far, but will double for a heavy skeeter fogger if I hit it too hard.
 
Turbine Doc said:
My point was the "king of fuel" I think you meant "kind of fuel" :D is same capability from any DS4 if it's asked for, I'm still testing that one, Bill is running a stock DS4 IP I asked him if there was a higher output IP or mech one, "If it was available, I'd be running it" Bill & Matt @ Peninsular are pretty hooked up with each other so if they could build a "h/o DS4" I think Bill would have it on the LSR already.

Bill did share with me that a h/o IP would be the next milestone, and sort of indicated it would not be based on the DS4, but would not share beyond that.

I just got another tune for my PCM yesterday that if I wanna smokes the highway similar to a wicked up notch 1/notch 2 Dmax now, it has shown good drive-ability thus far, but will double for a heavy skeeter fogger if I hit it too hard.
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from whom? Kojo?
 
Turbine Doc said:
I just got another tune for my PCM yesterday that if I wanna smokes the highway similar to a wicked up notch 1/notch 2 Dmax now, it has shown good drive-ability thus far, but will double for a heavy skeeter fogger if I hit it too hard.
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Thats the kind of tune I am looking for cause I wanna run a HX35 @ 25psi area with a intercooler, methenol and maybe pane. The thing is I know right now I am at my trucks current tune fuel limits @ approx. 16-18psi with a GMx.
 
buddy said:
Most of the stock S tunes I have been seeing actually peak at 62mm3 and the F ones at 67mm3, but its only momentary at 1800rpm WOT. They drop off at any pedal amount after 1800rpm.

Doing mechanical modification like larger plungers may not help at all, if you dont increase the amount of fuel put into the plungers. To get more fuel into the chamber you need longer pulse width (on DS4) or more transfer pressure. The meterning valve opens for the pulse width and so much fuel goes into the chamber then gets put into the plunger to be injected. To get more fuel into the spill chamber you need more time or more pressure. Whatever meters the fuel in the DB2 and DB4 is like the DS4's pulse width (time).

6.2 turbo, have you determined how much internal transfer pressure there is and is this regulated or increasing with RPMs? i assume it increases with RPMs, with the way its mapped in the program.

Does it make sense that it would work this way and larger plungers may not help you until the metering of the fuel is addressed?
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You are correct that pressure increases with rpm up to 125 or 130 psi internal transfer pump pressure, which is regulated by the little allen screw in the ip inlet, the one where we enlarge the holes,
 
Thanks Slim, I had always assumed that based on how the programming was done. I actually have that 6.5 electronic injection book that covered that as well. It also says our IP should be getting 8psi of supply pressure, so the GM LP was inadequate for their own recommendations.
 
buddy said:
Thanks Slim, I had always assumed that based on how the programming was done. I actually have that 6.5 electronic injection book that covered that as well. It also says our IP should be getting 8psi of supply pressure, so the GM LP was inadequate for their own recommendations.
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I had a hunch on this years ago when I had iced up sock my truck would stall out after drawing negative 7psi of vacuum. Thus I've stated in that thread that IMO anything under 7-8 psi leaves the IP doing unnecessary work, and my quest for PSI with the twin walbros.
 
great white said:
Could I get a few details on that particular book so I could look for one?

IE: full title, publisher, isbn, etc?

Any info of that sort would be appreciated.

Is it for the DB2 or the DS4?
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Its called 6.5L Diesel Electronic Fuel Injection, its a GM training manual. You can find it on ebay. Tonight I'll find it and see if there is publisher and other info in it. It also has a lot of the info that the GM diesel supplement has in it. The computer type information on sensors and pin numbers and what not. I like having both books though.
 
Yeah have had that book for some time, still doesn't give up any of the dirty secrets, LOL. The book is worth having if you really are trying to understand the DS4 pump.
 
Yes and it covers the 1994 PCM stuff, so although all of the info is good, the PCM pinouts are all for the OBD1 trucks. I dont know if there are newer materials for OBD2 PCMs.
 
i dont know much, but when my pump solenoid was going in my old ds4, it supplied enough fuel to roll coal on the highway with my wg wired shut... ds4 is able to supply plenty of fuel under the right conditions (worn solenoid) i dont know if it was cause the little socket head screw was stretched or hanging up and not pulsing? but man the truck ran like a raped ape untill the ip would run away on me... i would say the restriction is in the solenoid... my thought was to shim it some how like a mack puff eliminator... but i know next to nothing about db2's and even less about ds4's so just my 2 cents...
 
not sure of the boost pressure sorry... thats how i bought the truck, no guages,wg wired shut, bad pump blown head gaskets... but after i made a turbo master and could easily make 16-17 psi till i got it adjusted down to 12 on the guage and on my scanner... seriously put out Alot of fuel...wish i had a video of it it was a monster, the idle would surge towards the end, and belch black smoke... at idle the scanner would go from 80 something mm to 0 and back up, sorry again but it was a year ago i did the pump and didnt think this would be useful info,till i got the new pump and saw how little fuel it put out, chip helped alot, but truck is still a dog i have an engh motors chip and new from stanadyne ds4 now, and still no where near the amount of fuel as my old pump in the garage put out, i'm so disapointed i'm thinking of switching to the db2 i have, even though its only an 829 i think it could put out more, with the fuel screw maxed out...
 
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