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Old 11-07-2007, 11:42 PM   #1
sootman73
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Injection pump adjustments/modifications

Is there a way to change the governed rpm limit on a 7.3l turbo? mine seems to cut out at only 2900 to 3000 rpm. ive seen places where they build a pump calibrated for turbo(factory or not) that has the rpm limit at 3800 rpm. I was just wonderin if there was a way to adjust the pump i have. the pump is a XX31 model not the XX29. any help would be greatly appreciated!
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94' F250 7.3L turbo diesel extended cab 4wd IP maxxed out, Autometer Phanton II pyro and boost on a-pillar, straight piped, E40D auto and 3:55 gearing.
SOON: stage 1 injectors, high performance transmission, and 5in flapper stacks!
SOMEDAY: 4in lift with 37's and maybe twins
once hauled two gravity wagons with beans. Rig weighed in at 30,280#! and the only thing slowin me down was the bad wagon wheels!(and snow) it chugged :smoke with pride right up the snow covered ramp where a suburban with one wagon needed a tractor to push it through.

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Old 11-08-2007, 12:29 AM   #2
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To raise the rpm you need to change the governor spring under the top cover. The one from a 6.2 GM will put you at approx. 4000 rpm. The one from a 5.7 GM will put you around 4400 rpm. You could also shim the governor spring for ?? rpm.

I run 6.2 spring in mine and am fairly happy with how it runs.
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2000 F350 Cab/Chassis Crewcab DRW 4wd 7.3/Auto "Hamilton Custom Cruiser" conversion WesternHauler bed TFI 50 gal transfer tank 4" Exhaust DIY intake w/Napa 6637 85k miles

'85 F350 Cab/Chassis 190"wb Schawlbe 55" sleeper and Hauler bed 7.3 IDI/T19/4.10 Banks Sidewinder Holley red pump Over 500,000 trailer pulling miles.**SOLD**:crybaby2:

Other Diesels gone but not forgotten; '86 F350 Crew Dually 6.9/c-6 '89 F350 Crew 4x4 7.3/ZF5
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Old 11-08-2007, 03:16 AM   #3
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hmm i need to get me one of those. mine is pulling fuel at 3k.
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Old 11-08-2007, 03:44 AM   #4
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it just so goes that i have an injection pump from a 92 6.2l from my old truck when i blew up the motor! had no idea that that is what does it. What is involved in changing this spring? i know that you have to be careful when messing with the screw there! thats how i blew my old 6.2l. turned the timing advance and it ran away on me. didn't know how to shut it down at the time! blew up in the barn
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94' F250 7.3L turbo diesel extended cab 4wd IP maxxed out, Autometer Phanton II pyro and boost on a-pillar, straight piped, E40D auto and 3:55 gearing.
SOON: stage 1 injectors, high performance transmission, and 5in flapper stacks!
SOMEDAY: 4in lift with 37's and maybe twins
once hauled two gravity wagons with beans. Rig weighed in at 30,280#! and the only thing slowin me down was the bad wagon wheels!(and snow) it chugged :smoke with pride right up the snow covered ramp where a suburban with one wagon needed a tractor to push it through.

CHECK OUT MY TRUCK!
http://www.youtube.com/watch?v=lLO9vlAqMvo
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Old 11-08-2007, 02:57 PM   #5
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To change the spring you remove the top cover. There will be a block and shaft( might be poor desciption) with 2 springs on it. This is the governor assembly connected to the throttle shaft. Remove the guide pin ( screw at the back of pump with locknut) as it runs thru the center of the governor assembly. Count the number of turns to remove the guide pin as it is also an adjustment that you'll want to put back close to original. Once the guide pin is removed you can slip the governor out from under the shaft Be careful there is a small spring in the center of the governor you don't want to lose. Now if you have the whole governor out of the 6.2 pump you can just install it. If you only have the spring (which is the larger of the 2 on the governor) you'll have to unscrew the governor assembly to swap the spring. Again count the number of turns because the overall length of the governor effects idle rpm. When you reinstall the top cover make sure the FSS is properly engaged or you may have a runaway when you fire it up. I slide the cover on from front to rear and have never had a problem, or you can just apply 12v to the FSS if it clicks then it should be engaged properly.
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2000 F350 Cab/Chassis Crewcab DRW 4wd 7.3/Auto "Hamilton Custom Cruiser" conversion WesternHauler bed TFI 50 gal transfer tank 4" Exhaust DIY intake w/Napa 6637 85k miles

'85 F350 Cab/Chassis 190"wb Schawlbe 55" sleeper and Hauler bed 7.3 IDI/T19/4.10 Banks Sidewinder Holley red pump Over 500,000 trailer pulling miles.**SOLD**:crybaby2:

Other Diesels gone but not forgotten; '86 F350 Crew Dually 6.9/c-6 '89 F350 Crew 4x4 7.3/ZF5
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Old 11-08-2007, 06:06 PM   #6
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OR you could just adjust it the proper way and just back out the high idle screw on the throttle lever. That way you don't have to worry about takeing anything apart on the pump and you won't screw with your regulation by putting in the wrong spring or governer. The 6.2/6.5l min/max assemblies (the "block and shaft" described above) are completely different than the ones on the 6.9/7.3s. They are two piece and don't have a spring in the middle of them and they don't have a return spring on the throttle shaft for them either.

Anyway back the screw out on the throttle shaft that is on the back side of the throttle lever. So it's the one on the side of the pump as the fuel inlet cone. Back it out a half a turn or so at a time until you get the rpm you want. But be careful not to go to far and over rev it. If the pump has any kid of warranty this will void it as they usually either have a seal wire and or some laquer on them so the fuel shops know if you have tampered with it.

That being said if there is runability issues and it's not reving out to the proper RPM then it might be a good idea to pull the pump and have it gone through.
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739 with NČO

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"If you think you can do a thing or think you can't do a thing, you're right." Henry Ford

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Old 11-08-2007, 06:51 PM   #7
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Thanks for all the help. i am hesitant on unscrewing anything in that area as i had bad luck with results before. Can some one find me a picture of the underside of the cover from the pump? i have seen it before but it would be nice if you guys could point out the different parts you listed. thanks
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Ben

94' F250 7.3L turbo diesel extended cab 4wd IP maxxed out, Autometer Phanton II pyro and boost on a-pillar, straight piped, E40D auto and 3:55 gearing.
SOON: stage 1 injectors, high performance transmission, and 5in flapper stacks!
SOMEDAY: 4in lift with 37's and maybe twins
once hauled two gravity wagons with beans. Rig weighed in at 30,280#! and the only thing slowin me down was the bad wagon wheels!(and snow) it chugged :smoke with pride right up the snow covered ramp where a suburban with one wagon needed a tractor to push it through.

CHECK OUT MY TRUCK!
http://www.youtube.com/watch?v=lLO9vlAqMvo
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Old 11-08-2007, 08:22 PM   #8
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Adjusting the screw on the throttle shaft is not going to change the rpm that the pump goes into defueling/ fuel cut. If your pump isn't going into fuel cut then adjusting that screw will get you more rpm. Remember if the screw on yours has the laquer unbroken on it then it should be set to the correct Stanadyne spec. So adjusting it wouldn't be considered the proper way either. I remove my 6.2 springs from 6.2 pumps. I could be wrong about the whole assy. fitting in the 6.9/7.3 pumps as I forgot about the return spring issue. I have always just swapped the max governor spring. At any rate the 6.2 spring fits the 6.9/7.3 governor perfectly and is how the few I know of who build HP DB2 pumps raise the rpm limits of the pump.:shrug:
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2000 F350 Cab/Chassis Crewcab DRW 4wd 7.3/Auto "Hamilton Custom Cruiser" conversion WesternHauler bed TFI 50 gal transfer tank 4" Exhaust DIY intake w/Napa 6637 85k miles

'85 F350 Cab/Chassis 190"wb Schawlbe 55" sleeper and Hauler bed 7.3 IDI/T19/4.10 Banks Sidewinder Holley red pump Over 500,000 trailer pulling miles.**SOLD**:crybaby2:

Other Diesels gone but not forgotten; '86 F350 Crew Dually 6.9/c-6 '89 F350 Crew 4x4 7.3/ZF5
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Old 11-08-2007, 09:52 PM   #9
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Ok not trying to be a jerk or anything but when was the last time you actually overhauled a complete DB2 pump and when was the last time you ran one on a calibration stand? It would be last week for both for me. I work in a fuel shop and overhaul those pumps all the time. The throttle lever is more or less and rpm selector. The farther it moves foreward the more rpms it will give. At ANY throttle position you will get full load fuel if the engine rpm is less than desired for that position. To set the high idle on these pumps, which is the max rpm, you adjust the high idle screw on the throttle lever.

The governer spring does NOT effect RPM but rather governer regulation. Regulation is the rpm range that it goes from full load fuel to no fuel. For example if you want 5% regulation at say 2000 rpm you would go from full load fuel at 2000 rpm to no fuel at 2100 rpm. If you wanted 8% regulation at 2000 rpm you would have full load fuel at 2000 rpm and no fuel at 2160 rpm. The different spring tensions change the percentage of regulation. NOT the high idle rpm.

You are correct that if the laquer is not disturbed the setting is at what stanadyne or the last fuel shop set it at to be calibrated for the proper rpm. That's why I said before that if you're not getting full rpm out of it you may have something else wrong with it and it may need to be overhauled.
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'96 F-250 Extended Cab, GT'S injectors, GT'S intercooler install kit, custom turbo kit with a little HX40, Swamp's BIGEST oil.
466 on #2 only
739 with NČO

13.544 in 1/4 mi!

"If you think you can do a thing or think you can't do a thing, you're right." Henry Ford

Yeah I can keep up!:Thumbup:
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Old 11-08-2007, 11:29 PM   #10
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You're not being a jerk your just trying to explain something that it seems you know more about than me. That's fine.

Does the screw on the throttle shaft effect when it goes to no fuel/ fuelcut or does the governor spring?

Quote:
Originally Posted by gtspowerstroke

The governer spring does NOT effect RPM but rather governer regulation. Regulation is the rpm range that it goes from full load fuel to no fuel.
This statement tells me that if I take a pump that is functioning properly and goes from full fuel at 3000 rpm to no fuel at lets say 3300 and I change out the spring I will get more rpm out of it. Now all the stock spec IDI pumps I've had experience with gone to nofuel somewhere between 3300 and 3600. The original poster was asking about pumps he saw that were rated at 3800 which would mean no fuel at around 4000-4180? Now the way I know to get those rpm numbers is to change the spring becuase backing that crew out has never got me 3800+ rpm. How would you get a IDI spec DB2 to allow 3800 or more rpm?
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Keith

2000 F350 Cab/Chassis Crewcab DRW 4wd 7.3/Auto "Hamilton Custom Cruiser" conversion WesternHauler bed TFI 50 gal transfer tank 4" Exhaust DIY intake w/Napa 6637 85k miles

'85 F350 Cab/Chassis 190"wb Schawlbe 55" sleeper and Hauler bed 7.3 IDI/T19/4.10 Banks Sidewinder Holley red pump Over 500,000 trailer pulling miles.**SOLD**:crybaby2:

Other Diesels gone but not forgotten; '86 F350 Crew Dually 6.9/c-6 '89 F350 Crew 4x4 7.3/ZF5
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