Thread: Injection pump modification question

the onlything more bullet proof than the injector pump is the engine its mounted to.

the stock IP will happily deliver enough fuel to easily keep 15psi of aftermarket turbo happy and while there are mods you can do to them, if you were happy with the NA operation before dont touch it.

some of the mods that can be done are (and Im not talking adjustments of whats there, just part swapping stuff)

1. different torque plate
2. different auto advance springs
3. different plungers
4. different spill sleeves
5. electric solenoid fuel cut off (its a mod from a different IP that uses the same frame and not really worth doing as you loose the ability to easily jerry rig the emergancy start)
6. different delivery valves
7. different governor and control springs

typically items 1-4 get done all at once but you can pick and mix them to a limited expense but if you're getting down to pick/n mixing much else other than the torque cam you are running the risk of the local CDO nut looking over your shoulder and commenting "getting a touch obsessive arent we?"

I dont recommend pulling your IP apart as a DIY project, while it can be done its best done in a clean room and some mistakes once made if not caught can lead to you getting a runaway engine or blowing holes in pistons.

I HIGHLY reccomend not making the runaway engine mistakes, its bloody hard to haul up a tdi300 once its got a full head of "full steam a head and Damn the gudgeons" going on Doing it in a suzi (especially a turbod one) would probably result in enough net output to shift a tectonic plate

No I not going to strip the pump as a diy project. Ill just pull it off the motor. Are the parts 1-4 all from the 4bdt pump? Thanks mate for the quick repy

O 1 more thing whats the diff between the na pump and the 4bd1 turbo pump ie can you just bolt one on to a na motor

The NA pump is just as capable as the "t" model pump just that it may have different fuel delivery points as there is numerous different ones for different applications and year models...the torque cam can be modified and is not a big job especially for a injection shop with a test bench...from all my searching and investigation there is no other plungers/barrels that are larger than 9.5mm that suit the pumps found on a 4bd1 as the frame is to small there are 2 options both being very costly and or impossible in this country... I've had no problems with getting enough fuel outta my pump I can easily out perform a v8 cruiser on any incline

the pump frame is on many engines, all of the parts by generic description are on all of the pumps, some pumps also have boost compensators and other extra bits of fruit.

the configuration inside is what sets them apart, so long as the parts are suited to your pump frame then you can swap them one to the other. but some parts are matched to each other. For example lets say the plungers come in 10,11,12+ 13mm diameters and require the sleeves to suit, while you can put a 10mm plunger into a 13mm sleeve its not going to work. (the much larger plungers are from a different frame that has the same front bolt and drive pattern as the normal IP so can be bolted up if you need it)


the NA and turbo pump are direct interchange components when done as whole assemblies, the primary difference for the non compensated turbo IP and the NA IP is the torque plate.

I have a 1989 4BD1T from an Isuzu truck.

Some 4BD1T's have a boost compensator on the governor, some have an altitude compensator (also called aneroid), some have both a boost and altitude compensator. Some have a fuel enrichment lever on the governor.

Mine has none of those.

The manual IDE2140 gives the calibration for both the 4BD1 and 4BD1T injection pumps used between 1986 and late 1988. The pump id numbers were given as 101401-0290In for a 4BD1 and 101401-0660 for the 4BD1T, which BTW has a boost compensator.

For both of those pumps there isn't much difference in the fuel delivery rates at the various set points, which indicates to me that both would have the same diameter pumping elements (plunger and barrel), and only differ in the governor calibration.

(Edit): the torque cam is number "A50" for the 4BD1 and "A75" for the 4BD1T (end Edit).

The greatest fuel delivery rate (neglecting richer calibration for starting), per 1000 plunger strokes, is at maximum torque:
For the 4BD1 = 67.3 to 70.3 cc per 1000 st
For the 4BD1T = 69.6 to 72.8 cc per 1000 st if no boost pressure
For the 4BD1T = 70.2 to 72.2 cc per 1000 st if boost pressure above 110mm Hg (2.1 psi)

I know from my pump that it has 9.5mm plungers. This can be determined from reading the numbers from the id label attached to the side of the injection pump. I would expect your pump will also have 9.5mm plungers, but it will pay to check the label. I had my governor re-calibrated and when maxed out it delivered approximately 175 cc per 1000 st (180 if the control rack was pushed by hand). That should be enough fuel for 250 HP from the 1989 version of the 4BD1T (earlier 4BD1's are not as efficient).

My take on this is; there is no need to modify the injection pump unless you want large power and torque numbers, and calibration should get the performance you want, providing your air delivery matches it (turbo and intercooler).

From all my digging through Bosch records the largest diameter barrels that will suit our pump frames on our 4bd1s (C frame ? been awhile) is 9.5mm however an AD frame pump can accommodate larger...matching helixes is another thing...the only other possible way I can foresee getting massive fuelling out of our pumps is taking the pump cam out getting it custom ground if not maybe a whole new cam from another pump and then find a plunger barrel set with same diameter but longer extra volume gained via longer stroke...I have not figured out any more than that so anyone else feel free

no point in grinding the cam chief, the existing cam can be setup so that it passes the bump clearance.

if you really want to mod it there are different sleeves with a different rate cut on the angle of the helix that deliver the fuel more agressively in response to throttle application (less throttle movement gives more effective pumping height) but engines with these do not like idle or light loads, the slightest variations or slop in the racking causes hunting like you wouldnt believe.

short of building an archaic diesel drag landy I cant think of a single application for these bits in a landies IP and if you want the short cut method to the same effect you just fit a shorter arm between the throttle cable and the input spindle.

with the more agressive helix you can use a shorter plunger which gives you more height of fuel but I'm quietly confident anyone willing to have a crack at doing fuel this way is going to learn the fast way about "reliability shortfall"