Tdi Injection Pump Tuning Tips
                                                                             Injection Pump Tuning tips from the web

Aussie 200 TDI named Camila

"Project Gemini" -

The 200Tdi engine

by Alain Hoffmann

The engine is without bigger problems when you respect 2 rules: Change your oil frequently (I do it every 7000 Km, 5000 miles) and change the timing belt every 80.000 Km / 55.000 miles.

The engine is without doubt one of the best diesels ever fitted in the Land Rovers. Sure, it's a bit noisy but it lives very long, has no starting problems, pulls well once it's warm and, best of all, it
gives an excellent fuel economy. Real world figures are around 10 liters per 100 km with an achievable 8 on long runs and an upper limit of around 12,5/100 if you tow a heavy trailer flat out.

BTW, Discovery and Defender engines aren't identical. You CAN swap them but you need specific parts and you best ask a reputable shop what's needed.

It wasn't the smartest idea to fit an rubber timing belt to this engine but it was done to reduce the already harsh noise. You can buy an retrofit kit from ZEUS that eliminates the belt but it isn't exactly
cheap and it produces a lot of noise which is however only noticeable when driving slow. On the other side there's no preliminary warning if the belt goes to snap and this means in all the cases
I've seen a new engine.

The performance may be increased by having a reputable shop tune the fuel pump to increase pressure. This brings much better acceleration and an increase of about 10 Mph in top speed.

The next step would be a bigger Intercooler thus reducing the intake air temperature. By this 2 ways you can easily achieve around 135 Horses without impeding engine longetivity.

Some engines have a tendency to shake the fuel return lines loose thus soaking the right side with diesel. An correction kit for this exists. Or you do as my wife does- she always carries an 7/16
open ended wrench in the glove box.

Tuning the Bosch VE Injection Pump

So, you want to know how to get more power out of your 300Tdi (or 200 Tdi for that matter)? These engines are both fitted with the Bosch VE type fuel pumps, and although they work at different
out-put pressures, and some are fitted with immobiliser valves and throttle position sensors, essentially they work in exactly the same way.

This is not the case with the electronically controlled versions, where an engine management system is employed and there is no direct accelerator peddle to throttle link – the following methods
of adjustment should not be used on these types of fuel injection distributor pumps. These engines can be chipped to get the same sort of power increase.

Below is what I have done.
I went to a Japanese Car Breakers yard and bought a rather nice big intercooler from a 1990 Toyota Supra. It was in excellent condition, is about twice the size of the original Disco item, and cost
I then bought some reinforced 50mm rubber hose and some pre-formed 50mm reinforced rubber hose 90 degree Bends. I then fitted the new intercooler in-front of the Air-Con Radiator assembly
and plumbed in the pipe-work to the original intercooler inlet. I now have three times the cooling capacity of the original intercooler. This means more cold air = more power !!!

However, all this extra plumbing has added a little more resistance to the air flow, which means that you get your 1 bar at the turbo outlet, but you dont get 1 bar at the inlet valves. To get over this,
drill and tap a hole in the inlet manifold (plenum chamber) and screw in barbed hose fitting (available from your local plumbing merchant for about £1. Get a bit of tube and push it over this fitting and
lead it down to your waste-gate actuator plug it into that and blank off the hose you had to pull off, that leads back to the turbo outlet. Thus the waste-gate will now only get 1 bar when you get 1
bar at the inlet valves, and then it will start opening.

I plumbed a T into the above fitting and led a hose to an accurate pressure gauge mounted on the dash, so I can monitor the turbo boost. This can help you to drive economically too, but it allows
you to see how well you turbo is working.

If needs be, you can shorten the waste-gate actuator rod and increase the boost. You may need to remove the actuator and cut a bit off the end of the rod to allow sufficient adjustment in the
sleeve portion (dont take too much off at once better do it in 3mm increments !). What you will find is the rod is too long to get more boost, as too much of it screws into the sleeve and bottoms out.
You will have to shorten it quite a way to get more than 1 bar boost but this is often all you need. 200 Tdis run at 0.7 -0.8 bar  you can safely increase this to 1 bar ,300Tdis run at 1 bar already
best left alone!

In doing this you will find that you are actually having to pull the rod against the actuator spring to get it back onto the waste-gate  this is quite fiddly  use locking pliers and mind your fingers! Ensure
you put the circlip back on. This means that the actuator spring is now holding the waste-gate shut, and means that more boost is required to overcome the spring before the waste-gate is
opened. It wont fully open now either, so boost pressure is held at a constantly higher pressure for longer.

Now you have got all that extra nice cool air at 1 bar, you need the fuel to go with it to get the extra performance. Heres how to do that:

Diagram 1

Diagram 2

All Adjustments can be made without removing the pump from the engine.

Low manifold pressure (boost) fuel delivery adjustment.
See: â˜Smoke Adjustment Screw in either diagram 1 or 2
This adjustment is fairly simple and will help considerably around town at low engine speeds and low boost conditions.
There is a small cap in the centre of the  automatic fuel-control device(AFC) on top of the pump (the appendagethat is plumbed to the intake manifold and restricts the amount of fuel injected until
the manifold pressure is above atmospheric). This cap can be readily removed with two small screwdrivers and a gentle rocking motion.
Beneath the cap is a torx T-25 screw and a lock nut that holds it. The locknut is 13 mm and has a break-away torque of around 100 in-lbs. Turn the T-25 screw 2 turns clockwise and tighten the
locknut to 125 in-lbs. For additional fuel (and smoke) the screw may be turned farther (CW). Back it off (CCW) to reduce smoke.
NOTE: this will increase the exhaust gas temperature (EGT) by about 75 degrees F on long hills. Clean the plug with Brake Cleaner and then seal it with LocTite pipe thread sealant with teflon.
Externally, it will appear original.

Full load fuel delivery rate adjustment.
See: Diagram 3
This adjustment will TURN UP THE POWER and smoke.
NOTE: this will raise the EGT very quickly at full throttle.
The main adjustment is found under the Diaphragm within the fuel control device described above. This is held in place with the 4-screw cover.
MARK THE POSITION OF THE DIAPHRAGM, then remove the diaphragm - there is a stamped tick mark on it, so use a magic marker or scribe to note the position of the diaphragm  housing.
Remove the diaphragm and pin, and note the pin is both tapered and on an eccentric. Usually, rotating the pin 120 degrees clockwise will cause the machined cone to go to the ‘richest’
setting (smallest diameter, effectively) part of the pin.
You may want to start at 90 degrees, and then go further if that does not produce the power you want. The further you turn it, the higher and faster EGT will climb. The fuel stop lever runs up and
down the conical section of this pin.
NOTE: the way to install the pin is such that allows maximum travel of the fuel stop lever that hits this pin and is perpendicular to it.
CAUTION: mark stuff so you can put it back the way it was !
After adjusting the diaphragm eccentric pin, the low boost fuel rate may need to be adjusted slightly to reduce low speed smoke.
How it works:
The eccentric tapered pin thats attached to the diaphragm is the FUEL DELIVERY RATE pin.
From above, looking down at the pump, almost to the bottom of the bore that the delivery rate pin came out of, is the bore that the fuel stop lever rides in. The linear axis or centre-line of the fuel
stop lever is parallel to the axis of the pump drive shaft, or the engine crank shaft. The movement of the delivery rate pin (down with increasing boost levels) allows the fuel stop lever (which by
internal spring pressure is contacting it) to contact the increasingly smaller diameter. This allows the fuel stop lever to move rearward (on the fuel delivery pin), which increases the fuel delivery
rate. As a note: according to the Bosch injection manual, the stock or base line for the diaphragm position is 12:00 as you look at the pump from the side of the engine. In other words, the tick mark
is toward the valve cover, for the normal setting. If you look at the underside of the diaphragm, you can see where the eccentric aspect of the Fuel Delivery Rate Pin would push the fuel stop lever
deepest toward the front of the pump, that is the LEAST delivery rate setting. Consider that 12:00. Rotating the diaphragm clockwise from that point to 3:00 is a good place to go. Depending on the
injectors that are in, and your turbo boost, you may want to turn a little more.

Automatic Fuel Control Star Wheel Adjustment
See: Starwheel diagram 1
Remove the cap fitted with the 4 straight head screws. Under the AFC diaphragm and spring is a star wheel adjustment which sets the spring tension on the FUEL DELIVERY RATE PIN diaphragm.
If your star wheel (under the AFC spring) is set too high, the delivery rate pin wont move downward as it should with increasing boost levels. Turning the star wheel up (counter-clockwise)
increases the spring pressure, and slows the delivery rate. Turning the star wheel down (clockwise) in ¼ turn increments until you smoke, then back off (counter-clockwise) until the smoke has
gone to your satisfaction, or until just smokes under power (a black haze, not a black soot cloud) is ok. The retaining lock spring doesnt have to be removed, the star wheel will rotate with a small
screwdriver gently placed and pried between the wheel and it.
CAUTION: Note the original location of the wheel, mark it, and count any turns for reference.
Remember: Star wheel down = less spring resistance = increased fuel delivery rate

Full Power Adjustment

See ˜Power Adjustment Screw, diagram 2
On the rear of the pump, partially concealed by the fuel lines, and under a plastic ˜anti-tamper cap is an other adjustment screw. Remove the plastic cap and the metal collar tack-welded to the
screw, loosen the jam-nut, and turn the power adjustment screw clockwise about 11/2 to 2 turns. After turning the Full Power Adjustment, you may need to re-adjust the Smoke Adjustment Screw
to reduce low speed smoke, and the idle screw or throttle linkage to correct the idle speed.
To remove the metal collar it is best to use a Dremmel type grinder, or very carefully using an electric drill and 2mm or smaller drill bit, drill a series of holes along the collar and then gently chisel it
off with a very sharp cold chisel. The collar appears to be made out of a hardened steel, so a very sharp drill bit is required.

Idle Adjustment:
See ˜Idle Speed Screw Diagram 3
Once you have done the above, you will probably need to reset the idle speed adjustment. Loosen the lock nut and then unscrew (reduce revs) or screw in (increases revs) the idle stop until you
get 750 -800 RPM, then tighten the lock nut and recheck you havent moved the setting. Most, but not all, discos have a rev counter, but you can set those that dont have one by putting a dab of
white paint (Tippex correcting fluid is good) on the crank pulley (with the engine stationary!). Connect a standard timing light (according to manufacturers instructions) to a petrol engine car fitted
with a rev counter and parked close enough for the timing light to reach into the engine bay of your Disco. Start both engines and if the petrol engine is held at the revs you want the Diesel engine
set to, the correct revs on the diesel engine are reached when your painted mark is stationary.

Additional Notes:
If your smoke is only at full throttle load - back off the full load screw.
If your smoke is at low end through pull-up to full power - back down the delivery rate.
If smoke is heavy at immediate start-up - fine adjust the smoke set screw.

In order to increase the horsepower one must carefully make two adjustments: one is in the smoke-limiter and will be adjusted to allow greater fuel with low manifold pressure (initially, this is
adjusted to minimise black smoke at low rpm/low manifold pressure conditions... but, we cannot build exhaust manifold pressure without fuel !). You must remove the circular seal-plug from the
centre of the AFC device. This reveals the first adjustment. This adjustment will markedly affect the feel of the cars pull-a-way power, making it pull from a stop more strongly. Adjust this in ¼-
turn increments until you like the feel and record the adjustment so you can return it to normalin preparation for a smoke opacity test for the MOT.
The second adjustment is where the real gain comes from... There is a concealed adjustment on the ˜back side of the pump... essentially behind the fuel lines. [See the power adjustment screw on
diagram 2 above] You must uncover the adjustment screw and turn it 135-degrees clockwise. You may have to reduce idle speed back to 750 rpm after this adjustment.
I found some these details after many hours of searching on the Internet. I got the bits on how to adjust the VE pump from the following site: www.dodgeram.
I offer my sincere and grateful regards to those how posted them there they enabled me to transform my 300Tdi ES Discovery for very little money compared to what some of the advertised
specialists charge.
A word of advice though: incorrect adjustment of any of the above may destroy your engine and or cause it to fail emission tests if not done correctly. Be sure youre both competent and able to
make the adjustments before attempting them. Do them at your own risk. If in doubt, pay for an expert to do them for you. You may need to inform your insurance company of the modifications you
have made.

If you cant see the diagrammes on this page - go to the above web site and print them off from there.You will see that I have very slightly altered some of the information to make it easier to
understand. I have also taken out some of the stuff that isn't relevant.

James Forehand and his Disco 200 TDI powered 110 @ Pearl's Pond June 2008

Another Version
200/300tdi pump adjustment for +25 BHP
As normal people cannot be trusted to put posts on the Technical arcive it will have to go here.

The pump on a 200/300 tdi can be adjusted to give 25 BHP extra . This is particularly valuable with autos as it takes that dangerous lag away when
pulling away at junctions.
Proceed as follows.
Stage one is to increase the turbo pressure must shorten the waste gate rod by about 6 mm to raise the turbo pressure to 16 psi..easy on a
200 pig on a 300 ...mind you dont loose the circlip and loosen the locking nut first ...make a length of 1/2 in bar with a slot in the end to push the rod
back into place ...essential on a 300. Use a gauge to measure the pressure ...T piece in pipe to injection pump...fuel pressure gauge is often the
cheapest to buy ...plastic screen washer T is OK. ( the above adjustment alone will give no increase in performance)

Stage 2

remove the four screws from the power valve on top of the pump ( squarish plate with brass cover in centre ..big screwdriver very tight) The top of the
plate will spring up...notice how far it rises on top of the spring.(say 7mm) Remove the cover. Then you will see a black diaphragm..if you want with
tippex mark its positon relative to the casing and then remove the diaphragm (lift edges and pull up) remove the spring underneath (do not move the
trottle when the diaphragm is out !!) at the bottom of the cavitly you will see a toothed wheel. You need to screw this down to reduce the lift in the top
plate to about 3mm ( 7 - 4 =3 ) Wind it down with the edge of a screwdriver and then re fit everything to check the lift ..rarely I have had to remove the
ali wheel and grind some off the bottom to get it to go down enough. Now examine the shaft on the diaphragm will see an off centre cut out at
the bottom fit the diaphragm with the deepest part of the cut out towards the rear of the vehicle...this gives you max fuel. dont forget the sping
and check you still have some lift in the top plate as you screw it down...thats it done .....If you do have some smoke then you have two choices ...
increase the turbo pressure or reduce the fuel a little by rotating the diaphragm a little clock or anticloc it dont matter... I have rarely found this the
case need to re adjust for the MOT all mine had very low c02 and passed easy....
I do not advise adjusting the screw under the brass cap or the main fuel adjuster at the rear may get a tiney bit more but when you get smoke
its a pain to know what to adjust ..adjust only the three items mentioned ...turbo pressure...diaphragm rotation and spring pressure...done dozens
without problems one on a supermarket car park!

I hope the moderator puts this in the arcive and I hope the netative comments ( previous experience) are balance by the great comments from people
who have done this with no problem though I must say I have not control over the condition of your cylinder head gasket or radiator or header tank. (
header tanks splitting causes over heating causes head gasket to blow)


When you are examining the cone at the end of the diaphragm rod look how far the scratch marks come towards the deepest part of the cone...they
should come almost to the top...if not you will find a white plastic ring on the shaft ..this is thicker on the defender ..if the scratch is not to the top then
thin the ring by a suitable amount to allow full movement along the cone face ....( added 2008 )

Re: Defender 200Tdi Fuel Pump Timing Version 3


there is a slot in the pump gear and a hole in the backing plate which
when the timing gears are lined up will pass the pump gear hole over a
hole in the pump body , in which you locate a pin in order to lock pump
and shaft in position .

this is all done with No1 cyl at top dead centre .

the locking pin is about 10mm diameter and so you can use a drill if
you like to lock the pump in place .

the 3 bolts in the pump gear are there to allow the gear to move and
align itself in the timing belt without altering the injector pump
timing , however when tensiong a new timing belt you may alter the cam
timing by a very small amount but this is normal and seems not to be
worried about to some degree ..

the woodruff key on the crankshaft will be at 12 clock position when
engine is at top dead centre and the camshaft gear aligns with mark on
block .

if you take off top of rocker cover you can watch the rockers moving as
you turn engine over by hand and when No1 cyl is at top dead centre
neither rocker on No1 cylinder will be moving , if they are rocking you
need to go one more turn over until both are closed and note the crank
keyway to come up to 12 oclock , ie directly on top towards sky .

in gearbox bellhousing underneath the landrover , is a tapped hole ,
when engine is at top dead centre youll see a slot in the flywheel
aligns with centre of hole, this needs to be locked also, using a pin .

if you were to buy either a DIFFLOCK timing pin & puller kit at 99
quid , it has all pins and pullers necessary to retime landy diesels
from N/ A 200/300TDI , or if you look on internet there are BERGEN
timing pin kits available for landys .

youll need a crank pulley puller to remove the crank harmonic
damper/pulley and a 27mm socket to undo the crank pulley retaining bolt

you can screw the crank bolt back in so you can turn engine over for
timing purposes, no need to remove glow plugs , you can turn engine
over using knuckle bar and socket .

dont forget to tighten the crank pulley bolt nice and tight after .

to get crank pulley bolt undone , a sharp blow with lump hammer to
knuckle bar will loosen it .
use a little loctite on the thread when you reinstall crank bolt .

dont forget to remove the flywheel locking pin before you rotate engine

no need to remove timing belt in order to retime injector pump so long
as you havent rotated it by more than the gear slot allows .

if you are not intending on taking crank pulley etc off to adjust
injector pump timing , then watch rockers on no1 cyl to indicate
coming up to top dead, look under gearbox housing hole and line up
flywheel slot and lock in place if poss , then loosen 3 pump gear bolts
and rotate pump shaft locking nut back so to align with timing pin
hole and lock in place with pin .

then you can retighten 3 pump gear bolts and remove locking pins .

if you find the power is very high but you have lots of black smoke
from exhaust at all ranges , undo the fuel metering screw on rear of
pump and go out 1/4 turn at a time until smoke dissappears .
youll have to strike balance between power and smoke and so it may take
a few attempts to get satisfactory .

this screw is on rear of pum near the injector pipe unions , it has a
13mm locknut and a screwthread extending out about 25mm , there is
screwdriver slot in end of thread , you hold locknut loose with spanner
and then unscrew or screw the thread in or out as desired .
IN for more fuel, OUT for less .

the "smoke adjuster" is on top of pump housing,there is a small [gold]
blanking cap [15mm dia] on top of casting which has the 4 screws in ,
pry cap out with screwdriver and youll see 13mm locknut with a 8mm TORX
grub screw , this screw is screwed in for more fuel and out for less ,
locknut may be loctited and so might need a bit of effort to undo .

inside pump, under top casting , ie the housing on top of pump which
has 4 screws holding it down , is a diaphragm and shaft and a starwheel
adjuster which alters fuel delivery rates .

the metal plate holding rubber diaphragm has a dot mark on it and the
diaphragm can be rotated to change fuel metering rates , this will be
pointing somewhere between 12 oclock [to rocker cover] and 6 oclock
[towards wing ] , the leanest position is towards rocker cover and
richest towards wing .

just take it that youll position it somewhere from 12 oclock to 6
oclock , it does not screw in and out but rotates around a 360deg axis

you can pull the diaphragm assembly out by hand , in one piece with
rubber and shaft attatched .

on shaft youll note a tapered and eccentric shape of shaft , this
rests against a pin down in the pump itself and alters fuel rates
according to position the taper or eccentric is in .

the turbo boost pressure is applied upon diaphragm via pipe on side of
top housing and thus pushes shaft down using the diaphragm , allowing
pin in pump to come in and allow more fuel thru as revs and boost
pressure increase etc .

under diaphragm youll see large spring , this is just placed in there
and can be removed/reinstalled easily .

under spring youll see a starwheel adjuster , this has a click stop
adjustment and if you pry the lock spring using screwdriver you can
rotate the starwheel .

to lessen spring pressure effect of starwheel you will screw the
starwheel in clockwise , but only about 1/2 turn at a time and noting
smoke from exhaust [under load] after adjustment .

to lessen spring effect you undo the starwheel .

this starwheel alters the spring pressure against the diaphragm and
alters where the turbo boost is allowed to move the diaphragm downwards
to increase fuel flow .

basically only minor adjustment of starwheel should need to be made ,
if any adjustment .

there is a white nylon spacer on the metering shaft and dont forget to
make sure it is still fitted when refitting metering shaft/diaphragm
and spring assembly , as it stops length of travel of metering shaft .

the main adjustment that makes most difference is the full load
adjustment on rear of pump , if unscrewed too far youll note lack of
pull when in top gear at low [25mph ] speed when on flat road .

hope that is easy enough to understand.

ive been adjusting my pump for maximum economy , so all my adjustments
have been in reverse .
previous owner screwed everything IN , yes it went like stink but i
only got 23mpg locally and lees on motorway driving .

We are partial to the 200TDi engine over the 300 having owned both.

The engines are very,very, similar and many parts are interchangeable. They are both 2.5 liter 4 cyl's.

They both use the Bosch VE pump. Which is very tunable.The 200 uses individual drive belts and the 300 uses a serpentine belt. The 200 is a
simpler setup and gets better fuel economy which is becoming ever more important as diesel prices soar to nearly $5 a gallon.

The Defender 200TDi engines bring a premium over the 300TDi engines @ salvage yards in the UK.