Thread: D1 300Tdi Injector Tweak Question

Mine did the same,just made smoke.I have D/gas so mines a 1/8 turn down from factory. Pat

Originally Posted by PAT303

Mine did the same,just made smoke.I have D/gas so mines a 1/8 turn down from factory. Pat

Well i only have a half turn left ccw till the pump is back on stock but after turning it back 1 full turn ccw (1st Stage tweak) i thought there would be a difference in off idle pick up where mine stays the same as when you do the first stage tweak.

Just to clarify some terminology, you are talking of adjustments to the fuel injection pump, not the injector - the injectors are fitted into the cylinder head (1 for each cylinder).

There is no such thing defined as 1st stage. What is 1st, 2nd, .... is purely subjective.

There are at least 4 different adjustments that are easy to carry out on the boost compensator, plus a 5th which is more radical.

Two of those adjustment involving screwing parts, so you would be talking of one of those (but neither are what I would do 1st).

I believe you are referring to the screw with a torx head that is in the top cover of the boost compensator. This is a stop for how far the spring lifts the fuel pin when there is no boost pressure and affects acceleration off the line.

Moving the fuel pin down increases the fuel rate. When the turbo starts to produce boost pressure, the pressure acts on the diaphragm pushing the pin down against the spring to increase the fuel rate.

This stop screw has no affect once the turbo starts to make boost pressure. Turning this screw clockwise increases the fuel at no boost and the extra heat in the exhaust that the additional fuel creates will spin the turbo up quicker.

When the engine is warmed up, a little bit of black smoke off the line is ok, so long as it clears when the turbo starts to make boost pressure.

If you are blowing black smoke when the turbo is making boost pressure, there is something else causing it. If the only adjustment that has been made was the stop screw, there could be a number of other causes.

Black smoke is the result of incomplete combustion. Usually this is because there is not enough air for the fuel rate.

Lack of air could be due to:

• restrictions in the air inlet/filter, or intercooler hoses - hoses can be damaged inside and not seen from external inspection, intercooler full of crap
• leaking air between the compressor outlet and the manifold - hoses, clamps etc.
• turbo problems - e.g. waste gate opening pressure set too low
• valve adjustment or broken cups on top of the valve stems

Incomplete combustion could be poor fuel atomising - faulty injectors. This can lead to accelerated cylinder wear.

Low compression due to burnt valves, worn rings etc.

Incorrect timing of fuel injection pump.

I am confused at some of the terminology.

As BUSH65 has said, stage one two etc means nothing at all.

Torx on the top is the Low Manifold Pressure screw (or smoke screw). Would have had to pick out the anti tamper cover. I never touch it.

Boost compensator is the Star wheel under the diaphragm. You need to get inside the pump for this.

Which one have you been referring to.

The LMPressure screw will make no difference to motorway speed smoke and I am not surprised when you say you have turned it and does nothing put it back to stock and leave it alone.

Just guessing thats it blowing smoke though? Just get a mate to follow you!

Personally I would put it back to standard and check the boost first- 15 is stock, up to 17 is ok. Then you must check pipes, intercooler, RADIATOR inlet manifold gasket (you will have oil on the passenger side of the block), timing etc.

Then you know you have enough air and cooling to support tweaks and your engine will be running better anyway

The 300 will crack its head you are not careful and too much fuel is the best way to do it.

I got all this info from a link someone posted on here on one of the other tweak posts. Someone on here wrote up a "how to" and there's three different stages as he put it in his write up on tweaking the injector pump.

What he calls stage 1 is tweaking the stop screw on top of the diaphram cover buy cracking the 13mm nut then adjusting the torx screw 1 & a half cw turn to get better off the line acceleration. My friend on here said he only touched that and I put it back to stock.

Adjustments Stage 1

An immediate and noticeable improvement in off-idle pick-up can be had by adjusting only
the stop screw. If not confident about delving further into the innards of the boost
compensator, this is a good place to start. You will need a T-27 Torx bit and a 13mm socket.
Amongst other sources, Torx bits can be purchased in fairly cheap sets from Dick Smith
Electronics.
After removing the screw cap, just ‘crack’ the locknut loose, taking care to avoid moving the
Torx screw (see Figure 7). If not corroded, the locknut should turn freely without disturbing
the screw. If so, loosen the locknut about one turn. Now, taking careful note of the amount
of movement, turn the Torx screw inwards (CW) 1½ turns. Carefully re-tighten the locknut.
The diaphragm cover is light die-cast alloy – do not over-tighten any nuts/screws.
Now take it for a drive. If your engine was ‘factory standard’ to begin with, this should have a
noticeable effect on off-idle and low boost (<1800 rpm) driveability. If it also results in
unacceptable black smoke, re-adjust the screw a little back towards the original setting
(

Don’t forget to record each setting (in terms of turns or fractions of turns) from the original
position.) Once happy with the results, either replace the original metal cap or fit a substitute
cap as mentioned above.

Originally Posted by **Joker**

I got all this info from a link someone posted on here on one of the other tweak posts. Someone on here wrote up a "how to" and there's three different stages as he put it in his write up on tweaking the injector pump.

What he calls stage 1 is tweaking the stop screw on top of the diaphram cover buy cracking the 13mm nut then adjusting the torx screw 1 & a half cw turn to get better off the line acceleration. My friend on here said he only touched that and I put it back to stock.

...

I guessed as much, but did have to guess because those particular stages are only relevant in the context of those particular instruction. When you speak outside the context of those instructions (as in the 1st post), then stage 1 is meaningless/confusing.

Many people think of the tweaks to the boost compensator in the order of where the particular adjustment has an effect relative to the boost pressure, from no boost to maximum boost. This is the order of stage 1, 2 & 3 in those instructions.

However it is not the best order to follow if you are intending to adjust for improved performance across the full range.

It is best that the 1st adjustment is to get the fuel rate correct for when boost pressure is greatest. This is done by rotating the fuel pin - usually referred to as rotation of the diaphragm, because the diaphragm is attached to the fuel pin. The plastic stop/spacer, below the diaphragm on the fuel pin, limits the downward travel of the fuel pin and should be set before the fuel pin is rotated - i.e. check and ensure that the fuel pin is travelling through its full stroke.

If you go to the time and trouble to do the other adjustments (stop screw and star wheel), before rotation of the fuel pin, then you will have to re-do them after rotating the fuel pin. Rotating the fuel pin will increase/decrease the fuel rate across the entire range of boost pressure and affects those other adjustments.

There is another adjustment screw for maximum fuel, but is not part of the boost compensator and it is only necessary to adjust if you can't get enough fuel by adjusting the fuel pin (very unlikely if you have the stock turbo).

Originally Posted by Bush65

I guessed as much, but did have to guess because those particular stages are only relevant in the context of those particular instruction. When you speak outside the context of those instructions (as in the 1st post), then stage 1 is meaningless/confusing.

Many people think of the tweaks to the boost compensator in the order of where the particular adjustment has an effect relative to the boost pressure, from no boost to maximum boost. This is the order of stage 1, 2 & 3 in those instructions.

However it is not the best order to follow if you are intending to adjust for improved performance across the full range.

It is best that the 1st adjustment is to get the fuel rate correct for when boost pressure is greatest. This is done by rotating the fuel pin - usually referred to as rotation of the diaphragm, because the diaphragm is attached to the fuel pin. The plastic stop/spacer, below the diaphragm on the fuel pin, limits the downward travel of the fuel pin and should be set before the fuel pin is rotated - i.e. check and ensure that the fuel pin is travelling through its full stroke.

If you go to the time and trouble to do the other adjustments (stop screw and star wheel), before rotation of the fuel pin, then you will have to re-do them after rotating the fuel pin. Rotating the fuel pin will increase/decrease the fuel rate across the entire range of boost pressure and affects those other adjustments.

There is another adjustment screw for maximum fuel, but is not part of the boost compensator and it is only necessary to adjust if you can't get enough fuel by adjusting the fuel pin (very unlikely if you have the stock turbo).

I do apologize if i didnt word it correctly i'm very non-mechanicaly minded but does like to give things a go. I do how ever appreciate your help and info on the subject as it has broaded my non-mechanical mind lol.

i have now put it back to stock settings and will be getting a egt gauge and wont be mucking around with it until its installed. she drives just fine Now BUT as said will have to take it for a drive to see what she is blowing out while driving.