Thread: d1 injector pump tweaking

Originally Posted by PAT303

Originally Posted by Disco_owner

The 300tdi is already wastegated at 15psi , leave the boost where it is , you won't make extra ponnies with increasing boost ,

there are 3 adjustments on the Boost Compensator

Stop screw = increased the off idle
eccentric cone adjustment
star wheel adjustment

there is an excellent set of instructions somehere here prepared by one of the forum members. but an EGT is a good idea to fit prior to doing the Mod.

I'll try and search for it...

Edit: Mr Pedro the Swift has done well..

here is the Instructions..


Australian Land Rover Owners

The Good Oil is your Friend

With the stop screw it won't help off idle as it only increases the fuel when the boost comes on. Pat

I believe what Disco_owner is calling the stop screw, the torx head screw that stops upward travel of the fuel pin/diaphragm.

It most definitely will affect performance off idle. It adjusts the fuel rate when there is no boost pressure.

Screwing this down increases the fuel rate, which increases the heat in the exhaust gasses, and in turn spools the turbo up quicker.

If it is screwed down too far, the engine will blow black smoke at no, or very low boost pressure.

Yes that's right, it was the Torx Screw I was referring to as "Stop Screw" , I did actually carry out the off-idle 'mod' and it gave me slightly better off-idle take off as I tested this on an uphill start prior to fitting an EGT gauge for the latter stage Mods.

Originally Posted by 400HPONGAS

Ah yes , it was the far superior 200TDI engine that I tweaked , Could never understand why they quote the 300 and 200 at 84 kw when the 200 allways outpulls the the 300 ,and lasts twice as long , perhaps with a little more clatter .Ithink its the dreadful exhaust and inlet tract differences . Every 200/300 Ive measured boost on went 11 PSI , not even close to 15 PSI

i thopught the 200 only whent to 8psi, just some thing stuck in my head.

100% correct about the manifolds though

The 200-300 is incredibly easy to tweak. I have done mine and countless others. and all needed to be done differently, some were auto discos others defender 110 etc and owners wanted different things so its good to know how its done so you can do what suits you.

No you dont need to do the intercooler necessarily to get more power but it will help significantly once the pump is tweaked and it good for cooling EGTs a bit.

A handy mod to start with is replace the screws on top of the pump with allan key cap screws. This makes it much easier and quicker when you are fine tuning, you will be in and out of it a few times before you are happy. Leave the torx screw on the top alone and never play with max fuel screw on the side, the less things you muck about with the better and makes its easier to fine tune and fix messes.

Pull off the top and note and mark the position of the small dot at about 12 o'clock then remove the diaphragm. It will come out but you may need to move the throttle to free it.

Give star the star wheel one half turn to the right, this allows more fuel with boost.

On the shaft of the diaphragm there is plastic bush. Remove and keep in a safe place. basically this lets the diagram go down further. Some shave it down if they don't want to go the whole way, but who doesn't want to go all they way!

Replace diaphragm with the small point back where it was.

Put the top back on and go for a spin.

If its blowing no smoke and you still want more power, then you can take the top off the pump and by small degrees turn the diaphragm to the right untill it produces no more than a very slight haze at full noise, if any more smoke than this then turn the other way. If the smoke is at low revs then turn the star wheel back anti clockwise as it can give additional fuel at low boost too early or too much fuel is being added.

I have mine tuned for a bit of smoke under load at low revs which is very handy when you are climbing a steep hill off road or about to stall, it then clears up totally clean as soon as boost kicks in and then a very light haze all maxed. If its blowing any black you will end out loving the power. Tough titty, turn it back, even if it seems gutless by comparison, black smoke at load shags heads!

Without a big intercooler then maybe don't even have a haze at high revs but a bit of low rev smoke (under 1500) wont kill it.

if you want to tweak the boost there no point in going over 18psi as restrictions in the overall airflow means you will loose power beyond this.

REMEMBER AND NOTE EVERYTHING so you can put it back exactly as you found it if need to or if you get cocked up. Mark the point and count the clicks! As every ones says an EGT gauge never hurts and your radiator needs to be in top notch order. Seriously its a Hanes 2spanner job.

Buy the way these tweaks are what Jeremy J Fearn does. google him if you dont know who he is.

I have done heaps of these and never cracked a head yet and you will be fine if just don't over do it.

Again careful where and how you measure boost . T-piece into the wastegate actuator cylinder for the most accurate reading . Also I find 500-550 C a bit low as mine (200 and 300 TDI's)ususally run around the 600C range . Seeing that the heat generated is proportional to fuel burned , maybe thats why I am making a bit more power , and no black smoke under hard acceleration ( Diesel , hard acceleration ? an oxymoron LOL ) . fuel consumption 8 k around town 9 k to the litre country run , which after the stato , I find quite acceptable.

Excellent stuff nzlandies ! You wouldnt happen to know of someone that still has the 200 squirters , which are different to the 300 squirters , as Im positive Ive lost bit of power after being forced to use 300 squirts in a 200 engine. I am positive the nozzles rate and spray pattern are different on the 2 types of squirts .