1.9 DTurbo Lucas Pump Tuning Guide

guide reposted from http://www.tdocuk.com/index.php (i asked permission from the creatior)


hi,
There are many guides online about how to tune the 1.9 Dturbo engines found in various PSA group cars, such as Peugeot 306's, 405's and Citroen Xantia's, Xsara's etc.

Anyway, most of the guides you come across will say that the Bosch pump is far superior, and that lots of smoke and little power will be found with the Lucas pump setup.

While, to a certain extent, this is true - pretty much all of the guides I have found online tell you to tune the Lucas Pump in such a way that quite a lot of off-boost smoke is experienced, which has led to the old DTurbo motto "NO SMOKE, NO POKE."

Some of the information you will find in this article will be different to what you see elsewhere on the internet; and all I can say is that after many hours of playing around with the Lucas Pump, I have found that the "common" way of tuning the pump seems to produce a lot of smoke; and yield mediocre power gains... my way seems to give much stronger performance results, without all the off-boost smoke.

As with all guides found online, although there are many people running various states of tune on the 1.9 DTurbo engines, I cannot be held responsible if you blow your engine up from doing this.

OK - so on with the guide:

You should really run a turbo boost gauge when making these changes, as on a diesel most fuelling related changes will also affect the turbo boost produced (more fuel will give more boost!)

So the first job is to pop the bonnet up and locate your Lucas fuel pump, it's circled in red:



Once you've located your pump, you should see it looks like this:




There are two main bits here that we are wanting to adjust, the maximum fuel screw and the boost compensator.

Firstly, let's adjust the boost compensator.

Most guides online will tell you to increase the boost compensator fuelling. Most guides also tell you that this will increase the amount of fuel delivered whilst on boost. This is incorrect.

As my understanding goes, the boost compensator is more of an "off-boost compensator" and as such, turning it up actually delivers more fuel when running off-boost... i.e, smoke.

What I have done, is actually reduce this setting from standard - don't worry, we will claw back that extra fuel elsewhere on the pump, but we want to keep off-boost smoke to a minimum.

If you've not previously modded your pump, you will find a white anti-tamper plastic lug ontop of the boost compensator adjusted, you'll need to snap this off, and you will be left with the following:



Slacken off the surrounding lock-nut, using a 14mm spanner, and wind the boost compensator screw IN (clockwise) all the way. Then wind OUT (anti-clockwise) by about 2 turns. This gives you a setting of around 2 turns less than stock.

So now we've REDUCED the power of our vehicle, what we need to do is deliver some more fuel...

As we are going to spill the diesel out of the pump, cover up the altenator with a plastic bag, and put some kind of container under the black plastic bung on the side of the fuel pump, like so:



Then, gently, using a screwdriver and a hammer, UNSCREW this plastic bung by tapping it round ANTI-CLOCKWISE.. I found it easiest to make a slight indent in the side with the screwdriver, then once I had something to get some purchase on, tap with the hammer to undo. DO NOT TRY TO PRISE IT OFF, IT HAS A THREAD AND WILL UNSCREW.

The bung will unscrew from the pump, and eventually come out, draining all the diesel from inside it, which hopefully you'll catch in your plastic pot.



Once you've got the bung out, you should see the following - a mirror is a useful bit of kit to see inside!!



You'll see a cam inside, this turns inside the pump. What we are looking for is an adjusted screw which will come into view when it's turned.

I found it too difficult to turn this high-compression engine by hand, so I put the car in gear and rocked it forward and backward until the screw showed its head:



You should find a 4mm allen key fits in nicely, but DO NOT USE A SCREWDRIVER STYLE ALLEN KEY as the bit could get stuck inside. Use a proper allen key. (You'll probably need some kind of lever on the end to turn it, as it's v. tight!)



This is again where my guide differs to others online, as they will say increase by turning it around 20 - 40 degrees CLOCKWISE.

Because we have REDUCED the off-boost fuelling, we can go a bit further with the maximum fuel delivery screw, thus filling out that bottom end, and giving plenty more fuel once up onto boost.

I found I needed to adjust the screw round CLOCKWISE, about 90 degrees to see smoke at full throttle. I would suggest starting at about 60 degrees of turn clockwise, and adjust again if needed.

Once you've adjusted this, screw the bung back into the side of the pump nice and tightly, then re-prime the pump using the fuel primer (or so called Grenade, because it looks like one!) at the top left of the engine.

Take the car out for a spin, using all the revs.

If you do still see smoke off boost, then wind the boost compensator in a bit more (decreasing the bottom end fuel even further).

If you don't see ANY smoke at full throttle in the mid-range, you can probably dial in a bit more on the maximum fuel screw - just don't get greedy or you'll look like a freight train!!

You should be seeing around 17psi on your boost gauge now, assuming you are - you're done! Small adjustments can be made to find the limit before you start seeing smoke output.

If you are seeing less than 17psi boost - then some actuator adjustment on the turbocharger is probably necessary.


That should see a decent hike in power, and little to no smoke.

If you want to go any further..... change the Lucas for a Bosch Pump!!