Discovery 300tdi 1994 tuning .

[coachman]

I have been reading ( dangerous on a Saturday ) on how to `tune` a 300 tdi ,this guide was in LND RVR MNTHLY .Does anyone have knowledge of these proceedures ,they sound good to me , especially the one where the dvice at the injectors is turned around .Or any basic tuning advise please .

I do not necasserally have a power problem ,but I have experienced a lack of reesponse when setting of ,the car is an automatic .I have also read that an old fuel pump may cause problems .

[SPendrey]

Mine is a 300TDi auto ('95) and can be slow to accelerate, but if you push hard it'll shift OK. Just don't try comparing to a more modern diesel, or even a Td5 as they are poles apart. Tuning can be a good idea if you're willing to take the risks, changes in fuel efficiency etc. I didn't bother with any tuning as the car does well enough as it is.

Scott

[disco-shane]

I turned the Diaphram in the pump 90 degrees clockwise and the improvement on my 200tdi is amazing....apparently works the same on the 300tdi

[disco_al]

have a read of this article http://www.landroverweb.com/Pdf-files/Tuning_Land_Rover_Tdi_engines_Rev_2.pdf gives a description of what the tuning is, and all 3 stages to get the best. i've done this on both my 300's and the difference is amazing - better mpg, and more power, plus no flat spot (especially if you adjust the diaphragm spring nut as well)

bear in mind though, if you've only got a standard intercooler, don't wind the pump all the way up. it's easy to reverse for the mot smoke test too, just make sure you mark the start position of the diaphragm at 12 o'clock before you adjust it

[coachman]

have a read of this article http://www.landroverweb.com/Pdf-files/Tuning_Land_Rover_Tdi_engines_Rev_2.pdf gives a description of what the tuning is, and all 3 stages to get the best. i've done this on both my 300's and the difference is amazing - better mpg, and more power, plus no flat spot (especially if you adjust the diaphragm spring nut as well)

bear in mind though, if you've only got a standard intercooler, don't wind the pump all the way up. it's easy to reverse for the mot smoke test too, just make sure you mark the start position of the diaphragm at 12 o'clock before you adjust it

thankyou ,now THAT is some information ,spot on . coachman

[coachman]

I turned the Diaphram in the pump 90 degrees clockwise and the improvement on my 200tdi is amazing....apparently works the same on the 300tdi

Maybe we should meet up and share comments ,I will bring spanners and ginger biscuits .coachman

[Boydie]

Read the scrip very carefully, Ian knows his stuff and I have one of his EGT probes fitted however I overdid the fuel bit and found that my water temperature had gone up by 10 degrees - so had the EGT !!!

I had to back it off to almost the original settings before it was down to 95 degrees centigrade - normal running temp for my beast.

I went the additional mile by buying a magnetic impulse "strobe" that works off a clamp on No.1 fuel injection line -- this was so that I could fine adjust the injection timing from the standard 5 to almost 8 degrees BTDC, that made a huge difference, I found the fuel quantity a very minor change wise but in regards to EGT and head temperature it was serious stuff.

[reb78]

I turned the Diaphram in the pump 90 degrees clockwise and the improvement on my 200tdi is amazing....apparently works the same on the 300tdi

Just turning it might actually reduce fuelling if it is already in a position near max fuelling. You need to know where you are starting and what bits do/operate on before turning this and that!

As Boydie says, the article above is excellent and i often link to it when these threads come up. Understand that and you will understand what you are doing as you make adjustments.

[disco-shane]

Just turning it might actually reduce fuelling if it is already in a position near max fuelling. You need to know where you are starting and what bits do/operate on before turning this and that!

As Boydie says, the article above is excellent and i often link to it when these threads come up. Understand that and you will understand what you are doing as you make adjustments.

Well its quicker and doesn't use any more fuel so i would say job done lol.....im happy

[disco-shane]

Maybe we should meet up and share comments ,I will bring spanners and ginger biscuits .coachman

Perhaps mate....not a million miles away

[reb78]

Well its quicker and doesn't use any more fuel so i would say job done lol.....im happy

Thats fine, but it wont always work like that, so folks need a little more advice to understand what they are doing. They wont all be set at the same start point so the 90 degrees may or may not work.

[disco-shane]

I agree....I looked at all the info in detail before attempting anything.

[Boydie]

As I said, what Ian doesnt tell you - because its supposed to be obvious - is that the more fuel you pump into your cylinder hear the hotter the combustion temperature becomes, BUT higher combustion temperatures do not mean more power, what they do mean is increased damage to your head and head gasket.

The first tuning setting to adjust is the injection point, the general setting on the 300TDi is around 5 degrees BTDC and unlike a distributor on a spark ignition engine there is no vaccuum advance so the injection point is fixed and critical.

Most LR diesel tuners agree that an injection point between 8-10 degrees BTDC is far better and gives better combustion, I found that a tad over 8 degrees was perfect, I set this with an impulse strobe on No.1 fuel line with a CO probe up the exhaust, reading the carbon monoxide % to determine the best combustion for the given rev range (less CO being best as this indicates the best air/fuel ratios) this meant adjusting the fuel at the FIP while at teh same time playing around with the FIP pulley - it took bloody ages to achieve the best setting due to having to take the cooling fan off and timing cover off and back on again time after time to make the tiny adjustments and after all that I've really got to say improved power and economy wise you wouldnt want to pay someone else to do it for you as you would never recover your outlay in the life of your truck.

With a diesel fuel is simply fuel, yes it makes a difference but unless you're prepared to increase the boost pressure and in so doing reduce your engines top end life expectancy simply adding more fuel isnt the total answer.

[Boydie]

I should add, (before howls of protest) that regarding my comment of fuel is fuel ------ I'm refering to "old" mechanical fuel injection engine units such as mine, electronic injection diesel motors are far more complex, constantly adustable via their sensors and computor and bear as much resemblance to my engine a s a Ford Model T does to a Bugati Royale

[vulcan bomber]

The first tuning setting to adjust is the injection point, the general setting on the 300TDi is around 5 degrees BTDC and unlike a distributor on a spark ignition engine there is no vaccuum advance so the injection point is fixed and critical.

So what about the 12 degrees of advance the pump provides? Or the 16 it can provide with mods?

[Boydie]

Vulcan, Sure the range of adjustment is considerable, but do you need it ? I think this is doubtful. I used the method I described, by testing the combustion by reading the exhaust gas (CO) to determine the "perfect" combination of air / fuel / injection point.

I did this as a project on a mates dyno rolling road one Sunday when it wasnt being used, I dont know of any other way you can do it as you need to be able to make adjustments on the fly as the turbo pressure alters the mix.

The right injextion point for my engine was, as I said, 8 degrees, more than that and I neded to increase the fuel for no significant power gain and a drop in economy and an increase in water and exhaust gas temperatures.

I found I hardly had to make any adjustments to the stop torx screw, (idle power) the real problem was getting / selecting the right "side" of the eplilictical cone to give the optimum running fuel range, this involved constantly removing the diaphram top cover and tiny turns of the diaphram assembly to select the right curve.

I also backed off the spring retaining plate by 2 notches to bring the turbo in sooner, before this adjustment the turbo didnt start to work the diaphragm before 5 psi. since the adjustment the diaphragm starts to move at 3 psi and is fully extended / compressed at 15psi when the waste gas valve cracks open, it then sits on 15psi for as long as the engine is accellerating.