MTDI building and tuning. New Holset p.7, plan runing 30 psi!

[vic003]

Hi guys!

I'm French and had to use the french section but it's a little bit dead now...

So excuse my english language!

I drove a Seat TDI for 2 years, and now I just buy et golf 2 and mounted a MTDI with a pump that I made myself.

The first had problems with the iddle but ran good with enough power, it was fun!

I made a new one to correct my iddle problem and put new components in!

But I have now another problem, the iddle is good it start very well without pushing the pedal. Now the engine with full throttle don't go over 2000/2500 RPM.

I use a 17mm shaft pump from 1.6TD, cam plate and head from TDI, timing piston and spring from 1.9TD with the regulator, lever modified in 10mm and throttle lever modified in 17mm. I also put a longer pin on the governor piston.

So why could my engine don't go in high RPM?

[libbydiesel]

Most likely there is an issue with the assembly of the governor spring capsule.  Possibly the control lever assembly is bent/damaged/indexed to the governor springs incorrectly.  Maybe the accelerator to shaft orientation is incorrect or max fuel screw is way off.  The accelerator pedal/cable could be failing.  The accelerator cable clip that sets its position on the pump could have fallen out. 

[vic003]

Most likely there is an issue with the assembly of the governor spring capsule.  Possibly the control lever assembly is bent/damaged/indexed to the governor springs incorrectly.  Maybe the accelerator to shaft orientation is incorrect or max fuel screw is way off.  The accelerator pedal/cable could be failing.  The accelerator cable clip that sets its position on the pump could have fallen out. 

Thanks for your answer.

What is the thing you name governor? The shaft with the 2 springs that go on the control lever?

All the part of the acceleration control are good, no damage since last time and it worked great.

It's a lot better with the change of the pin, I'll upload a pci to show, I don't know the name!

Now I've a problem with the timing piston and spring, doesn't work well, I'll replace it tomorrow.

How do you name this part:

[vic003]

So I found the problem, it was the primary pump (feed pump) that causes all my troubles, I don't know why!

[vanbcguy]

The VE pumps pass a ton of fuel through to the return - lots of smaller feed pumps just can't keep up with the flow requirements especially at higher RPMs.

Glad you found the cause! If you choose to run a lift pump make sure whatever you run will pass fuel even when it isn't operating. I have a Facet Posiflow lift pump on my Mk3 - it's supposed to flow around 40 GPH I think, plus the IP can draw fuel through it fine even when it is switched off.

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[vic003]

I think I wasn't really clear! I don't use lift pump before IP. I'll do some pics and explain you tomorrow, I'm not sure to find good words to explain you!

[vanbcguy]

Oh you mean the feed pump IN the IP?

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[ORCoaster]

As in bad Vane pump section? 

[vic003]

Hi guy's I'm sorry for the late answer, I was so buisy in my job, my VW was in stanby!

To answer, yes it was the feed pump in the PI, these pices seem to be appaired, and I took them in another PI.

Now I try to fine tune of the PI, but I don't find tuning to limit smoke at low RPM when turbo don't charge. I've a more agressive LDA cone 75 from Peugeot and I don't have the max flow for my 0.260 nozzles. I try to have the max flow with 1.7 bar (approx 25psi) on my K24.

[vanbcguy]

Reduce the fueling via the main fuel screw and increase the fueling added by the LDA if you are getting smoke off boost.

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[vic003]

Hi, I know that, but there is just a little problem I don't find.

It seems like on boost fueling is good, so if I reduce the main fuel screw I will reduce on boost too.

My LDA is at the max, and I changed it for a number 75, much agressive, more fuel at full boost. I searched a LDA that have the biggest range of fueling, and this one seems perfect, good angle of the cone.
I think I can make a bit more aggressive LDA but I can't find one.

[vic003]

Hi guys,

I drove with my MTDI tonight, after tune my LDA, I put it at the less aggressive part of the cone.

I have what I want, no smoke at low RPM off boost, but I'm to the max of the LDA cone on boost and no smoke at 1.1 bars (16 psi). But I want to put my K24 at 25 psi, and I don't know how I can have more fuel on boost with no smoke off boost as I already use 100% of my LDA cone without any smoke...

[vanbcguy]

There are more aggressive LDA pins available than the VW one; lots early Cummins guys have VE pumps and run very high boost.  You're also saying you have the pin on the 'less aggressive' part of the cone - you can increase the preload on the LDA spring which will delay the LDA action until higher boost levels and rotate to a more aggressive position on the pin.

[vic003]

Ok thank you for the answer.

The lda I'm runing is the most agressive one I can find in France, it comes from a Peugeot and is number 75. I can't find cummins parts here, or it is very rare. Maybe someone can find me the part number or something like this I could find on eBay from US or maybe UK.
For the agressive side of the LDA, the angle of the cone doesn't change, and what I need is more angle to have a bigger movement of  the LDA.
I agree with you on the fact I must change the preload of the spring as I made, but in my mind the problem is the same, if I want more fuel on the max of the LDA I must screw the main fuel isn't it? And if I do that I get the fueling I need for my boost but lot of smoke off boost, it's very annoying in France, as smoking cars are scapegoats here...
Do your mtdi smoke at full throttle in low rpm when your are runing for approx 150 WHP?

[vanbcguy]

With the VW pins anyhow the angle of the cone definitely does change as you rotate the pin, it is quite a bit different from one side to the other. I'd imagine the Peugeot pin is the same story. The Cummins pins I'm talking about are performance aftermarket parts so you probably will never find them in a vehicle.  Dieselmekken makes something similar on the European side... See the attached image.  There was a French seller on the VWDiesel.net Facebook group a while ago selling them too.

The LDA and fuel screw operate independently (though they are of course related).  The LDA can open up more than it is currently with your existing fuel screw setting - it can add more fuel at full boost than you are right now with a more aggressive pin.  Set up the fuel screw so you are just below smoking with the LDA disconnected then set the LDA up, you'll probably find you need to back it off!