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Author Topic: M-tdi hangs in high RPM's, newbie, help please...  (Read 28909 times)

December 05, 2007, 03:27:37 pm

Vento G60

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M-tdi hangs in high RPM's, newbie, help please...
« on: December 05, 2007, 03:27:37 pm »
Hello everybody. Let me first introduce myself as this is my first post on this forum.

I'm Sander, 30 years old, and a complete VW-nut. I live in a town called Beuningen in the Netherlands and own 2 VW's:

A '94 Vento (in US called jetta mk3), with originally a 1.8 90hp engine, and now converted to a G60 engine (3 years ago), with modded exhaust, G-charger (selft rebuilt and flowed) 68 pully, chip and FMIC. Should chuck out about 200 hp and 300 Nm of torque.

A '80 golf convertible mk1, originally a 1.5 gasser engine, converted first to 1.6 D, then converting that engine to a TD with IC and some pump mods (lda pin, governor spring mod, wastegate closed running @ 1.6 Bar). Now, after the head gasket blew (after giving a BMW 318TDS a very hard time till around 170 kmh and keeping the pedal down for about 25 km's straight) I've put in an AHU tdi engine from an mk3 golf.

Here is were the trouble starts. After reading a lot about m-tdi's on this forum, I decided to go for it, with help from my friend Bert, who is also on this forum sometimes. I would build in the TDI myself and he would build me a pump that would work with it.

So the way it is now: I have the AHU in, with original AHU nozzles, a rebuilt KKK K24 turbo, a 60 mm exhaust till the rear wheels, going into a 54 mm muffler for a TD mk1. The pump that Bert built for me is a hybrid from a 1.9 D (1Y) pump housing, governor, tension lever and governor lever assembly, the rollers, camdisc, the control sleeve and plunger assembly come from a tdi pump, the plunger is 11 mm. The current static timing is 1.10. The pumphead is of a 1.6 GTD (the 80 hp version) with LDA.

It starts up (without the glow plugs) at first turn of the key, runs smoothly through it's rpm's (no tacho, so don't know exact rpm's), and makes a normal diesel engine noise apart from the fact that it has a cone filter.

After starting to set the fuel screw (full load adjusting screw) and the residual fuel screw accordingly, the engine would develop more hp, untill I reached a point where the rpm's wouldn't go down smoothly after revving, this was after turning in the fuel screw 1/4 of a turn from the last (not so powerfull) setting. Now I turned the fuel screw bak in untill the revs would stop hanging, but then I have almost stock 1.9 D power. By turning it in a little more, the power increases, but certainly not to the same as it was with the 1.6 TD engine with upgrades. Now I have to shift very fast, to not have the engine hang in rpm's when shifting. When in 5th gear (4T type gearbox of a 1.6 GTD), going at a speed of 100 kmh and over, the rpm's come down real slow.

Now I've modded the pump with the governor spring mod, cutting out the intermediate spring, and I've put on a TDI advance timing spring cover and spring, I've also turned the star wheel on the LDA all the way down and the LDA pin is turned 180 degrees from it's original position. The governor mod made the rpm range a little bit longer, a little more hp (so it feels), and also al little wider powerband as for the torque. The advanced spring and cover swap just made it run a little more quiet. On changing the LDA spring load and turning the LDA pin it just seems to make a difference in low rpm's, torquewise. Now it makes about 1 Bar of boost at 140 kmh and over (3500 rpm and on). No IC yet.

I am sure (and so is Bert) that this engine should be able to make more hp with this pump, but we are just missing something. I've been searching a long time on this forum, but couldn't get the answer to the following questions, could any of you please help me with these?

1. I read everywhere that once the pump starts to hang in rpm's, you should turn the full load fuel screw back in, but just what is it that causes the hanging in rpm's? I can't imagine what it could be, because the control sleeve is mechanically forced back to stationary position, and that is the only way to raise the rpm's, or am I wrong?

2. Are there any others with a K24 on a AHU and what boost does it achieve?

3. Being in Europe, I can probably get my hands on all sorts of pumps to put on this engine. Could someone tell me what bosch pump codes to look for, on what engines they were supplied and how plug and play they are?

Sorry for writing such a terribly long story, I hope someone can get through it and maybe help me with my questions.

Thanks in advance,
Best Regards from Holland,
Sander aka Vento G60


Vw's rock!

Reply #1December 05, 2007, 05:20:33 pm

jimfoo

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #1 on: December 05, 2007, 05:20:33 pm »
Put the intermediate spring in and only shim the main spring.
Jim
1966 Land-Rover 88" with 1.9 1Z which has been transformed to an M-TDI
TFO35 mechanically controlled VNT, IC , and 2.5" exhaust.
Driven daily

Reply #2December 05, 2007, 06:08:53 pm

Tintin

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #2 on: December 05, 2007, 06:08:53 pm »
If your pump is assembled with the control of idle on the throtle shaft,
probably that the governor shaft is not shimmed correctly, when you add more turn on the fuel screw, you need to unscrew the idle, but the governor shaft is in the end of its travel and cannot control the RPM any more.

Add a bigger shim behind the governor carrier, but when you play with these shim, that affect the travel of the feeler finger boost pin,  there are it have different longor of it.

If it is not the problem, that can be the idle spring which is too hard or too soft.

To do-it when I built a M-pump, I have an open LDA to see in the pump which occurs when it is assembled, that facilitates largely the assembly.

Reply #3December 06, 2007, 11:55:10 am

Vento G60

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #3 on: December 06, 2007, 11:55:10 am »
First, thanks you guys for your replies. But maybe I haven't been clear about my problem.

The hanging in rpm's already occurred when the governor spring assembly was still original and unshimmed. After modding the governor spring assembly by cutting the intermediate spring out with shims, the only thing that changed was that the engine had a wider powerband, before the mod it would cut out at higher rpm's (3000 and on), after the mod it pulled on till about 4000 rpm.

So does anybody know what the hanging of the rpm's could have been caused by? I guess it should be something else than the governor spring assembly, because the hanging in rpm's didn't change with the mod, also taking off the pressure feed line of the LDA doesn't change anything. So in my opinion it should be something in the pump.

What is it that makes a normal 1.6 TD hang in rpm when you turn in the fuel screw too much?

Thanks again for your replies.

Greets Sander
Vw's rock!

Reply #4December 06, 2007, 12:08:39 pm

jimfoo

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #4 on: December 06, 2007, 12:08:39 pm »
Throttle lever off 1 spline so that residual fuel screw can't be adjusted out enough?
Jim
1966 Land-Rover 88" with 1.9 1Z which has been transformed to an M-TDI
TFO35 mechanically controlled VNT, IC , and 2.5" exhaust.
Driven daily

Reply #5December 06, 2007, 12:41:58 pm

Vento G60

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« Reply #5 on: December 06, 2007, 12:41:58 pm »
Thanks again Jim for your reply. I had to put the throttle lever in another position so I could adjust the residual fuel screw again, because it was all the way in, the throttle lever was touching the housing where the screw sits.

After that, I could turn in the full load screw more and back off the idle rpms with the residual fuel screw.

Before turning the throttle lever it didn't hang in rpms, but it also wouldn't really go!

So what could it be? Turn the throttle lever back to its old setting, but then I don't have any power, or not much at the least.

Thanks again.
Vw's rock!

Reply #6December 06, 2007, 12:42:13 pm

Vento G60

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #6 on: December 06, 2007, 12:42:13 pm »
Thanks again Jim for your reply. I had to put the throttle lever in another position so I could adjust the residual fuel screw again, because it was all the way in, the throttle lever was touching the housing where the screw sits.

After that, I could turn in the full load screw more and back off the idle rpms with the residual fuel screw.

Before turning the throttle lever it didn't hang in rpms, but it also wouldn't really go!

So what could it be? Turn the throttle lever back to its old setting, but then I don't have any power, or not much at the least.

Thanks again.
Vw's rock!

Reply #7December 06, 2007, 12:42:29 pm

Vento G60

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #7 on: December 06, 2007, 12:42:29 pm »
Thanks again Jim for your reply. I had to put the throttle lever in another position so I could adjust the residual fuel screw again, because it was all the way in, the throttle lever was touching the housing where the screw sits.

After that, I could turn in the full load screw more and back off the idle rpms with the residual fuel screw.

Before turning the throttle lever it didn't hang in rpms, but it also wouldn't really go!

So what could it be? Turn the throttle lever back to its old setting, but then I don't have any power, or not much at the least.

Thanks again.
Vw's rock!

Reply #8December 06, 2007, 12:42:46 pm

Tintin

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #8 on: December 06, 2007, 12:42:46 pm »
Quote from: "Tintin"
the governor shaft is not shimmed correctly, when you add more turn on the fuel screw, you need to unscrew the idle, but the governor shaft is in the end of its travel and cannot control the RPM any more.


It's difficult for me to explain what causes this problem and how to correct it because the english is not my first language, But I know exactly what occurs in your pump.

As I said in my first post, and you does not seem to understand what I explained,  the problem is improper shim behind the governor carrier, or improper cap on the governor tube.

Other thing concern the idle spring,  but, all my explanation is coorect only if you have the idle control on the throttle lever, not like a 1.6TD.

If the fuel screw is screwed at the maximum When the problem appears, It's normal, in this case, you need to change or adjust pieces in the pump to give more fueling reserve.

Reply #9December 06, 2007, 01:31:49 pm

Vento G60

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #9 on: December 06, 2007, 01:31:49 pm »
OOps, the last reply shouldn't have been placed 3 times. My internet cut out and I wasn't able to reach the forum.

Tintin: I've already read a lot of your posts on this forum, and I think you really know what you are talking about, especially regarding m-tdi pumps. As so I very much appreciate your reaction, but unfortunately I don't understand at the moment precisely what you mean.

My governor assembly is about the same as the one in the picture in this link. Could you explain maybe from this picture what you mean?

http://memimage.cardomain.net/member_images/10/web/418000-418999/418501_13_full.jpg

Thanks again!
Vw's rock!

Reply #10December 06, 2007, 03:16:46 pm

RabbitGTDguy

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« Reply #10 on: December 06, 2007, 03:16:46 pm »
Martin,

Since you and I are "close" on this, maybe I can take a stab of explaining what you mean here later on. I am at work, don't have all the time right now to do it...but it is an important thing to consider. I think I can help out.


Also, throttle shaft indexing, if not properly set will cause the RPM's to hang as well.

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #11December 06, 2007, 06:51:04 pm

snakemaster

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #11 on: December 06, 2007, 06:51:04 pm »
my Mtdi pump dose the same  and from the info here  ,i need to put a nother shim between the square washer and round one at the start of the govner, so it shimes the hole govner forward , nearer to the control lever
, so when the engine is at 1000rpm idle no load there will be more forse aplying on the control lever , that means i can turn up my fuel max screw with out the revs hanging on ,   is this right    and if so what thickness of shim in needed
Glenmorangie  single highland malt

Reply #12December 07, 2007, 11:05:02 am

Vento G60

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #12 on: December 07, 2007, 11:05:02 am »
Ok, but I still don't understand how shimming the governor so it sticks out of the caged assembly more (this is what I understand I should do) would do any good? The same effect could be reached by putting the throttle lever on another position on the throttle shaft, or am I thinking in the wrong way now?

Please guys, Martin and Joe, help me out here!

Greets Sander
Vw's rock!

Reply #13December 07, 2007, 02:50:28 pm

snakemaster

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« Reply #13 on: December 07, 2007, 02:50:28 pm »
or you can shim the nose (the bit that pushes the control lever back gov side)  or washer at the other end of the rod. i beleve this is right
Glenmorangie  single highland malt

Reply #14December 10, 2007, 09:47:03 pm

RabbitGTDguy

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M-tdi hangs in high RPM's, newbie, help please...
« Reply #14 on: December 10, 2007, 09:47:03 pm »
Quote from: "snakemaster"
or you can shim the nose (the bit that pushes the control lever back gov side)  or washer at the other end of the rod. i beleve this is right


This is correct.

Readjusting, or reindexing rather the throttle shaft into a different position does not do anything for the gov. assembly itself. Also, it can only be reindexed so far until you really start fouling the idle circuit and you get a s similar "hanging" rpm situation. I had this problem when I first started the mTDI up initially.

Haven't had much time to post...maybe more later. Beat from grad school work/finals at the moment.

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

 

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