LT 35 engine ATA -2000

cabbagecreek

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Joined
Aug 25, 2021
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8
I have a LT35 that had a broken dieselpump (and some other issues related to bad maintenance)

Installed new glowplugs and dieselpump from the same ATA/year. Checked all specs on the dieselpump and they are equal.

The engine starts on 1 rev even at +5C. ("Winter is comming" , but not yet in Sweden)

Running at 50-70kmh it works like it should. Not alot of power but milage-pr-litre is 1.2l / 100km.
Can go upp to 80kmh without any problems. On 4th gear and 3000 rpm I reach 90kmh. Change to 5th gear is only woking on flat/downhil road. Reach 110 on downhill on 5th.
On 4th gear and 90kmh/3000rpm there is no power more. Its impossible to rev more than 3000rpm. Even on downhill the revs are max 3000rpm. I dont like the idea to press the engine , but 3000 rpm sounds not good. The rev meter has a green area and it stops at 3000 rpm.

I have tested the "turbo-boost-pin"/LDA and its easy to remove. My conclusion of that is that the pin from the throttlearm to the LDA is retracted. So with the LDA removed I increase the throttle and can feel that the pin is moving against the LDA. Pressing the pin back and I can feel some "o-ring-resistans/friction" and that indicates that there is no leak from inside the dieselpump into the LDA chamber. IMHO the LDA looks OK and should increase power when turbo pressure is increasing.

I cant find any way to indicate that the LDA is moving so I start seaking for tubo pressure leaks. I use soap-water on allhose/clams/pipe/sealings/intercooler and search for bubbles. There is no leaks found.

Next test is to find the pressure at the intake-to-LDA pipe. What is the turbo-pressure that should be present at the LDA?


I have a manual that says that the injectors are "multi-stage" injectors. In previous troubleshoot I removed 2 of the injectors to get the serial number. Got 1 part from the first and secund part of the serial number from the secund injector. Rost and "patina" has hidden the numbers.

I also disambled the injector and cleaned the inside. I just found a spring, shims and the piston inside. Looked for me as a normal 100% mechanical injector. What about the "multi-stage" . I can't understand how a single spring can create a "multi-stage" solution. Is there more items inside the injector that I have hot discovered yet? I also was not able to find injector nozzles. Ist this a type of injector that can't be opened and cleaned without new testing/adjusting shim?
 

TommyLT

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Dec 2, 2012
Messages
73
Location
Liverpool
Hi,

I'm not familiar with the ATA but just had a quick look at the setup of it. It sounds like the govenor needs adjusting on the diesel pump, if I'm looking at the correct diesel pump there should be two adjuster screws with locking nuts, one on the left for the maximum rpm adjustment 3800...3860rpm , and one on the right for idle speed rpm 750....790rpm.

If it is a dual stage injector there will be two springs in there, it might need a bang down to loosen them up. If you do bang it down make sure it's on a softer surface like a piece of wood because you don't want to damage the mating faces of the injector and nozzle. Also make a note of the position of the springs and shims for reassembly. You can test the injectors for opening pressure and leaks on a normal pop tester but will need a special/modified shim to test the second stage pressure.
 

cabbagecreek

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Aug 25, 2021
Messages
8
@Crasher Its an ATA engine from year 2000. LT35 2.8 TDI LT-Serie (II) VIN: WV1ZZZ2DZYH015456 carcode: 309994
Looking in the manual this modell was manufactured from 1999 ro 2002
 

cabbagecreek

New member
Joined
Aug 25, 2021
Messages
8
@TommyLT I have already adjusted the idle screw. When the dieselpump was mounted the idle rpm was at 500rpm. I increase it to 750-800 rpm.
The fuel/govetator screw is sealed. I have not touched that. It also have color makers on the seals. I belive that this pump is totally untouched from manifacturing of the donation car.


I have a foggy memory about a pressure valve on the Bosch VE pump. Its located under/below the spring fro the throttle/gas arm. The 2-stage injector has a first stge of 190bar and a secund stage alot higher. I belive its so high as 300bar.

Can it be that the diesel pump on the donor car was less power? The scrap-yard say it was an ATA engine but I search for resons why the pump is deliver to little with diesel. IMHO the diesel engine will produce power that is ekvivalent with the amount of diesel it gets to the injectors.
I still have the original dieselpump and the able to replace the regulator valve. I do not do that of I do not know that this might solve the case. I have toremove the dieselpump to be able to replace the regulator valve. I don't want to do that alost blindfolded. The LDA clock is hiding the visibility and its narrow and dirty. I do that on a clean space and in a wise.

So the idea about moving the fuel/govenor screw might be the next thing to do, Just turning it 1/4 turn and do a "dyno" test on a hill and meassure the time it takes to climb the hill. (=Hillbilly-dyno-test)
I will take a digital caliper an meassure the existing length that is visible. Then do a notch that indicates "12:00".
I will also set a Go-Pro under the car to see the smoke during my "hillbilly-dyno" test.

Question is:
Turn the govenor screw in = clockwise or out counterclockwise.
 
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