1984 Jetta , TDI WE MUST! (1.9 AHU M-TDI)

[8v-of-fury]

I wish I had the time to tear my car down and do an overhaul... Guess I have to find a beater Mk 3-4-5 first eh?

UGH. Daily driving an MK1 and an MK2 has been quite the adventure. I bought this car when I was completely green to mechanics at 16.. I still have it, and have replaced every single thing, EVERY THING.

.. got big dreams .. got no time or money lol

Had my fuel filter plug up and leave me 135kms from home. Luckily I have CAA GOLD!!

Also it is running good GREAT on the 75/25 diesel/motor oil mixture.

[snakemaster]

i allwas carry a spair fuel filter in the car and tools and 5L of diesel , i ran a 1.6 td on 50% old engine oil turps and any thing it would run on , on that sucker i had 3 filters spaire , i would eat a filter every 3 days and still pull 125mph there was a rige reek from her to when you were to the max only, done this for a few weeks and then sold the engine ,back to the good old MTDI ,life dont get any beter than MTDI

[8v-of-fury]

M-TDI till I die. I think I will have this made as a decal.. Catchy lol.

SO! It has been a while since I have posted a real problem, or something I couldn't figure out with my brain tanking.. But this damn throttle has me stumped so I come to you people, lets see what you got.

Ok, it is a single external spring on the throttle lever like so;



And has the left governor setup; (Rover left, AAZ right) As can be seen, every spring appears stronger than the VW equivalent right beside.




410 and I had speculated that because of the blueish smoke at idle that maybe my engine was not properly timed, and was in fact too retarded on the timing. So I referenced some other online photos and found another guy running a rover pump and he had used an AHU pulley as well. We both had our pullies referenced the same to the bracket (the pulley lock is useless when using a Rover pump and an AHU bracket and Pulley btw, rovers keyway is like 3* different than the AHU shaft) so it seemed proper. I could advance my timing all the way to the advanced position and get a good TDI sound going on but still had smoke. We assumed maybe I was a tooth off on the belt for the pump. So I moved that one forward today, and started off with the pump in its most retarded position.. as that should be close to max advance with the other belt position. Started and ran just the same, with heavy idle smoke.

I advanced it more while running, to only get MORE blueish smoke while running and no more noticeable clatter.. Why is this pump and engine combo not acting like any other diesel I have had my hands on? More blue smoke, as though I were retarding timing.. with a rougher idle. So I backed it down until I had what felt like the best sounding idle.

However! the issue does not really lie with my smoking issue as I am chalking it up to poor spray pattern on my 500k original injectors.. The issue lies with not being able to set a steady idle for the life of me.. Again, not reacting like any other Bosch Diesel I have worked on.. Like probably 20 different engines, all with varying pump setups.. no issues. Until this damned abomination lol.

No matter where the timing is, where the throttle stop screw is, where the max fuel screw is OR EVEN WHERE THE throttle arm to throttle shaft orientation is.... I cannot get a solid lower idle at all. The only idle that will hold solid when I turn on any electrical load sounds like it is well over 1100RPM and has my tiny k03 sounding like it is boosting a few lbs at idle for Christ's sake. I can set a lower idle where I cannot hear the turbo spooling over the engine noise, but then even using my windshield wipers will put enough load on the alt to bring the idle down to a chug-chug-chug of what sounds like 450RPMs.

What in the hell is going on?

[snakemaster]

i took out one of the idle spring behind the cup thing and that helped me a tage, i had a shorter rod that holds the gov springs and it was a bit like the greef your geting at one point  , i say a M  i say a T i say D  i say a I , going to get some chear leaders round to shout it out the next time we get the vdubs to gether and a we dram of  Glenmorangie , cheers

[8v-of-fury]

Yes, but what of this??

I advanced it more while running, to only get MORE blueish smoke while running and no more noticeable clatter.. Why is this pump and engine combo not acting like any other diesel I have had my hands on? More blue smoke, as though I were retarding timing.. with a rougher idle. So I backed it down until I had what felt like the best sounding idle.

What do you have yours timed to mate? And for clarification, you have the lowest most spring in my governor picture removed?? Would it be possible to get a video of one of your rigs running?? Just so I can hear another m-tdi for reference? Thanks a bunch.

It is just a sihtloaf of misery with this damn car lol. Shoulda went E-TDI..! GAH. \

Here is another thing.. the idle differs greatly from cold to warm.. Like, whatever idle setting that is good warm? Will not hold an idle when you first start it or until it warms up. If you set it to idle cold? Then it screams at hot idle.. I am at wits end, I have tried it all and nothing is reacting as it should.

#fedup

HAHA #hashtags #for #the #win (srsly tho, kiddddinglol.)

[theman53]

The E tdi has the computer to adjust idle warm and cold. You may have to settle on a comprimise. The E tdi are supposed to be timed with the vag com when warm-final time not mechanical. Maybe you idle should be set the same.
I rode in the toaster and it went well, sounded a bit loud when cold but the idle was ok I thought.

[8v-of-fury]

Yes, the computer changes the timing and the idle based on fuel temps, air temps, coolant temps and load.

If I set it where I want it warm, it will idle at 400rpm cold. It will never die out, but it won't hold a high idle.

If I set it where I want it warm, even using the window wipers will put enough load on the alternator to bring the idle down to chug-chug-chug of 400-450rpm.

Chris and I are using a different rover pump, his has a completely different style of governor assembly IIRC. I think like a Cummins, the one spring un-caged.

[snakemaster]

4 of my MTDIs will start from cold 650ish rpm and then warm 800 rpm

[8v-of-fury]

650 might be more accurate as to what my idle is, so alright I guess that is something I will have to live with. Shakes an mk1 something horrible lol.

I could not set an idle of 800RPM and get it to hold that idle when I turned on anything electrical.. Dunno what is up.

[RabbitJockey]

I set idle at 1k in mk1s. They just shake too much any lower.  I'm thinking since the governor is designed for a much larger engine, that once u turn the fueling down so that it keeps a much smaller engine at the correct idle ,  what used to take a small amount of adjust from the governor to compensate for small amounts of added load now takes much more since the fueling is turned down so much for idle.  Maybe u already no that and it's only theoretical from my understanding of these pumps, but perhaps u gotta swap over the weights and everything from an aaz or 1.6 if that's even possible.

[libbydiesel]

It would be possible to swap the weights/governor but I don't think that's the issue.  The mTDI pumps I build from Cummins base pumps have fairly solid idle speeds. 

I also have my idle raised a fair amount in my Rabbit to alleviate the vibration. 

[8v-of-fury]

Yes, and those 12mm pumps are from like 3.9L engines are they not? So it would seem the "larger governor weight" idea doesn't really seem to be the issue either.

So Andrew, if you have a solid and consistent idle can you take the idle screw and back it out to bring the idle way down consistently?? Or does it just get to a point and drop off?

The weird thing is this fellers..

I have another mk1 diesel with an AAZ and k03 combo just like mine but IDI in my driveway to compare with. I cannot get mine to idle consistently like I can the AAZ.. Or the 1.6 TD I also have to compare with. It can either be what I feel is too low and chugging, or what I feel is too high and screaming. One or the other... no in between. I also have a throttle hang between shifts.. Not so much that it hangs the idle, but takes a long time to come back down and I am usually already engaging the next gear..

I have set a bunch of these, Like I say I have two perfectly running other diesel in my driveway that will start and idle perfectly right away with out the use of the cold start.. they could even both have the fan and defrost on.. no issue.

[8v-of-fury]

I also have my idle raised a fair amount in my Rabbit to alleviate the vibration. 

What turbo do you have? The k03 is screaming at anything over what feels like 900rpm..

[libbydiesel]

I had one used Cummins 4BTA pump that I built into an mTDI pump that had a difficult idle.  It would either idle high or very low.  If I set it at a reasonable idle it would idle low to start and then idle high.  I sounds much like your issue.  I figured that the idle spring was weak and that the low idle was when only the idle screw was engaged and the high idle was when the idle spring was fully compressed and the governor spring was starting to come into effect.  I solved it by stretching out the idle spring. 

The dual idle spring setup may be what is giving you fits.  You may want a single stronger spring instead. 

[8v-of-fury]

Alright. Thank-you.

I will be taking the pump lid off tomorrow and checking that out. Everything else about the governor is alright, so I guess it is just the idle spring.

Weird however, as engine size should not matter? I assume the 2.5L would have actually idled around the same RPM which means the springs and governor weights should still have the same effect to the throttle. Did your 4BTA have a dual idle spring? I will find my toughest idle spring, stretch it out and give it a go lol.

I like how it lopes at the lower idle I can set, and that the turbo is not spooling 23psi at idle lol.