having a few 1.9 mtdi problems

[Tintin]

You idle spring is too strong, below a certain RPM it cannot govern anymore, that's your problem.

There's no spring rate I can recommend you as it's dependent of the lever ratio, but definitely you need a softer one than what you have.

Best is to go to a hardware store that have a rack with a lot of different spring for sale, and pick up a few one, there'r not the best but will do the trick for you.

[iamdieselnutmechanic]

I had the same issues with the very weak 2 piece Land Rover idle spring setup, a stock 1.6 idle spring and as well as a stretched 1.6 idle spring as that was someones test idea that the stock LR spring was TOO weak.

I don't know, all in all.. this Land Rover pump has never idled properly. Any alternator load ALWAYS brings the idle down, and if it is big enough causes it to start to buck and snort at a struggling idle.

[iamdieselnutmechanic]

Another thing,

yesterday I played with the injection timing. Everywhere from 0.75mm to 1.65mm of injection timing.. The idle tone or blusih smoke (associated with retarded timing) never changed or went away. The difference was felt in the test drives with where the power was and the exhaust note under fueling.. Why does the idle not change at all?

Further more, the exhaust STINKS it is a very very wretched smell. I am not burning any coolant or oil, and timing doesn't clear it up.. So I don't see what is going on here.

[vanbcguy]

Is it driveable currently?  It sounds suspiciously like a pump that is timed 180 degrees out...

[iamdieselnutmechanic]

Is it driveable currently?  It sounds suspiciously like a pump that is timed 180 degrees out...

It does sound that way.. but it definitely isn't. I have had it apart probably 3-5 times since installation for various reasons. The car is drive-able.. and very well, other than idling or when you clutch and let off the pedal. Sometimes it doesn't catch idle on the way down and stalls out. Cold operation, even on a warm day needs throttle applied to keep the idle up where it is not shaking things to pieces.

On the left, the 1.6 idle spring. I swapped it out today for the stock land rover idle spring(s) on the right. Way less tension to them. Holley bowl gasket makes a perfect little display area loll.

[Tintin]

First thing to remember, is with a correct idle spring you should be able to drop the clutch at idle in first gear and you car should start moving strong without stalling the motor.

A too strong idle spring will be fully extended below certain RPM, lets say 1000rpm, so below 1000rpm there's no more governing from the spring and any load applied on the motor will make it die (the spring does not add anymore throttle to compensate) It's also true for a too soft spring that anything higher than a certain RPM, lets say 1000rpm again, the soft spring is fully compressed, so the RPM will start to raise and hang there, or until the middle spring start to govern at its rpm range.

You need to find the right ''strongness'' of your idle spring, you can also extend your spring to give it more headroom to govern.

As of your rough idle and bad smelling, it's due too a not enough aggressive cam plate (too soft injection) for what a VW TDI engine need.

[iamdieselnutmechanic]

Thank-you for your replies!

I am using the stock 1.9 AHU pumps cam-plate and advance piston/spring/shims/cap. I feel that those are actually the best possible match to the AHU's injectors, don't you? lol

That is a real pain in the behind, however here is another symptom maybe helping lend eyes to another issue with my setup??

Upon starting the engine cold, it doesn't catch and run unless your foot is on the pedal. EVER. There is a good shot of black out the tailpipe and the engine actually "fires" but then it dies immediately because the pump doesn't continue to fuel. I have a fair knowledge for the inner workings of these pumps.. but this is eluding me. I have never seen another pump/engine combo SO HARD to get to run properly.

As for the dropping the clutch and the engine taking off, yeah right.. If you bring the idle down at all engaging the clutch the engine starts to drop to its stumble idle.

Just for reference.. this thing did this when it was a FULL ON STOCK Land Rover setup.. What else could it be causing this if not for the governor springs and their setup??