Okay folks,

My sick little 1999 E300 Turbodiesel is about to drive me mad, but I think I've got it now.

The car has been acting like it has a fuel leak/air incursion/maddening flow problem for the last seven months. The Injection Pump nails a bit, the car will stutter and stall when the temp outside drops, and there are some funky events from time to time. The stalling never occurs at idle, only when at highway speeds. It feels like the car wanders on the road due to the engine missing... frequently. Injection Pump clatters and nails a little at idle, like it's starving for fuel. The only plus side is that my fuel economy is up a bit.

At first, I suspected the "lift pump". All the symptoms were there: poor flow, stuttering, nailing. So I was prepared to repair/replace the lift pump. Then my girlfriend told me something the other night. She had put the key in the ignition and when turned the car did not crank. Not that it would not start, the starter itself refused to turn. The next night the blower regulator fried. The remote lock/unlock is funkier than usual too.

Soooo..... I'm leaning toward the K40 now.

I've vacuum tested all of the fuel connections, and everything is airtight. There are no more air bubbles in the system. So it has to be this or the lift pump.

That was the main symptom I was experiencing when my K40 was dying, though not just on highways but generally when driving. But you might also have other problems, like air getting into your fuel system (through leaky o-rings) or bad injectors. I'd go over the engine in detail looking for fuel leaks (including the injector area) and air bubbles in the plastic hoses and then replace the K40 if it's still acting up.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

In my experience, with a bad K40 the engine will run fine and then shut off as if the key were turned off w/o warning. I dont remember anyone frying their regulator or having stuttering power or nailing that was attributed to a bad K40.

The engine not starting, but then doing so the next turn of the key does sound like a K40 symptom though.

The K40 is ~$80 so is not too expensive. You could take yours apart and look with a good magnifying glass and if cracks are present on the circut board attempt to repair it knowing if you screwed it up it wouldnt cost too much or just replace it. I think ALL dealers stock them as they are high fail parts.

If it is new to you and you have no records of its replacement I'd do one or the other of the above.

The stuttering and nailing is fuel delivery or mixture more than likely. Might be time to check the inj spray patterns and pop pressures. There was also an IFI (ECU) fault that also occured which affected perfromance. Not common, the fix was a new ECU.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

If you do attempt to solder it, use a big iron for the big conductors. I used a 180W butane-powered iron. Once you do all of the big conductors, go over all small ones that connect to the relays, or these will crack from the thermal stress of soldering the big ones. I made this mistake, but luckily wasn't stranded for it.

This is what happened this morning on the way to work. No power at all for about a second or two then purring along with a slight stutter.

This has happened more than once. I didn't think anything of it the first couple of times as I assumed my keys had flat batteries, but I've replaced them since. I wonder if the key would work with a dead battery?

I did call the dealer and told them I had a high fail relay and also knew the part number. The parts guy said okay what are the last four digits, he already knew the 000 540 XX XX. But alas, he had none in stock.

The K40 is the original from assembly in Sindelfigen. Yes, I'm weird, I visited my car's birthplace.

The stuttering and nailing dosn't happen when it's warm. Only when it's cold at idle, and only when running off of the tank. I can run LM Diesel Purge in a jug while on the road no stutter, no nailing at idle. Also will not nail or clatter on initial startup. This is definitely a low flow/starvation problem from the tank when cold, and I suspect the K40 for this as well. If not, I will replace both K40 and lift pump.... Or replace K40 and rebuild lift pump. I will probably put Viton o-rings in the lift pump if I rebuild.

Pulled vacuum on all system components & lines. Also tested component/line connections and combinations: key on, key off, lift pump check valve, SOV function, etc. Fuel mechanical components seem to be fine. No air leaks, no oil leaks, no fuel leaks, no dampness. Eliminated Prefilter with bypass setup and still no leaks, but stutter persisted. Made sure flow dynamics are working properly, but the test criteria for the lift pump is a bit strange.

From WIS and AlldataDIY
"Run pump for 30 sec., Flow should be 150cm".... Huh!?!

So the only thing I can come up with to test the flow of the lift pump could be to pull the output and collect the fuel output into a container while cranking the engine for 30 sec. I'm guessing the output fuel should be about 150cm^3 or 150 mL.

This is the only test I haven't performed, but I doubt that it's bad. This is why I suspect the K40. Everything else seems to be working correctly.

I will replace before I solder. My soldering skills are sufficient, but I don't want a hot spot in the IC, so I will opt for a factory soldered component. Not that "factory soldered" means anything special.

Key battery only provides power to IR to trigger door locks, etc. Nothing to do with security/ignition system. That handshake is accomplished via transducer/receiver when the key is inserted in ign.

If yours is OEM you are WAYYYYYY overdue for a new K40.

Don't put too much stock in the smooth running while doing a DP. Dp has entirely different combustion characteristics than D2. For same reasons Bio runs smoother than D2.

FWIW I've personally never heard of anyone with a bad lift pump on a 606.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Figured that.

That figures.

You're probably right. There's not oil/diesel mixing going on, and it obviously is moving fluid otherwise the IP would be extremely noisey. The lift pump rebuild might be in order, because Biodiesel might be in my near future.

Yea, I don't think you'll go wrong with a new part.

I'm sure that the factory solder joints are sufficient too, even without lead.

I would still pull the injectors and test them if this were my car.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Okay folks,

I'm starting to make more sense of this. It's somewhere in this system, I just need to find where exactly. This post sounded familiar and made sense:

http://mbworld.org/forums/showthread.php?t=227697

I have checked my K40 relay and it's a 000 540 01 72 with an 0199 stamped on the outside. There appear to be no broken solder joints, but there is what looks like a swollen spot on the IC board.

I looked at the vacuum transducers (000 545 04 27) for the EGR and the Wastegate. The wastegate transducer has a filter on the vent to atmosphere where the EGR transducer doesn't! Which means that the vacuum system has been sucking this wonderful dusty desert air!

I also looked at the MAP or in this case the Turbo Pressure Sensor (011 542 07 17). It appears to be fine, the date on it doesn't fall into the replacement range mentioned in the TSB I found on AlldataDIY, but the vacuum hose is pretty dry and cracked. I will probably replace that when I start in on replacing items.

Since it really doesn't rumble or rattle on deceleration I'm hopeful that there is nothing wrong with the Engine Control Module (025 545 55 32) which costs around $700-$800.

Now I'm pretty confident about the IP, fuel lines, SOV, lift pump, and injectors. I've read plenty about people chasing this same problem and it does make sense that it would be an electronic management problem. I'm just hoping I can get a few more days out of the car. Finals are next week.

Michaveli is here and knowledgeable on your model.

You've got multiple unrelated issues.....the car carnking and not starting, then starting the next turn of the key is the K40 not providing elect power to open the SOV. The surging isnt related.

Oftentimes cleaning the IM, crossover pipe AND flaps has helped with surging problems; we get a lot of 96/97 issues espically when cold weather sets in and the grease/sludge gets thick and sticky. Of course always look for bad vacuum lines. I've never heard of issues with corroded elect connectors before but seems others have. I'm curious whether that is a Salt Belt issue only, or not.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

I don't mean to confuse anyone, but I do have a '99. I'm starting to think that it is likely a combination of problems.

After reading a few posts concerning the K40, replacement of that should take care of the "no start" problem. However, as I've been told, it will not likely take care of the stutter/flutter/surge at speed.

Taking care of the stutter/flutter/surge will likely involve the transducers (controlled by ECM) and/or the Turbo Pressure Sensor (sends info to ECM) or as stated earlier the IFI/ECM (N3/7). Hopefully I can just replace a couple of vacuum parts and not have to buy an expensive ECM.

I do appreciate all of the help that everyone here has provided. I just like to "think out loud" in order to make sure my logic is sound.