TDI Golf problems

heres the problem 2001 TDI gulf was at the dealer in Nov. and got new glow plugs, relay and the rubber harness. Now I believe the glow plug relay is bad ( no power to glow plugs) and one of the glow plug tips is burnt like it had been arcing . I don't want to hand this back with a new relay and such to have him have problems in 6 months, anyone hove an idea what would cause the relay to be taken out so quick?

Reply to
Kafertoys
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Have you checked the glow-plug fuse? They have a habit of dying every so often and if OEM, yours is well past its 'sell-by' date.

Peter Wieck Melrose Park, PA

Reply to
pfjw

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Glow plugs glow, not spark/arc. If they look bad it is because someth>heres the problem 2001 TDI gulf was at the dealer in Nov. and got

Reply to
Jim Behning

I was told that it could be some water got on the glow plug tips causing them to erode/crack.

BTW the dealer should be warranting those parts if they put them on within

12 months.

Reply to
dave AKA vwdoc1

Lean? In a diesel engine? Comm'on Jim you know better than to say that.

Reply to
PeterD

OK how about a glow plug not fully seated thereby creating a slight vacuum leak there and cold air over a hot glow plug? I am not sure that this is even possible with the TDIs or if an exhaust leak would happen there too.

Reply to
dave AKA vwdoc1

Again, think about it... A diesel basically has no vacuum (other than that generated by the air cleaner, but that is trivial).

Were a glow plug not fully seated, you'd know it the second you started the engine! The sound would be substantial if it were a slight leak, and were it a gross leak, the cylinder wound probably not fire except at very high revolutions because of insufficient compression.

Reply to
PeterD

AFAIK and IDEALLY (or when there are NO problems) Diesel engines usually create a vacuum too, since they have pistons that move up and down with valves that open and close. Air is sucked in at their intake manifold and that is a vacuum even though it may be through a large opening. Like you said it is trivial if measured there. ;-) Of course these TDIs start to pressurize the intake manifolds when the turbo is creating the pressure.

What would happen to that cylinder if the intake valve's hydraulic lifter had collasped or if the camshaft lobe was worn down? Hmmm let us consider that there is a problem with this engine. :-) Hard thing is that I can't hear the engine run on this newsgroup and I think the engine was not running correctly or why is it in the shop or its problems being discussed on this group?

OK YOU give us a reason for the 6 month old glow plug eroding away. ;-) Water over hot plugs? 8^o

Reply to
dave AKA vwdoc1

A diesel is supposed to squirt 50 units of fuel. It squirts 22 units of fuel while the other three squirt 50 units. Would that be called a lean condition?

What causes rising exhaust gas temps in a diesel?

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Reply to
Jim Behning

No, lower throttle! The concept of lean doesn't exist in a diesel engine, the mixture ratio is different for each throttle position.

Reply to
PeterD

You missed my point. In a four cylinder diesel engine there are 3 injectors delivering 50 units and one is delivering 22 units from the same setting on the injection pump. The inection pump is trying to deliver 50 units to all 4 cylinders but one clogged injector is delivering significantly less. What is that condition called when a cylinder is being delivered significanly less fuel that the others are the same injection pump setting?

Reply to
Jim Behning

In that case you'd probably feel a (slight) 'miss' but it would not affect the cylinder temperature other than to make it lower.

Reply to
PeterD

Question not answered. Miss is a result but not a correct description of the condition. So what is the condition called when one injector is delivering significantly less fuel than another and what is the resultant cylinder mix called?

Reply to
Jim Behning

Maybe diesel engines can't burn up running lean!

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"Diesel engines operate at an air/fuel ratio that supplies more oxygen than is required for combustion, a condition referred to as "lean" operation." I learn something new everyday! :-) I still wonder why that glow plug eroded/got damaged at its tip.

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"Plug failure is usually caused by excessive heat and high voltage. The heat can be caused by a defective glow plug controller keeping the current turned on too long causing the plug to burn up. Overly advanced injection timing, leaky injectors, or running gasoline in your engine will cause the combustion temperature in the pre-chamber to get hot enough to damage glow plug tips. Over voltage can be caused by voltage regulator problems in the alternator. Some aftermarket high output alternators can produce excessive voltage also."

Reply to
dave AKA vwdoc1

What are you doing citing an article that uses that word "lean?" ;-)

That Beru article I cited did mention timing and injector problems causing glow plug problems. My glow plugs lasted 200,000 miles or so. I did replace my injector nozzles at about 180,000 miles. Someone had suggested that the nozzles are wear items. I got slightly bigger nozzles as bigger must be better. That thought of worn nozzles making bad spray patterns and excessive flow makes me wonder when I see some of those old Benz cars smoking like crazy. Sometimes I see the same excessive smoking on some older farm tractors when I get hay.

The turbo article is >Maybe diesel engines can't burn up running lean!

Reply to
Jim Behning

IMHO in a diesel engine it isn't called anything except underfueled. Lean (implies) a mixture ratio, which in a diesel is not meaningful since the mixture ratio varies with throttle, RPM and other factors.

It certainly won't cause overheating in a cylinder (unlike a gas engine where it definately will!)

Personally I wonder if the glow plug controller was/is leaving the glow plugs on too long causing the damage? That would be a much more likely cause.

Reply to
PeterD

Great post, Dave! I don't think the CARB paper is significant in this discussion however, as they are mostly describing emissions reductions. The DieselBombers site thread was great too.

BTW, I have several diesel trucks (no VW ones, however) and glow plug failure in these trucks is always due to issues such as glow plug failures.

Reply to
PeterD

Nozzles do seem to wear on the engines that I work on... We notice first a lack of power (insufficient fueling) and if not fixed, eventually hard start/no run conditions (rare).

Did it make more power? What you should consider is 'pop-off pressure' which is the pressure that the injector starts injecting the fuel. An injector with a slightly lower pop-off pressure would, in theory, allow more fuel.

Someone once asked why water was so bad for diesel engines. What happens is that a slug of water makes its way to the injector. The cylinder temperaturs are so high that the water instantly vaporizes, and actually damages the nozzle tip. The result can often be a crappy spray pattern, and black smoke+poor performance.

Consider a badly atomized spray, where the fuel comes out in clumps (great visual, right?) not all burns, there is just too much mass for the O2 to get at. Instead some unburned fuel goes out the exhaust still burning, but poorly, creating black smoke. So the concept is absolutely valid, the injectors are probably worn out.

Hay? Also check your air-filter. This can easily cause similar problems. Does the tractor have the same power it always did? (I know, that's hard to tell!)

Reply to
PeterD

Good answers. I know I don't know much about diesels.

Those new nozzles made power like crazy. Smoked like crazy. I had to play with my IQ to fool the pump into squirting less. Different performance chip helped clean up the left over smoke but the power went down a lot.

I have seen some posts about crummy spray patterns where instead of a misty spray from 3-5 holes it comes up in a stream which I gather causes tons of problems.

Most of the folks I buy hay from have pretty good running tractors. Every so often I see and smell a real stinky one. I bet you may be correct that cleaning the air cleaner might help. If they were making hay that filter is probably clogged up.

The water vaporizing is interesting.

Thanks for fill>>

Reply to
Jim Behning

No problem... One of my companies makes aftermarket parts for diesel engines, so I've spent a lot of time with 'em. Having several diesel trucks helps too...

It is always true that generally speaking black smoke equals wasted fuel. You may get more power (if the black smoke is due to overfueling and not a restricted air intake) but the cost of that additional power in increased fuel consumption is really high.

Reply to
PeterD

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