2002 vw tdi wont cold start

[AndyBees]

So, if it is starting and running, maybe a scan to see what codes are showing up would be helpful to further sort out what's going on.

 

[Rfanslau]

Oh and I am told never lossen the large nut on the injection pump. Or you will throw off the factory timming but is there a keyway on that shaft anyway

 

[Rfanslau]

Question I am told never lossen the large nut on the induction pump or you will throw off the factory timming. But is there a key way on that shaft.

 

[Vince Waldon]

There is no keyway, as shaft/sprocket alignment needs to be micro-adjusted at the factory.

DO NOT loosen the nut!

There is a procedure to reset it, but some specific tools are needed. Far easier to mind the yellow paint and leave it be.

 

[tdi_my live]

Try a new camshaft sensor and good is.

 

[P2B]

Try a new camshaft sensor and good is.

No such sensor

 

[Zak99b5]

Just to get technical:
There actually IS a keyway in the shaft. But no key is used, and no provision for a key in the hub.

 

[AndyBees]

To get more technical, the end of the IP shaft has a Morse Taper. Even if you loosened the big nut, you'd need an appropriate puller or use grunt force and hammer to break it loose the hub. (I suspect you'd need a counter hold to break the big nut loose anyway.)

The big nut (22mm) can be used to rotate the shaft (ever so slightly) when the three bolts on the Timing Belt Cog are loosened to set the timing. There is literally no chance of breaking the big nut loose doing the timing procedure.

 

[Prairieview]

The ether probably softened the rings so much (took out the temper) all the carbon fell out and it will now start until it no longer will again.

There is no such thing as a "free lunch" with ether.

 

[Rfanslau]

Well guys problem solved it wad the timming was set at the lowest retard timming at 180 degrees and if you follow the chart at 60 degrees you will be way off the chart. That now it starts in the first crank and no smoke.
Thanks for all your help one great forum site
Again thanks bob

 

[Rfanslau]

But also I am having a rpm surge at first warm up like. 100 rpm up and down and after a few minutes it smoothy goes away. It's been doing this for sometime now. I guess it's time for new filters, vacuum lines. Etc. Routine maintenance does anyone recommend a good diesel injector cleaner

 

[GlowBugTDI]

The ether probably softened the rings so much (took out the temper) all the carbon fell out and it will now start until it no longer will again.

There is no such thing as a "free lunch" with ether.

Ohhh, common now. Its not that bad. A lil shpiisht shpiisht never hurt anybody.

 

[Rfanslau]

I guess. But it's time to catch up on routine maintenance. Vacuum lines, filters, etc.
Again thanks for all the great advice you guys had.
Thanks bob

 

[GlowBugTDI]

But also I am having a rpm surge at first warm up like. 100 rpm up and down and after a few minutes it smoothy goes away. It's been doing this for sometime now. I guess it's time for new filters, vacuum lines. Etc. Routine maintenance does anyone recommend a good diesel injector cleaner

Diesel purge is the go to around here, but atf works well too.

With a surge I'm not convinced thats an injector issue. Usually dirty injectors will cause a rough idle.
More likely to be pump related.

 

[Rfanslau]

Yes it's a ruff idle for the first few minutes as soon as you drive a block or two it smooths out.

 

[Rfanslau]

It's like a 100 rpm up and down only for a few minutes after a cold start in the morning. After that smooth all day

 

[AndyBees]

This is what I'd do, go to the nearest truck stop and buy some fuel additive (or wherever). Add the additive according to the instructions for a full tank but in about a half tank of fuel. If you need to add some fuel, fine as long as you've got about a half tank. Then, drive out that fuel down to almost empty. Repeat with a full tank.

If you do that, the engine may very well have smooth starts. But, at 350k miles and 23 years old, the 2001 engine in my '03 Jetta has rough starts, smokes a bit sometimes on start-up and an occasional hiccup. However, I don't give it a second thought because if I drive it everyday, it doesn't do those things.

 

[Rob Mayercik]

Glad to hear you got it sorted out.

Another thing to look into doing as part of "maintenance catch-up" might be the "diesel purge", where you buy a can of that stuff and run the engine directly on that stuff to do a proper injector cleaning. If it's never been done to the car, it probably needs to be.

Here's the DIY for doing the diesel purge: https://forums.tdiclub.com/index.ph...sel-purge-how-to-with-pics.87948/#post-823760

 

[AndyBees]

Or, you can build one of these and use it over and over! I made this one in 2012.
Jif Peanut Butter jar, JB Weld, plastic fittings, hose, etc. (JB Weld is very compatible with diesel fuel)

 

[mmeeks1]

To cure the slow turning over problem, I replaced both of my TDI battery cables with stranded number 4 welding cable. Amazing what the difference was. The things spin over much faster

 

[mmeeks1]

Correction number one cable

 

[batryonmend]

Do you have a large air bubble in the clear fuel line after sitting? What about while the car is running? My initial guess is timing is too retarded.

 

[P2B]

My initial guess is timing is too retarded.

No need to guess, OP solved it a year ago

 

[ghohouston]

Do you have a large air bubble in the clear fuel line after sitting? What about while the car is running? My initial guess is timing is too retarded.

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• ghohouston
• Mar 30, 2025

Did you directly copy what I said, or was that a genuine post of yours?