03 tdi with working good glow plugs and wont start in the cold

I have no idea what this could be. I pulled the glow plugs and checked them. They work fine. I put a test light on the glow plug connector and turn the key and they get power. But on cold mornings even if i wait till the light goes out 2 times in a row i still do alot of cranking and it just stumbles and sputters and smokes. Does anyone have any idea?

Have you checked your static timing on VCDS? Did it just start doing that or has it been going on for awhile?

I didnt own the car last winter. But i did adjust the pump timing on vcds and did the hammer mod because both were out of spec

dieslin said:

I didnt own the car last winter. But i did adjust the pump timing on vcds and did the hammer mod because both were out of spec

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That may be your problem.
The pump timing adjustment is done manually and then checked with vcds.

maxmoo said:

That may be your problem.
The pump timing adjustment is done manually and then checked with vcds.

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I 2nd this^^^... OP, I bet you adjusted the IQ and not the actual timing...

Get the car up to FULL operating temperature and then check your timing with VCDS, adjust manually accordingly

Starter and battery. if the engine dont spin fast enough it will be a pain to start. Starters get lazy over time and will crank slower as a result

dieslin said:

I didnt own the car last winter. But i did adjust the pump timing on vcds and did the hammer mod because both were out of spec

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And?

You don't say if you had trouble after doing that. I have to assume you were able to get it within spec and all was good until now. When did you do all of this? Was it because it didn't want to start?

dieslin said:

I pulled the glow plugs and checked them. They work fine. I put a test light on the glow plug connector and turn the key and they get power.

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How did you test the glow plugs, ohm meter or power them up?
I prefer to test high amperage things with an amp meter.
They should all be the same amperage.
The wrong voltage glow plugs could also cause it. Not sure if your 99.5 has the 2 voltage plugs available or not.
If the connector at the glow plug is not making a good connection the plugs also will not get hot enough.

Please, people, provide actual numbers rather than "I adjusted it to spec."

What are the outside/ambient temps? How long does the GP (wait to start) light stay on?

Does it sound like the starter is spinning the engine well? (raised by 94cobra2615) Battery?

Do you know if you've got air in your fuel lines? (should be able to check if you've got a clear fuel line going to the IP)

Any codes?

I pulled the 3 that would come out and tested them with a jump pack. They started glowing almost imediately. I also put a test light on the glow plug harness and hit the key
It turns the test light on so im assuming they are getting power??

I made sure the engine was at operating temps when i watched and adjusted the timing by adjusting the pump sprocket. I went off what the video on youtube said. I also just had a malone stage3 tune done with hopes that it was gonna help the starting issue some. And it did nothing. Battery is new and its cranking just fine. It just acts like the glow plugs arent working. Glow plug light stays on for 15-30 seconds

dieslin said:

It just acts like the glow plugs arent working.

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However, you've confirmed they're ok. They glow, are getting power, and the power is staying on long enough.

Also of note is that the ECU monitors the glow plug system pretty rigorously... if there was a glow plug system problem you were missing the ECU would likely catch it.

So: glowplugs / timing / starter / compression

Sounds like you've checked off glowplugs, timing, and starter... a compression test, with the engine stone cold, might be a helpful next step.

dieslin said:

I pulled the 3 that would come out and tested them with a jump pack. They started glowing almost imediately. I also put a test light on the glow plug harness and hit the key
It turns the test light on so im assuming they are getting power??

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Not necessarily......you may get power to the harness and the glow plugs themselves may be good but the harness may not make a solid connection with the glow plugs....this is a fairly common problem as the harness ages.

Are you sure the harness is firmly pushed down on the glow plugs...should take a fair bit of pressure to make the harness snap down all the way.

Some here have used small pieces of tin foil wrapped over the contact portion of the glow plug in order to temporarily get a better connection when the harness is worn.

A quick and easy test for working glow plugs is to throw a little snow on each glow plug, when the engine is cold, and glow the plugs with the ignition a couple of times without starting the car.....you should see the snow melting at the base of each glow plug that is working.

Assuming the glow plugs are working and your timing and IQ are within spec, and the battery is new. It sounds like it may be new or reman Bosch starter time.

Yesterday I put a reman Bosch on my daughters beetle, it cranks so much faster and starts so much quicker now.

The glow plug harness has been replaced, the guy before me replaced it. They do firmly click on to the glow plugs

Maybe an air leak isn't too too bad. Yet.

dieslin said:

I made sure the engine was at operating temps when i watched and adjusted the timing by adjusting the pump sprocket. I went off what the video on youtube said. I also just had a malone stage3 tune done with hopes that it was gonna help the starting issue some. And it did nothing. Battery is new and its cranking just fine. It just acts like the glow plugs arent working. Glow plug light stays on for 15-30 seconds

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Do you have the coolant sensor off to cause the glow plug light stay on for 15 to 30 seconds? Way to long unless it's well below 0F.

You indicated the glow plug harness was already replaced, should be OK.
You also saw 3 plugs removed and glowing. OK
I would try a clamp on amperage test on the wires going to the glow plugs.
This would confirm you are getting the current through and no bad connection in the circuit.

Bentley manual indicated 6 amp per plug minimum or 24 amps total or higher.

Someone also posted putting snow around the base of the plugs and listen for hissing when it melts. I never tried it.

Last, if your plugs are staying on for that length of time and they are the correct voltage for the glow plug controller relay they should be more then hot enough to start the car.
My light hasn't stayed on more then 5-6 seconds this winter so far. (Monroe NY)

Have you measured the voltage at the starter while cranking the car?
If it drops below 9.6 volts the ECU shuts off.

dieslin said:

The glow plug harness has been replaced, the guy before me replaced it. They do firmly click on to the glow plugs

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If I had a nickel for every time someone performed electrical work that later failed.....My glow plug harness came with unterminated wires on the other end that required a wire splice. If the splice was sloppy or not properly sealed from the elements, it may be causing a voltage drop.

Also, you checked 3 of 4 glow plugs. If that 4th plug is not working, it will make for an awfully rough running engine. An ammeter on each circuit will tell you a lot.

And if there was a problem with the harness... or a glow plug... or multiple glow plugs... there's a 99% chance the CEL would be on.

If anything, it's TOO sensitive. It looks for tiny differences in the current to each plug... be it because of the glow plug OR the harness OR the connections to the harness OR the relay OR... . It can get fooled if the CTS out-and-out lies about the temperature, but the OP has confirmed there's voltage to the glow plugs when expected, so everything upstream is working just fine.

Only pointing this out 'cause troubleshooting is a process of elimination... and in my opinion given all the evidence listed above re-thinking and then rethinking the glowplugs is probably wasted effort at this point. IMHO, of course.

Where exactly is the timing set, and where is the IQ set? You mention a Stage 3 tune, what nozzles size do you have now?

Pp502 nozzles .210 and a malone stg 3 tune. I had it done through ecs tunning and they messed it up, cause the check engine light is still on for the egr and they were supposed to tune that out

dieslin said:

Pp502 nozzles .210 and a malone stg 3 tune. I had it done through ecs tunning and they messed it up, cause the check engine light is still on for the egr and they were supposed to tune that out

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Where is the timing on the graph: above the line below the line, below the low line above the high line?

dieslin said:

Pp502 nozzles .210 and a malone stg 3 tune. I had it done through ecs tunning and they messed it up, cause the check engine light is still on for the egr and they were supposed to tune that out

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Don't blame ECS Tuning unless you can PROVE that they messed up! (I wouldn't go through them for tuning stuff, but that's because of my preference and not experience).

Again, you've provided little in the way of providing actual numbers here. You had a problem before you got a tune and then you went with a tune "hoping" that the problem would be resolved. As you are noticing, this is WRONG! One gets the engine operating properly BEFORE making any modifications. Now you've only complicated things, added a lot of confusion.

Prove that your battery is sufficient.
Prove that your starter is sufficient.
Prove that your timing is within spec.

You could be getting air in your fueling. Have you even checked for that? Might be compression issues, has this been checked? Again, this problem has existed for some time. Going to have to start from scratch lest you want to chase your tail.

PS - I'm assuming you meant that you have PP520 nozzles (not PP502). New? I'm also assuming that they were professionally mounted?

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/232585427578

These are the nozzles. And i didnt say that ecs tunning caused the starting problem. I said they never deleted the egr and were impossible to deal with. I'll get numbers today

dieslin said:

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/232585427578

These are the nozzles. And i didnt say that ecs tunning caused the starting problem. I said they never deleted the egr and were impossible to deal with. I'll get numbers today

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I'd be willing to bet nozzles is part of your problem...

JDSwan87 said:

I'd be willing to bet nozzles is part of your problem...

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I didn't have any luck with the one set of ebay nozzles I tried.

Waste of money for me.

My timing is at 48 pretty much at the blue line when its at temp idling

Get the car warmed up and adjust the timing so it’s flirting with the top line. Starts will be easier. Have you thought about another starter yet?

A new or reman Bosch will give you much better starts.

After checking the eBay link, you do realize I assume that those nozzles are from China?

A local VW mechanic told me he once found that the check valve on the fuel filter was leaking by a tad. Overnight it would allow enough fuel to leak back that it took a few crank attempts before refilling the filter fully, hence reluctance to start. After starts fine but not because "warm" but full filter.

Those nozzles are almost certainly fake Chinese knockoffs. A bad spray pattern will make cold starts hard.