Shudder at 2,500

My car, 04 1.9 PD had been sitting over the winter and tried to start it one day and killed the battery. Charged it up for a few days and got the car running, went for a drive and all was good until for no reason it started shuddering. I was barely able to get it home.
Today I started it and seemed to be fine, would rev over 4,000 but as the engine got to running temp it won't rev over 2,500.

Sad days when you can't drive your TDI. Any ideas?

When was the last time you changed the fuel filter?

aja8888 said:

When was the last time you changed the fuel filter?

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Just before winter. I temporarily put a new one in and same thing. Also the inline gage seems it's holding pressure, 4 PSI at 2,000 RPM, 7 at idle.

Ordered a lift pump today. Just trying to eliminate potential problems. Actually don't know when it was changed before, before me anyway. Car has 264k

Could it be a MAP sensor?

Lift pump was no help. But there is plenty of pressure, over 15 LBS.
Now it wants to die just over 3,000 RPM cold.

And it's getting worse as it warms up. Dies like you turned the ignition off.

Seems odd, now that it has more fuel the problem is worse. Which means fuel is not the problem? Seems to be pointing to not enough air... So what can it be?

Another thing to add is the engine has plenty of power below the kill zone.


From what I see on the forum it could be the crank position sensor. So where can I find that little bugger?

Just ordered a CPS.

You're just throwing parts at it. That can cost a lot of money and get you nowhere. Try to get some error codes.

Honestly,you really need to run some VCDS scans and see what's going on, or not going on. Throwing parts at it is a guessing game.

aja8888 said:

Honestly,you really need to run some VCDS scans and see what's going on, or not going on. Throwing parts at it is a guessing game.

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Yeah, but for us here it's not costing a dime- basically free entertainment! But, it's a bit painful reading about folks bashing their heads...

UhOh said:

Yeah, but for us here it's not costing a dime- basically free entertainment! But, it's a bit painful reading about folks bashing their heads...

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Yeah, the cost of the lift pump he didn't need would have paid for a VCDS cable.

But, Tony, he's now got a spare lift pump! (never hear of anyone having spare VCDS cables!)

The quick and dirty test for a lift pump is to disconnect the battery cable, turn the key to the 'RUN' position pull the line from the filter to steel line that goes to the tandem pump off It will have an arrow pointing toward the tandem pump stamped on the fuel line. With the line in a catch can, touch the battery cable to the terminal. You should get a surge of fuel for about 2-3 seconds. If it does that, it's rarely going to be the lift pump. Although they can be intermittent, it's rare.

As a side note, we have done some experimenting with lift pumps. Several of them will 'hum' but no fuel. We stuck the pumps in our ultrasonic cleaner and got some sand out of the pump. It went back to working.

It's not like the only thing that can go wrong with the lift pump, but we have done the same thing to 5 pumps and 4 out of the 5 returned to working condition. At $200 a crack, that's not chicken feed.

So, maybe I should get another couple of VCDS cables..

Truthfully, there are a lot of guys who have the VCDS and would be willing to help in your area. 101 section/ VAG-COM Locator. Also, anybody who runs a European garage must have programming for MB, BMW, Volvo, VW Etc, and can run codes for your car. If you get right down to it, any auto parts store worth walking into will have a OBD-2 and even THAT could be a start.

There is another test point you need to check for fuel pressure. On the Tandem Pump, there is a allen headed bolt with a copper washer behind it. It's on the arm of the pump that goes down from the body of the pump. That is the place you can test the tandem pump pressure. At idle, it should be 25psi. At 2500rpm, it should be 100psi, but it will rack the needle at least 30 lbs either side of 100 lbs, if it's working correctly.

I recently had one car that had a plugged air vent in the fuel cap. I doubt that is your issue. But it's easy to check. When the issue comes up, loosen the fuel cap.

I would want to see the values for the injectors when cold and hot. What the advance is running ciold and hot.

Make sure you have good grounds and check your crank sensor wire is not messed up and that your cam position in VCDS/ engine module/ measuring blocks/ Block 4/ torsion value... is usually .-5 to -1.5 for starters. Usually, if the engine starts quickly, that isn't the issue, but as things warm up, it could be wiring.

Good luck.

Franko6 said:

I would want to see the values for the injectors when cold and hot. What the advance is running ciold and hot.

Make sure you have good grounds and check your crank sensor wire is not messed up and that your cam position in VCDS/ engine module/ measuring blocks/ Block 4/ torsion value... is usually .-5 to -1.5 for starters. Usually, if the engine starts quickly, that isn't the issue, but as things warm up, it could be wiring.

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I would like to check the values for the injectors but don't know how. Is there a wright-up on how to do that?

Wires for the crank and cam sensors look good.

Every thing you mentioned after that I don't have a clue on. Computer sensor crap is not my thing. Anything mechanical is a pice of cake. I replaced the turbo, cam, lifters, water pump, timing belt and everything involved in doing them.

I have a HP Tuner for my truck, I can navigate threw it but I know better not to change anything serious without consulting an expert.
A VCDS is next on my list, ASAP.

As far as the lift pump, it needed replaced anyway. I was able to resurrect the old one but the pressure was always low.

Thanks for the help Franko6!

A tuner isn't a diagnostic tool. You can change behaviors, and, perhaps, they might tip you off on something that's out of whack, but they aren't diagnostic tools. We can guess for a long time but only through interrogating the computer(s) using a proper diagnostic tool can we really start to see where the problem is originating.

If you replaced the cam (and lifters) and you don't have VCDS then chances are looking good that your injector torsion values* are off (and causing your problems). I'm not a PD expert, so don't quote me here. I'm just trying to provide positive thought that with VCDS you'll be able to spot what's happening and, fingers crossed, find that it's just a matter of some simple adjustments.

* For future reference (more great stuff from Frank): http://forums.tdiclub.com/showthread.php?t=336279

You need a VCDS or someone who has one. It's the way to go. Anything else, you are spinning your wheels.

Crank position sensor!

Car runs as good as it did before.

I am still going to get a VCDS. Need to check the torsion values. Didn't really know what torsion values meant but seems I set it when I installed the cam and timing belt... Don't know what their set at but it's set and runs good.
Torsion values A.K.A. Crank angle A.K.A. KW. What else is it called?

Who knew throwing parts at it would actually work, I didn't, but after searching this forum and comparing the symptoms it seemed logical to try it.

Anyway, thanks for the help and funny comments, hope everyone had fun, I did.

God bless!
Blue

Good for you! That would have coded on the VCDS and unfortunately, now you have 'test parts'. The most common symptom for a crank sensor is the engine will not start. The signal from the sensor is critical. We usually find an intermittent crank sensor fault by jiggling the wire. If you do get the engine's codes pulled up, you probably will find a latent code for the crank sensor. Clear it. That would also have coded on any OBD-2 tester.

We have had several wiring issues crank sensors, especially the BHW. The insulation on the four wires inside of the crank sensor sheath cracks to pieces and falls apart. We use the FTE brand for replacement.

The business with Torsion value ends up being really quite important. We have a rather large thread that with the help of several people, tackled 'The question about Torsion Value' It turns out 0.00 is rarely correct. We use the VCDS/ engine module/ Block 4; Torsion value/ Block 13; idle balance and /block 15; liter per hour fuel usage to figure the best torsion value.

First, the torsion value is usually inspected before any alteration is made to the engine. That would be a baseline to operate when reestablishing the cam position. Then, we check block 15, to see what idle fuel usage is. On the BEW, it's usually .2 to .4. Adjust the value and usually, you will find a 1.0 range +/-, it does not change the fuel usage number in block 15. Then, change the torsion value to see what value setting gives the most even reading on idle balance in block 15. that will be your best fuel economy setting. .5 difference in torsion value can mean 4 mpg in economy.

So, you still could use the VCDS.

Here’s an interesting little tidbit. The new crank sensor I got stopped working. Every time I started the car it took longer for the engine to fire. I put the old one back in and it runs perfectly fine. I finally bought a VCDS. I started another thread about it if you care to join. http://forums.tdiclub.com/showthread.php?p=5407647#post5407647