2004 jetta tdi (bew) loss of power

I have an 04 jetta that has just undergone several maintanence issues. The turbo was just replaced, intake taken off and cleaned, all of the solenoid valves removed and checked, all of the vaccum lines checked for leaks, and the inake manifold flapper motor replaced. vagcom shows no faults anywhere and the car still has zero power. any help on figuring this problem out would be appreciated.

Also could anyone tell me what the injector pressures should show using vagcom? should the readings all be the same or close?
car has 160,000 miles. oil used came from dealer and dont remember what it was. i did all the work.

how about more details in so far as:

1. mileage
2. oil used
3. why was the turbo replaced
4. who did the work for you

I.e. as much history on the car as possible would make helping you easier.

troubleshooting BEW low power

TN
If you have data from groups 1, 4, 11, and 43 that may help us help you, too. the second item in group 43 is turbo actuator position.

What group are you looking at for injector pressures? I have never heard of this.

Dan
edited to correct group number to 43.

troubleshooting BEW low power

values from groups are as follows

group 1 903/min 6.0mg/str 7.1cf 85.5deg C
4 903/min 4.0deg BTDC 7.6cf 3.4cf
11 903/min 1040.4mbar 989.4mbar 80.5%
41 86.4% 21.2% 21.1% 10%

also i replaced the timing belt as well. This car will start up with ease and run. just no power throughout any of the powerband. shes weaker than a popcorn fart.
hope this is what you were asking

TN,,
Sorry I was not clear in the first place and made an error in the second. Pretty sorry post.

the groups of interest
were 1,4,11, 43
and what would really help is a log of these groups as you accelerate, maybe in third or fourth from 2k to 4k. Well, log groups 4, 11, 43 during the run.

Dan

04 jetta no power

sorry values from group 43 were as follows.

81.3% 100.6% -5.1% 00000001
these values were at idle. the second value of 100.6% never changed if i accelerated or left at idle.

limping BEW data

Here are some data graphs from the problem BEW
[/IMG]

[/IMG]

[/IMG]

[/IMG]

more data from problem BEW

more data from problem BEW

[/IMG]

[/IMG]

[/IMG]

[/IMG]

comparison data from healthy BEW

some data from a healthy BEW
[/IMG]

[/IMG]

[/IMG]

Some observations on the data

I have used the term limping to describe the performance, but there is no CEL, so it is probably not truly limping, but the performance is described as very weak, with heavy smoke.


Three things stand out to me:
1) MAF actual is low. The MAF is new. Performance did not alter when he ran the car with the MAF unplugged.
2) There seems to be a torque limitation signal from some source. Anyone know where it could possibly be from?
3) The fuel injection quantity is lower than it should be during heavy acceleration, only 25 mg/stroke, when it should be 42 or so.

So what does all of this mean?

Please chime in...

Check to make sure the brake switch is not on, or at least the ECU does not see it on.

Maybe drop the downpipe and see if the catalyst is plugged up.

Check the thrust sensor for proper seating (it is under the washer bottle area).

Remove the cam cover and inspect the cam lobes for excessive wear.

Recognizes correct answer when told

TN,
Oilhammer's advice is the best you can get. No one knows more about these cars than him.

I can help you use your Vag-Com to check the brake switch input to the ECU.

The plugged up CAT is next on his list. It could explain everything. The odd exhaust/intake noises you hear. The slow windup of the turbo.
If we logged and graphed block 8 we might see the smoke limit from the low MAF actual airflow was causing the ECU to limit fueling. We chose group 9 so we could log your transmission torque limit, which was ok. Also explains why it will start and idle flawlessly.

For testing you could either take the CAT off and run an open exhaust (the turbo provides enough back pressure) or you could take it loose and run piece of 1" pipe inside to beat out the honeycomb and ensure a free flowing path, then reinstall it. Replacing it later, of course.

You have already examined under the valve cover.

Then check out the thrust sensor. I am not familiar with this, and cannot find anything on it in my Bentley, so if you cannot find it we may have to ask for more help.

My money is on the CAT.

(This makes me think of the old US Navy joke about the minimum acceptance criteria for an officer. "Recognizes correct answer when told.")

Dan

limping 04 jetta

the thrust sensor hes referring to dan is the map sensor we talked about mounted on the intercooler if im correct. the bently dvd that i have doesnt refer to it as a thrust however. when i took the intercooler off the first time when i cleaned out the intake oil poured out from the intercooler. however i did not actually remove the sensor from it. i am going to do so now. also i am taking loose the cat again and trying it this time. anyone know which blocks to use on vagcom to compare or test this "thrust sensor"?
once again thanks all for big help.

TNfirefighter said:

the thrust sensor hes referring to dan is the map sensor we talked about mounted on the intercooler if im correct. the bently dvd that i have doesnt refer to it as a thrust however. when i took the intercooler off the first time when i cleaned out the intake oil poured out from the intercooler. however i did not actually remove the sensor from it. i am going to do so now. also i am taking loose the cat again and trying it this time. anyone know which blocks to use on vagcom to compare or test this "thrust sensor"?
once again thanks all for big help.

Click to expand...

Since you had oil come out of the intercooler, have you looked at the intake to see if it is clogged or not?

Just throwing that out there as something else to 2x check.

limping 04 jetta

yes the complete intake and intercooler and all hoses and egr tubes were removed during this process and cleaned. the only sensor i didnt remove was the one on the intercooler. how ever the intercooler was removed and washed out.

From all this, I would attack the MAF first. The MAP hardly ever fails, and it is registering boost as it should.

limpin 04 jetta

Anyone help with using vag com to see if the ecm is seeing the brake light switch on?

TNfirefighter said:

Anyone help with using vag com to see if the ecm is seeing the brake light switch on?

Click to expand...

I just looked, and in Group 6, "Switch positions" will show the brake switch. The two Zeros on the far right will be ones when the Brake pedal is pressed.

weedeater said:

From all this, I would attack the MAF first. The MAP hardly ever fails, and it is registering boost as it should.

Click to expand...

I have replaced 4 of these on PD-equipped A4 cars, so they most certainly DO fail and they rarely set a DTC but just exhibit low power, excessive smoke, and an otherwise normal idle speed.

The other thing I forgot to mention is the fuel temp sensor. Again, so long as it is within a normal range of its limits, it can be bad and still not set a DTC and you will get some pretty bad driveability problems.

On the VE cars it was inside the pump, on the PD cars this fuel temp sensor is in the fuel feed line (just follow the lines to and from the tandem pump and you'll find it).

update, not final

Eric (TNfirefighter) has run the car with the exhaust removed, with no change in driveability, still runs very weak. No change in Vag-com data.

MAF actual is still very much lower than requested.. same as graphs above.

The MAP sensor is well seated, and as indicated in the graphs above gives very realistic results. No way to tell accuracy.

The brake pedal switches are both working properly per VAG-COM. (Thanks for stepping in and picking up my slack this morning, Whitedog. I was strapped in a guerney giving platelets for 2 hours (with a 45 minute drive each way.))

The valve train has been inspected and still looks pristine, mirror finish and no wear.

Will check out the fuel and coolant temp sensors.

Eric is going to round up another MAF sensor to try, it could explain all of the symptoms EXCEPT the abnormal noise from the exhaust/intake. I am just helping over the phone (he's in Chatanooga, I am in central South Carolina) so I cannot use my ears to help out. From the description it could be the EGR is not closing, which would cause the low MAF reading, and the abnormal flow noises. He describes as whistling and chirping.

The EGR was cleaned and tested out of the car, and it repositioned properly. The duty cycle is shown on one of the graphs above, during operation.

Would it be worthwhile to block off the EGR for a test? (Can you do this on a PD?)

Hmmm....I wonder if the throttle plate is so gunked up it is not flowing enough air, or the intake runner butterflies are stuck or gunked up. You said the intake was removed and cleaned....the intake MANIFOLD itself, all the way to the intake ports on the head? Were the intake ports themselves gunked shut?

Was all the work (turbo, intake, etc.) done to try and cure the problem, or was it done as PM and now a problem exists?

Second hand information from Eric.
The intake manifold was completely clogged up with gunk at 160 kmiles, down to a pencil sized opening. He cleaned it all the way to the head, and did clean out the head ports also. He had to replace the throttle plate and either replace or clean the intake runner slider valve assembly.

He has used Vag-com to check out the throttle plate and the intake runner slider motion and EGR motion.

He has done a compression check and got 375 across the board.

The car starts instantly and idles well. Very Weak under acceleration.

LOW MAF readings. He was not able to get a second replacecement MAF yesterday to try.
Since he has low MAF air readings and abnormal noises from the intake/exhaust we were wondering about the EGR and throttle plate operation.
How can he fail the EGR closed, and the throttle plate open for a test run? Or would this be something to try?

Eric is not certain that he managed the slack in the timing belt assembly properly. Would it be possible for it to be a tooth off? And still start easily and idle well? But have low power and low air flow? Whistling and chirping and strange noises from the intake and exhaust?

This is the first TDI Eric has ever worked on. I have been impressed at how fast he has taught himself, and his determination.

If the belt is off, your cam timing will be off, so the valves will not be timed correctly and can cause low air flow, noises, etc.

A severely retarded or advanced timed VE TDI will start, but will be down on power and smoke I have no idea what a PD would do but I assume very similar. However one would think the PD's CKP and CMP sensors, if way off from one another, would set the appropriate sync DTC.

I would look in the VAG-COM datalist and see if there is any CMP/CKP sensor info in there, and compare to a known-good PD to see what the numbers are.

If the timing belt's integrity or installation is suspect, confirm that is correct because if that is not right, all bets are off. You MUST do that job correctly with the correct tools in order to get it 100% right. There are no shortcuts.

CKP: crankshaft position sensor
CMP: camshaft position sensor

VAG calls these "impulse senders"

limping 04 jetta

Oilhammer, i used the the small tool set from metalnerd to do the replacement. all the pins and locks were used to intsall the belt. the only question i had during installation that wasnt clear to me in the instructions by bently was during the tensioning phase of installation. when u place tension on the belt do u remove the pin that holds the cam in postion and leave the 3 cam bolts loosened and then tighten the belt? or leave the pin in the cam and leave the 3 cam bolts loosened and then tighten the belt. im pretty sure that i left the pin in the cam sprocket slot with the 3 bolts as i tensioned the belt. if i am incorrect with this proceedure let me know. the crank lock was in place during the whole procedure until finish of belt.

limping 04 jetta

by the way, i did remove the thrust aka map sensor from intercooler yesterday. it was clean but had a small amount of water on it still from the cleaning. i ran the car with it unplugged and it did throw the code for it and it ran worse with it out. i dried it off and reinstalled cleared code and rechecked vagcom and the code never returned.

the only thing possible that i can think of now is that i didnt properly tension the belt. if u think i didnt by the message i sent u (oilhammer) is ther a way that i can retension the belt without having the remove the motor mount which was a real pain in the rear. and all the other components. but if need be to recheck all the locks and pins i will do so.
thanks all again.

It sounds to me like you did the tensioning procedure correctly. Did you answer the question as to if the problem existed BEFORE all this work was done?

limping 04 jetta

yes same problem before all the work was done.

OK, and it was stated it was smoking. Is this black smoke (too much fuel or not enough air) or white smoke (incomplete combustion or NO combustion or severely retarded timing)?

limping 04 jetta

black smoke

OK, so you have black smoke and low MAF readings. That spells air-restriction to me. Snowscreen, or the left headlight area full of stuff maybe?