Cold Start Injector Test

[Justy]

Hi,

I have a 98 Jetta TDI that is running rough at idle. RPM's at idle sit just below the 1000 mark. They used to sit right at teh 1000 mark. All output tests work great (vag-com) but I cannot tell a difference in idle noise when testing the Cold Start Injector. It may be because it is already running rough. I am not sure what action to take next. The injection quantity is low. Here are my vag-com groups:

000
1. 43
2. 52
3. 0
4. 12
5. 99
6. 204
7. 88
8. 157
9. 126
10. 149

001
1. 903
2. 2.4
3. 1.41
4. 77.4

002
1. 903
2. 0
3. 010
4. 80.1

003
1. 903
2. 250
3. 440
4. 4.8

004
1. 903
2. .4
3. .4
4. 57.6

013
1. .8
2. .4 - cyl 2 .8 cyl 3
3. 0.0

Thanks for your help!

-Justin

 

[GoFaster]

group 000: I take it that it was not in "basic settings" when you took these numbers. If it was not in "basic settings" then these numbers are meaningless.

group 001: Injection quantity is within spec (2.2 to 9.0 mg/stroke) but it's on the rich side. Recalibrate it to 3.0 mg/stroke the way the TDIFAQ says, and see what happens. I don't think this is the problem, though. Idle speed of 903 is exactly what it should be. If it was different before, it was wrong before, and it's right now.

group 003: I can tell that the engine had been idling for more than 1 minute by the time you recorded this, because the EGR is off (very low duty cycle, and actual does not match requested). But that's a good thing, because I can also tell that the MAF sensor is reading low (should be 480 +/- 20, and you have 440), and you have not recalibrated the EGR (requested is 250, should be 370). There is a distinct possibility that the intake manifold is clogged, and that the clogging extends into the intake ports, where it might be buggering up the airflow into the engine. A piece of sooty crap could even be making intake valves hang open a little ((this would explain the low MAF reading) - this has happened before. Suggested corrective action: inspect condition of EGR valve and intake manifold and clean if necessary (probably will be necessary); clean MAF sensor just to be sure; recalibrate EGR system per TDIFAQ to prevent future problems in this area. It is very unlikely that the MAF sensor is faulty - they almost never break on that model - but it could be dirty.

group 004: Injection timing is late; I can tell by the high duty cycle. Requested matches actual, so the advance syste is working, but due to late pump timing, it is working overtime. I like to set these so that actual injection timing is 0.4 to 2.0 degrees BTDC with duty cycle below 20% (if you don't have group 000 "basic settings" info to work with).

group 013: within specs.

 

[Justy]

Thanks for the quick response Brian! Although much of it was over my head it will be real helpful and has me going in the right direction.

I took my group 000 again in Basic mode - good catch! You must know what your doing! I am one of those guys that trys to be smarter than I am... It has served me well so far.. Anyway..

group 000
1. 43
2. 20 to 29 (fluctuating)
3. 000
4. 14
5. 98
6. 204
7. 115
8. 155
9. 144
10. 79 - 81 (fluctuating)

group 001: Injection quantity is within spec (2.2 to 9.0 mg/stroke) but it's on the rich side. Recalibrate it to 3.0 mg/stroke the way the TDIFAQ says, and see what happens. I don't think this is the problem, though. Idle speed of 903 is exactly what it should be. If it was different before, it was wrong before, and it's right now.

<font size="2" face="Verdana, Helvetica, sans-serif">Are you refering to the mechanical injection timing? http://www.tdiclub.com/TDIFAQ/TDiFAQ-7.html#k

group 003: I can tell that the engine had been idling for more than 1 minute by the time you recorded this, because the EGR is off (very low duty cycle, and actual does not match requested). But that's a good thing, because I can also tell that the MAF sensor is reading low (should be 480 +/- 20, and you have 440), and you have not recalibrated the EGR (requested is 250, should be 370). There is a distinct possibility that the intake manifold is clogged, and that the clogging extends into the intake ports, where it might be buggering up the airflow into the engine. A piece of sooty crap could even be making intake valves hang open a little ((this would explain the low MAF reading) - this has happened before. Suggested corrective action: inspect condition of EGR valve and intake manifold and clean if necessary (probably will be necessary); clean MAF sensor just to be sure; recalibrate EGR system per TDIFAQ to prevent future problems in this area. It is very unlikely that the MAF sensor is faulty - they almost never break on that model - but it could be dirty.

<font size="2" face="Verdana, Helvetica, sans-serif">Cleaning the intake system does not sound like a fun job. I bet it needs it! I have 145k miles - the intake system is probably due a Merry Maid visit. I cannot find the EGR calibration instructions in the TDIFAQ section.

Thanks for all your help!

 

[GoFaster]

With regards to your first question asking if I am referring to the timing (comments concerning group 001): NO, I am referring to the quantity: http://www.tdiclub.com/TDIFAQ/TDiFAQ-7.html#h

However, you ALSO need the timing adjusted, and your post of the "basic settings" numbers confirms that, the pump timing is late. The link you posted is the correct one for that.

Here's the EGR recalibration, it was right next to the section that you were reading before

http://www.tdiclub.com/TDIFAQ/TDiFAQ-7.html#j

 

[GoFaster]

By the way, here's intake manifold cleaning: http://www.tdiclub.com/TDIFAQ/TDiFAQ-7.html#g

 

[Justy]

Here are the results of adjusting the EGR and ignition quantity. I have not yet had time to clean the intake system or perform the ignition timing procedures.

The engine still seems the same at idle. We at least got intake quantity and MAF closer to spec.

000
1. 43
2. 22
3. 0
4. 19
5. 100
6. 204
7. 72
8. 144
9. 146
10. 146

001
1. 903
2. 3.6
3. 1.44
4. 91.8

003
1. 903
2. 355
3. 478
4. 4.8%

004
1. 903
2. .4
3. .4
4. 58.2%

Will this level of retarded ignition hurt things?

Thanks!

-Justin

 

[bowlerman]

justin let me tell you something when my timing was at 20 the car sounded like an old diesel knocking alot. when i adjusted it up to 55 it sounded smooth big difference! oh and also gofaster thanks for all these notes on the charts they help out alot!!!