Testing Glow Plugs on CJAA

[thecause17]

I've been searching and can't seem to find any info on testing glow plugs for the CJAA engine.

I've been having a hard cold start problem when the car has sat for about 24 hours or so, and it will run rough for a few minutes after it starts. If the car has been ran within the last several hours it's fine seemingly because the engine is still moderately warm. I'm sort of suspecting there is a problem with the operation of the glow plugs, but do not have any codes being thrown. The glow plug light stays on for 1-2 seconds or so. The owner's manual states that once the car is warm the light won't come on at all when it's time to start it, but this isn't the case with mine. It still comes on for the same amount of time, so I'm not sure if it's working correctly at all.

Does anyone know how to test the operation of the glow plugs while in the car? I have VCDS and the only thing I can find in there is testing for glow plug light. I'd also like to see how long they're staying on, but the problem is since they only come on when you first turn the ignition on, I lose my connection with VCDS if I turn off the key to turn it back on again to operate the plugs.

 

[oilhammer]

There is nothing wrong with your glow system, the engine computer checks that every time you turn the key on. If you had a problem with the glow plugs, your MIL would be on.

You have some other issue. Fuel prime problem, water in charge air cooler, etc.

 

[thecause17]

Yeah I thought most problems would show up with a code, but wanted to check them anyway. If you're sure that isn't the problem then I will move on. Here's the thread to my actual problem.

http://forums.tdiclub.com/showthread.php?t=424539

I'm working on logging some data, but haven't played with this feature of VCDS yet, and haven't gotten that figured out. I thought I logged data correctly the other day, but after recording I only had a text file with no real data in it, which could also not be used with VC Scope as well.

 

[JSWTDI09]

You have some other issue. Fuel prime problem, water in charge air cooler, etc.

Another possibility would be that pressure retention valve in the return line from the injectors. According to the "Self Study Guide" this little valve is supposed to maintain a minimum 10 bar (145 psi) in the injector return line. It says that this pressure is necessary for the proper functioning of the injector. When this valve leaks, the pressure can slowly bleed off. If you restart the engine within hours, it works fine, but the longer the car sits (not running) the longer it takes to start. It takes a while for this "back pressure" to build so that the injectors work right. There is no pressure sensor on this return fuel line, so the ECU is not aware of the functioning (or malfunctioning) of this pressure retention valve.

Have Fun!

Don

 

[thecause17]

Another possibility would be that pressure retention valve in the return line from the injectors. According to the "Self Study Guide" this little valve is supposed to maintain a minimum 10 bar (145 psi) in the injector return line. It says that this pressure is necessary for the proper functioning of the injector. When this valve leaks, the pressure can slowly bleed off. If you restart the engine within hours, it works fine, but the longer the car sits (not running) the longer it takes to start. It takes a while for this "back pressure" to build so that the injectors work right. There is no pressure sensor on this return fuel line, so the ECU is not aware of the functioning (or malfunctioning) of this pressure retention valve.

Have Fun!

Don

I knew this valve existed, and have considered it as a problem as well, but was not aware of it's reasons for being in place or the necessary specs. I think I know where it is now that you've described it. It looks to be a small black canister like item after the rubber return lines from the injectors all join up and start making their way back to a hard line. I would love to replace it as it looks to be a rather inexpensive item. Do you happen to know a part number for that, or if it comes as an assembly with that particular piece of line what that would be?

Also, where is this "self study guide", I've looked all over for it and cant seem to find it.

 

[JSWTDI09]

Do you happen to know a part number for that, or if it comes as an assembly with that particular piece of line what that would be?

Also, where is this "self study guide", I've looked all over for it and cant seem to find it.

It looks like it is item #25 on this page: http://www.partsbase.org/vw/jetta-j...0-high-pressure-pump-fuel-rail-injector-unit/
Part number: 03L 130 235 They list an F, K, & S versions - S is probably the latest, but a VW dealer could run your VIN and tell you which one you need. List price is a little over $100 and online prices between about $80 and $90 (depending on which one you need).

As for your second question, this is courtesy of another member here: Common Rail SELF STUDY

Have Fun!

Don

 

[thecause17]

Thanks for the info, that's the part I thought it was. It looks like it the K supersedes the F version according to ECS Tuning. I'm not sure about the S though. It's a little more expensive than I expected, but I honestly have not seen anything in monitoring that is pointing to any other issues that I can tell, so it may be best for me to spend the money to replace it and see what happens. It does make sense that it could be an issue, but I have no way to test it in the system.

 

[JSWTDI09]

If you have access to a pressure gauge, it might be possible to install a gauge upstream from this valve and monitor the pressure over time. This would tell you for sure if the valve was leaking. If you do not have access to a gauge to put in the line, you can just replace it and hope for the best.

Have Fun!

Don

 

[thecause17]

Yes, I don't have anything here good for above 100 psi, plus just because the minimum is 145psi, that doesn't say much about what the pressures actually do get to in the line. I find it odd though there are no clamps on these lines.

 

[thecause17]

According to to Volkswagen dealer #2 correct part is 03L130235S. My local dealer is really shady about giving out part numbers, so I had to call another dealer thousands of miles away to get it...I don't think they want people checking their prices...they were $30 more than elsewhere. The one that gave me the part number was $45 more.

 

[ss~zoso~ss]

so this is ironic, i'm also located in Dover with the same exact car as yourself, even the same color!

and I've been having the same issue since earlier this year! (jan timeframe)

I thought it was the ol' water in the inter cooler situation, but winner vw didn't find anything in the hoses that looked abnormal

After driving this whole year so far i still have a slight roughness rpm fluctuation during initial start.

My car has 34k on it, so this has been a frustrating issue.

I'll keep my eye out on here, but if you find a solution to your problem please let me know via PM!

Jeff

 

[thecause17]

http://forums.tdiclub.com/showthread.php?t=424539

This thread is continued here, since it's a more appropriate title.