Rough idle question, 2005 Passat TDI

lynnejohn

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CT
TDI
2010 Jetta TDI
My 05 has been doing the same thing, rough idle and even smoking on cold start ups. The car is all stock with a BSM completed last spring. I was talking to a friend with a TDI Touareg about my problem and he asked what type of fuel have I been using. I told him that I fill up a Road Ranger and he said that their "crap fuel" could be causing my problem. As I got closer to needing fuel I thought that his idea was too simple and I should try a different brand to prove him wrong. I filled up at Shell and within a couple of days I noticed the rough idle wasn't as bad and the smoking was less. I have filled up at Mobil 2x since then and I have noticed a huge improvement. The rough idle is there just a little bit but it goes away very quickly and the smoking is gone.

I don't know if this is just a coincidence but it is worth a shot.
Well I do always fill up at the same station so I could try using another. On a second note it appears that when the car had the glow plug update they forgot to put in the correct plugs (they were not NGK's as thundershorts had suggested.) It was done yesterday so I don't know if there is any difference.
 

aja8888

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Well I do always fill up at the same station so I could try using another. On a second note it appears that when the car had the glow plug update they forgot to put in the correct plugs (they were not NGK's as thundershorts had suggested.) It was done yesterday so I don't know if there is any difference.
The correct VW specified glow plugs in the last TSB go around by VW are the 7 volt ceramic tipped NGK branded ones.
 

lynnejohn

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2010 Jetta TDI
The correct VW specified glow plugs in the last TSB go around by VW are the 7 volt ceramic tipped NGK branded ones.
The mechanic was surprised that the wrong glow plugs had not throw an error code, but at least it's one less thing to worry about with the New England winter is around the corner. I hope it helps the idle issue but I have my doubts.
 

aja8888

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This has been a see saw adventure with VW. The original glow plugs in the 04-05 Passat TDI's were ceramic 5 volt ones. VW came out with a TSB for a replacement to 7 Volt steel ones and for some reason, that was also an issue (hard starting). Along with this TSB was a code change in the ECU software. Then VW (silently) re-specified the NGK ceramic plugs and a code change again.

It has been a circus with VW on this issue.
 

aja8888

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The mechanic was surprised that the wrong glow plugs had not throw an error code, but at least it's one less thing to worry about with the New England winter is around the corner. I hope it helps the idle issue but I have my doubts.
Glow plugs won't help with the idle unless they are on (or in some cycle of operation) under 40 F while the car is warming up. Idle is set at 817 (I believe) RPM by the ECU.
 

lynnejohn

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Location
CT
TDI
2010 Jetta TDI
This has been a see saw adventure with VW. The original glow plugs in the 04-05 Passat TDI's were ceramic 5 volt ones. VW came out with a TSB for a replacement to 7 Volt steel ones and for some reason, that was also an issue (hard starting). Along with this TSB was a code change in the ECU software. Then VW (silently) re-specified the NGK ceramic plugs and a code change again.

It has been a circus with VW on this issue.
Maybe that is why they said the TSB (software was correct) was done, yet the glow plugs were the wrong type. I did get VW to give me a service credit for the labor spent on the plugs (as it should have been done correctly when the TCB was originally done.)
 

thundershorts

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Something here doesn't make sense. You can scan to see if the correct software has been installed, or did the vw dealer do a scan. Also a possibility the assumed the software was correct for the ngk's but isn't. The date the gp/recall was performed would be a good start. If after dec 2010, it would be latest, if not it isn't. I thought you had some kind of tune performed on your car?
 

lynnejohn

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Location
CT
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2010 Jetta TDI
Something here doesn't make sense. You can scan to see if the correct software has been installed, or did the vw dealer do a scan. Also a possibility the assumed the software was correct for the ngk's but isn't. The date the gp/recall was performed would be a good start. If after dec 2010, it would be latest, if not it isn't. I thought you had some kind of tune performed on your car?
When I bought the car I took it to my dealer who checked the VW computer records to see if the TSB was done. They said it was done and there were no outstanding recalls on the car. I can do the scan, but I have no idea what software version I'm looking for. I did do the Malone ECU tune but I also own the programmer as well. When nothing simple was working for the rough idle, I programmed the original ECU version (the programmer can hold 4 or 5 versions) to insure it was not partly the fault of the tuning. The entire glow plug check started last week when it got down into the 20's here in CT and the car started very poorly the next morning. So I had them check the glow plugs and they saw some variance on the glow plug resistance and checked them to find they were the wrong ones. So the car starts well, but I have not had any time to see if the rough idle is still there (I fully suspect it is.) I'm still hoping to find the mystery rough idle issue as I rather like the extra power from the Malone tune, but I have not heard back from him after a couple emails.
 

thundershorts

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The tune would have overwritten the older vw software/bosch plugs when you loaded it, Had the newer software/ngk plugs been installed, it would have done likewise. The newer software/ngk plugs were never installed on your car. Now that you have 7v plugs vs the 5v plugs which came out, the question may be what voltage/heating duration/afterglow is incorporated in your tune. Some tunes apparently for the 5v bosch, increased the heating times. Your present tune may be in fact proper for a 7v plug as indicated by the damage to the 5v bosch gps. A good indication may be the cold starting smoothness. At least you won't damage the 7v plugs running them at lowe voltage, they just won't get as hot as fast. Glad you got the ngk's done, as it may help in ruling out causes of your rough idle warming up.
 

abctdi

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2005 Passat GLS
Just a reminder. The glowplug debacle and extended warranty ends on 31 October, a few days from now.
Even though I only have problems when very cold and/or at high altitude (8000 ft +), should I try to get the latest setup in place of my steelies?
 

lynnejohn

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CT
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2010 Jetta TDI
The tune would have overwritten the older vw software/bosch plugs when you loaded it, Had the newer software/ngk plugs been installed, it would have done likewise. The newer software/ngk plugs were never installed on your car. Now that you have 7v plugs vs the 5v plugs which came out, the question may be what voltage/heating duration/afterglow is incorporated in your tune. Some tunes apparently for the 5v bosch, increased the heating times. Your present tune may be in fact proper for a 7v plug as indicated by the damage to the 5v bosch gps. A good indication may be the cold starting smoothness. At least you won't damage the 7v plugs running them at lowe voltage, they just won't get as hot as fast. Glad you got the ngk's done, as it may help in ruling out causes of your rough idle warming up.
The newer VW software was loaded in the car as I put the original code in the car several weeks ago, and the dealer verified this week it is correct. So if Malone did not change the glow plug settings, then I should be fine with it.

As far as the rough idle, I really don't notice it like before (so far.) I don't see how it should make a difference as last month the rough idle was apparent even after driving 1 1/2 miles down the road to get coffee. At this point if the glow plugs fix it I'll be happy as this thread is getting to long.
 

lynnejohn

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Feb 7, 2002
Location
CT
TDI
2010 Jetta TDI
Just a reminder. The glowplug debacle and extended warranty ends on 31 October, a few days from now.
Even though I only have problems when very cold and/or at high altitude (8000 ft +), should I try to get the latest setup in place of my steelies?
Thanks for the reminder as the VW dealer had mentioned the end of the warranty.
 

thundershorts

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you had said that you put original coding back in several weeks ago. If so you had 5v plugs running at 7v. abctdi, If I were you I'd get the ngk's alomg with the software update done.Smooth easy starts at low temp and smoother idle. I've had mine in for 2 years.
 

lynnejohn

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you had said that you put original coding back in several weeks ago. If so you had 5v plugs running at 7v. abctdi, If I were you I'd get the ngk's alomg with the software update done.Smooth easy starts at low temp and smoother idle. I've had mine in for 2 years.
I believe that's how it was when I got the car and who knows how long it had been that way. The car did come from Nevada so there was a chance it never needed to use the plugs.
 

thundershorts

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the gp's are always functioning, regardless of ambient temp. I did some work in Sandy Valley, Nevada a couple years ago in Winter, -20f at night, tee shirt daytime.
 

thundershorts

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If the dealers don't give a positive response, just call vw customer service.
 

abctdi

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One has called me and I have an appointment on Wed for the upgrade, free of charge.
I can't prove hard starting below freezing, yet, so they took my word for it.
 

abctdi

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Okay, so I dropped it off this morning and just got a call. They say it works as designed, so they can't do the work. I countered it does not, due to the hard start in cold temps, which was the point of the extended golw plug warranty. He said he'll do some more research and I said I wll contact VWOA if need be, so we left it at that for now.
What the heck?
 

truman

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Okay, so I dropped it off this morning and just got a call. They say it works as designed, so they can't do the work. I countered it does not, due to the hard start in cold temps, which was the point of the extended golw plug warranty. He said he'll do some more research and I said I wll contact VWOA if need be, so we left it at that for now.
What the heck?
I put my own plugs in at 10ea and paid 100 to have the program updated, rather than deal with the run around. The cold start problem with mine occurred at about 15F or below. Look at the hassle owners have had with he iced up inter cooler problems on Jetta and Golf CRs and the BSM issue on B5.5s as well. VW seems to have patterned their warranty program off the after market insurance industry.
 

thundershorts

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why not either call the other dealer and get it there if they act like jerks at the dealership where it is presently, or call vw customer service. they can extend the time limit. I'd just get your car out of where it is on principal alone for giving you the runaround. I had mine done before the program officially started and paid 60+40 I just sent the receipt to vw and they paid. You could have course have had this done this a long time ago, and enjoyed easy clean starts last winter.
 

dhuddleson

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abctdi,

At least you have a "complaint" logged at the VW dealer's Service Department before the VW extended warranty expired, so you should keep fighting and they cannot say you are "too late"...
 

lynnejohn

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you had said that you put original coding back in several weeks ago. If so you had 5v plugs running at 7v. abctdi, If I were you I'd get the ngk's alomg with the software update done.Smooth easy starts at low temp and smoother idle. I've had mine in for 2 years.
Just came back from the dealer (2nd time) for cold start and it seems that they got the glow plugs correct on the first visit but did not get the correct version of ECU software. So after an hour to put the newest ECU software in, the car seems to start a whole lot better in the cold. Thanks for the help as I don't know if the dealer would have gotten it correct if I had not told them that the TDI club forum had mentioned 2 software updates.
 

thundershorts

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that dealer does seem pretty dumb...This can't be the first time they've ever updated a b5.5 tdi....or maybe it is.
 

lynnejohn

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At least they found I had a bad thermostat. During they test drive they noted that the engine temp was around 75C. I check my engine log of my drive to work and sure enough, 74-80C. So I'll give them some credit. It's nice to have some extra heat on December mornings in New England.
 

CharlieT

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At least they found I had a bad thermostat. During they test drive they noted that the engine temp was around 75C. I check my engine log of my drive to work and sure enough, 74-80C. So I'll give them some credit. It's nice to have some extra heat on December mornings in New England.
Curious to see what your CTS temp log is now, bet it is still 74-80C (ie there was nothing wrong with the thermostat). All the BHWs I know run cool in winter unless you drive them hard.
 

thundershorts

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as you can see the dealer wasn't that dumb, he got you for a job that was not needed and generated shop profit. apparently vw is having a promotion on thermostats at the moment, I saw that idparts is deep discounting oem stats
 

aja8888

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Maybe I'm lucky, but I have not changed a "faulty" thermostat in any of the cars I have had in over 30 years (can't remember farther back than that).;)

I'd have to believe the temperature error tolerance on any bi-metallic thermostat is probably + or - 5%. (and that is being conservative)
 
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