Low compression on all cylinders full DPF Help

[Canuck07]

I have a 2011 VW Jetta 2.0 TDI. I do alot of driving, I bought it new in May 2011 and am currently at 370,000 km (230,000 miles). It has always been serviced at the dealer engine and tranny oil services as well as timing belt. They have previously said the DPF filter was full but to leave it till the next service to see of it would regen. It has been awesome and never had a problem until 2 days ago when the check engine light came on, then yesterday the glow plug light started flashing. Took it to the dealer and they said it was a glow plug fault and ordered in some control mod. They put it in and nothing changed. Now they have told me that there is low compression on all 4 cylinders 20-20.8 bar (around 300psi). They are saying that they now need to start taking the bottom end apart for a possible rebuild. Seems to me like they are really stabbing in the dark on this. I also dont know how all 4 cylinders would all of a sudden have even low compression. Is there a possibility that the DPF has become so plugged that its creating way too much back pressure?? Any help or insight would be great. I've told them to hold off on going any further and I will let them know Monday to go ahead or not.
Thanks.

 

[nord]

Clogged exhaust shouldn't have much to do with compression. It will, though, have a lot to do with performance and economy. If the DPF really is clogged, then the dealer did you no favors by delaying service.

Lower ends on the TDI's are robust at minimum. Only if you determine that there's excess blow by and resulting pressure in the crankcase should you suspect a lower end problem. My guess if compression actually is low would be exhaust valves.

The the dealer saying all four cylinders. Do you know how unlikely it would be for all four cylinders to fail? Even more unlikely for rings and pistons to all go bad.

No mention was made of codes. A flashing glow plug light can mean many things, It also means that codes have been stored. What are they?

My inclination? Run! Get your car to a real diesel tech.

 

[Canuck07]

All they told me was it was a glow plug fault coming up on all cylinders. After they replaced the control module with no change they did a compression test which came up low right around 300 psi on all cylinders. I just cant get my head around how all 4 cylinders could evenly loose compression. To add to the mystery I have recently in the last couple months started to have improved fuel economy.

 

[wrenchman30]

unbolt the exhaust clamps and retest the compression, if it cant blow it cant suck and it cant squeeze

 

[Vince Waldon]

unbolt the exhaust clamps and retest the compression, if it cant blow it cant suck and it cant squeeze

My thought as well.

 

[Chris Thomas]

Compression

Copied from the service info I use at the dealership where I work.

Compression Pressure

New:.......................................25.0 to 31.0 bar (362.5 to 449.6 psi)

Wear limit:.................................................19.0 bar (275.5 psi)

Permissible difference between all cylinders:.........maximum 5.0 bar (72.5 psi)


From this info compression is not the greatest, but, is not the problem.
I agree with plugged exhaust (I have seen low compression do to melt gasoline catalytic converter). Also have seen diesel injectors "wash" the cylinder walls creating low compression(Add a little oil to each cylinder and recheck compression).

 

[Canuck07]

Thanks for the info guys. I am going to take the car to a private garage that deals a lot with VWs and TDIs and hope they are better than the dealership. I will give an update once it is fixed.

 

[Vince Waldon]

Probably for the best... a flashing glow plug light is NOT related to the glowplugs, regardless of what the dealer said.

 

[wrenchman30]

do not add oil to a diesel cylinder for a compression check it could be a disaster

 

[Canuck07]

I picked up the car from the dealer today and had a chance to talk to the mechanic that did the diagnostics on my car. The compression recorded was actually #1 20.3 #2 20.2 #3 17.4 #4 19.3. A bit different than what the service advisor had relayed to me. They had also gone ahead and done a test with oil and the results were #1 22.3 #2 23.8 #3 21.7 #4 23.4. The mechanics feeling was just that the engine is wearing and the low reading on #3 caused the light to come on as there is a pressure sensor in the glow plugs. I am still going to take it to the private VW shop and get them to look at it. Will update once that is done.

 

[weasel]

A pressure sensor in the glow plugs?? That's a new one.

 

[meerschm]

http://www.natef.org/NATEF/media/NATEFMedia/VW%20Files/2-0-TDI-SSP.pdf

see page 48

"A cylinder pressure sensor is integrated into each of the Glow Plugs."

this applies to the CBEA and CJAA engines. 2009 -- 2014 pretty much.

 

[Black_Smoke]

I'd be interested to know what codes the car is throwing.

 

[Canuck07]

I'd be interested to know what codes the car is throwing.

Codes are P0263, P0266, P0269 and P0272. There were also codes from the exhaust system for temperature to high but I do not have these.

 

[Ski in NC]

Does engine start well cold? Low compression usually shows its first symptom and rough smoky cold starts. How was it last winter?

 

[Canuck07]

Does engine start well cold? Low compression usually shows its first symptom and rough smoky cold starts. How was it last winter?

Car starts perfectly, just like new. This last winter it was fine as well no difference, no smoking at all (wasn't sure if this is just because of the DPF). Also in the last 2 months I've got some of the best fuel economy I've ever had with this car. I usually get 800-850km a tank all the time I drive almost all highway at 120-125 kph approx 2300 rpm. The last 2-3 months I've started to get some tanks as high as 950 but most around 900.

Just really makes no sense to me which way I look at it. Good news is the car is finally going to be going into the shop this Wednesday so hopefully have a good answer to this.

 

[wrenchman30]

bad fuel (low cetane) lmao

 

[japedo]

Have you got any sort of answer from the garage yet cannuck?
Also, I'm in the same province here. How has you 2011 held up in regards to rust? Impressive mileage you have there! Hope you get I figured out

Curtis

 

[Canuck07]

Well I got the car back last night. The mechanics chatted with me for a bit before taking the car into the shop to get the history of what happened and the dealer diagnosis. With the car running great, great mpg, starting perfect they were thinking this was not a compression issue. After a quick start up and taking the car in the shop they were pretty certain that chasing the dealers findings were pointless. So they disregarded the dealers compression test and direction and plugged the car in and did there own diagnostics.
What they found was that the fault was coming on even without the engine starting. They would clear the fault and turn the car power on and the fault would come right back. They did some more digging with ross-tech and found that the glow plug coding had been wiped from the car computer. They reinstalled the glow plug software coding files and no more faults. They also checked the DPF and said that it is not full and I can get a bit more out of it. So a couple hours in the shop with them $169 tax in, faults are gone and she is on the go again. Drove about 400 kms today and no issues at all.
What I don't know is what could have tripped this in the first place or how the files got wiped out of the car. I do know that there was an update that was done at the dealer (after the check engine and glow plugs lights came on) no idea if it is related or not. It is listed on my receipt as Perform Service Act 2306 Software Update. Long and short, very glad I took it from the dealer and got it to Autobahn Autohaus in Moncton. Will update if it comes back again and if there is any findings.

 

[Canuck07]

Have you got any sort of answer from the garage yet cannuck?
Also, I'm in the same province here. How has you 2011 held up in regards to rust? Impressive mileage you have there! Hope you get I figured out
Curtis

Hey Curtis,
Yep got her back and on the road again thanks to Autobahn Autohaus. For rust I don't really have much, there are 2 very small pinholes at the top of my windshield where it looks like a rock chip. Other than that no rust that I can see.

Rob

 

[japedo]

Glad you got it on the road! And that all is well mechanically.
Where abouts is the garage you mention?

Thanks

 

[Canuck07]

Glad you got it on the road! And that all is well mechanically.
Where abouts is the garage you mention?
Thanks

Here is there website.

http://www.autobahnautohaus.com/

They are off Mill Rd near Elmwood Dr.

 

[japedo]

That's great to know, I do what I can myself but they sound like a decent shop.
And only about 20 mins away for me.

Best of luck