Misfire diagnosis?

jjcsnlynn

Veteran Member
Joined
Nov 18, 2007
Location
Felton, DE
TDI
02 & 03 Jetta TDI,99 Beetle TDI, 04 Chevy Duramax 2500HD 4x4
I recently picked up a 05 B5 TDI with 150K miles and it has what I call a misfire. When I got the car I had the trans P0741 (I think...for the TC) but I changed the filter and fluid. It had an oil leak, but I fixed that.

Since picking it up, I've had an occasional misfire. I'll be going along, mostly in an uphill or acceleration mode, and the engine will feel like 1 cylinder will not fire once or twice. Then it straightens out and all is good. It happened once in nearly 200 miles we put on it yesterday.

I pulled the VCDS and no codes. Even my trans code is gone.

What can cause this and why doesn't it throw any codes? I'm new to the BEW but can I easily diagnose if an injector is going bad? I just don't know why it doesn't give me a code.
 

jjcsnlynn

Veteran Member
Joined
Nov 18, 2007
Location
Felton, DE
TDI
02 & 03 Jetta TDI,99 Beetle TDI, 04 Chevy Duramax 2500HD 4x4
I changed the fuel filter and Diesel Purged the injectors. How do I tell if the cam is wearing without pulling the valve cover?
 

Trcoelho

Active member
Joined
Sep 8, 2014
Location
Saskatoon
TDI
Jetta MK4
I have a similar misfire issue that occurs only during startup. Usually only cold.
IP timing is set at 65 and the engine fires up right away when cold (-5 Celcius).
Just recently installed new injector nozzles (PP764's) and new fuel lines, filter, no leaks.
With the tune, 11mm IP and bigger nozzles, feels like it's running a bit rich.
My engine shatters a bit and doesn't rev up smoothly when parked in neutral.
Rev's up smoother when the engine is under a load.
Any thoughts would be helpful.
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
I have a similar misfire issue that occurs only during startup. Usually only cold.
IP timing is set at 65 and the engine fires up right away when cold (-5 Celcius).
Just recently installed new injector nozzles (PP764's) and new fuel lines, filter, no leaks.
With the tune, 11mm IP and bigger nozzles, feels like it's running a bit rich.
My engine shatters a bit and doesn't rev up smoothly when parked in neutral.
Rev's up smoother when the engine is under a load.
Any thoughts would be helpful.
Post in the MK4 forum - this one is for PD passats... :D

That said, have you checked or set the pump IQ after the nozzle install?

VCDS injector balance group 13 - have you checked that?

What tune do you have - was it made for PP764s and an 11mm IP?

What turbo?
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Just for kicks replace your 219 relay at the ECU. I have seen a couple cars with what you are describing and it was the 219 relay losing power for a split second.
 

Warthog

Veteran Member
Joined
May 16, 2004
Location
Clemson, SC
TDI
see Bio
vwz, There's nothing you do on the 2005 that is just for kicks. Gee, it IS as nice ride but the engine compartment...OMG!
So is the 219 relay near the ECU or on the relay panel?
[should I "take my lunch" when I start this job?]

Next...Will I find this relay on another older TDI somewhere...so I can change it just for fun without buying a replacement?
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Next to ecu "box' in cowl area on driver's side. There are 5 8mm screws holding the cover on. One is hidden on back side and is accessed through removable plug next to drivers side wiper arm pivot point. Move wiper arm to up right to full wipe position on windshield. Pop plug out and slide 8mm socket through hole. Having a magnet handy helps. And FWIW I think the B5 is easier to work on than the B4
 

Warthog

Veteran Member
Joined
May 16, 2004
Location
Clemson, SC
TDI
see Bio
B4 vs. B5: ha-ha. Well.....since I managed to replace gaskets on the B4 IP, then pull the pump, send it away to be rebuilt and get the whole mess reassembled (TB-kit) nicely some years ago and it's still running fine...I guess it just seems easier; "The devil you KNOW vs the other one...".
Ok back to the issue at hand. Since the noise varies from a marble in a coffee-can up to a definite knock and accompanied by the vibration, I really do think it's unlikely to be the power relay. The problem is not the occasional miss.
I seriously suspect a faulty injector (O-gee!) or some weird happening in the the ECU. It runs fine up to around 1900 rpm. NO codes are thrown.
Turbo boost seems to come in when it should and the MAF is not misbehaving.

Old experience with Diesels is that pinging/Knocking is related to bad timing or bad fuel or both. I do not see how the computer could get off-time (lightning strike?) so the bad fuel was why I changed the fuel filter...a clogged filter would also tend to starve the engine causing a very lean condition which also could cause poor acceleration.
Which groups are ones to monitor the injectors...are they identified as "coils"?
I'm reading the ROSS-TECH PDF now but there's a LOT of stuff there so asking someone who knows more is always better than feeling around in the dark.
 

Warthog

Veteran Member
Joined
May 16, 2004
Location
Clemson, SC
TDI
see Bio
Looks like no one is following this very closely. I ran Meas. Block 23 -engine- and got some interesting numbers. Cyl #1 read -20 while the others were small single digits hovering arouond -1 up to +3.
Accelerating up to 3200 rpm showed Cyl #1 staying at -23/-19 while the other 3 cyls changed in the + direction all about the same. These are called "Solenoid valve status"...I assume this is the injector solenoid valve which is operated by the ECU?

I've read a number of postings on this forum and other forums that mention cams wearing out and broken valves. I doubt I have a broken valve as that would affect the idle and it is very smooth down at 900-1200 rpm.

Cams don't wear out suddenly but can it wear to the point that the problem would not be noticable and then would be? That really doesn't seem likely either but frankly US-123 between Clemson and Greenville is in such bad shape you can't tell if you need new tires, new shocks or a new road. Well, we KNOW we need a lot of new roads...same story on I-85 going down to Atlanta...
 

Warthog

Veteran Member
Joined
May 16, 2004
Location
Clemson, SC
TDI
see Bio
Ok folks.
It is a worn cam.
Fortunately the lifters are not damaged so we do not have to go after metal fragments.
VWZ, do you think this might possible be the 2nd. cam on this engine? From reading a zillion other posts about soft cams, It seems they usually fail before 100k miles. I have 239K now. (Yes, WE are using it a lot!!)
 

vwztips

Veteran Member
Joined
Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Seriously doubt it is second cam. Like QTD said most last between 200 and 300k and then a lifter usually goes bad.

How did you determine a bad cam? You also stated it comes and goes. A bad cam will be consistently bad.
 

Dimitri16V

Top Post Dawg
Joined
Jan 30, 2005
Location
DE
TDI
01 Golf, 04 Golf
when checking for a worn cam , check groups 13 and 23

the cylinder that has the highest IQ and highest deviation should match

of course that could be a bad or misdjausted injector
 

Warthog

Veteran Member
Joined
May 16, 2004
Location
Clemson, SC
TDI
see Bio
I thought I'd closed this out but apparently I didn't.
(1) It was a worn cam because I saw it.
According to the "official" info, the cam has a grind that is special ("fast")and WILL cause early wear. (Read: FAILURE)
(2) New cam and all is well. Lots of other little new parts too!.
 

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
Warthog, my car is having some of the similar problems. What was worn on your cam? thanks mark
 
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