Cylinder not firing… help

VW Jetta 2004 BEW wagon automatic, 104K.. Always used biodiesel.

Computer reading initially showed cylinder 3 misfire, so I had injector harness replaced as it looked like it was malfunctioning. Problem came back after 40 miles of driving. Then yesterday I replaced injector and still having same problem, computer still shows misfire of injector 3.

Already spent around 800 dollars.

Now they are doing more diagnostics. Mechanic says perhaps the biodiesel is a culprit, clogging lines, etc. Or perhaps a timing issue. Timing belt was replaced at 93K.

Any suggestion much appreciated.
Thanks

Have you checked the compression?

Is the misfire reading as an electrical fault or just as a misfire?
Any idea what the code is (number)?

Biodiesel IS the culprit....

No mystery there, Let us know, we may be able to resurrect the set despite the damage the Biodiesel does to the insides...

Biodiesel breaks down due the EXTREME heat generated inside the injectors, BIODIESEL CANNOT BE USED IN PD INJECTORS!!!

Time to pay the piper...

bri4msn said:

VW Jetta 2004 BEW wagon automatic, 104K.. Always used biodiesel.

Any suggestion much appreciated.
Thanks

Click to expand...

What percent of Biodiesel was used? Was it home brewed, or does it meet the standards?

FWIW, even ASTM is prohibited due to the injectors exceeding the maximum safe temperature range by 4 fold.

Prohibited by whom at what percentage?

Bosch, VW don't allow any percentage in PD's due to the temperatures internally.

[cough]
www.volkswagen.co.uk/assets/common/pdf/general/biodiesel.pdf

VW approves B7 in ALL vehicles

Biodiesel in the context of Europe is "RME" not the crap FAME in the U.S.

If you read the documents fine print:

"Biofuel, derived from Fatty Acid Methyl Ester (FAME). The use of this fuel in Volkswagen Group vehicles may invalidate the engine and exhaust system warranty."

So no, you cannot use biodiesel in the PD engines, and again because of the instability of the Fatty Acid Methyl Ester that is sold in U.S. Markets.

As vegetable oils tend to have a degree of unsaturation (which is preserved during transesterification), chemical reactions can occur in which the double bonds slowly undergo oxidation and rearrangement, forming numerous primary and secondary oxidation products. This leads to an increase in the total acid number (TAN) of the fuel, and the formulation of insoluble particulates that can block filters. As such, FAME is not currently seen as a suitable ingredient for power generation, aviation, or marine fuels. However, the widespread use of FAME as fuel for terrestrial vehicles generates an increased risk of inadvertent contamination of mineral fuels. Methods of analysis for trace amounts of FAME are thus becoming increasingly important.

Click to expand...

LOL @ DBW !... you keep posting the same worn out pictures of the same PD injector over and over trying to get your "sky is falling" point across ... i know of several PD's personally that have run very high concentrations of bio if not B100 for well over 100k miles each with zero issues and i guarantee you none of the injectors look anything like that worst case scenario you posted above ... i know you claim that injector was run on good bio but i'm calling BS as i've seen a pd injector run over 80k miles on homebrew that looked nothing at all like the fear mongering photo you keep copy pasting all over the web.... dismount the horse please, and put down the lance...the dragons are all in your head !!

jimbote said:

LOL @ DBW !... i know of several PD's personally that have run very high concentrations of bio if not B100 for well over 100k miles each with zero issues

Click to expand...

Look, the fact is we see injectors that look exactly like that WAY TOO OFTEN...

As to your Several, well thats a statistically valid comparison.

The HUNDREDS we see that DO have these issues, the hundreds that DO show up looking as bad or worse, the HUNDREDS that we have seen that failed with all four injectors clogged and sludged up despite the owner swearing up and down they ran "Good Quality Fuel"...

The rest of the owners either give up and sell the car, or get another set of used injectors an limp along. The vast majority of the PD's don't run Bio-anything and live long relatively trouble free service lives.

The PD's will run until they don't, example the original poster.

This explanation of why the fuel fails in these motors is best described here:

"As vegetable oils tend to have a degree of unsaturation (which is preserved during transesterification), chemical reactions can occur in which the double bonds slowly undergo oxidation and rearrangement, forming numerous primary and secondary oxidation products. This leads to an increase in the total acid number (TAN) of the fuel, and the formulation of insoluble particulates that can block filters. As such, FAME is not currently seen as a suitable ingredient for power generation, aviation, or marine fuels. However, the widespread use of FAME as fuel for terrestrial vehicles generates an increased risk of inadvertent contamination of mineral fuels. Methods of analysis for trace amounts of FAME are thus becoming increasingly important."

So every PD engine that is run in a state that mandates use of Biodiesel will fail.

Good to know.

There are o-rings in the Solenoid that ARE NOT BIODIESEL COMPATIBLE (not Viton).

The PD runs TOO HOT TO RUN BIODIESEL DUE TO OXIDATION INSTABILITY!

The PD Superheats the fuel under pressure causing breakdown of the BIODIESEL into Sludge, Varnish and other solidified matter that coats the internal surfaces.

Biodiesel has HIGH SODIUM and this corrodes the internal surfaces in the retraction piston areas and other high pressure ports making repair or overhaul impossible.

Run the stuff if you want, but its not going to end well, and PD injectors and Common Rail injectors were never intended to run anything that can't be heated under pressure without breaking down like Diesel Fuel can.

superheats the fuel !?!?.... care to be more specific ? is this like superheated steam ? i'm sure "super heated" anything in the injector is super-bad for any fuel short of super-dooper-dino-diesel ... charts or proof of any "super-heating" would be appreciated ...

The mechanic is still trying to diagnose…

2 codes on the computer: 16687 and 18076.

Question…Any problems anticipated in switching and going to regular diesel? Though I will miss that sweet smell in the mornings.

• 18076/P1668
  == 18076/P1668 - Valve for Pump - Jet: Cylinder 3 (N242): Electrical Malfunction ==
  720 B (107 words) - 03:38, 15 June 2006

Could be a chafed wiring harness...the one that runs to the head. Look for wear in the starter area of the electrical harness. They swapped injectors and the same code came back. Doubt if it is the injector.

One guy who rebuilds diesel injection systems for a living. A bunch of people who owned one or two, or know some guy who has one and they're the experts.....

As you said, eplaced injector, no improvement
I will pass this on to the mechanic.
Thanks.

Time to trace injector wiring back to the ECU

PD will look like those pics even if they are ran on ULSD . Think DBW has seen more PD injectors than all of us

vanbcguy said:

One guy who rebuilds diesel injection systems for a living. A bunch of people who owned one or two, or know some guy who has one and they're the experts.....

Click to expand...

One guy who has a history of scaring people into worst case scenarios, who makes money rebuilding injectors and doesn't have all of the information to help this person or people that are trying to get to the bottom of the problem and help him get it fixed.

indeed.

No one has said flat cam yet.. but sounds like the computer is triggering a circuit code, which would mean harness electrical problem most likely.

Nice little debate going though...

This whole thread could have been answered in two posts.

http://forums.tdiclub.com/showthread.php?t=439418

Link to the final results. It was wiring, not biodiesel.