Fault code 01268 - Quantity Adjuster (N146) **New developments**

Looking for some diesel-guru advice...

The other day the car (MK3 TDI, AHU engine) decided to take an age to start. Cranked fine, but was a good 5-6 seconds before it fired.

It`s similar to what happened last year that turned out to be a split fuel hose drawing in air, but at that time it would smoke badly, then start hesitantly.

This time there`s nothing at all (no smoke, or coughing). Just cranks for an age, then fires normally, and runs well enough. (On the first day it did it, it would have a little hesitancy/cough every now and again, but seems to be fine now)

Last time there were no fault codes, but this time I have code 01268 - Quantity Adjuster (N146).

A Google around shows this as normally being accompanied by a flashing glow-plug light and power loss, but mine is steady and normal, and power is fine through the rev range.

There`s no fuel leaks/split lines, and all the wiring checks out, so that would point to quantity adjuster/pump failure (hope not!), but I`ve not found any other info where people have had the issue without the glow-plug light flashing, so I`m a bit stumped...

Any help/guidance much appreciated as always.

PS; I`ve had the Avry Mod disconnected since it began to rule it out.

 

The evry mod is usualy what causes that fault code, but not the symptoms you describe.

Have you cleared the code and then driven again and it has come back?

You could try reseating this shown at 6:05, http://www.youtube.com/watch?v=9h2WZxQ08lQ

 

Nice one Mike.

I did clear it, but then left my reader at a mate`s () so won`t be able to re-check till later.

Re-seating that relief valve looks pretty simple. Hopefully it`ll do the trick!

 

I the exact same problem, started the other week, but I don't know what is causing it.

I ran it very low on fuel and that may have done it. Taking the advice of that video, I changed the fuel filter yesterday. Had a nightmare starting the car and same a few hours afterwards. Will try again shortly.

The relief valve is very difficult to get at and the tool is bespoke. I may try making one today, but I'll be welding a hex nut on top of it if it comes out.

My patience is generally wearing a bit thin on my TDI. There seem to be any number of faults and accurately diagnosing is what I want to do, and I absolutely refuse to blindly replace with new components in the hope of convincing myself it will cure it. I think a scrappy trip is in order.

 

Being a pig to start after a fuel filter change generally is due to air in the fuel lines, sometimes caused by the recirculating valve on the filter being poorly seated or the o ring being knocked out of place. I had the same symptoms when euro car parts gave me the wrong filter and it was designed for a different recirc valve.

 

You can get rid of that pish problematic plastic valve by using a different fuel filter. StuMc did this last year after consultation with the "oily boys" on here.

http://www.clubgti.com/forum/showpost.php?p=1979339&postcount=27

 

Sorry to sound daft but have you checked the glow plugs? from the symptoms of runs normal etc, but slow start thats my first port of call.

they can be checked easilly just requires you to remove ,put a live feed direct and an earth to the body of the glow plug. It will be obvious if they are working 100%

 

On mine the glow-light comes on, then extinguishes just like it always has, and when it`s warm out I almost never wait for the light to go out and it starts fine.

Generally these older TDIs will start pretty well without the glowplugs working, and the symptom I have doesn`t seem like the poor start you might expect from duff plugs (worth a check though I suppose anyway. )

It`s in a fiddly spot, but needs a bit of lateral thinking...

(For others) Here it is. It only has two flats, and there`s no space to get a 10mm spanner on properly for the leverage needed to undo it.



I thought there might have been an Allen or Torx head under the the yellow witness-marking, but no, so had to place the spanner thusly, and use a screwdriver as a tommy-bar. Comes undone with a fair crack, but easy enough.





As per the video Mike posted, the valve is in the unseated position.



Quick tap with screwdriver handle re-seated it easily enough (there will be a little bit of fuel squirted out).



Then simply screw it back in, and re-tighten.

Didn`t make a difference to the starting issue mind...

Fault code was cleared, and didn`t reappear until the Avry mod was used, so that`s clearly not the issue.

 

glow plug check its a freebie and a quicky ! cant hurt

 

Lateral thinking FTMFW

Had spent an hour or so making a tool and it was bending. Open ended, screwdriver and off with a bit of shank twisting!

Plunger the same.

Still reluctant to start from warm, but monitoring. Ok on instant restarts. No fault codes as Vagcom and myself are still incompatible

Glow plugs test next?

 

I`m sure Elephant Engineering could knock up a decent T-bar type tool now the `design` is known...!

 

Ten minute restart fail !

So that's eliminated too.

Glow plugs that have never - to my knowledge - been removed... snap risk?

 

That`s the only thing that worries me about going near them...

I have read somewhere (but would need somone to confirm) that if two or more plugs fail that`ll lead the dash light to flash at start-up. If it`s only one (or none of course!) then the light stays steady.

If that is indeed true, then the fact my light is steady is enough for me to leave them well alone!

 

My glow plug light illuminated briefly on warm ignition-on, and went out.

Left 20 mins, same. Very brief appearance - and straight off, before the starter is turned.

 

Modern shizzle problems.
IIRC the glow plugs are triggered depending on engine temp. IE If the engine is warm they will not be on for as long as if the engine is cold. It is not just a set time they are triggered for like in the olden days.

TDIs will start without glowplugs on all but the coldest days.

 

Is your Vagcom giving realistic water temp readings?

 

in the very olden days the light was a good indicator, as it got brighter the longer you held it in glow position the brighter(so long as plugs were good) however the newer cars its on a time relay so goes out after xsecs.

 

This isn't a glow plug problem, I can go out and start my tdi without even letting the glowplugs come on at the moment.

 

Theres only one varible ajuster on the unit, and thats the one your altering with the Ervy Mod!

it's this from your picture, the top part right bottom corner, with the 3 30Torx, and one security head bolt


well the top is just a cover,with some electrics under it the, the square block under it (where the loom goes in, black loom block on removable) has the adjusting motor in, which is the one your fooling it's location with the resister

is it worth removing the mod as temp soution during diagnois??
All it is motor that turns with a offset pin that controls the amount of juice that goes to the head of the pump