Fuel delivery problem?

[dgmp]

Car: 2001 fabia 1.9tdi.

 

I'm having an issue, I believe with my fuel delivery. I was wondering if anyone had experienced this before and knew what it is a result of?

 

Normal low load, low throttle driving is generally fine.

Sometimes, not every engine start, the car will begin to have very lurchy/inconsistent power delivery at around 2300-3000rpm, after a varying amount of time. It gives a very juddery feel from behind the wheel. This does not happen straight from engine start every time, but does sometimes.

 

Sometimes, the engine runs very poorly straight from start.

 

In both circumstances it usually goes away when I cycle the ignition, but sometimes needs a few ignition cycles.

 

There is no 'noise' associated with the problem really, which makes me think it's not a boost related issue. But I've not ruled it out.

 

I have changed the MAF and tried it unplugged and this has not changed the situation. I have changed the fuel filter.

The fact that the problem is very irregular makes me think it's not an injector being dirty, I believe this would make for a continual fault.

 

I've read a few posts on here, one of which seemed like it may be related, the fuel pressure regulator, (post #22):

http://www.briskoda.net/forums/topic/195615-need-help-with-the-skoda-octavia-19-tdi/#entry2329573

But this is to do with the low pressure regulator whereas I am getting trouble with what would appear to be the higher pressures.

 

Any help/advice would be much appreciated.

 

 

 

[dgmp]

Forgot to add, I don't have an engine management lamp on the dash.

[sepulchrave]

It sounds like the injector wiring loom may be playing up, can you get the codes read?

[WilliamVRS897]

From what you have described it does sound like a fuel pressure problem. I know (from experience) that when something like a leaky injector etc. that obviously the fuel pressure drops, the car senses this and dumps slightly more fuel in to accommodate for the drop in pressure and from there it will run sluggish.

So it does sound as you say to do with a fuel pressure problem.

[dgmp]

I'm going to try and read the codes this evening. I'll post up the result.

[dgmp]

Ok, only fault code I got was:

18076 - PD Unit Injector'; Cylinder 3 (N242): Electrical Malfunction

P1668 - 35- 10 -  - - Intermittent

 

Has anyone had this before?

[SKYHAWK]

i got a injector forsale if needed

 

http://www.ebay.co.uk/itm/221588808491?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

[vindaloo]

It's more likely to be the injector loom than the injectors. Especially given the age of these cars now.

 

That Octy 110 TDi runs a completely different injection system to your car, so please blank it.

 

ISTR the part loom to the injectors that's needed is around £60.

http://www.darksidedevelopments.co.uk/products/genuine-vw-injector-wiring-loom-for-vw-1-9-2-0-8v-tdi-pd-engines.html

 

Have a shop around maybe....

 

J.

[SKYHAWK]

i got a loom aswell

[dgmp]

Thanks. I've not managed to get under the bonnet yet though. I'm staying optimistic and hoping it's a bit or wiring or a bad connection that is easily fixed etc.

Does the loom run inside the rocker cover?

Will it need a new seal of I take it off to check out the connections etc?

[WilliamVRS897]

I can look up the injector resistances tomorrow if you want to check the injectors for ohms?

[dgmp]

Just in case anyone else has this issue, I changed the injector loom and the problem seems to have been fixed. I had a quick look on youtube at a video of a guy changing the part first which was useful.

Also, when I took the old part out, I tested for continuity and resistance between the main plug and the injector plugs. It all checked out ok, continuity between all appropriate connections and resistance of 3-4 ohms everywhere too. I'm assuming it must have been a problem that was made worse when the engine got warm; it always took 5 minutes before the problem would start happening from a cold start.