Intermittent 2004 VW Polo 1.9tdi Sport 100BHP Missfire

GDM-Polo

Member
Joined
Dec 2, 2011
Location
UK
TDI
2004 VW Polo 1.9 TDI (100BHP) Sport
Im trying all I know this weekend, My car a 2004 VW Polo 1.9tdi 100BHP, Is starting to missfire, it is quite a heavy missfire as if maybe an injector has went down.

Then..........It drives fine, mainly misses when it gets warm, and has only started on friday night. So mainly when you start from cold engine runs fine, then heats up and misses, the amount it misses can be from outright heavy chugging under acceleration, to just a little miss, but the hotter it gets or the longer journey the worse it gets. The Engine Management light will come on, and also go off eventually also.


i cannot see any visual issue, ive read about MAF Sensor and EGR Valve, Ive Also temoved the air flow meter? Which is a black box whit loads of what looks like fuel pipes, there are 6 pipes, and when you open up when the car is running there is no difference, and I feel that only two pipes have a vacum on this, on the plug side rather than the black box side if that helps.

The car has 100,000 miles on it with full service history, the fuel filter was last changed 2 months ago, and I also tried to empty the bottom of the fuel filter in case of water.

Any Idea? Is this a common issue and easy fix. Or dreaded mega cash? As Injectors appear to be mega cash
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
Possibly this could be the beginnings of camshaft and lifter wear. If it is, it will get steadily worse.

--Nate
 

GDM-Polo

Member
Joined
Dec 2, 2011
Location
UK
TDI
2004 VW Polo 1.9 TDI (100BHP) Sport
--Nate, PD Jetta,

Many thanks, but, it is an intermittent fault, camshaft lifterwear, would constantly be there and as you say get gradually worse.

Regards

Gary
 

Lee_Taylor

Veteran Member
Joined
Sep 26, 2004
Location
Kent, England
TDI
Audi A3 1.4 COD
The "air flow meter" sounds more like the N75 solenoid from your description. Is the problem any worse with low fuel level?
 

GDM-Polo

Member
Joined
Dec 2, 2011
Location
UK
TDI
2004 VW Polo 1.9 TDI (100BHP) Sport
Hi, the car was fully serviced 2 months ago with new fuel, oil and air filters. I must admit, I dont know if its worse with low fuel, but......I put a Diesel cleaner through the car with quarter a tank and then I have filled it, It did seem worse at a point on friday, saturday is better, there was a full tank, the "Air Flow Meter" or N75 Solenoid. Deffo not the solenoid, the "Air Flow Meter" is on left hand stut top just behind, with a spring clip multi hosed attachment, you remove this and it has around 6 holes, the pipes rubber are numbered 1-6 and attached onto the EGR Valve and other things at the Air Filter and all that I think.

I dont know what it does though, im trying to work out what is going.

I did google an N75 Solenoid and its not what I see on the car, Though, I google air flow meter and I can only get a MAF Sensor Pic maybe I have my terminology wrong.
 

GDM-Polo

Member
Joined
Dec 2, 2011
Location
UK
TDI
2004 VW Polo 1.9 TDI (100BHP) Sport
Arghhhhhhhhh!!! Replaced MAF Sensor, and..........cleaned the egr which was in essence spotless.

Next........????????????? I dont think an injector can be away if its an intermittent fault.

Ive read other things on injector wiring loom.
 

GDM-Polo

Member
Joined
Dec 2, 2011
Location
UK
TDI
2004 VW Polo 1.9 TDI (100BHP) Sport
Guys, for the record, Reading elsewhere and working out and "Guess Work" the Injector Wiring Loom, I replaced today at a cost of £56.50 from the VAG Dealer and it has cured the problem, the car is showing much better MPG and driving Better, WooHoo!! A Fidley Job, and able to fix, took me 2 Hours today So...........Total Spent £56.50 Loom, Rocker Cover Gasket £17.00 - MAF Sensor £90.00 Which seems dear but wanted Bosch Parts to replace live for like.
 
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