2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling

Honest John Back Room » Technical matters
View Threaded
Thu 5 Jan 2012 17:24
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - PX-230A

My engine mis-fires when idling for a minute or two, but only when the engine is hot. If I stop and re-start the engine, it runs fine again for another minute or two before mis-firing again. When driving, the engine runs perfectly fine and does not feel sluggish or anything. There are no start-up issues either.

Looking at the rev counter, it seems to drop (not suddenly) to around 700 RPM when the mis-fire happens.

The diagnostics I had done on the engine confirms an intermittent mis-fire on cylinder three (but does not say what the cause of the fault is). I have had the coils and spark plugs replaced, timing checked and all the engine wiring tested. A compression test has also been done and rules out a burned valve.

Before I had the coils replaced, the diagnostics reported an intermittent mis-fire on all three cylinders. Since the coils were replaced, the mis-fire is on cylinder three only.

The mechanic now believes that the fault could be with the ECU. He said that a faulty coil (before I had them replaced) could have sent a charge back to the ECU, causing damage.

I am just after some advice really before I spend more money! Any ideas?

Edited by PX-230A on 05/01/2012 at 17:33

Reply | Report as offensive | Link
Mon 30 Jan 2012 20:26
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - The-Mechanic

A common problem on these 3 cylinder engines are the fuel injectors failing. Double check the code for the misfiring cylinder and note it. Remove the fuel injector rail (two torx screws and the fuel pipe) and then swap the injectors around (No1 to 2, No2 to 3 and No3 to 1). Bolt the rail back on making sure the rubber seals are still attached and give the car a roadtest. Read the codes once again and see if the misfire has migrated to a different cylinder (in your case the misfire should now be on No1 cylinder). If it has, replace No1 injector. In rare cases the fault lies in the rail itself so a new (or known good second hand one) is needed. Seeing as you've had all the stuff I'd have checked out first confirmed as good (plugs, coils, compression etc) I'd say its the injector and / or rail at fault.

Let us know how you get on.

Reply | Report as offensive | Link
Wed 1 May 2013 22:34
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - nashe

I have the very same problem, please share how you rectified this anomaly

Many Thanks

Reply | Report as offensive | Link
Thu 2 May 2013 12:53
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - Shen84

Hi

I have the same car and mine is misfiring too. Its been doing this for about 5 mths. It is graudually getting worse everyday. I have taken it to 6 different independent garages and no one can tell me what the problem is. They say that the problems range from the Valves, Injectors, Spark Plugs, Coil Pack, Wiring and now they are saying its the ECU.

My diagnostic said misfing on injector 1, got that changed for (£210) - problem still there now garage is telling its the wiring, had that checked over its fine - now there telling me its the ECU. I have 34000 on clock.

I have phoned V.W but they wont do anything with is being diagonsed first which is £150. I called VOSA as i want them to re-call the vechile, i am in the process of doing this.

If you go goole and type in "V.W Polo 1.2 Misfing" you will see that there are loads of us out there with the same problem!

V.W has a lot to anser too. Im getting rid of mine as im just wasting money fixing it!! I suggest you do the same.

IF THERE IS ANYONE THAT CAN HELP PLEASE REPLY!!

Reply | Report as offensive | Link
Thu 2 May 2013 18:34
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - elekie&a/c doctor

It is the valves in the cylinder head.Rarely anything else,and certainly not the ecu,although VW recommend a new cylinder head and an ecu software update.hth

Reply | Report as offensive | Link
Fri 3 May 2013 16:00
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - nashe

I would have thought if its valves it would constantly misfire and loose power, instead everytime i switch the egnition off and on again, the problem goes away, seem more like an electrical issue than a mechanical problem.

Its really wierd, and i am skeptical to take it to the garage as they keep saying coil pack, could injectors cause a similar thing, or some kind of sensors?

Reply | Report as offensive | Link
Sat 4 May 2013 10:39
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - Shen84

Its definitely a electrical problem. My mechanic is baffled. Keeps suggesting things to help but to be honest i don't have guessing money. So I'm getting rid. Everyone is telling me never get a 1.2 engine again. Go for 1.4. You live and you learn.

Reply | Report as offensive | Link
Sat 4 May 2013 10:44
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - Shen84

When you switch off engine and turn on. Your just resetting the problem. My garage phoned me to tell me that someone else has just bought there vw polo 1.4, 55plate to him with the same problem. Im guessing its the 55 plate models that are the problems. If only i knew before i purchased mine. I haven't even had it 2 years yet! Or paid for it!

Reply | Report as offensive | Link
Wed 19 Jun 2013 20:23
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - littlestone

it may be as simple as a new distributor cap an rotor arm-not that expensive. hope this helps

Reply | Report as offensive | Link
Mon 22 Jul 2013 16:06
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - oldwrigley

Do a compression check, 1.2 engines usually only fail from igntion coils or valve seats burnt out

best regards

Reply | Report as offensive | Link
Mon 22 Jul 2013 16:28
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - Braunschweig

I had the exact same problem and symptoms with my car - 2005 Volkswagen Polo 1.2 (9N).

After trying loads of different things (including changing the timing chain), the problem was cured by replacing the crankshaft and camshaft sensors. These never showed up on any diagnostics as errors, but I decided to replace them on the off chance that it may cure the problem, and it did!

This was about six months ago and the car has been running perfectly ever since. Be very weary of "mechanics" that say straight away it is a burned valve - a lot seem to jump to this conclusion without testing other things first, and it could cost you money that you don't need to spend.

Edited by Braunschweig on 22/07/2013 at 16:36

Reply | Report as offensive | Link
Tue 23 Jul 2013 11:12
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - oldwrigley

blimey, bizzare that the sensors didn't show up as a problem

OP has done a compression check and it was ok so it can't be valve seats so maybe he's got the same scenario as you

i bet you could have set fire to it after changing the chain etc

vorsprung durch tecknic!

Reply | Report as offensive | Link
Tue 23 Jul 2013 23:30
2005 Volkswagen Polo 1.2 (55PS) E - Engine Mis-fire when Idling - Braunschweig

Tell me about it!

The car has just short of 130,000 miles on the clock (I've had it from new) so the timing chain probably needed changing anyway. I know Volkswagen don't have a set change interval, but the chains on these engines aren't as maintenence free as they suggest.

I think the worst thing for me was that it kept going into limp mode and wouldn't go much faster than 40 MPH.

All this aside, it's a brilliant little car and it still feels really nice to drive despite the mileage. The engine runs as sweet as a nut. I think this problem is very minor considering how long I've had the car, and that nothing has ever gone wrong before, and of course the mileage. Guess a car will last a long time though if it's looked after properly!

Edited by Braunschweig on 23/07/2013 at 23:31

Reply | Report as offensive | Link