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rmim

Hi All,

 

I have had what used to be an intermittent problem with my Polo 1.4 petrol 2005 for years - you used to hit the accelerator but it seemed to lose power.

 

I think I once read a code, crankshaft sensor - but I have never seen that again.

 

The problem has now become permanent (if related) - the engine shakes.

 

I got a few codes. I think I got an engine warning light once. Cylinder 2 Misfire (P0302). [I cleared the codes and engine light a few times or the years. At the moment there are no fault codes or light, but the engine still shakes.]

 

So anyway I thought I must have a misfire problem.

 

I changed the camshaft sensor (confusing it with crankshaft sensor) through seeing things on youtube. The problem was still there.

 

I changed all 4 coil packs and spark plugs yesterday. The engine still shakes

 

I would have changed the crankshaft sensor if I knew where it was!

 

I found those ignition spark testers (goes between the spark plug and lead and lights up if there is a spark).

 

The last sparkplug is not sparking I think! (Will have to wait till it's dark to double check).

 

So the engine is shaking as 1 sparkplug is not firing I believe.

 

What could the problem be? - car starts with no problem!

 

I want to try and avoid buying unnecessary parts again so thought I would come here.

 

Mileage 65,000.

 

Thanks

 

 

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nige8021

First Welcome to the forum.

 

If all the plugs are giving a nice fat blue spark, thenI would start by doing a compression test as valve seat problems are quite common on these engines, even at low mileage, if there is one or more cylinders low, pour a small amount of oil into the cylinders that are low, if the compression doesn't increase it is the valves, if it does increase then it's a worn cylinder bore/piston ring problem, if the compressions are all good & matched (10~15bar lowest limit 7bar & no more than 3bar differnce between any cylinders) then try swopping the injector for the cylinder that reported a misfire to another postion and see if the misfire follows the injector or stays with the same cylinder.

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rmim

Thanks for the reply nige8021 - 

 

I think only 3 out of the 4 are sparking.

 

I tried it again in the dark 

https://www.halfords.com/workshop-tools/tools/hand-tools/laser-ht-lead-ignition-spark-tester

and sure enough, only 3 were lighting up.

 

How reliable is that test? Or do I have to take the spark plug out and see if it sparks directly? 

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dvderlm

Not sure I was told by a breakdown guy that I had spark using one of those, but actually 2 of my plugs were melted as wrong heat range..

 

Can you swap cable of not lighting up plug to a known good cable? 

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nige8021
3 hours ago, dvderlm said:

.Can you swap cable of not lighting up plug to a known good cable? 

 

Individual coil packs David 👍

 

I would try removing the sparkplugs and see if they are giving a good fat spark, and if there is one not then try swapping the coil packs around to eliminate either the coil pack or the wiring to it, it's not uncommon to have a faulty pack even direct from new

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rmim
2 hours ago, nige8021 said:

 

Individual coil packs David 👍

 

I would try removing the sparkplugs and see if they are giving a good fat spark, and if there is one not then try swapping the coil packs around to eliminate either the coil pack or the wiring to it, it's not uncommon to have a faulty pack even direct from new

 

thanks for the reply nigd8021 - i will try that now.

 

So if the plug and coil pack is fine but I still get no spark on that one, what do I try next?

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rmim
3 hours ago, nige8021 said:

it's not uncommon to have a faulty pack even direct from new

 

 

 

OH MY GOD!

 

I said to myself - this guy is trying to freeze me outside for nothing to test a brand new coil pack and brand new spark plug - lucky I tried anyway!

 

You seemed to have fixed the problem! The brand new coil pack seemed not to work. I have used one of the old ones. Now the engine runs smooth.

 

Now I bought a set of 4 cheap coil packs on ebay, from this test one seems dud - should I be able to get a refund for the dud coil pack? Will he even believe me? (I dont even believe it myself!)

 

Do you think the car could have broken the new coil pack? I have not driven it anywhere, it only been on for a few minutes?

 

And all 4 of those tester things are working. And I have seen the sparks directly by leaving the spark plug out.

 

I wish I could drive the car but I have no MOT.

 

Will order new wiper linkage and go for an MOT soon I hope.

 

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nige8021

Unfortunately, you pay the price and get the quality, like any of the engine sensors only ever buy genuine ones from VW/TPS 

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rmim

some further testing tells me this is not the end of the story.

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rmim
1 hour ago, nige8021 said:

Unfortunately, you pay the price and get the quality, like any of the engine sensors only ever buy genuine ones from VW/TPS 

 

I'm beginning to suspect there was nothing wrong with my original coil packs - as I can see them all working with the ignition tester. However, with the new set 1 is not working.

 

The problem is not due to faulty coil packs I believe. Although the engine is running much smoother (as it was running on 3 sparkplugs due to introducing a faulty coil pack) the engine still does not sound right - sounds a bit like a diesel engine.

 

What else could I try?

Edited by rmim

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rmim

is there a crankshaft sensor? I want to try and clean it - read there could be bits of filings on it?

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nige8021

There is a crankshaft sensor, it's a bit of pig to get at, mounted down where the gearbox and engine bolt together, at the rear of the engine by the starter motor

 

417099264_G28sensorloc.thumb.JPG.d13a01017c51a359283bd850703969d4.JPG

 

Here's how to test it 6N2 testing G28CrankSensor.doc  however if it was faulty you would of had a fault code for it and if it's dead the engine shouldn't even start.

 

As I said before I would get a compression test done 

 

 

 

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rmim
5 hours ago, nige8021 said:

 

As I said before I would get a compression test done 

 

1

 

Can I do that myself with a cheap kit from Amazon or something? - I dont think it's worth putting too much money in this car. I will be lucky to get 600 quid from webuyanycar.

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rmim

thanks nige8021 - will order that kit.

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rmim
14 hours ago, nige8021 said:

 

I have done the test what do the results mean? 170/190/150/180

 

So I had a quick look on you tube on how to do a compression test - it's was a real quick look and all I saw was take off all spark plugs and do the test.

 

I put the spark plugs back and coil packs - now the car does not start at all - lol. What have I done now? Flooded?

 

Oh dear from further reading I might have done something bad to the car - I actually took off all the coil packs completely when I did the test. So what's broken now?

Edited by rmim
added

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rmim

oh and I forgot to warm up the car first! Doh!

Edited by rmim

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nige8021

#3 is just on the lower limit, try putting some oil down the sparkplug hole and see if the compression changes 

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rmim
6 minutes ago, nige8021 said:

#3 is just on the lower limit, try putting some oil down the sparkplug hole and see if the compression changes 

 

Im really stuck nige8021 - The car refuses to start at all. I dont think im getting any spark.

 

I must have done something wrong with the compression test and now it refuses to start. I was hoping you could tell me what i've probably blown up! 

 

I think I need to get the car starting again before I test again.

Edited by rmim

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nige8021

Just by removing the sparkplugs and spinning it over for the compression test shouldn't of done anything to stop it from running, Doing a "Cold engine comression test" is not a bad thing as it tests the engine at it's worst condition, as a warm engine the components expand making it look beter than it really is.

 

Have you checked for any blown fuses ? 

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rmim
10 minutes ago, nige8021 said:

Just by removing the sparkplugs and spinning it over for the compression test shouldn't of done anything to stop it from running, Doing a "Cold engine comression test" is not a bad thing as it tests the engine at it's worst condition, as a warm engine the components expand making it look beter than it really is.

 

Have you checked for any blown fuses ? 

3

 

Thank for the reply nige8021.

 

There are fuses on the driver side when you open the door - I checked all of them. They seemed fine.

The battery lid also had fuses I checked all of them, all seem fine. Any more?

 

For each test I only ran the starter for about 3 seconds.

 

Has the ECU somehow been damaged? What else can stop everything from sparking? It used to start with no problems.

 

edit - not only did I remove all the spark plugs at the same time, I disconnected all the coil packs - does that give any clues at to why it's not sparking now?

 

Edited by rmim

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nige8021

No just spinning it over for the test won't of done any damage to the ECU, backtrack over what you did, any other plugs you disconnected etc ?

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rmim
1 minute ago, nige8021 said:

No just spinning it over for the test won't of done any damage to the ECU, backtrack over what you did, any other plugs you disconnected etc ?

 

nothing.

the big square filter thing was already off.

unclipped all coils and removed

took out all sparkplugs

tested with compressor tester thing spinning for only about 3sec each time.

 

put everything back

 

would not start. sounded like no spark (you could not hear any sputtering).

 

waited hours tried to start again, the same thing. 

 

Think I will go charge the battery and try tomorrow

 

Any other ideas?

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nige8021

If it was running before you did that, it must be something you have done to stop it from running, as I said just spinning it over won't of done anything to stop it from running

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rmim

the leads that plug into the individual coil pack - where do they go back to? to the ECU? or is there another box of tricks?

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