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VW Polo 1.2 12v 2004 - Cam timing query (waveforms) #

Posted by Peter Holland on May 11, 2010, 1:48 pm

Year of Manufacture *: 2004
Engine Size and Code *: 1.2 AZQ
( Optional ) Scanner Used: VAG COM
( Optional) Fault Codes: None

This car has come in from a local body shop as a non starter after the battery went flat (apparently!)

No fault codes stored but has ignition, injection, fuel pressure etc. Compressions all check out at around 170 PSI. It does try to start if I remove the fuel pump fuse, which is odd as the plugs don't seem to get very wet. There is no attempt to start all if the time the pump is running. It won't even fire on easy start!

I've scope cam and crank signals but have nothing to compare them with. Does any one have a scope picture for this engine? I can only assume that I have a timing issue now.

Re: VW Polo 1.2 12v 2004 Cam timing query

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on May 11, 2010, 3:37 pm, in reply to "VW Polo 1.2 12v 2004 Cam timing query"
Peter Mutlow

Hi Peter,

If this thing has spark, fuel and compressions then I would expect some attempt at firing - especially with easy start stuffed into it. Have you considered a blocked exhaust?

Regards

Pete M

Re: VW Polo 1.2 12v 2004 Cam timing query

Posted by Peter Holland <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5256' width='330' height='300' border=0 style='border:none;'> on May 11, 2010, 5:04 pm, in reply to "VW Polo 1.2 12v 2004 Cam timing query"
Peter Holland

Pete - Good point! Hadn't thought of that. But sadly its exactly the same with the lambda sensor removed.

Re: VW Polo 1.2 12v 2004 Cam timing query (waveforms)

Posted by David Hindmarsh on May 11, 2010, 5:11 pm, in reply to "VW Polo 1.2 12v 2004 Cam timing query"
Message modified by board administrator May 12, 2010, 8:00 am

I would look at the timing remove the blanking plugs. The one I did the cam crank signals looked ok but exhaust cam without sensor had jumped no codes hope this helps

Re: VW Polo 1.2 12v 2004 Cam timing query

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on May 11, 2010, 7:05 pm, in reply to "Re: VW Polo 1.2 12v 2004 Cam timing query"
Peter Mutlow

Hi Pete,

Shame about it not starting with Lambda Sensor out. I went to a Sportstrack a few weeks ago which was a non-starter. Generally I have always found non-starters the easiest to diagnose because there is usually a lack of spark, fuel or compressions and you then follow the relevant avenue. This one was different in that it had all the ingredients to "go" with reasonable compressions of 140 PSI. So I whipped out the Lambda Sensor expecting it to burst into life but unfortunately it did not. Now heres the thing. I wrongly assumed that because the compressions were OK then the cam-timing would be OK. In this case, the crank woodruff key had broken up. So, where is this all leading to? I cannot understand why you do not physically check the cam-timing instead of trying to trace cam and crank sensors, unless you have already done this and I am missing something patently obvious

Regards

Pete M

Re: VW Polo 1.2 12v 2004 Cam timing query

Posted by Mark Mcgrath <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2806' width='330' height='300' border=0 style='border:none;'> on May 11, 2010, 9:54 pm, in reply to "Re: VW Polo 1.2 12v 2004 Cam timing query"
Mark McGrath

im with pete on this one pull out the blanking plugs it is less than ten minutes and check the cam alignment
if the chain is worn it jumps on starting up if stood a long time
we had one that the chain seemed reasonably tight
but when the oil pressure had gone after a short time you could lift it off sprockets

Re: VW Polo 1.2 12v 2004 Cam timing query

Posted by Peter Holland <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5256' width='330' height='300' border=0 style='border:none;'> on May 12, 2010, 8:47 am, in reply to "Re: VW Polo 1.2 12v 2004 Cam timing query"
Peter Holland

Pete - I take your point about checking cam timing, but I'm electrician who's been given this job from another garage. In an ideal world, they should of checked cam timing before chucking it at me. Besides, checking cam & crank signal with a scope is a job that takes a few minutes and is always worth a try before delving in too deeply.
I have to agree with you though, I'm left with little option but to check it now!

Re: VW Polo 1.2 12v 2004 Cam timing query

Posted by kelly clarke <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1397' width='330' height='300' border=0 style='border:none;'> on May 14, 2010, 7:50 pm, in reply to "Re: VW Polo 1.2 12v 2004 Cam timing query"
Kelly Clarke

This sounds much the same as the one i had the other week only it was a seat ibiza. cam/crank looked good had fuel and spark but no attempt to run.

The inlet cam and crank timing were right but the ex cam was two teeth out, compresions were reasonable but much improved after chain fitted.

Kelly

Re: VW Polo 1.2 12v 2004 Cam timing query

Posted by Chris Angus on May 15, 2010, 1:49 pm, in reply to "Re: VW Polo 1.2 12v 2004 Cam timing query"
Message modified by board administrator May 17, 2010, 2:18 pm

<< Besides, checking cam & crank signal with a scope is a job that takes a few minutes and is always worth a try before delving in too deeply.>>

Unless it's a single cam, scoping the cam/crank is in my opinion a total waste of time, it proves nothing.

Just my two cents worth.

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