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VW Polo 1.4 16v 2000 (X) - Runs rich around 2700 rpm, CO 2%+ and HC 600 ppm - Fixed #

Posted by Ian Staples on March 7, 2009, 11:59 pm

Year of Manufacture *: 2000
Engine Code or Type *: 1.4 16v

Hi all.

A late nite posting, so im sorry if the spelling wanders a bit

VW Polo, x-reg, 1.4 16v. MOT'd and failed emissions, holding a fast idle the engine suddenly gives a cough and emissions go through the roof, co% 2+, hc 600, lambda 0.9

Let it idle and its fine, try the fast idle again and its fine for a few seconds, then gives a cough and emissions go out again.

Ive narrowed it down, fast idle it around the 2700rpm and the emissions go out, bring it down to around 2400rpm and they come back in.

Its the same when you drive it, get it to around 2500-2800rpm and above and you can feel it choking up.

No faults stored and live data is all ok until fault present, when fault is present the lambda sensor stops switching and stays around 800mv, it starts switching again when the engine speed comes down to around 2400rpm.

Everything is indicating the system suddenly goes rich.

Any ideas?

And if anyone is gonna suggest resetting adaptions, sorry but dont, unless you can tell me what channel and why the adaption has gone out. It bugs me when people tell me to just reset the adaptions. Ive always found resetting adaptions back to factory is a temp cure, the fault is still there and eventually comes back. Fix the fault then reset.

Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above

Posted by Dave Harney <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2603' width='330' height='300' border=0 style='border:none;'> on March 8, 2009, 1:59 pm, in reply to "VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above"
Dave Harney

Hi Ian,
What scanner are you using to view live data ?
Whats the map, injector duration, temp reading before during and after the "choking up" issue ?

Don't suppose you can post a log !

Regards
Dave

You can trim a sheeps wool many times, but you can only fleece it once !

Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on March 8, 2009, 10:49 pm, in reply to "Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above"
Ian Staples

Im using a Solus v8.4 and tried it in both heritage and new software, what difference does it make on a common vehicle like this? I would get the same info using one of my other machines.

As i said, the live data is ok before the fault occurs. You cant watch it during choking up as it just suddenly gives a cough and does it. And during the fault the live data is ok apart from the o2 which sits around 800mv, the injection pulse is a little high which you would expect from running rich.

Other than that it seems ok.

The fault happens quite instant. Bring the throttle up to 2700rpm and it gives one cough and over fuels and starts to hold back slightly, bring the revs down slightly to about 2400rpm and it smooths out and starts to run nice. Its quite hard to hold a steady fast idle speed for the MOT.

The gas readings and the live data all indicate the system runs rich when the fault is present, you would think the lambda sensor voltage would make the ECU back off the fuel.

Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above

Posted by Dave Hill <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2783' width='330' height='300' border=0 style='border:none;'> on March 9, 2009, 12:32 am, in reply to "VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above"

Ian

It is hard to help someone who already knows half of the answers, but on the other hand can't accept the question asked with good intention. We aren't allowed to ask what scan tool you use, or even suggest that you reset the adaptations?? Do you know more than you are letting on?

You seem to have half the answers you are after, but are not receptive to the answer you need!

maybe a change of tack is required???

Good luck out there!

Dave

Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on March 9, 2009, 11:46 pm, in reply to "Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above"

ok. Sorry if i came across like that. I said nothing about not asking what machine im using. I did reply with what machine i was using, and i only asked why that question was asked, not to have a go, but out of curiousity.

As for the adaption suggestion, im just trying to save people wasting their time by saying to me "have you reset the adaptions?", without suggesting what may have caused the ECU to adapt so far out. Check out the recent posting on the audi by chris, he clearly says he fixed any air leaks and cleaned throttle and reset the throttle, yet someone still posted a very short reply saying reset the throttle,

.

Im open to any suggestions that are backed up by a line of thinking.

Maybe you read my post wrong!

Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above

Posted by Mark Storey <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5564' width='330' height='300' border=0 style='border:none;'> on March 10, 2009, 8:45 am, in reply to "Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above"

Hi Ian,

Have you tried it with a vacuum gauge attached?

If you have not already done so, I would also have a look at the cambelt while you are there.I did one the other month and was shocked to find one of the idler pulleys in bits. Car ran fine though.
Hth
Mark

Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on March 10, 2009, 9:28 pm, in reply to "Re: VW Polo, 1.4 16v, X-reg, runs rich at around 2700rpm and above"
Ian Staples

Hiya Mark

I normally check the vac, you can tell a lot by looking at the manifold pressure, but now you've mentioned it i didnt as another garage has borrowed my gauges, i'll try and do it tomorrow.

Thats a good point about the cam timing, i had a corsa like that a couple of years ago, another garage had uprated the engine and replaced the cams and sprockets but couldnt get the emissions down and brought it to me, i told them to go back and check the timing, it was a fraction out.

Fixed #

Posted by Ian Staples on March 19, 2009, 11:16 pm, in reply to "VW Polo 1.4 16v 2000 (X) - Runs rich around 2700 rpm, CO 2%+ and HC 600 ppm #"
Message modified by board administrator March 20, 2009, 3:39 pm

Checked the cam timing, was amazed to see the tensioner for the belt between the 2 cams had lost its plastic outer, so i suggested i replace both the belts and all runners before i go any further, which i did. But that wasnt the main problem. The bits, of which there was 7 of them, had found their way below the crankshaft sprocket and wedged themselves between the back of the belt and the belt cover, bits of these plastic pieces were mashed into the cam belt teeth itself and the crankshaft had jumped 2 teeth, the cams were still timed together ok though. Replaced everything and set up correctly and emissions were instantly borderline, a good hard thrash got the cat clean and hot and the emissions came right down. How the hell did this not break, and how did it run so well with the crank 2 teeth out? Its all good fun.

Thanks all.

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