MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Technical Workshop => Topic started by: sixpot on February 12, 2009, 07:44:04 pm

Title: Erratic idle
Post by: sixpot on February 12, 2009, 07:44:04 pm
I have noticed the revs hunting when idling recently, the car also seems jerky when coming off the gas at part throttle, do you think there is something amiss?
Title: Re: Erratic idle
Post by: billyboy on February 12, 2009, 07:53:32 pm
summits not right there lar,
hope ya get it sorted lee, keep us posted
bill
Title: Re: Erratic idle
Post by: tony_danza on February 12, 2009, 08:51:56 pm
Could be the MAF on its way out? pull the plug to it and see if it runs any different?
Title: Re: Erratic idle
Post by: john_o on February 12, 2009, 08:55:57 pm
worth a check for air leaks etc.
However mine does 'hunt' occasionally and the effect is made worse by what I believe to be cr*p engine mounts with too much play!
Did it do it before? If not then somethings changed of course
Title: Re: Erratic idle
Post by: sixpot on February 13, 2009, 07:10:54 am
My first initial thoughts were maybe the throttle body needs aligning, which is easy enough to sort with a battery disconnection.
I may also take the MAF off and clean the element with some carb cleaner, and I'll also check the diverter valve for any obvious rips/tears etc. Other things I've considered are a faulty lambda sensor (but surely this would illuminate a dash light?)
Are the MAF's still prone to fail like the older VAG ones?
Either way I think I'll get a code scan done and see if anything is thrown up.
Title: Re: Erratic idle
Post by: vRStu on February 13, 2009, 07:14:55 am
nooooooooooooooo - Don't clean the MAF.  Bite the bullet and order a new one if you think that is the problem.  It's not so much about being prone to fail like the old ones but the fact that it should really be a service item,  it monitors every bit of air coming into your car so it's pretty much in the firing line all it's life.
Title: Re: Erratic idle
Post by: 182_blue on February 13, 2009, 08:01:27 am
Have you vag com'd it, someone may be able to help, what area you in
Title: Re: Erratic idle
Post by: sixpot on February 13, 2009, 11:17:17 am
Have you vag com'd it, someone may be able to help, what area you in

I don't have VAG COM myself. I'm in Warrington, Cheshire.
Title: Re: Erratic idle
Post by: CocoPops on February 13, 2009, 02:13:10 pm
I'm in Chester next week with work, so will bring my vagcom cable with me.

PM me next monday.
Title: Re: Erratic idle
Post by: Norbreck21a on February 13, 2009, 10:39:51 pm
Sixpot,

I work in Warrington, If you can pop down one luchtime, I'll happily do a scan for you ?

let me know.

Cheers
Andrew
Title: Re: Erratic idle
Post by: sixpot on February 14, 2009, 09:04:02 am
Sixpot,

I work in Warrington, If you can pop down one luchtime, I'll happily do a scan for you ?

let me know.

Cheers
Andrew

That would be great, as I'm working late shift next week, so I could do that at lunchtime.
I'll fire a PM over.

Cheers
Lee
Title: Re: Erratic idle
Post by: Norbreck21a on February 15, 2009, 12:17:05 am
No sweat sixpot, I work in Birchwood just off the junction for the M62. I'm not in the office until Wednesday, but any time from then onwards suits me. Send me a PM as you said and I will give you my details.

PS if you have one, bring a memory stick with you so that the scan can be saved onto it for your records.
Title: Re: Erratic idle
Post by: sixpot on February 15, 2009, 08:31:48 am
No sweat sixpot, I work in Birchwood just off the junction for the M62. I'm not in the office until Wednesday, but any time from then onwards suits me. Send me a PM as you said and I will give you my details.

PS if you have one, bring a memory stick with you so that the scan can be saved onto it for your records.

OK, that suits me fine. Cheers.
Title: Re: Erratic idle
Post by: billyboy on February 15, 2009, 09:02:35 am
WOW lee
great, carnt get fairer than that,
lets know wots been found.
bill
Title: Re: Erratic idle
Post by: sixpot on February 15, 2009, 07:50:32 pm
WOW lee
great, carnt get fairer than that,
lets know wots been found.
bill
I did a throttle body alignment today, so we'll see how she runs tomorrow. Yep thats the beauty of forums, there is always someone willing to help you out. I will keep everyone informed of the outcome. Cheers.
Title: Re: Erratic idle
Post by: sixpot on February 16, 2009, 11:22:34 am
Update: After unplugging the air mass meter (MAF) the car ran instantly better, with a constant tickover, and no jerkiness coming off part-throttle, so it looks like this could be the problem! quoted £79.41 for a genuine replacement with my discount.
Although I might try cleaning it with carb cleaner spray first and see what happens.
Title: Re: Erratic idle
Post by: sixpot on February 18, 2009, 05:07:32 pm
The MAF is pretty much a sealed unit now on these cars, so I wasn't holding out much for cleaning, and sure enough it did not work!
So I've replaced it and the car is running fine now.  8)
Thanks for the offers of a VAG COM scan to everyone that offered.
Title: Re: Erratic idle
Post by: bacillus on February 18, 2009, 07:34:54 pm
Glad to hear a bit of good news.   :happy2:
Title: Re: Erratic idle
Post by: tony_danza on February 18, 2009, 08:16:12 pm
MAF? Bingo - as someone said they should be replaced as a matter of routine every few years, they cause no end of annoying issues and don't always throw codes to give a hint.

Glad to hear it's cool.
Title: Re: Erratic idle
Post by: Norbreck21a on February 18, 2009, 08:36:07 pm
Glad you got it sorted  :happy2:
Title: Re: Erratic idle
Post by: john_o on February 18, 2009, 08:38:13 pm
yeah good to hear you got it sorted and reported back  :happy2:
Title: Re: Erratic idle
Post by: bacillus on February 18, 2009, 09:31:19 pm
MAF? Bingo - as someone said they should be replaced as a matter of routine every few years, they cause no end of annoying issues and don't always throw codes to give a hint.

Glad to hear it's cool.

Checking your fuel trim with vcds could give an indication if your maf is on its way out especially if there's no cel.

http://wiki.ross-tech.com/index.php/Fuel_Trim_Info
Title: Re: Erratic idle
Post by: illyun on February 23, 2009, 11:33:14 pm
Interesting... mines booked in at JKM this Friday with the same problem... will let you know how it goes.  The VCDS shows lean fuel at idle ...
Title: Re: Erratic idle
Post by: bacillus on February 24, 2009, 09:26:35 am
Interesting... mines booked in at JKM this Friday with the same problem... will let you know how it goes.  The VCDS shows lean fuel at idle ...
You mean you are seeing a positive percentage in the first value?  My value is -0.4%
Title: Re: Erratic idle
Post by: illyun on February 24, 2009, 12:27:31 pm
Interesting... mines booked in at JKM this Friday with the same problem... will let you know how it goes.  The VCDS shows lean fuel at idle ...
You mean you are seeing a positive percentage in the first value?  My value is -0.4%

Not sure what you mean as I'm a bit clueless but this is my readout :grin: :grin: :grin:

004506 - Fuel Pressure Sensor (G247): Malfunction
               P119A - 001 - Upper Limit Exceeded
             Freeze Frame:
                    Fault Status: 01100001
                    Fault Priority: 2
                    Fault Frequency: 2
                    Mileage: 44781 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 00:12:18

             Freeze Frame:
                    RPM: 891 /min
                    Load: 14.1 %
                    Speed: 6.0 km/h
                    Temperature: 84.0°C
                    Temperature: 45.0°C
                    Absolute Pres.: 1000.0 mbar
                    Voltage: 13.716 V

001287 - Idle Control System RPM: Higher than Expected.
               P0507 - 001 - Upper Limit Exceeded
             Freeze Frame:
                    Fault Status: 01100001
                    Fault Priority: 2
                    Fault Frequency: 2
                    Mileage: 44781 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 00:18:15

             Freeze Frame:
                    RPM: 964 /min
                    Load: 14.9 %
                    Speed: 0.0 km/h
                    Temperature: 84.0°C
                    Temperature: 13.0°C
                    Absolute Pres.: 1000.0 mbar
                    Voltage: 14.351 V

008583 - Bank 1; System too Lean at Idle
               P2187 - 004 - No Signal/Communication - MIL ON
             Freeze Frame:
                    Fault Status: 11100100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 44781 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 00:13:03

             Freeze Frame:
                    RPM: 838 /min
                    Load: 14.9 %
                    Speed: 0.0 km/h
                    Temperature: 90.0°C
                    Temperature: 31.0°C
                    Absolute Pres.: 1000.0 mbar
                    Voltage: 13.970 V


Readiness: 0000 0000
Saturday,31,January,2009,03:16:51:01199
VCDS Version: Release 805.2
Data version: 20090111

Title: Re: Erratic idle
Post by: bacillus on February 24, 2009, 02:45:02 pm
Ah, I see where you are coming from. Hope you get it sorted.

btw VCDS version 805.3 is available for download.  :smiley: