Mixture Problem On 1.9 Gti

[Guest cupra_matt]

Hi all.

 

You will be hearing alot more from in the future as i have bought my brothers 205 1.9 GTI as a second car.

 

Its a minter and runs really nice, but its running rich, i got it on gas tester at work and found the CO to be around 3.5 - abit too rich

 

I tried to adjust the mixture via the AFM and idle screw and it makes hardly any difference.

 

I have already replaced the following parts:

 

AFM

Dizzy Cap

Rotor Arm

HT Leads

Spark Plugs

Air filter

fuel filter

Oil filler cap (breather)

Cleaned out all the breather pipes

 

The car runs sweet.

 

Could it be the coolant temp sender, ( BLUE plug?)

 

Any advice would be appreciated.

 

Thanks

 

Matt

[j_turnell 137 3 Cars]

Yeh replace your ECU temp

[Guest cupra_matt]

I have checked a couple of things tonight on the pug.

 

Checked SAD, when i started it from cold i squeezed the pipe that goes back in near the throttle body and it nearly cut out, once warm i did the same and it made no difference, so its working? am i correct?

 

Whilst doing this i checked the ECU temp sender, (BLUE PLUG)

 

when stone cold i was getting a reading of around 2500 ohms and as it warmed up to operating temp it dropped to around 300 ohms, does this seem ok?

[paulh 0]

Whilst doing this i checked the ECU temp sender, (BLUE PLUG)

 

when stone cold i was getting a reading of around 2500 ohms and as it warmed up to operating temp it dropped to around 300 ohms, does this seem ok?

 

Wrote some figures down from doing a search on this subject a while ago.

20 deg c 2280 to 2700 ohms

60 deg c 600 to 700 ohms

80 deg c 290 to 370 ohms

100 deg c 180 to 220 ohms

 

Looks like your temp sender is not that far out. Are the connections onto the temp sender ok??

[Andrwn8304 0]

Try removing the anti tamper screw and adjust the co via the allen stud, if that fails it sounds like the needles are worn on the throttle body housing.

 

Whats the Hydrocarbons reading but I'm assuming youve set the ignition timing up as youve changed the Distributor.

Edited March 22, 2007 by Andrwn8304

[tom_m 0]

Try removing the anti tamper screw and adjust the co via the allen stud, if that fails it sounds like the needles are worn on the throttle body housing.

 

what's the Hydrocarbons reading but I'm assuming you've set the ignition timing up as you've changed the Distributor.

 

yeah, sounds like someone has been messing around with the mixture screw on the AFM

 

could it be a dodgy afm? in need of re tracking maybe?

[Guest cupra_matt]

Try removing the anti tamper screw and adjust the co via the allen stud, if that fails it sounds like the needles are worn on the throttle body housing.

 

Whats the Hydrocarbons reading but I'm assuming youve set the ignition timing up as youve changed the Distributor.

 

 

I haven't changed the dizzy, just the dizzy cap and rotor arm.

 

 

 

 

I have already removed the anti tamper thing from AFM, and tried to adjust it, but it makes very little difference.

 

If i completely removed the adjustment screw from the AFM hence giving it an air leak, the CO drops into spec, weird!

 

I have won a coolant temp sensor on ebay so gonna pop it in anyway.

 

I have had the throttle body of it and there is a pipe underneath on the throttle body with no hose connected, is this right?

Edited March 22, 2007 by cupra_matt

[Guest cupra_matt]

yeah, sounds like someone has been messing around with the mixture screw on the AFM

 

could it be a dodgy afm? in need of re tracking maybe?

 

 

The AFM is a couple of years old but has done less than a 1000 miles, what do you mean by re tracking?

 

Thanks and sorry for all the qustions, iam more used to VAG cars.

[Andrwn8304 0]

I haven't changed the dizzy, just the dizzy cap and rotor arm.

I have already removed the anti tamper thing from AFM, and tried to adjust it, but it makes very little difference.

 

If i completely removed the adjustment screw from the AFM hence giving it an air leak, the CO drops into spec, weird!

 

I have won a coolant temp sensor on ebay so gonna pop it in anyway.

 

I have had the throttle body of it and there is a pipe underneath on the throttle body with no hose connected, is this right?

 

 

The small connector for the pipe is for the vacuum advance unit which goes on to the distributor vacuum advance.

 

Try adjusting the Air Bypass screw on the throttle body housing. Normally this is what is used to set the CO% up.

[Guest cupra_matt]

The small connector for the pipe is for the vacuum advance unit which goes on to the distributor vacuum advance.

 

Try adjusting the Air Bypass screw on the throttle body housing. Normally this is what is used to set the CO% up.

 

 

Air bypass screw, where is that, i know where the idle screw is but never knew there was another.

[Andrwn8304 0]

Gonna pm a a pic to you

[Guest cupra_matt]

Thanks for that mate,

 

Tried setting it up by the book but it wont drop below 2.5 CO, think its burning too much oil causing the mixture to be out.

 

Time for a rebuild i think, gonna rebuild head and sticks some new piston rings and big end bearings in aswell for good measure.