Idling Issue So Far

[erbs 42 1 Cars]

Ok, this has what has been done since my last post

 

Miles goodhoody helped me sort a few bits

 

Tested and working, TPS,AFM

 

trying to get the engine to idle properly, discovered fuel regulator was not holding 3 bar, replaced that.

 

Had the injectors cleaned,now working at full capacity.

 

Got the dizzy set up for ignition timing spot on.

 

Everything has been cleaned prior to engine rebuild.

 

Idle can sometimes sit at 1100 and sometimes hunt and stall

 

I'm going to take the AFM off and give it a good clean to see if that makes a difference, if that makes no difference, what else should I try?

 

Also it makes no difference when adjusting mixture on the AFM for CO although we have tested to see if working OK and it is

Edited February 25, 2016 by erbs

[Anthony 1,003]

When you say that the AFM is "tested and working" - what exactly have you done and what have you adjusted the idle mixture to?

[erbs 42 1 Cars]

Put a multimeter on and tested the afm and opening and shutting the flap and seeing what readings they give. All come back as per what I have seen in other threads on testing afm

[hoodygoodwood 71 3 Cars]

Multi meter on TPS shows its working perfectly , AFM readings are all within the Haynes manual tolerances .TPS 'clicks' in correct place .

Gunsons exhaust gas analyser showed CO at about 3.5% and adjusting the screw on AFM all the way in or out hardly changed the reading . We pressure tested the fuel rail/injectors and found the faulty fuel pressure regulator , changed it for a used spare and it now releases pressure at 3 bar ( instead of about 1 bar ). Tickover was then more stable and could be adjusted down to about 1000 rpm without it stalling after revving . CO reading was still around 3.5 % and adjusting the screw did nothing .Will check the Gunsons meter on one of my cars to make sure its working ok as its not the most robust bit of kit .

[Anthony 1,003]

If the CO really is around 3.5% then I'm not surprised it's not idling - whilst it might scrape through an MOT like that, it really needs to be nearer 1% to idle properly and not suffer with hunting.

 

If winding the adjustment out (anti-clockwise) on the AFM wasn't bringing the CO down then there's something amiss.

[erbs 42 1 Cars]

I will clean the AFM today and see if that makes a difference

[erbs 42 1 Cars]

UPDATE!!

 

Gave the AFM a thoroughly good clean in my parts washer, used compressed air to clear any crap out

 

put it back on the car, still ticksover at 1100 and sounds like it hunts a little

 

should i try another AFM???

[welshpug 1,661]

yes.

 

Preferably a remanufactured one.

[erbs 42 1 Cars]

so what could possibly cause the high idle on the afm? what part of the afm controls this???

 

dont want to spend a lot of money and make no difference when i get it back

[hoodygoodwood 71 3 Cars]

Its impossible to know if someone has messed with the flap tension spring on the AFM which would affect the mixture . Jamie said the car originally had a 1.9 AFM fitted so he sourced a correct 1.6 item . We checked the ECU is the correct Bosch number for a 1.6 GTI - is there a different ECU for 105 / 115 BHP engine types .

[hoodygoodwood 71 3 Cars]

There is an air temp sensor in the AFM and the movement of the air flap . We checked the readings with a Sykes Pickavant multimeter and they were all within the Haynes readings . Could be a wiring fault between sensor and ECU .

[erbs 42 1 Cars]

ok, got a new temp sensor(bosch) the one in the car is a grey coloured sensor,not sure what make, but i would imagine it pays to have the bosch one in there.

 

will come back tommorrow and let you know the results

 

would the aftermarket one have different values?

 

because the car runs fine when driving,just tickover is a bit naff

Edited February 26, 2016 by erbs

[erbs 42 1 Cars]

Put in the new bosch temp sensor, does not hunt anymore

 

i tested the old sensor and the got reading in K ohms from around 2500 and tested in hot water the values went down,i thought they went up when heated ???

[Anthony 1,003]

Hotter equals lower resistance as you've found.

[erbs 42 1 Cars]

it runs better, doubt if i will ever get it to tickover at 950 rpm with conviction, not sure what else i can do really, everything has been cleaned, only thing is the loom or ecu that can be checked

 

the old sensor was not a bosch part so using a genuine part make a difference?

 

The old part worked

Edited February 27, 2016 by erbs

[welshpug 1,661]

turn the throttle stop or air screw in, get it back on the emissions tester.

[erbs 42 1 Cars]

Ok will do that next week, the tappets need shimming as they are a little errrr? Tappety, would this have an effect in the idle?

[Capa 0]

Thought about the air lines going to & from the SAD? I'd have my doubts, but you've done most of the major things...