Engine Running Problem

[bad_boy_nova]

Right, my engine is really really p*ssin me off! (Its a Nova GTE Engine) It was runnin sh*t, so i took it to the local rolling road. They rolling road tuned it and found out that it was running bad because the mixture was so lean, it would barely idle. After they set it all up, it ran mint! Then about a week later, it went sh*t again. They also said that the Air Flow Meter was faulty. So i got another Air Flow Meter and took it back and they set it up with this Air Flow Meter on it and it ran mint again, but only for about a week. I took my car for its MOT yesterday and when they did the emissions test, they said that it was basically fresh air that was coming from the exhaust because the mixture was so lean. The car seems to run ok through the rest of the rev range, its just at idle. Does anyone know what this could be? Sorry for the long story. Cheers

[peester]

.. I took my car for its MOT yesterday and when they did the emissions test, they said that it was basically fresh air that was coming from the exhaust because the mixture was so lean... .

thats gotta be a first. fresh air. youll be a millionnaire. take it to inventors r us or something.
my gsi suffers the same, shite idle fine wen moving. my links are thinking its the crank sensor. i think i should go and crank them one. I'll try to join you in your quest if i may.

[bad_boy_nova]

Yeah, feel free to join me in this quest! Because i want to find out what it is a.s.a.p.!! My engines not going to last much longer if it carries on idling the way it is because the worse it idles, the more i put my foot down. Have you got a bosch jetronic air flow meter on your engine?

[peester]

yeah i believe it has. why you think thats the cause? ive still got a few mates on the hunt for a remedy my end. see what they come up with.

[bad_boy_nova]

The Bosch Jetronic Air Flow Meter is an Air Flow Meter and an ECU in one! At first i thought it was the Air Flow Meter because it was running bad, then when i took it to the tuning place, they took the top of the air flow meter off and adjusted this needle thing, so it made the mixture richer and then it ran fine for about a week, then went bad again. I then changed the air flow meter and it ran fine after a tune for about 2 weeks, but now its gone bad again, i dont know what it could be. I still say the air flow meter, because the second air flow meter that i bought, may also have a fault in it. Like i said, it only runs rough at idle.

[peester]

bastards, that must be annoying having moments of it fixed then coming back again. i would say if both did last a few days each, before going back to bad again something else is making AFM do this maybe. When i went to velos yesterday the chap told me to look at this cold air something or other... its attached to the cam cover, (above the head) its small, round-cone shaped thing. (a lot of people use it to grasp as they take the head off i think -it sticks out a bit)

one of my mates has just phoned with my other problem: the car inconsistantly performing. Velos said my knock sensor might be faulty; i don't think ive got a knock sensor. My mate says it could be called a pre-ignition vacuum sensor. It takes the pee don't it? Nothing majorly wrong, just little tit bits. balls to it for one day.

[Aragorn]

there should be no need to take the cover off the afm

the springs in there are setup to the exact specs for your engine

there is a mixture bypass screw on the side of the afm u can use to adjust the mix if its wrong

could also be the timing out or the idle speed setting on the throttle body

peester - gsi engiens dont have knock sensor - inconsitant performance is prolly an airleak of some description or the secondary air valve u mentioned sticking

[peester]

ok mate cheers. i'll chase that up at the weekend. weather permitting. Hope its not an air leak, sounds a bit of a needle in a haystack.

[bad_boy_nova]

Im going to have i fiddle with the idle speed screw on the side of the throttle body today when i get time and see if that does anything. Ive got a feeling that could be the problem

[Dicko]

if the rolling road set it up and it was ok then, still running ok now but somebody else says its very elan, maybe hole in exhaust? or leaky gasket

[bad_boy_nova]

Right, ive just turned the idle speed adjustment screw on the throttle body, 5 full turns anti-clockwise. It seems to be idling 100 percent better now! How long this will last, no one knows.

[Dicko]

dabble some paint using a touchup pen onto the screw!! or bang a load of gasket sealer on it!!

[bad_boy_nova]

Why??

[Dicko]

good chance the screw turns on its own

[bad_boy_nova]

Good idea! I will do that a.s.a.p.

[peester]

glad you've got yours sorted out mate for the time being. keep us posted if it comes back.
my performance inconsistancy problem is at the stage of vauxhall technicians still thinking mine does have a knock sensor, (but im just ignoring them now.) and velos saying it could also be the crank sensor. like aaragon said earlier i'll be checking the secondary air valve thing @ the weekend also as reguards to my cold idle problem.

[bad_boy_nova]

Its defonately the idle control screw on the throttle body, because i took note of what position the screw was in after i adjusted it yesterday and ive just looked at it today and it has turned by 90 degrees. I will have to adjust it right and put a blob of paint on it as dicko suggested.

[Aragorn]

crank sensor?!

the E16SE didnt have one and im pretty sure the C16SE didnt either - cranksensor is a 16v thing none of the 8v's have it

[peester]

although its kinda good to hear i haven't got as many sensors as i thought, the annoying thing is the different responces im getting from people. at least its narrowing down the possibilities. like i sed ill check all this out at weekend.

[rikih]

just got a nova gte , yeh i do no what all you lot mean by the weird tickover... it almost sounds like the car is running on 3 cylinders when its really cold! is the bosch airflow meter the thing that the induction kit goes onto? i have only had it a week! also can any one tell me some friendly engine mods that wont make the car run complete sh*t?
cheers

[peester]

well since then mate rikaaayyy, velos told me to check out the secondary air somethingorother on cam cover, cone shaped with a plug on the end; this opens when cold to allow more air through, these can block or partially open in turn suffocating the engine on cold so idles naff. haynes manual tells you a test to can perform to see if thats working. i haven't tried mine yet but will soon.