Few CQ20v Questions.

[kieronholden]

Hi guys, im new here and ive just aquired a great 91 year Coupe Quattro 20V.

I have a few small concerns, first of all a small "tick" from the engine, only during acceleration. Its a progressive tick, as in the more I press the pedal, the louder the tick, not correlated to engine speed, only load/ throttle opening.

Its deffinately not from the head, or from the block, so it shoudlnt be too serious a problem, engine runs smooth and free. I have a feeling it could be a crack in the exhaust manifold, as when i have looked around the engine bay when running there is a faint odour of exhaust fumes, and sometimes in the cabin after sitting in traffic.

Or perhaps it could also be the distributor drive gear, ive heard these are prone to failing and wear due to being made of nylon.

Also, when driving around slowly, ie below 2000rpm, if i accelerate, sometimes a wooshing sound can be heard, and it only does this at slow road and engine speeds. Does the engine have a dual throttle butterfly or is someting else causing this.

My questions are, first how far off are my diagnosis, given the info i have provided.

Im a fairly competent mechanic, my hands are normally dirty from working with aircraft engines as my day job.

So, any heads up or information would be great.

Thanks, Kieron.

 

[shineydave]

great choice of car there, i had one a while back. not had the sounds you describe on mine, strange, could it be a valve ticking away?

it's relatively easy to make a simple fault code reader that will also allow you to run some basic output tests, you might be able to recreate the noise by testing the various solenoids and valves

have a look here, it may help you
http://20v.org/engprob.htm#faultcodes

 

[kieronholden]

Thanks for the reply Dave, im fairly sure its not a valvetrain issue, as i said the noise only varies with throttle opening and not engine speed. Everything is quiet at tick-over, even if you accelerate the car and let it run down from 6000 revs back to idle theres no noise.

Thanks for the input again.
Kieron.

 

[shineydave]

yup, i didn't mean an inlet or exhaust valve i meant a solenoid valve, there's a couple on the emission control side of things attached to the charcoal filter. might even be the idle stabalisation valve, think they had either a hitachi or a bosch, one was more problematic than the other but i can't remember which was good or bad, don't think it's the dizzy drive, mine just whirred a bit but never ticked