Strange whine after setting valves on m20b25?

[GovR]

Hello zoners,

Looking for abit of help....


I set the the tappets according to the wiki guide to 0.25mm on a cold engine today - however when I put everything back together - it started making a strange whining noise? Rev the car - whine goes louder?

It also wont stay running without giving it some fuel? What could be wrong?

Ive replaced the pipe from the rocket cover to inlet manifold with a new one when I shot blasted my rocker and inlet manifold - so it cant be the pipe?

Any other pointers? Have i set them wrong?

Cheers

Gov

[badassyas]

Were the tappets previously way off adjustement? If they were then maybe a previous owner may have set the co and/or butterfly flap to compensate?

[GovR]

It was very 'tappy' before so they must of been off adjustment - after setting them they went quiet but i got a whistle/whine noise in return?

Apologise for my ignorance but what is the co / butterfly flap?

[badassyas]

The butterfly is the flap inside the throttle body. If someone's played with it previously as it has an adjustment screw to open or close it.
The co is also an adjustable allen key in the air flow meter. To set air/fuel mixture.

I would re check the gaps though first... Too tight and it will keep the valves open which cause it to cut out.
In regards to a whine, god knows...
Also, check that your throttle position sensor. If it's a manual 6 cylinder engine there are three maps. One when the car is meant to idle, it'll have a idle map. Then a part load map after idle. And when the butterfly is fully open (foot to the floor) a wot map. (wide open throttle) from the engine bay with the car not running, open the throttle up, as if your accelerating and then close it. When your near close you should here a very faint click. That is your idle map engaged. Do a search there are loads of references of which pins to check with a multimeter. And what values they are meant to be. This throttle position sensor is located under the throttle body.

[johnl320]

Whistle is probably an air leak, recheck your hoses

[GovR]

badassyas nice one for that!! Il have a look at the throttle body in the morning.

One thing wierd is that the car will not start with the the fuel pedal slightly pressed - it needs a constant 'flick' of the throttle to get it started, but I assumed this is because of the 1 smoked injector ive got in there (new ones ordered - just taking the mick turning up) but as you mentioned about the maps it could be related.

Thanks johnl320 for the pointer but Ive replaced the hose from the rocker cover to the throttle body with a new one. Which other hose should i check?

Cheers for the help guys!

[johnl320]

Might sound odd but is the Oil filler cap on properly? The engine breather system can actually draw air in through the open filler hole and into the inlet manifold giving you a weak mixture.
Check the main pipe from the throttle body to the AFM check the hoses around the Idle control valve.
Check the pipe going to the brake servo.
Check the thin pipe going to the fuel pressure regulator.

HTH
john

[GovR]

The oil caps on fine. It just sounds like a fan belt noise but from the inside of the engine near the inlet manifold.

Ill check everything over in the morning though.

Thanks guys.

[Ajsingh]

I had the same problem once... Turned out to be the 10mm bolts for the bracket into the inlet were not tight enough causing an air leak (bracket from rocker cover to inlet manifold)