335 m30 engine power loss

Wed Apr 23, 2008 12:37 am

This is only slight power loss 10-15 bhp on my butt dyno,

Its not there all the time it only happens when its hot, I don't mean red hot just anything over 1/4 temp

Its definetly not a missfire, it sort of changes the sound of the revs and drops loads of power off

It feels like its restricted by the exhaust (cant be this as its not always there) or its geting to much or not enough fuel

I have a feeling that it could be the blue ETC sensor, does this sound feasable?

Would the tappets being slightly tighter than recomendations cause this? I have them set at 0.28mm instead of 0.30 (according to autodata)

Wed Apr 23, 2008 1:26 am

E30drifto wrote: Its definetly not a missfire, it sort of changes the sound of the revs and drops loads of power off

It feels like its restricted by the exhaust (cant be this as its not always there) or its geting to much or not enough fuel

I have a feeling that it could be the blue ETC sensor, does this sound feasable?

Would the tappets being slightly tighter than recomendations cause this? I have them set at 0.28mm instead of 0.30 (according to autodata)

The exhaust can't be totally ruled out, I had an Escort brought to me a while back with severe lack of power, then it would backfire and be ok for a while.
The backfires turned out to occur when a load of silencer wadding blew out of the tailpipe! A new rear silencer fixed it.

A temperature sensor is feasable if it only happens when warm, and it's probably where I'd start looking.

I have run M30 engines at 0.25mm valve clearances and not noticed any difference so yours should be fine.

Wed Apr 23, 2008 7:10 pm

Thanks,

Well Ive got a supersprint centre section and at the moment straight pipes out the back, so don't
think its the exhaust!!
But I will try and check the baffles.

So the clearences should be fine,good.

Ive just changed the sensor, I'll take it for a spin in a bit, fingers crossed

Wed Apr 23, 2008 7:19 pm

I wouldn't waste time checking that exhaust, that would be highly unusual!

Thu Apr 24, 2008 12:58 am

Had a test drive but its still the same

not sure were to go from here!

Ive got a chip fitted from speedtouch im wondering if that has adapted wrongly,

another one is I have a cone filter (with cold air feed) fitted could I feel the powerloss that would give from the exhaust mani?

an then the choices are TPS, AFM or Its losing compression (unlikely as I have had the head off recently due to a couple of snapped rockers)

Its really bugging me

Thu Apr 24, 2008 1:12 am

Ooh, the plot thickens!

You didn't fit the chip backwards, did you?

They do fit the wrong way.

I've had a K&N cone on my M30 and I'm now running a standard M30 air box and element. You wouldn't notice the difference.

Camshaft timing a tooth out?
Knocks the power down noticeably, I know because I got mine a tooth out once!

If no to all the above I would investigate the electrical stuff myself, could also be the coil ? Spark plugs very old ?