Loss of Low Down Power

Post by **wanderinstar** » Wed Oct 11, 2006 9:19 pm

Is there a simple reason for loss of low down power, particularly when going up hills. Have to change down an extra gear now when going op hills.

Post by **bmcecosse** » Thu Oct 12, 2006 7:22 am

Look to your ignition timing perhaps ? Compression check to see if everything is ok inside the engine - is this when running on lpg ? If so - could be too rich (or too weak) - I don't really understand how the mixture is controlled across the engine speed range by the lpg system. If it's on lpg - does it run any better when on petrol ?

Post by **wanderinstar** » Thu Oct 12, 2006 8:50 pm

Yes Roy, I wondered if it might be timing. It does it on gas and petrol.
Thing is do I advance it or retard it?

Post by **bmcecosse** » Thu Oct 12, 2006 8:58 pm

Look to see if the mechanical or vacuum advance mechs have packed up ! Of course - maybe it's the h*a* g*s*e* starting to let go again !! Hope not.

Post by **wanderinstar** » Thu Oct 12, 2006 10:19 pm

Dont think it's the later, it's been like this for about a fortnight. Don't think it would have lasted so long. But which way do I go with timing?

Post by **rayofleamington** » Wed Oct 18, 2006 5:18 pm

Vacuum advance has nothing to do with power going up hills - it only advances the timing (for fuel economy) when you are off the gas pedal.

If the timing is ok, then it may be worthwhile to try a compression test

Post by **wanderinstar** » Thu Nov 02, 2006 5:58 pm

Finally got round to replacing timing chain. The amount of slack was unbelievable. Must have been 1/2 a tooth out. Fitted decent chain now along with Mini tensioner.
Also found that vacuum unit diaphragm was holed, possible another cause of loss of power and definatly low MPG.

Post by **bmcecosse** » Thu Nov 02, 2006 8:08 pm

If the vacuum unit has failed it then encourages the owner to set more static advance to get the car idling smoothly - this then is too much advance when running - can lead to pinking or even detonation - and I'm not sure if this would be easily detectable with lpg ? It also 'dulls' the engine - it is less responsive when moving from cruise (closed throttle with high vac) to open throttle with low vac. Normally - the vac advance would 'hang on' for a second keeping the engine nicely advanced as it picks up - often detectable as just a wee burst of pinking as you open the throttle. Without this vacuum advance - the engine is less sharp. And the hole in the diaphragm also allows a spot of extra air into the engine - insignificant when running, but important at idle - so again the owner compensates to get a decent idle by richening the mixture slightly - which leads to further loss of mpg !!