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loss of power when engine warmed up-distributor fault
Posted: Mon May 20, 2013 9:47 am
by vanzep
Got a problem with loss of power on my BB4 once its reached normal operating temp. Was out on Saturday at the workshop and it was running well - plenty of power - got back into town and went to pull away from the traffic lights and there was nothing there - well just enough to creep along. Managed to get back home left it 10 mins went back and it starts up and idles perfect but once its warmed up it feels like no power at all. No rise in revs so cant be clutch can it. I feel it wants to catch so im thinking it must be spark or fuel. Any suggestions on what could cause this
best way i can describe it - there is a change in the exhaust note and it feels.sounds like its running on 3 cylinders
Posted: Mon May 20, 2013 11:39 am
by Lude-dude
checked plug area?
my old leads used to keep popping off the spark plug, leaving me running on 3 cylinders
Posted: Mon May 20, 2013 11:54 am
by NafemanNathan
You haven't tinkered with your valve clearances recently have you?
Posted: Mon May 20, 2013 12:08 pm
by BMCC
Is the catalytic convertor still on the car?
Posted: Mon May 20, 2013 12:18 pm
by vanzep
valve clearances were done about 12 months ago
no cat on the car as it got the hytec rep manifold and 2.5" straight thru
leads are on fine - but going to check spark plugs today
could it be main relay on its way out - would explain why it starts fine but not working fully once warmed up

Posted: Mon May 20, 2013 12:27 pm
by NafemanNathan
I suggested valve clearances as I've had those symptons before and they had worked themselves loose and slacked off. Unlikely though after 12 months.
Unlikely to be your mains relay. It's not being able to start the car when warm which is caused by cracked solders in the mains relay.
It could be your FITV is letting in too much air.
Posted: Mon May 20, 2013 12:29 pm
by Merlin
When my main relay was faulty the car ran fine, apart from when trying to start when hot. Do you want to try my spark plug leads to see if that makes any difference? The set on the track car are old but work fine.
If it was FITV would that show itself though affected idle?
Posted: Mon May 20, 2013 12:36 pm
by NafemanNathan
Merlin wrote:If it was FITV would that show itself though affected idle?
Yeah true. My thinking was that the A/F ratio was out, so what could be causing it. If there was too much fuel, you'd be able to smell it, plus it wouldn't start up too well after it was hot, so could it be under-fueling/over air-ing
It wouldn't necessarily hunt, but no it would be revving faster.
Posted: Mon May 20, 2013 12:37 pm
by vanzep
yep idle is fine as is start up - just when u put the foot down its feels like a big sponge
i might try the ht leads - are they at the workshop?
nafe - it could be a fuelling issue of some sort...and the car has a tendency to run rich anyway-hence the flames on overun when its been right up to the limiter
just a bick of fekin pain after its was running so well 5 minutes earlier

Posted: Mon May 20, 2013 12:42 pm
by NafemanNathan
It could be your coolant temp sender or thermo sensor is at fault. That'd cause the ECU to potentially over fuel when warm.