15 replies to this topic

[bert998]

Model:
Year:
Description of problem (please be as in depth as possible):

On motorway journeys the car is losing power. Car is fine around town and when first joining the motorway car flies along. However after a couple of minutes 'spirited driving' the car starts losing power and has to be backed off and pootled along at 50-60mph. A couple of minutes and we are back to square one, foot down then feels like its being strangled again.



Any non-standard parts that might be involved with the problem?

Engine is a 1330, 3k since nut and bolt rebuild with aftermarket cam (not sure whether its a 266 or 276 off the top of my head), stg 2 head, roller rockers. Running aldon dizzy, vac sealed off (if that matters).

Car was rolling roaded last summer for this reason. All seemed good, however I dont think the tuner pushed the car long enough for the problem to arise. Not their fault I know! They changed the needle and plugs and altered the fueling. Car ran better on the way home but only had it on the motorway recently and problem still there.

This is my bro's car, not my own. Any ideas as to where the problem might be?

[Saxo-Fiesta-Mini]

what stat and rad you got sounds like the engines gettin too hot and affecting performance maybe try making the mixture richer as this will cool the engine more

[Ethel]

The lack of vac advance would seem relevant to part throttle cruising.

[bert998]

Engine temperature is fine. Car is fitted with 2 core rad and temperature doesn't budge.

The vacuum being blanked off is what is bugging me, but I know nothing of aldon dizzys (electrixkery is beyond me anyway!)

Hence the plea for help. Secretly planning on stealing this car for riv run.

[BLUE ITALIAN JOB]

might be worth getting the fuel pump checked out , maybe ok for town driving but not pumping enough for long motorway stints , also the pickup pipe in the tank has a mesh filter and can sometimes get clogged , has also been known for the fuel hose to colaps and starve the pump/carb on long high speed runs .

[twiggy]

Mine was doing just the same thing; flat out at 50/60. I just took it easy for a while until one day the rad went pop and head gasket went pop

[bert998]

Interesting point about the filter in the tank, i hadnt thought of that one

[Dan]

I was thinking the problem may be down to fuel supply as well. You haven't said but I assume it's a carb'd car. Sounds like the fuel flow isn't keeping up with demand at high speed and the level in the float is dropping. What fuel pump is it using?

[bert998]

Its running a hif44, im uncertain on the fuel pump as its not my car. I will go round his later and investigate further.

Edited by bert998, 15 April 2009 - 10:46 AM.

[sazal]

Ive been having a similar sounding problem. If im doing motorway driving at a constant speed of about 60, then I get a really bad flat spot and she doesnt want to go. I was told it was the carb icing up cause I have a pancake filter

[twiggy]

Ive been having a similar sounding problem. If im doing motorway driving at a constant speed of about 60, then I get a really bad flat spot and she doesnt want to go. I was told it was the carb icing up cause I have a pancake filter

Mine was head gasket blowing between middle two and exhaust gasket had had it too.

[pogie]

Ive been having a similar sounding problem. If im doing motorway driving at a constant speed of about 60, then I get a really bad flat spot and she doesnt want to go. I was told it was the carb icing up cause I have a pancake filter

Carb icing was my thought when I read the first post as I had a the same symptoms on an Alfasud on a cold foggy day on the A1, but even on the coldest days I’ve never had a problem with the Mini which has a K&N cone filter.

In the Alfa I pulled over and took the top off the air filter and I could see the ice in the carb slowly melting. The warm air duct from the exhaust shroud had come off its mounting and the engine was drawing cold air from behind the front grill, I reattached the duct and everything was fine and dandy once again.

[bert998]

But would carb icing occur in mild weather?

[Dan]

A carburettor is essentially a refrigerator, it can ice up in fairly warm weather if it's not in a well designed system. It's rare though and what a lot of people think is carb icing is actually fuel condensing in the manifold (because they've fitted an alloy inlet and read somewhere that connecting up the heating is a bad thing).

[Jack_Pot]

Hi all, im bert's brother and the owner of the car in question. I believe the fuel pump to be the original one on the engine, it is a mechanical pump. I suspect this may be the problem and am looking at replacements. Could anyone recommend an ideal replacement?
Just to add i took the mini out on sunday and the problem seemed to be replicated even when cruising about 65/70mph when going up any slight inclines, hadnt really noticed this before, just thought i'd mention it.