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18/10/2004 09:42:58   Steve B   V4 fans,
I don't know about other drivers, but sometimes I like to drive my 96 fast, especially round the corners :)
One of my regular routes involves a roundabout which I turn right at. On a clear day I take this turn at about 25mph, but as I exit the roundabout the engine sometimes dies.
Any idea what's causing this. It's happened several times now ?  
18/10/2004 10:21:36   paul   Hi steve,
Could be starvation of some kind, is the oil pressure light on before the engine stops? My best guess would be fuel starvation either at the tank or the float bowl caused by the centripetal forces as you go arround the corner forcing the fuel away from the tank outlet or the fuel jet? does it happen when youve got a full tank of fuel, or only when youre scraping the barrell, if it only happens when the tanks near empty then its probably the fuel tank, which can be helped by fitting a tank with baffles in.
Im guessing youre on the throttle as you exit which would make this problem worse as the fuel demand increases...
18/10/2004 12:27:37   Richard   I would check the carb float level, if its set too low you will have next to no fuel in the float chamber  
18/10/2004 13:12:42   steve h   In 15 years of fast exits to roundabouts with various v4s and carb set ups I have never had this problem so would not say its an inherent v4 problem. I suspect its either your float as richard says, or fuel pump if the car dies as you try and get the power on, or some weird electrical problem to do with something shorting when its thrown sideways. This would not be obvious unless you were under the bonnet while high speed cornering!
The only thing I have had that is similar is when my fuel pump was on its way out and the car would die if pointing up a hill but was fine going backwards up a hill. (Lifting fuel from the fuel tank problem)
Tricky one. It's a take apart, put back together and try again type problem.  
18/10/2004 16:49:39   Richard   Yes Steve it sounds like a lack of fuel. The pump could have a damaged diaphragm and not be supplying enough fuel.
Blow the fuel line back and replace any rubber fuel hose that looks like it may be on its way out.  
19/10/2004 17:55:32   paul   Surely if the float was set too low the mixture would be running lean? I would hve thought a dodgey fuel pump would result in fuel starvation under throttle in any conditions, including cornering...  
19/10/2004 18:47:26   ian   we always have this problem on autotests turning just bogs out then picks up....we are looking into fuel level in carb or pick up in tank...would not have thought it was pump...  
20/10/2004 07:50:09   Richard   Float level is nothing to do with how lean a carb runs. If its set low the fuel level in the carb will be low, therefore when turning or going up hills the fuel will go to one side in the carb and the jets will not get any fuel.
I have never had a problem when cornering fast in a Saab apart from keeping all the wheels on the ground.  
20/10/2004 08:49:10   paul   Im a bit confused now, surely a fixed venturi carb draws fuel from the bowl depending on the pressure felt at the fuel outlet/spray bar etc... If the fuel level is low in the float, then a greater venturi depression (more throttle) is required to flow the same amount of fuel due to the fact that the head of fuel above the float level is greater. This would mean you need more air flow for a ceratin amount of fuel,therefore leaner...  
21/10/2004 07:51:25   Richard   You have a lot of vacuum in the venturi area of the carb, so this is not a problem. The mixture is controlled by the jet/choke combination (fuel/air). The bigger the choke the larger the jet will need to be as the air velocity will be less, therefore the vacuum is less and you will have less pull on the jet.  
22/10/2004 13:17:02   steve h   Ian, you mean auto testing on V4s!  

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