I have a Hyundai Coupe which completely threw me this morning.
I find that if the car is slopeing to one side or the other, often if the petrol is below 1/3 full, then if the car is left for a while then it will not start. I put this down to petrol starvation due to the position of the tank and slope etc.
I jacked up the drivers side to make it flat and after the engine turned over for 30 seconds, and therefore pumped the petrol to the engine it started.
To start the car you have to depress the clutch so I was inside it. After starting I got out to remove the jack and was stunned. The OSF wheel was spinning ie guess 5 mph in first.
But the car was in neutral and stationary!. Obviously the NSF was on the ground and stationary. This made me stare in disbelief. I used my foot to stop the wheel spinning, but when I removed my foot the wheel imediately started to spin again. the car is of course front wheel drive.
I dropped the car and the wheel stopped with no noticeable change in engine note.
please explain.
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Explain? What a drag!
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Yes - if my bike is on its stand with the engine running, and in neutral, then the back wheel will begin to turn.
The engine drives the gearbox input shaft and the output shaft will rotate with it - as FT says it's dragged around.
There's no real power being transmitted - it's just enough to spin the wheel.
I still wouldn't want to get my fingers stuck in the rear sprocket though ...
:-)
(some people like to lubricate their chains this way)
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There's no real power being transmitted - it's just enough to spin the wheel. I still wouldn't want to get my fingers stuck in the rear sprocket though ... :-) (some people like to lubricate their chains this way)
What, with blood? There's quite a lot of energy stored in the "fly"wheel, so no, don't get things caught! I used to lubricate chains like that, sometimes...
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colynn
Perfectly normal; all cars do it. As FT alludes, it's just the oil drag in the gearbox spinning the cogs. This is a very weak effect and is only noticable if the wheel is free to spin.
I think you may be howling vertically at the incorrect deciduous with your non-start conclusion - at the very least, the fuel reaches the correct pressure in milliseconds after key-on. No cranking required.
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Thanks for the replies.
Q How can the oil in the gearbox being spinning when the car has not moved, and in neutral all the time. I am glad I am not an engineer too much for my brain to understand.
Q. Not the first time the car has not started when 1/3 fuel in the tank or lower, and car on a side slope. the last time, I pushed it 5 feet onto the flat, turned the engine and it fired after 20/30 seconds.
time before OSF on the pavement, pushed the car onto the road to make it flat, turned the engine and after 20/30 seconds it fires. therefore it seems like fuel drained out of the injectors. When on the slope the engine just turns over and does not try to fire .
any idea why if it is not fuel.
thanks
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Colynn, i'm going to hazard a wild guess here.
Could your fuel pickup in the tank have come loose/separated or similar, so maybe your pickup is an inch or so higher than it should be, hence you are getting symptoms of running out of fuel and have to level the vehicle (happens all the time delivering new vehicles esp vauxhalls)
Simple answer, keep the tank half full or so, or take out the sender unit/pick up and have a butchers.
Very usefull sometimes the transmission drag, if you want to check for wobbly wheels etc by having the wheels turning relatively safely.
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Q How can the oil in the gearbox being spinning when the car has not moved and in neutral all the time. I am glad I am not an engineer too much for my brain to understand.
I know as little as you about it. But then I thought our shared ignorance might help me describe it in terms we both understand! (Assuming of course that I have correctly understood the posts above)
One end of gearbox is shaft from engine, which will of course spin with engine revs.
Other end is shaft to wheels.
In neutral these are not connected together by any cogs, but the oil in the gear box will be spun by the engine shaft movement, and this motion will be transferred (very weakly) to the shaft to the wheels. So there's no solid connection, but some energy is transferred.
How's that experts? Am I barking up the wrong tree?
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>>How's that experts?
Tip Top!
There's more drag when the oil is cold and more viscous.
This is the same drag that's avoided by pressing your clutch in when cranking the engine over - when it's really cold, the engine speed during cranking will actually be affected by this source of drag.
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