Trouble Restarting Engine After Stalling?

[Mackass]

Okay, usually if I stall the car, I'd keep the clutch down so the engine and wheels are disconnected, and I would switch the engine off, and restart the engine, no problems.

However, sometimes when I stall, follow the same procedure and restart the engine, the engine won't turn over i.e. it coughs but won't actually start. At which point I start to panick - as I would be holding up traffic, and I would instinctively put the car into neutral before restarting again and it usually works - it fails sometimes when I put it in neutral too. This is only when I stall, starting the engine normally has no problems.

So my question is, when I stall, can I restart the engine in any gear, providing that the clutch is depressed? If so, howcomes the engine doesn't start sometimes after I stall?

My car is a VW Golf 1.6 SE Mk4 if that helps.

 

[Mackass]

AS long as the clutch is in, gear doesnt matter one iota.

It could well be an engine management problem in the form of a failed sensor somewhere. Exactly how is it stalling? What kind of situations?

EDIT: Just re-read and I possibly misunderstood. Its not stalling itself, you are just driving it badly?

When I meant stalling, I meant as in releasing the clutch too fast or just rusty clutch control.

Sorry if I was unclear.

 

[Mackass]

Could be a variety of different things, has the car been serviced according to the proper schedule, it could be one of those problems that occurs because of a dirty air filter or the like. Otherwise it could be a couple of things, it could be the crank sensor as they sometimes act strangely when they get hot, it could be the ignition module, it could be a sticking idle stepper motor or it could be a faulty coolant temperature sensor.

As you can tell it can be a pain to track a problem like this down as there are loads of things that can cause it, if you’re feeling brave you could try changing the crank and coolant temperature sensors yourself as they shouldn’t be too expensive (then again it is a VW) or you could just ignore the problem and try not to stall the car, if however it is a sensor that’s going you might find that the problem gets worse and you won’t be able to start your car at all, but until that point just consider it a learning aid.

Cheers for that mate.

The cars been serviced every year on the dot, every six months for the first couple of years, and recently a couple of months ago. It could be either one of those I guess, but I lack the skills to perform such a thing like changing something, I'm actually scared to be honest. I guess I've just got to improve my clutch control then, I very rarely stall it anyways, but when I do, I'm just worried that something's not quite right. I'll keep an eye on it, and I'll see if my normal engine starts are effected in any ways.

Thanks again.

 

[Mackass]

Then its bad driving then

Go find yourself a private road or somewhere and practise take offs. Don t be scared to give it some accelerator while releasing the clutch. and take it out slowly

You will get the hang of it soon enough

Rofl.

Nah mate, stalling isn't really the problem for me, as I've pretty much mastered my clutch. I only stall perhaps once per week, and that's usually when in heavy traffic and when I'm using only the clutch to move me along - sometimes I release it past the catch point a bit quick you see. But other than that, normal take offs are no problem, just sometimes a lapse in concentration.

Not stalling it I can manage, I'm just worried as I think something may be broken, as it won't restart sometimes when it should do.

 

[Mackass]

You could try a simple test, next time you have been driving for more than 20 minutes and you reach your destination let the engine fall back to idle and turn the engine off, and then reasonably quickly turn it back on again. If it starts fine then I wouldn’t worry it’s probably just stalling that’s causing your engine trouble. If however it doesn’t start then you could have a problem, however because you can repeat the problem then you’re halfway to fixing it and a decent mechanic should be able to figure out if it’s fuel, air or lack of a spark that’s causing your problem.

I'm going to try that mate, I'll let you know what happens.

 

[Mackass]

I've not driven my car yet as I'm here doing a piece of coursework, but I thought I'd bump this to see if anyone else has any ideas if possible.

 

[Mackass]

Sounds normal to be honest, bit of excess fuel.

What doesnt sound normal is stalling once per week.

What causes the excess fuel if you don't mind me asking? Also, how does that prevent me from restarting the engine straight away, as I've managed to do this before, but now now. Could I get this fixed at a garage?

As for the stalling, I'm a new driver, and have only been driving for a few weeks, hence the occasional stall.

 

[Mackass]

The engine revs go up so extra fuel is added by the engine management ready for the higher engine speed and hence more fuel requirements, however your clutch control suddenly stalls the engine and this extra fuel doesnt get burnt.

When you come to start the engine again this extra fuel make it difficult for the mixture to ignite. Its taking a while to start as when your cranking the engine over the air is 'cleaning' the extra fuel out and then it can start.

Try opening the throttle a little when you start it to let more air in.

Thanks Simon.

So, before turning the ignition, I would press down on the gas a little, and keep it at that position until the engine turns over? If so, how far down do I need to press the pedal until the throttle opens enough for the extra air to get in? I would guess 2/3 inches, would that be enough?

Also, do you have any ideas why some cars can restart straight away without needing to 'remove' the excess fuel?

 

[Mackass]

I was gonna say.....my clutch is practically digital and operates an inch off the floor yet I don't stall it

My biting point is quite high up though, which makes it a little more tricky. But as I said, I've only been driving for a couple of weeks, over time I shouldn't stall.

 

[Mackass]

I'm just guessing at that theory, might not be right.

All depends on the car/engine/ecu. Personally I wouldn't worry about it and just try not to stall as much.

But will the theory work though?

i.e. will I be able to restart the car quicker this way by opening the throttle?

 

[Mackass]

It depends on what your pedal is like, 2-3 inches is likly to red line it.

You only need a few cm's

Did you mean two thirds of an inch?

Yeah, kinda the same amount of gas as I would use when moving off, which is around 1500RPM or so.

Sound about right?

 

[Mackass]

Only one way to find out.....

Will it do any harm?

Starting the engine with the throttle partially open?

 

[Mackass]

If it does im screwed as I do it when its wet, if I dont one of my belts slip.

Really dont think it would do any harm.

Alrite cheers mate.

First I'll make sure not to stall it anymore, secondly I'll try that method if I have one of those off days.

 

[Mackass]

This happened to me once, i got out from work started the car less then a minute later i had to slam on the anchor to avoid 2 chavs on bikes riding straight in front of me. I tried to restart the car imediately after it would turn over but not fire. i left it for a couple of minutes then started fine with a bit of throttle applied while starting.

thedazman

Imagine that happening in busy traffic.

 

[Mackass]

Firstly a fuel injected engine should not get flooded (excluding Mazda rotary engines), assuming you don’t stall in the first couple of minutes of driving on a cold engine it shouldn’t happen, and it definitely shouldn’t happen every time you stall, thedazman67 gives and example of when an engine will flood, a very harsh stop on a cold engine without using the clutch will flood an engine, stalling while pulling away shouldn’t.

If the problem has only started recently I think that also shows that something is amiss, it could just be that the engine is running rich, which would increase the chances of it flooding, have you worked out your fuel consumption recently? If it seems higher than it should be then this could be the source of your trouble.

You can usually tell when an engine has flooded by the characteristic sound it makes when you eventually start it, one cylinder at a time will begin to fire so the engine sounds like it is almost stuttering back into life.

Also starting an engine with the throttle pushed down or pumping the throttle can actually cause it to flood, if the engine is turning over without ignition occurring then opening the throttle will simply cause more fuel to be pumped into the engine. If, for example, you have no spark, holding the throttle down while cranking the engine for an extended period of time will increase the compression because of the excess fuel in the cylinder, which can lead to all sorts of trouble.

So I should really get this checked out then, as it's an indication of something not being right, if my engine shouldn't flood when it stalls. My fuel consumption hasn't really changed, I still get around 40MPG depending on how I drive it, so I don't think it's 'running rich'.

Once I manage to restart the engine, it sounds fine, there aren't any indications of the cylinders firing up one by one - if the engine does stutter or sound strange, I would definitely notice it, so maybe it hasn't flooded - but I do get a smell of petrol once I get out the car.

As for starting the engine with the throttle open, I actually done a little research and was going to question whether it will make the problem worse - sending more petrol into the engine.

Either way, I should be able to restart my engine instantly when I stall, as I've managed to do it before, so there's definitely something that's gone wrong then. I've got a three year warranty on my car, and this should be covered as a fault, so I'll get it checked out by a garage.

*Edit*

I sound as if I stall all the time, but I don't. It's easy to say don't stall and you won't encounter the problem, but the fact that there is a 'problem', I want to get it fixed.

 

[Mackass]

Yeah, if you've got manufacturer’s warranty use it, that's what it's there for. If the car isn't that old then it definitely shouldn't have this problem.

It's not a manufacturers warranty, it's an additional warranty which I purchased when I bought this vehicle - which is seven years old by the way. But thanks for the advice above.