Has she got away with it?

#1
Right, I've been working away for the last couple of days and I got a phone call from my daughter yesterday to say that her car wouldn't start. She's not good at explaining stuff but I got the impression that the fault was with the starter motor, either being stuck or not getting power to it. Not being able to describe what a starter motor looked like, I suggested that she put the car in a low gear and rock the car backwards and forwards a few times to see if that released the starter motor. It ended up that she went back to the car, tried the ignition key one last time and, as luck would have it, it started so there was no need to do anything else.

Later in the day she had the same problem but somebody looked in the engine compartment, didn't touch anything and the car started again.

Same thing happened this morning - you get the gist.

Anyway, as she leaves work tonight, the car wouldn't start. So she sticks the car in 2nd gear, lets it roll backwards down a hill and flips the ignition on. (If you've been paying careful attention to the words, you'll have noticed that the technique is a little bit, shall we say, unusual).

The result was a loud bang beneath the bonnet and on looking inside the engine compartment she noticed (to use her words) that the engine had blown up with broken bits of engine lying all over the place.

After returning home, I went to have a look at this (now) heap of junk, expecting to find a gallon or so of oil coursing down the road. Instead, I find that the top of the air intake had blown off. I know it's the air intake because the top of the butterfly valve of the carburretor is clearly visible. The car's a Clio btw.

Piecing together the bits of information, I suspect that what happened was that the engine tried to run backwards and with the timing not being intended for such an action, the exhaust was sent through the air intake, the pressure being too much for the plastic housing.

So, Question 1. Is my assumption of events plausible?

Question 2. Is it likely that there's more damage hidden away as a result of the big bang? Something that could render her pride and joy BER?

Question 3. Would driving the car 4 miles from its present location to home without the top on the air intake cause further damage? Obviously, the carburettor would be sucking in air that hadn't been through the air filter but driven gently for a short distance...


If the responses are favourable, I'll disconnect, clean and reconnect the electrics to the starter motor and hopefully get the thing started, then it'll be a trip to the scrappy for a large bit of doubtlessly expensive plastic.
 
#5
Think about it. She could not run the car down hill backwards in 2nd gear. It just would not move, it is in a forward gear. She may have run it down hill with the clutch depressed in 2nd gear and let it out at the same time as turning the ignition, maybe. or even if she had it in reverse going down hill and turned the engine over the engine would still run the right way round. For the air filter to blow off there would have to be a large misfire with unburnt fuel building up. Even then for it to come off screws would have to be missing, If you can get the AA out or get it towed to be on the safe side to a garage. Then hold her by the sides of her upper arms and shake her for a minute or so that will help you.[video=youtube_share;39qdhbkTko4]http://youtu.be/39qdhbkTko4[/video]
 
#7
probably air fuel mixture was too much, when the engine fired up, the over pressure would have destroyed the plastic cover.

Check the cables and earth lead to the starter motor, might be corroded.

As described, with the ignition on, when she turns the key do all the dashboard lights go off? Also try starting with the lights on, see if the battery is ok, lights should remain bright when turning for ignition.

If they dim slightly then possibly either the starter motor, or the ignition cable from the barrel to the loom needs replacing
 
#8
I find that the top of the air intake had blown off. I know it's the air intake because the top of the butterfly valve of the carburretor is clearly visible. The car's a Clio btw.


Question 3. Would driving the car 4 miles from its present location to home without the top on the air intake cause further damage? Obviously, the carburettor would be sucking in air that hadn't been through the air filter but driven gently for a short distance...
I wouldn't worry about a short drive with unfiltered air. I would worry about any debris that may have dropped into the intake.

Checking for this could mean quite a lot of dismantling. Possibly borescope/endoscope into the spark plug holes as well. You don't want bits of crap getting in to the engine.

(Also, surely its fuel injection, so unlikely to be a carburettor below the butterfly valve.)
 
#10
Think about it. She could not run the car down hill backwards in 2nd gear. It just would not move, it is in a forward gear. She may have run it down hill with the clutch depressed in 2nd gear and let it out at the same time as turning the ignition, maybe. or even if she had it in reverse going down hill and turned the engine over the engine would still run the right way round. For the air filter to blow off there would have to be a large misfire with unburnt fuel building up. Even then for it to come off screws would have to be missing, If you can get the AA out or get it towed to be on the safe side to a garage. Then hold her by the sides of her upper arms and shake her for a minute or so that will help you.[video=youtube_share;39qdhbkTko4]http://youtu.be/39qdhbkTko4[/video]

I've thought about it.

She essentially tried to bump start it in a forward gear with the car going backwards. No screws needed to be missing - because there aren't any. The top half of the intake manifold broke off as a result of excess pressure inside, i.e. it blew apart - it's a one-piece plastic component with all joints heat welded during manufacture. This component fits between the air filter and the carburettor.

Getting the RAC to sort out the car would have been the easy option. Unfortunately, although she paid for RAC cover as an extra when she arranged her motor insurance, it looks like her broker or insurer (she's currently trying to find out who cocked up) didn't get around to arranging this with the RAC. It's Saturday morning, the insurance broker and garages pack up at 12:30 and don't open again until Monday. If the car can't be taken to a garage today, we'd rather the car were parked near home, rather than in a street 4 miles away if for no other reason than I'd have access to my tools and could have a go at getting it started.

But I'd like some confirmation that getting the engine to turn over isn't going to push potentially bent valves or whatever (caused by the bang) through the cylinder head.
 
#12
So, Question 1. Is my assumption of events plausible?

Question 2. Is it likely that there's more damage hidden away as a result of the big bang? Something that could render her pride and joy BER?

Question 3. Would driving the car 4 miles from its present location to home without the top on the air intake cause further damage? Obviously, the carburettor would be sucking in air that hadn't been through the air filter but driven gently for a short distance...


If the responses are favourable, I'll disconnect, clean and reconnect the electrics to the starter motor and hopefully get the thing started, then it'll be a trip to the scrappy for a large bit of doubtlessly expensive plastic.

Put it back together and start it. If it starts and runs alright then there is unlikely to by any big problems hiding away.


Driving without an airfilter won't do any harm over a short distance. Assuming its a carb engine and not injection, if its injection it may not start until all the components are back in place.

Check the engine earth strap too, easiest way is putting a jump lead from the engine to the battery negative. Poor starting is often doen to poor engine to chaddis earthing on older cars.
 
#14
Best bet is to throw the Clio away and get something decent.
When she rolled her previous Clio, the five occupants survived without a scratch. That's enough to encourage brand loyalty.
 
#15
probably air fuel mixture was too much, when the engine fired up, the over pressure would have destroyed the plastic cover.

Check the cables and earth lead to the starter motor, might be corroded.

As described, with the ignition on, when she turns the key do all the dashboard lights go off? Also try starting with the lights on, see if the battery is ok, lights should remain bright when turning for ignition.

If they dim slightly then possibly either the starter motor, or the ignition cable from the barrel to the loom needs replacing
She says that the battery was holding good charge but when turning the ignition key there wasn't so much as a click, let alone a struggle to turn the engine over. My first thought is a dodgy connection.
 
#17
If any internal damage has been done then it`ll be too late to worry about it, turn the key and try and start the engine. If it seems to be running ok without misfires then it`ll in all probability be ok.
I`d hazard a guess that the big bang was unburnt fuel sat in the inlet manifold. Depending on the age of the car it`ll either be an injector to each cylinder with the butterfly purely as a venturi, or the butterfly will be part of a single point injector which feeds all cylinders.
If your daughter wasn`t even getting a click from the starter motor, either it`ll be on it`s way out or more likely a dirty connection on the small wire which feeds the solenoid.
Take a chance and turn the key, it might run a bit odd due to no air filter, but the lambda sensor should adjust the injection system to allow for the lean mixture, it just won`t perform as well but should allow you to potter the four miles home.
 
#18
1. Path of least resistance has probably saved rods etc by taking off the plastic but it would still be wiser to tow it home.
2. Get the insurance broker to pay for repairs in lieu of suing them - due diligence/mis-selling/mis-representation/distress etc etc.
 
#19
Many thanks to all, I'll be more profuse later - I've got to take my daughter to her car as she was successful in stamping her foot up and down and the RAC man is on his way...
 

Similar threads

New Posts

Latest Threads

Top