46 replies to this topic

[Vipernoir]

Battery terminals are different sizes to prevent this from happening - did you hammer the smaller terminal on to the larger post ?

[Captain Mainwaring]

Did the engine run backwards?

A diesel could have....
At least one without an electronic pump....

[Captain Mainwaring]

 

Potential for a knackered ECU!

 

Fingers crossed that's not the case

 

Damn yes, it's a 96 model  thinking about it the starter probably just turned in reverse hence the car firing and should be / could be OK, there's so many electronics then after this in an spi/mpi - not sure how is best to diagnose, but at some point I'd reconnect the battery to then find out; not sure how to check out the ECU apart from opening it up & looking for component damage.

 

How does that work then?.....
Sure it's only an airpump....but how would the fuel get its way into the combustion chamber if the engine is huffing out of it's inlet manifold.

 

Think what you said....it ran backwards, therefore there must have been a spark, and there must have been fuel injection....therefore there must have been ECU function with reverse polarity.....

[Captain Mainwaring]

Battery terminals are different sizes to prevent this from happening - did you hammer the smaller terminal on to the larger post ?

This is a "nice forum" friendly sort of thing, and I already got told off for growling at someone...which is fair enough....but if it wasn't...I'd say, well, let us just say that the OP was "confused".

Perhaps other people's earth leads are longer...but my battery wouldn't connect up if it was installed the wrong way around.

You could of course jump a flat battery and connect it the wrong way around...but let's be honest...it still wouldn't start.

[mini-luke]

A petrol engine with minimal ignition advance is perfectly capable of running backwards, just not very well

[CLM]

Starter motor will spin the correct way irreguarless of polarity due to how it's built. Alternators, electronic ignitions, ecu... Anything with modernish electronics in it, diodes transistors capacitors etc, will be suceptable to damage with reverse polarity as their components can't handle it. Wires, fuses, starters, wiper motors, relays, lights, heaters... On a mini don't know the difference.

Chris

[Vipernoir]

 

Battery terminals are different sizes to prevent this from happening - did you hammer the smaller terminal on to the larger post ?

This is a "nice forum" friendly sort of thing, and I already got told off for growling at someone...which is fair enough....but if it wasn't...I'd say, well, let us just say that the OP was "confused".

Perhaps other people's earth leads are longer...but my battery wouldn't connect up if it was installed the wrong way around.

You could of course jump a flat battery and connect it the wrong way around...but let's be honest...it still wouldn't start.

 

 

Genuine question Captain M - battery terminals ARE different sizes to prevent this from happening...
 

To get the smaller clamp onto the bigger terminal must have taken a decisive effort, and trying to clamp up the larger one onto a smaller terminal was also not the work of a moment.

[CLM]

A petrol engine with minimal ignition advance is perfectly capable of running backwards, just not very well

2 stroke, yes. 4 stroke, not so much, unless you are able to feed fuel into the exhaust ports. The cam makes running backwards almost impossible, you might get a pop or two through the intake but it won't be running.

Chris

[tiger99]

You can be absolutely sure that the alternator has been completely ruined (its design makes that inevitable), but I would expect an ECU to be protected against transient overvoltage, negairive-going spikes, and lots of other nasties that happen in car electrical systems, so if you have one it will most likely be ok. Radio possibly fried, or not, depending on type. Instruemnt voltage stabiliser, if electronic, possibly fried, tacho maybe. The starter motor will not have been harmed, nor will any lights etc.

[petey81]

my dick of a brother did this to mine once when I wasn't  looking and blew the alternator but everything else was ok.

[Ethel]

 To be fair to the OP the most you can say is the battery posts (if round) are different sizes. The cable terminals should be different sizes, but could have been splayed, stretched or replaced incorrectly.

[maccers]

Mine are the same size, and they have definately been replaced at some point. Although they wont reach over without pulling them very very tight to the point you would see its not correct.

[Tamworthbay]

Did the engine run backwards?

I am sure you are joking, but 2 strokes are happy to run either way. If the timing is set too close to TDC it can cause problems. I saw a guy on a run with a BSA Bantam do just that at a junction. The bike stalled and when he got it going and dumped the clutch, only to disappear backwards into a ditch. It was his first run after spending 3 years rebuilding it :-(

[Gremlin]

Did the engine run backwards?

Thats what I was thinking, if he put it in first, it would have gone backwards!

[paulfoel]

Battery terminals are different sizes to prevent this from happening - did you hammer the smaller terminal on to the larger post ?

 

Nope/ Was same size.