Another A series problem - backfiring

Chris Roden · 21 Oct 2013, 14:10 (Ref:3321043)

Hello again....
The Mini 1275GT has been running perfectly since I took Gordon's advice on the starting problem, Ta!

BUT now....

The other day the engine started perfectly but when it got warm it cut out occasionally and backfired through the exhaust, much to the amusement of people following me!

If the engine died totally, it was easy enough to restart but then started backfiring....

I assumed that the valve clearances were too tight and that heat expansion was causing the exhaust valves to stay open.

I reset the tappets, which were a bit tight but it made no difference.

I've checked the plugs, points and dizzy timing and all seems ok.

Anyone have any ideas where to go next?

sebring115 · 21 Oct 2013, 20:35 (Ref:3321281)

Air leak maybe, I would have said ignition timing but you checked that. Is it at all revs or just when you get higher up the rev range?

Good luck

Mark

VIVA GT · 21 Oct 2013, 20:40 (Ref:3321285)

Just wait for Gordon to tell you what's wrong again, but this time, believe him and more importantly, follow his advice straight away!

GORDON STREETER · 22 Oct 2013, 18:33 (Ref:3321784)

How I'm supposed to diagnose it from a distance christ knows !

Can you plug the ECU into the phone and download it to my workshop ?
Oh it's an old Mini, possibly a condenser (are the points black ?
Could be the coil (I trust you are not running 12 volts into it) as I seem to remember it's got a cold start system on it.
I wouldn't think it's fuel related as you say it starts straight away.
Just bung an old 12v coil on it and juice it up from a 12v feed to see if it runs OK.
Just had a thought, a lot of these replacement coils leak the oil out if they are fitted on their sides or upside down, that will cause this problem.

Chris Roden · 22 Oct 2013, 21:18 (Ref:3321880)

Thanks chaps....

I'll fit a new condenser and see what happens, yes the points contacts were black.

Today I went over everything again, it started instantly and ran perfectly so I left it running until it was hot. It picked up and ran cleanly, all seemed ok.

I let it cool and then took it out for a run, within yards it was popping and banging again, so it seems to be a problem under load.

Chris Roden · 22 Oct 2013, 22:03 (Ref:3321906)

If the condenser doesn't solve the problem, I'll swap out the coil for a known good one.

Gordon remembers well, it is a ballast resistor system, but meter readings are the same as they were when I implemented Gordons advice.

(I tried to edit my last post but wifi kept crashing)

Copperbottom · 23 Oct 2013, 07:49 (Ref:3322042)

Classic symptoms of a condenser problem, it's best to replace the points at the same time as the condenser and vice versa.

Chris Roden · 23 Oct 2013, 21:39 (Ref:3322320)

I had a new condenser in stock so fitted that, engine started fine and a mile, or so, trip showed no evidence of the problem. I'll take the advice and fit new points when convenient, but, for the moment, all seems fine.

Thanks for all your help, I'm learning a lot.

GORDON STREETER · 24 Oct 2013, 22:36 (Ref:3322738)

Blimey I only wish things are as simple now as they were years back !

We have now got to the stage where some cars are being scrapped or costing more than the car is worth to sort out some engine problems.
Certain "lateish" common rail diesel cars are pretty bad for this and taking into consideration the price of diesel vs petrol vs MPG there isn't much difference in fuel running cost.

SidewaysFeltham · 29 Oct 2013, 20:21 (Ref:3324876)

Just popped in for a quick visit.

Funny, innit, Gordon, how with all these cleaver whizzy things on cars today, everyone (except you and I

) seem to have lost sight of the basics.
In reality, nothing much has changed since Fred Lanchester's day in engineering concept.

However, unless they can plug in a code reader.................

GORDON STREETER · 29 Oct 2013, 23:21 (Ref:3324924)

Quote:

Originally Posted by SidewaysFeltham

Funny, innit, Gordon, how with all these cleaver whizzy things on cars today, everyone (except you and I

) seem to have lost sight of the basics.

I think there are quite a few on tenths that still know about all the old stuff but let's face it I don't think that a new road car has been made in the last 20 odd years that has had points fitted as standard.
I think overall that "most" modern cars are reliable and don't break down as much as the "old days", the only downside is that when they do they can't normally be repaired beside the road and cost a fortune to fix.

While I'm on my soapbox, can anyone tell me the reason why some idiot at Renault designed the late Clio so that you have to take the front off to replace a headlamp bulb !!!! I know some other cars are not exactly easy" and it makes me smile that you are supposed to carry spare bulbs on the continent as the "normal" driver has no chance of fitting them

Clive Brown · 30 Oct 2013, 17:10 (Ref:3325205)

Quote:

Originally Posted by GORDON STREETER

While I'm on my soapbox, can anyone tell me the reason why some idiot at Renault designed the late Clio so that you have to take the front off to replace a headlamp bulb

They're French....

**Tim Falce** · 30 Oct 2013, 18:07 (Ref:3325219)

Quote:

Originally Posted by GORDON STREETER

While I'm on my soapbox, can anyone tell me the reason why some idiot at Renault designed the late Clio so that you have to take the front off to replace a headlamp bulb !!!! I know some other cars are not exactly easy" and it makes me smile that you are supposed to carry spare bulbs on the continent as the "normal" driver has no chance of fitting them

We've got a Clio 2 and 3, the bulbs are easy enough to change except for the N/S Clio3 but I know a contortionist with very small hands to change that one.

GORDON STREETER · 30 Oct 2013, 18:56 (Ref:3325232)

Sorry it was a Modus I was working on (brain fade) when working on Froggie cars !

SidewaysFeltham · 30 Oct 2013, 19:19 (Ref:3325237)

Quote:

Originally Posted by GORDON STREETER

I think there are quite a few on tenths that still know about all the old stuff but let's face it I don't think that a new road car has been made in the last 20 odd years that has had points fitted as standard.
I think overall that "most" modern cars are reliable and don't break down as much as the "old days", the only downside is that when they do they can't normally be repaired beside the road and cost a fortune to fix.

My son's Mini Cooper S Turbo R56 being an excellent exemplar.

Well, it is said that BMW means "Bring A Massive Wad!"

Quote:

While I'm on my soapbox, can anyone tell me the reason why some idiot at Renault designed the late Clio so that you have to take the front off to replace a headlamp bulb !!!! I know some other cars are not exactly easy" and it makes me smile that you are supposed to carry spare bulbs on the continent as the "normal" driver has no chance of fitting them

Minds me to recall trying to change a battery on an early Triumph Stag. First, remove the power steering pump..........

And a fanbelt adjustment on a Dino Ferrari 246 GT.

Jack up car: remove offside rear wheel.

Remove nasty cover from wheelarch, having first scraped off all the mud and junk to actually find the PK screws.

Adjust fanbelt using new midget Japanese contortionist mechanic.

Put it all back together again.

Fun.........

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
A series 1275 starting problem	Chris Roden	Classic Cars	33	21 Feb 2013 13:45
Driver Series or Technology Series - the future of F1	Nicholosophy	Formula One	19	29 Dec 2006 13:10
A problem...	Craig	Trackside	11	18 Dec 2000 00:57