Backfire/ rough starting (CU)

[meehaja]

Since the MOT I've not taken the van on any particularly long runs. First run from the garage was round trip of about 20 miles and it back fired loudly, with a big cloud of black smoke and cut out. this was after leaving a roundabout in fourth at about 30mph so I put it down to wrong gearing. After this it started fine and continued to run fine. I have used it since for short journeys of similar length without complaint.

Today took the van for a longer run (serves me right for making plans on my day off!) and after 15 miles or so it began to backfire. After the first bang it started again fine, but then began to backfire with increasing regularity and struggled to restart. This culminated in the van completely dying on double yellows in the queue for a busy junction in Halifax (always the way!). I checked all the obvious (fuel/fuel filter/everything plugged in in the back) and also checked connections to the coil as this has been an issue in the past and the Lead from the coil seemed a bit loose? Gave it a good push and it started again with some effort and continued to run all the way home, albeit with some occasional power loss.

The only changes I have made recently are fitting an air hose (where there should be one anyway) to the vacuum unit (which I fitted prior to the first backfire and removed today after the first backfire).

On examining the van at home, the connection from the heat exchanger to the heater duct had corroded at the hose clip and was falling away from the body. This should be a fairly simple repair and I don't think the two are related?

Anyway, the van is going back to the garage tomorrow for them to take a look over it, just wondered if anyone had any suggestions of things I should check/do in advance?

Thanks all!

[edoh]

did u check to see if distributor clamp on tight? ignition timing ok?

[edoh]

rotor arm? distributor cap? - all fine?

[dugcati]

If they will/can, get the garage to check timing/carb settings and possibly a compression test when there

[orangebooboobearcrew]

Hi,

Sounds very similar to the issues we had been having until we finally stopped altogether on the M5 at Bristol.

The intermittment thing could well be the ignition amplifier on its way out - common sign apparently. You can get new one from Brickwerks,etc and a doddle to fit.

Have you got the right coil on? We changed ours a few months ago with one from JK which said was for 2l petrol air cooled but after checking on here, found out other people had issues with these and they weren't the correct coil (JK does it again - well done lads! ). Got the right one from Brickwerks now (silver body).

Is the Hall sensor in your dizzy faulty? Again, can get replacement from Brickwerks - again I bought originally from JK but had wrong plug on so had to buy another (correct one) from Brickwerks - JK does again, more money wasted

Is there a wiring break somewhere between coil live feed and dizzy? Get garage to check your spark is good, strong and regular...

Please learn from my mistakes and don't buy rubbish from JK - this has cost me hundreds of £'s - get the proper stuff from Brickwerks - might be a tad more expensive but you know it will work

[meehaja]

All sorted thanks. I took it to the garage and typically it ran faultlessly. Took it on the motorway and drove flat out, took it down country lanes working through al the gears, queued in traffic for ages. Burnt off £20 of fuel and it never skipped a beat.

Two issues found when I had a proper look, first off the air hose I'd fitted had a slight kink so was probably restricting air flow, also, since it had run fine without, it clearly wasn't helping anything. Also, the lead from the coil seems to have quite a wobble to it, which might explain why I've broken down so many times, then miraculously started again 20 mins later? Anyway, seems to be running fine at the moment so i'm going to spend the evening rewiring my old dash pod (getting rid of that silly plastic and copper nonsense and putting some wire in!.)

Thanks all for your help!

jim

[edoh]

good result!

if your up for it - and can take a few photos - would love to see how your rewiring dash pod project works out!
good luck

[meehaja]

Not thought of that... I'm on it now!

[orangebooboobearcrew]

Nice one - glad you sorted...

Chris