Backfire issue sorted (hopefully)!

[itchyfeet]

An intermittant ignition live fault would give the same problems as an intermittant earth fault.

I see you have the original crimps on the coil, I long since cut them off and remade them.

[300CE]

An intermittant ignition live fault would give the same problems as an intermittant earth fault.

I see you have the original crimps on the coil, I long since cut them off and remade them.

Cheers Paul - will change those connectors tomorrow. I also bought a carb refurb kit and thinking that I might just change the pump diaphragm as well.

[ermie571]

Have you changed the ignition control unit itself??

you ren't that far from me - sure I have a couple of known good spares I could look out for you?

Em
xx

[300CE]

Many Thanks for the offer Em', much appreciated! The ignition module is a new one along with the coil, HT Leads, plugs & vacuum advance. I've actually got a spare Bosch one which I've swapped across but alas symptoms are the same.

Do you have a spare dizzy that you would let me borrow as it'd be good to rule that out? No worries at all if not

[ermie571]

as it happens i do


my number is to the left....best you get in touch


oh have you checked the manifold (?? big metally thing the carb sits on) for cracks?

Em

[300CE]

Cheers Em', I'll give you a buzz tomorrow if that's ok with you?! I've sprayed WD around the manifold to listen out for a change in Tickover but all seems to be fine there.

I'm thinking that it could possibly be the Hall Sender Unit in the dizzy as my mate reminded me that it was full of fluid which can't have done it any good (this was when we changed the engine over a couple of years back).

[rockthebus]

Cheers Em', I'll give you a buzz tomorrow if that's ok with you?! I've sprayed WD around the manifold to listen out for a change in Tickover but all seems to be fine there.

I'm thinking that it could possibly be the Hall Sender Unit in the dizzy as my mate reminded me that it was full of fluid which can't have done it any good (this was when we changed the engine over a couple of years back).

I'm not sure about your engine compared to mine...
I had a similar issue..
On mine there are some green wires (and grey) which come out of the loom on the front bulkhead. Check the connectors. Mine pulled apart!!
Good luck

Sent from my SM-G930F using Tapatalk

[300CE]

Cheers RTB - I'm going to change the green wiring connector on the coil as per Paul (Itchyfeets) suggestion. I've moved the wiring from the loom about that comes out of the module whilst the van is running and it doesn't make any change but could possibly be something that is breaking down when the engine gets hot.

I do have a spare loom so may give that a go if need be.

[ermie571]

Cheers Em', I'll give you a buzz tomorrow if that's ok with you?! I've sprayed WD around the manifold to listen out for a change in Tickover but all seems to be fine there.

I'm thinking that it could possibly be the Hall Sender Unit in the dizzy as my mate reminded me that it was full of fluid which can't have done it any good (this was when we changed the engine over a couple of years back).

before 1 if that is ok x

[300CE]

[300CE]

OK, pump diaphragm replaced today - I also took off the top of the carb along with the gasket. Cleaned and put back & checked all bolts for tightness. I then put new insulated connectors on the live wires on the coil:

New diaphragm shown at the top:



Took for a 45 min drive locally so no motorway roads & she was fine, no hesitancy & no backfire. That said, it was exactly like this when I took it for a local spin the other week after putting the earth leads on - wasn't until it was driving at a constant speed like on the motorway yesterday (55 mph) that the problem returned albeit one backfire.

Em is kindly letting me borrow her distributor so will test this on a run and see where we are with that.

[ermie571]

Looking forward to meeting you

[ermie571]

mate - just thought of something that I read ages ago


your brake servo hose....is that becoming porous and scuking air?

now I get iffy so tell me if the science is wrong...but on local roads I presume you are using the brakes quite a bit...but on the motorway at constant speed you wouldn't be....probably just deceleration and acceleration...

I remember reading that someone had covered the hose in gaffa tape and the issue stopped (but can't remember if it was same issue as yours)

Em
xx

[300CE]

Hi Em! Cheers for the suggestion - the Brake Servo Hose is a new BW one, but I'll check to see if the connections are tight enough. I suppose there's a possibility that there could be e problem with the valve it's connected too?

[300CE]

Well, after another backfire episode at the weekend, this time 2 yards off of the drive & then she wouldn't start - I set off over to Em's to pick up a spare distributor which she had kindly dug out for me. I put this on this morning and she turned over first turn of the key!

I then went on an hour's drive via Aaron (top man) at HT Racing at Brands Hatch who proceeded to the re-do the timing for me, plus wanted him to set it accordingly as I run the bus on super unleaded.

She run absolutely spot on so am hoping this is the final cure!