Backfiring through airbox

Hi, thanks again for all the help.
I just swapped the male disconnects to metal so they are still as in your photo, not possible to confuse (I hope) as I have a both males going in flow direction. Incidentally return is now weeping so need to change o ring. I have struggled to get this to seal.
I have been back out to garage and pinched the return pipe, all this does is raise the revs. It did seem to allow it to run a little longer before it backfired but didn't stop it.
I then moved onto exhaust temp and basically I can touch the left pipe, barely any temperature in it so guess its not firing on that cylinder.
 
Can I check which way the pipes are flowing as I'm now worried they may be wrong due to the leak, I can't see why a low pressure pipe would be a problem. They should be right as I only changed the male ends but it would at least rule that out.
 
Ok so one cylinder isn’t firing - that’s making it backfire into the air box and rubbish running.

You need to check - fuel, spark, air, timing of spark, timing of fuel.
 
It was running OK.
I think the backfiring issue is going to be because of it not firing on one cylinder, I think I will try to sort this out before I try switching back to the other sensor.
It has to be something I've done whilst it's been sat on the bench. I won't get a chance to have a look again until later in the week. Will check fuel spark etc
 
Always ...

... worth a look :blast
 

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Oh FerFuck Sake!!!!!

Its the lifted tank Cable not seating problem!

That's the pic I was just away to Look for, Paul! That saved me hunting the PC for it :aidan

Talk about Red fucking Herrings

Makes sure your throttle body cable quadrants are all returning to their base settings i.e. against the throttle stops !!

If not look for a displaced cable and reseat it and this will "likely" fix the problem
 
You stated that one of your fuel quick connects was damaged.

Is there any possibility that debris from it could be partially blocking your fuel supply to the injectors.

Did you use metal quick connects with the built in check valve?
 
Cables both fully seated.
I am certainly leaning towards the fuel supply, whilst it could be a coil etc I've not touched anything related to them and they were working when I parked it on the bench. Not ruling them out though and will still be checking.
They are the metal quick connects, second hand from motorworks. It was only the plastic part that snapped off, I still have it the broken piece and can see where it attached to so sure it can't have got into the system.
 
Purplegerbil said:
Cables both fully seated.
I am certainly leaning towards the fuel supply, whilst it could be a coil etc I've not touched anything related to them and they were working when I parked it on the bench. Not ruling them out though and will still be checking.
They are the metal quick connects, second hand from motorworks. It was only the plastic part that snapped off, I still have it the broken piece and can see where it attached to so sure it can't have got into the system.
Click to expand...

Then pop your injectors out and check you have a good spray pattern. If not, then remove the fuel lines from the injector and allow the system to flush fuel through.
 
Purplegerbil said:
Cables both fully seated
Click to expand...

What you are describing sounds very much like an open throttle from working under the tank / working with fuel lines

Did you check that the throttles BOTH clack against their stops

The cables can come out at the Splitter box end !
 
Will check the splitter box end.
If the cable is not correctly seated would thar cause it to not run on the affected cylinder?
 
I managed to take a quick look at the throttle cables, no time yet to try any of the other suggestions yet.
Cables are fully seated in both throttle bodies and in the splitter box so i guess that's not the fault.
Good job I did check as I hadn't uncoupled the return fuel hose with the split o ring and this has been leaking a bit of fuel, had a nice crystal growth on it !
 
Quick update, checked throttle cables and fully seated both ends.
Popped out injectors, both spray fuel, not necessarily well but they are both working.
Stick coil not firing on left, fat spark on right, secondary coil firing.
So no spark from stick coil on left cylinder. Is there something I could have disconnected under the tank or is just a coincidence? (Tank back on at the moment, I've lost my bench to crochet so nowhere safe to put it)
The coils do look different, the left has some corrosion on the body and i suspect is the original.
 
Last edited:
Purplegerbil said:
Quick update, checked throttle cables and fully seated both ends.
Popped out injectors, both spray fuel, not necessarily well but they are both working.
Stick coil not firing on left, fat spark on right, secondary coil firing.
So no spark from stick coil on left cylinder. Is there something I could have disconnected under the tank or is just a coincidence? (Tank back on at the moment, I've lost my bench to crochet so nowhere safe to put it)
The coils do look different, the left has some corrosion on the body and i suspect is the original.
Click to expand...

I’d have thought it’s pretty obvious - Swop the stick coils over from left to right and vice versa, see if the problem follows the coil. But usually it’s a failed stick coil, they are well known for failing, corrosion isn’t a sign of a problem, I’ve had them so corroded that the bodies have swollen and you couldn’t get the coils out of the head but they worked perfectly.
 
Switched coils, it's knackered so new one on order. Thanks for the advice.
 
sparkplugs.co.uk is a good source for coils. Buy the champion coils which are just rebranded beru, same as oem. Much cheaper at around £50...
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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