MORE issues, now missfiring and backfiring!!

[chris71920]

In short, the truck started to idle funny again after being fine since I cleaned the carb out so I did the same again, and idle returned to normal

Left the truck overnight and went to go out in it today and got 500yards up the road and it had a flat spot about 3k and wouldnt pull through it :( If I drop the clutch it revs up!

I pressed on for a mile or 2 and it still did it, and then started backfiring from the exhaust if I let off for a few seconds and then went back on the gas, also being pretty gutless to the point where it was hard to pull away from a standstill

This engine/carb is doing my head in!! Oh and plus it now decides it wants to smoke when giving it some gas and on overrun.

Missed out on the Dirty Weekend show too due to the problems

[chris71920]

Had a quick look again, it LOOKS like the 2 "accelerator jets" (the ones that point at 45degrees down into the throat if looked at from above) dont seem to be squirting as much fuel as they did before, maybe its my imagination?

I noticed if its idling and stab the pedal hard and let go it just sounds "strangled"....not sure if its a fuel issue or ignition. Im swaying towards fuel (again!!)

[ScottieJ]

Just to check its a 1.3 samurai yeah?

Are you sure you dont just keep picking up crap from the fueltank and blocking the jets over and over again.
Try running a fuel filter from an injected vehicle as well as the traditional paper filter, they filter out smaller particles!

Could be worth dropping the tank for a good flush/clean out as well.

As a last resort just ditch the stock carb and fit a HIF44 SU carb.

Could be an ignition problem? Is there a nice strong spark from every plug? How old is the coil? Have you checked the plug gaps? Dizzy cap and rotor for excessive wear etc?

[chris71920]

Its a '92 1.3 Samurai BUT its running a weber 32/36 carb.

It could be that I guess, it was fine yesterday driving back from my garage with no flat spots etc.
Then it started to run roughly last night after I took it down the road and idled erratically again, so blew the jets through and it idled ok. Went to drive it this morning and big problems as I mentioned earlier.

I went to check the fuel filter this evening only to find it not there, its just been joined with some hose and its running one of those small clear inline filters before the fuel pump, not ideal.
There doesnt seem to be any dirt in the float bowl like there was previously though.

Thats not a bad idea to be honest, its getting to that point just to eliminate it.

Ive been thinking about an SU too, at least that would stop the problem with the weber flooding out when climing slopes too but not sure how much it would cost to convert the intake manifold. I can get hold of a HIF44 for fairly cheap if I need to.

I will check the sparks tomorrow, and the coil is the one it has been running since Ive had it, but I bought a new one when I was having problems before (which made no difference) so its back in the box as a spare. Not checked the gaps but they are new plugs and were running fine until now. Also dizzy cap and arm are pretty much as new too

[ScottieJ]

I would stick the new coil on to be sure and keep the old one as a spare.

How long was it running fine before it started happening again the first time? Just want to know how often it happens? days, weeks, hours or everytime it warms up etc.

[chris71920]

Last time it was fine (months) until I went to a P&P day (my 1st one) then it started cutting out a few hours in, as soon as I came to a stop with the clutch in. It did it all the way home and until I cleaned the carb out.
Then drove about 10miles home yesterday and started to idle roughly again (like before)....Maybe its worth taking the whole carb off and immersing it petrol for a few days and then blasting all the jets and passages out again and cleaning it inside and out, along with dropping the tank and cleaning it out too.

Its still smoking though which I assume is oil/blow-by as it blows a fair bit out of the rocker breather too.

[ScottieJ]

have you still got the pcv valve hooked up? and is it working?

[chris71920]

Yes its still hooked up but mine tee's to the rocker breather and another pipe that would go to the plenum (i dont have one, just foam filter at the moment), but it kinda just sits there venting above air filter.

Ive cleaned it out as best I could and go most of the gunk out and the ball inside moves freely now.

[ROBBIE]

When my SJ had the 1.3 in it had a webber carb and I was having all the problems you say you are getting. I changed the filters dropped the tank and flushed it, would still fart about. I changed the coil because when that got warm i would cut out. I was forever checking the timing, always the same thing go off road or laneing and run like crap. So in the end i got an su and that sorted the thing out.
I sold the webber to a bloke whos SJ was standard and not used for dirt and he had no probs.
My conclusion was a webber is a good carb but i dont think they are made for the kind of treatment they get in a SJ off road.


I will say I learnt a lot in the time i had a webber

[Edweird]

That's a good point Rob.

Webbers are generally used for fast road engines. Personally, I'd go for an SU over a Webber.

Having said that, you've already got the Webber and carbs are bloody expensive.