fuel problem and running rough

[GarryB]

Hi

I need a little help with my little gem.

Blew the air box to china a couple of weeks ago when it had its first backfire!!!! Not fun. Before it blew it ran perfect. Just got the new air box back in and now its missing on 1 cylinder. found which cylinder by pulling the leads off. swapped the injector to another cylinder and that cylinder wasn't firing. Aha! injector must have died during the sitting around for 6 weeks. Put a new injector in and now the engine pops and is still misfiring on that fuel line. I am supposed to take the wife away for a long weekend getaway so are limiting in spending weeks and 2 hours each night trying to locate the little gremlin that's doing this.

Has anyone got any ideas that will help me locate the cause.

Yes i put all new gaskets on the CIS system. The only other thing i did was removed the top of the fuel distributor to check the plunger and then put it back together.

In appreciation...

[Harvs11]

 The only other thing i did was removed the top of the fuel distributor to check the plunger and then put it back together.

It looks like you're down the rabbit hole now

[GarryB]

Maybe a little but in the end i will resolve it but a shortcut to the exit would help.

[Peter M]

In the absence of any experts speaking up:

So Garry you're pretty confident that if you compared the fuel flow of no.1 injector with any of its buddy's that it would be flowing less?

If not, I'd pull all the injectors, place each injector into its own beaker/measuring cylinder/glass jar, trick the engine into thinking it's running (I forget now what you need to do this as its been almost 30 years since I've done this myself!), lift the air flow flap and confirm that no. 1 is indeed flowing less than the others.

If you are confident that the lack of flow in no. 1 is the issue, I'd be pulling down the fuel distributer to find out why or just exchanging for a rebuilt one.

I guarantee money will fix it!

Good luck and please post when you find the cause?

 

PS Are you sure the misfire is caused by a lack of fuel?  Might be worth replacing that spark plug and checking the lead first.

Also might be worth establishing why the injector failed in the first place?

[GarryB]

Hi Peter

Thanks for responding. well, the plugs were fine 6 weeks ago when it stopped so crossed that out. When i swapped the injectors, with lines, to its neighbor, the miss moved cylinders, so that told me it was the injector as the end of the injector was dirty and its neighbor was clean. I did run the engine with that fuel line off and fuel was coming out and increased flow with the throttle vavle up.

i did rig up a home made injector cleaning system and under very low pressure the injector was dribbling fluid. 

Would a vacuum leak cause a CIS problem? If you know.

i guess i will just have to buy a pressure test kit and try and make up a better injector tester with pressure gauges...

No, i dont know how to trick the engine into running but i am sure there will be something on the internet somewhere.

Thanks again Peter.

And its also popping faintly when running. After i put the new injector in!! Go figure.

[Peter M]

Would a vacuum leak cause a CIS problem? If you know.

And its also popping faintly when running.

 

Garry,

So it barely idles but will run better at a higher speed?

If that's the case maybe there is still a vacuum leak to fix?  Maybe the backfire dislodged one of the vacuum hoses that's enough to cause the rough running.  I reckon that's worth investigating before chasing anything else.

[tazzieman]

CIS cure all vac leaks first. Then check fuel flow/pressures. Then chase individual cylinders , spark strength etc.

The airbox explosion may have split some other lines/connections as has been suggested. 

Playing with the FD is playing with fire! What happened first is what has caused the problem. Possibly a loose /split hose.

Unless you have fiddled with the mixture...