Hello all, new to this site and very nice it is too!!!

Anyway i'll try and keep it simple.

Felicia 1.3 mpi - missfire cylinder 2, have replaced coil pack and brand new spark plugs

Remove injector multiplug for inj 2 and no difference is heard, engine judders the same, remove 1,3,or 4 and it makes a difference and almost stall. That would lead me to believe that the injector is faulty.

However if i remove inj 2 plug which makes no diff, and then inj 1 plug, and put 1st plug onto the 2nd injector, the engine note changes as if fuel is now being injected.

Any Ideas???

Many Thanks

Sounds like it might be the injector driver in the ECU, BUT that's just idle Sunday night banter. I'm not sure if they're driven all together on the Simos 2P ecu and the wiring diagram is in the garage. It could, of course, also be a bad connection/connector. What happens when you just swap the two injector plugs over (i.e. 1 onto 2 and 2 onto 1) - does it still misfire, but only on 1 cylinder?

Yes it still missfire's, becuase i dont think there is power on the 2nd multiplug and the fuel timing would be wrong for the 1st cylinder now. 2nd hand ecu or does it need coded by vag? or any other possibilies? valve clearence?

Thanks

The Felicia MPi isn't sequentially timed on injection, plus it would make a minimal difference even if it was, so it'd still run fairly well.

The ECU would need to be coded to your immobiliser box, TeflonTom on here would tell you what to do, BUT I'd do a lot more faultfinding before condemning the ECU, it could be a wiring issue apart from anything else. You need to know 100% that there's not power there, and also that the connection from the injector plug back to the ECU is OK. generally electronics are pretty reliable.

at this point i would be tempted to remove the injector rail as a whole unit, turn the car over and see what comes out of the injetors. Have lots of rags and a fire extinguisher handy! (foam / CO2 not water)

Yeah, or four little jam jars (useful for making quantity tests) It's only 2 bolts on an MPi to get them out.

at this point i would be tempted to remove the injector rail as a whole unit, turn the car over and see what comes out of the injetors.

don't be so bloody daft! that's the sort of thing that will land you up in A&E....

if you have a multimeter with a duty cycle tester you can see if you are getting anything out of the plug on the loom.... i would try stretching the wire across to an adjaecent injector to see if it still does it.... besides, on the simos 2p they are fired in pairs (semi sequential) , so if the cylinder 2 injector driver was dead you would loose cylinder 3 as well... 1+4 are paired, and 2+3 are paired.....

by logic it can only be a dodgy injector, or a corroded / bad wiring connection at the injector

Edited 25 January, 201016 yr by TeflonTom

I would generally agree with Tom, but I know of several reputable tuners who do the jam jar test to test injectors for volume flow rate.

or low compression/broken pushrod , tight tappet. i would be tempted to swap the injector over to cyl 1 or 4 and see if the missfire changed with it or not

Thanks people, i will give your suggestions a try this weekend hopefully, weather premitting, and reply with further findings/fix

Thanks Again!

Thanks people, i will give your suggestions a try this weekend hopefully, weather premitting, and reply with further findings/fix

Thanks Again!

Did you get anywhere with this? Was it electrical or mechanical?

Problem here too with Felicia 1.3 mpi. Engine rough / misfire / smell of petrol / high fuel consumption. Have unplugged individual injectors. When I unplug injector 1 there is no difference. When I unplug each of the other injectors there is a difference in running. Since the injectors work in pairs does this point to a bad injector 1?

 

Regards Colm O'Dwyer

Turned out to be a bad coil pack (fits over spark plugs) put in different one and problem sorted.

Thanks to Teflon Tom for the steer on this

Did you take any pictures etc? You could write up a quite for the tech guides part on here.