Hi to you all, I'm new on this forum and having read up on this forum, there seems to be a common fault with these Fabia's misfiring, so the story, so far go's like this.

 Bought this 05 Fabia 1.4 16v 100bph model a few weeks ago with a little crash damage on it that l repaired, the only wiring damage to it was to the pas pump, so I replace the pas pump and a section of the loom to the pump.

 On starting there seemed to be no issue's, although on tick over it seemed a little fluffy, so last Thursday took it for an MOT and it past with no issues and all seemed OK, but that's when the trouble started as on the Friday l was driving it back home and had not got far and as l pulled out of a junction the revs dropped and the battery/charge light flash up and it almost stalled, but the EML light came on, at first it stayed solid then started to flash, so pulled over turned ignition off then tried to fire it up again, did not fire up right away but on second turn of the key fired right away and drove home.

 On the Friday drove the car on about a 12 mile round trip and about a mile from home the EML light turned itself off (happy days). Saturday done about 24-26 miles and all was fine.

 Today (Monday) a friend cleared the code showing a misfire on number three, ok new set of plugs, starts it up and misfire comes back and EML comes back on flashing? ok next step new coil pack, clears codes and EML, starts up and all seems good, go's on test drive, pulls like a train for about a mile then the EML comes back on (face palm).

 Next step, test injector 3, no pulse to injector, test wiring from ECU all good, test ECU from port 88 no pulse, ok got to be a dodgey ECU as these have a bad failure rate from what I've read (another face palm).

 Anyway started to put bits back on, plugged injector 3 back on and right away it started to fire again and give out the same pulse readings as 2 and 4, drove home with the EML flashing but it was running ok, now wondering if its got anything to do with a lamda fault as the car had stood for a few months and when first started was coughing out quiet a bit of water and condensation from the exhaust, but am l now clutching at straws?

Car has done 45,600 miles from new with history, so if there's anyone who can point me in the right direction, I would be most grateful, cheers.

Seems as yet that no help has arrived with the problem l am having, but would like to point out my concerns about this problem, as l have already said' l purchased this vehicle with a little accident damage to it and am now wondering if in some way the accident might have been caused by this misfire.

 When pulling away and as you bring the clutch up and bring the revs up, on the odd occasion its like the vehicle is going to stall and it was on one of these moments when pulling out of a junction that the EML came on.

 Its at times like this that you start to question yourself, is it me is it my driving style as over the past few years l have been driving auto's but still on occasions moved the odd manual motor about.

 Also as the car is very low mileage for its age, 45,600 miles over the course of ten years, its not really been anywhere, which in turn may have contributed to its rough running as the engine may have choked up, so will have another tinker with it today and see what transpires.

 One last thing, I've noticed whilst having the airbox off that the air filter looks pretty dirty, so will change that (so much for main dealer servicing) lol.

Check wiring to coilpack 3.

Compression test to rule out mechanical/ring/valve problem.

Where have you read about ECU failures. News to me, they're usually the very last thing to consider.

Agreed with #3

 

Something else to consider if you're going into stall pulling away; check for fault codes involving the "Steering Angle Sensor", particularly ones stating "implausible value". The electric motor for the PAS puts a heavier hit into the electrical system than even the starter motor does so if you're trying to pull away gently and get that hit, then the engine could fluff but the fault not be fuel or HT related.

I also have a 2005 1.4 16v elegance bbz that was spitting water out the exhaust when I first got it (doesn't anymore), mifire cylinder one, seems you have more knowledge than me about cars, if you find the problem give me a shout, I'm yet to test my injectors, wiring, ECU and sensors etc. It's a very slow process for me though :(

Check wiring to coilpack 3.

Compression test to rule out mechanical/ring/valve problem.

Where have you read about ECU failures. News to me, they're usually the very last thing to consider.

Thanks for your input, but as stated have checked all the wiring, even swopped coil packs round but there was no pulse from port 88 on the ECU to injector three, it was totally dead, but tested the other injectors and they all had a good pulse readings, strange thing is after testing the wiring to injector 3 for continuity , which was fine and tracing the fault directly back to the ECU which did not show any pulse reading coming from it, it was sod it, looks like the Ecu is kaput, plugged wiring back on injector and by some miracle the injector started to fire again?

As for reports on the ECU, I found out via other bibs and bobs on the tinternet, not only that but on my way to pick up a new air filter for the car (old one as black as a minors face) l popped into a local repair shop, just to pick there brains and was told that every thing that was done, was the correct way and it looked like the well known erratic behaviour ECU fault.

ECU will shut down fuelling to a cylinder that has registered a certain number of misfires, but will re-instate with a key-off, key-on cycle. Maybe you measured that shut-down phase?

Agreed with #3

 

Something else to consider if you're going into stall pulling away; check for fault codes involving the "Steering Angle Sensor", particularly ones stating "implausible value". The electric motor for the PAS puts a heavier hit into the electrical system than even the starter motor does so if you're trying to pull away gently and get that hit, then the engine could fluff but the fault not be fuel or HT related.

Thanks, will check that out as the pas pump was FBR and had to be replaced with a second hand unit £50 from VAG spares in Sandwich, along with the wiring harness with connector plugs, as everything was pretty crushed around the pas pump area.

ECU will shut down fuelling to a cylinder that has registered a certain number of misfires, but will re-instate with a key-off, key-on cycle. Maybe you measured that shut-down phase?

Yep you maybe right, been out and about in it today and its been going ok with no issues, well apart from the EML still flashing away, but this is when the fear factor starts to creep in, if the EML is cleared, will the misfire return grrrrrrr, only one way to find out lol.

Misfire will be coil pack, spark plug or wiring loom to coil pack.

Does seem a electrical problem and not mechanical as engine runs well, when everything else electrical does what its suppose to do.

Just a quick update, seems that all this faffing about to try to find out the cause of the misfire on number three cylinder was a complete ghost hunt, on getting home last night and with the car going into misfire mode yet again, on the way back, I pulled off the air box and started looking at the vacuum system and low and behold the brake vacuum pipe on the inlet manifold that connects just under the throttle body fell off as soon as l put my hand to it, this was due to the pipe having not one, not two, but three crack/splits in it and on further investigation it was also split where it joins onto a valve and also on the longer pipe to the servo also at the joining valve.

Today after doing a temporary fix (washing machine hose) cut to length, drove over to a friends breakers yard and from some brake servo pipe l got there, with the correct bend on it, repaired the pipe work.

Even with the temporary fix it ran well and is still running well with the correct type of pipework fitted, so fingers crossed, this for now could be the end of the misfire issue, oh yes and the brakes feel much better to, happy days.

Good news, and cheers for feeding back to us all about what you discovered. 

 

Your comment about the cause of the accident maybe being related to the fault turns out to look highly likely. Front impact, brake servo not getting good vacuum...