My s2 was running great until 2 days ago then all of a sudden its missfiring and overfuelling, took it to my m8 james at woodford garage to check the fuelling (again) 12.5%!!!! and for some reason it will not adjust but we managed to get it down to around 7-8% but it didnt cure missfire have driven it home very carefully with it popping and banging and missing but now it wont idle and it seems better up the rev range from about 50mph onwards, has anyone any ideas as to what the problem is??? I am thinking metering head or the little black unit on the side of it is knackered am i right??? thanks in advance for any help

 

Anyone???????????

 

I would have said them 2 mate,They are never right

 

anyone else???

 

The mettering head might be fooked. make sure the plugs are good and make sure the ht leads are all in the right place.

 

yeah plugs are new 071c's and new motorsport leads, looks like i will be fitting another metering head then!!! Are they easy to fit as never done one before???

 

easy to fit the two bolts under the unit can be a pain, just dont knock any pipes they damaged easy

 

Don't blame the metering unit too quickly, the black box on the side of the metering unit adjusts fuel pressure (and therefore mixture) based on information it gets from the sensors.... meaning you could have a duff air temp/water temp sensor...

Secondly, if you warm the engine up and unplug the wire from the 'black box' it will default to its set position, which should mean the correct fueling on a warm engine and NO BOOST.

Give that a go and let us know what happens.

Rob,

 

Yeah Rob is spot on!
Could be CLT Temp sensor or Black fuelling ECU, or as mentioned the EMFPA (little black box on MU).

 

I had already warmed engine up and unplugged the empfa unit on the side of the metering head and made no difference still missfiring & chucking out loads of unburnt fuel!!!! fucking rst's they get on my tits!!!! any other ideas, would it be a sensor breaking down????

 

yea lol, i remember yours wernt in right order that time

 

Could be something really stupid like the cold start injector stuck open? this could happen if the sensor had failed, is it unplugged?

Rob,

 

Rob yes m8 its unplugged, the other day i soldered a new cold start injector plug and wiring with the existing wires and plugged it in as its a pig to start when cold it made no difference so i cut the wires again and took the plug off, would i have jammed it open maybe when i plugged it in??? as it was fine before

 

No mate, if the injector has no power it will be closed, i have never seen one jam open.... but its easy to check....

I think your looking at the main fuel reg, the emfpa or the fuel ecu now tbh mate, you can do a check on your sensors with an ohm meter i have the correct results at home so will post them up when im back.

But saying that..... if you unplugged the EMFPA and it was the same it could well be that, i have the test procedure for that at home too buddy so will put that up as well.

Rob,

 

Have changed metering unit along with the black box now rob so going to try and fire it up in the morning, fingers crossed lol

 

How did it go mate?

Rob,

 

Fucking thing still wont go!!!!!! got fuel to the metering unit and spark at all 4 plugs, and there was fuel on the plugs so there is obviously fuel getting through but it just wont fire up!!! am going to try again this morning, just a quick question would it be the fuel ecu???

 

It could well be the fuel ecu, if the engine is warm and the EMFPA is unplugged the fuel ecu will have no influence over mixture. i doubt the engine will fire from cold like this though.

Check your ignition timing, swap the black fuel ecu if you can and really check all wiring carefully.

Good luck!

Rob,

 

Its going into woodford garage as my brain is beginning to hurt lol, have changed the black fuel ecu and again made no difference checked wiring no breaks in any of the wiring then checked fuel again and have fuel to the injectors, fuel filter, and metering head, have spark but car still wont go!!!!!!!!!! i give up

 

Car is now going but is misfiring when you rev it on idle its fine, any ideas???? airleak maybe

 

Wouldnt idle is there was an air leak.

 

Any ideas then karlos???

 

Probably just the fuelling out, but whats causing it is the question?!
Take it for a setup mate, if they cant get it right on the RR then they should be able to point you in the direction of whats wrong.

 

Well the metering head is a new (2nd hand) one, so will need the fuelling adjusted anyway, would the fuelling cause it to misfire when you put your foot on the throttle?? as on idle its fine, getting sick of rs turbo's to be honest!!!!

 

try unplugging the cold start, my fiesta was over fueling cause the cold start was constantly on, if that works then the yellow sensor under the inlet is fooked

 

Never had a cold start injector plugged in from the start mate.