OVERFUELLING: what are the signs?

 

borewash

 

when the petrol starts to run down the 1/4 panel onto the floor

 

lol

 

black exhaust

 

i Have wet plugs, trouble starting, blackish smoke, petrol below plunger in the metering unit

 

Is it a cossie engine? usually the exhaust stinks rich if its over fuelling. I'm led to believe that its better to over fuel than run too lean as this can cause all sorts of nasty thing to happen. EVO's ive worked on always seem to over fuel until you get your foot down. you'll know when you come to have it MOT'd!

 

Its an erst engine in my fiesta just put new engine in, as last 1 blew, am told to put it on emissions macxhine and that it has to be about 3%?? trouble is its running so bad cant get it to stay running (coughs splutters runs and cuts out etc etc

 

I'd guess it is an rsturbo due to the mention of a metering unit.

You are not supposed to end up with fuel BELOW the flap on the metering unit. Only air should be going through there and you might also find a little oil coming back through the breather return.

It does sound like its "over fuelling" but my question would be, is the metering unit stuffed or has someone been playing with the little black box on the side of the metering head which kinda controls the fuel pressure?

Did it ever run right?

RW

 

my cossie managed rst was overfueling last time i took it for an mot.co was over 9% lol which apperently is quite high. plenty of smoke,black exhaust and stinking of fuel

 

Well if u only changed the "engine" not any of the fuelling components which were working previously, I can't figure out what would have changed.

Give more circumstancial information. IE - it was running mint, engine fell to pieces, replaced only the engine and head as a complete unit. I didn't take lots of plus off (well u probably did) I reconnected everything perfectly, maybe u didn't etc - then we can give u more of a suggested fault finding path than "get it checked by a pro" which is what is probably coming!

Cheers

RW

 

Sounds all wrong to me! 9% is quite a bit too high. I suppose the idea of sticking cossie management on it, is so you can set it up better. So far not so good

RW

 

Had an hydraulic lock blew bottom end right up,
Ran sweet as before
New engine is fresh everything
was told metering unit would need adjusting to suit new engine? as old engine had a power engineering sticker on it though wasnt sure what theyd done 2 it,(i.e old engine say 150bhp new one 130bhp would hav 2 adjust it to make up difference?).
booked in at interpro to be set up on their rollers, but it only runs then cuts out now, will they tell me 2 bring it back once its running or will the guy try and get it running as part of setting it up during the session?

 

Statey - first of all, I would check that you have plugged EVERY plug in properly. Especially those behind the inlet manifold, they control water temp check etc. If they are unplugged it will run really rich thinking its freezing cold. They are all colour co-ordinated and people here will be able to point u in the right direction for most of them if you are confused. I once forgot to plug one in behind and below the inlet manifold (it is part of the sandwich plate between inlet manifold and head) and it ran like a bag of shit iirc.

Once you are sure EVERYTHING is plugged in right, then I would be surprised if both are 1600 cc's if they are needing fuelled that much different, suppose they might. Interpro, I guess, if you tell them in advance, will be more than happy to set the base fuelling.

You could always adjust it yourself, but it might be a bad idea. I would check ALL the plugs are put in the correct places first!

Cheers

RW

 

Thanx steven, i do actually have a dodgy connection on the plug which sits at the back of the inlet manifold in the middle, what does that control? will sort it this pm

 

Statey - I sold my rsturbo in about 2000 or something so it has been a while!

However I spent LOTS of time working on it and you don't tend to forget!

It will tell the ECU the temperature of the water in the engine. From this, the ecu decides if the car is cold or hot. If it thinks it is cold, it adds lots of fuel, kinda like a choke did on an old motor.

So basically the thermostat "thing" provides a different resistance when cold to hot through an entire range of movement/values. When you don't plug it in, it assumes the car is utterly freezing as the resistance is really high and therefore adds tonnes of fuel.

That is all correct in theory, however, I didn't ever check the resistace so the scale might be opposite to how I have mentioned. IE higher resistance when hot than cold, but at the end of the day, the theory is the same and if that plug is not connected properly, the car will decide to add tonnes of fuel

Good luck sorting out the wiring, check all the plug colours match their connector colours too

Cheers

RW

 

Thanx Steven u have been much help will check plugs and let u know how i get on