djleeroy

Hi all, I'm having a problem with my Mondeo ST200 V6. It idles a little lumpy, picks up fine until about 4300rpm, hits a flat spot, then flies off again at about 5000rpm until the redline....

It's been regularly serviced at least every 10k, I have checked the IMRC unit, which is working fine and I have recently replaced the MAF sensor ( a garage diognostic check revealed a fault code related to this) but nothing seems to have changed... still wont rev smoothly throughout the range!

It's really annoying too because if I sort this out, the car will then be A1 (which is rare for me! lol)
Someone on the ST owners site suggested the knock sensor... does this make sense to anyone and where might i find it?

Any help would REALLY be appreciated.

Lee.

cozmeister

iTrader: (1)

MAF or MAP sensor needs some attention. Don't know if the MAP sensor has a rubber hose on those engines, but if it does, it may have perished a little bit and is making an air/vacuum leak...

Does it rev smoothly through the range when it's not under any load, ie, stationary in neutral?

tabetha

It won't be the knock sensor, as it would do it all the time, worse the more load you are under.
I think you need to look for air leaks, as the system is not tolerant at all of air leaks on the induction side, then reset the ecu by pulling the "KAM" fuse(violet 3 amp) for a minute or two, the ecu will then go into a relearn mode, it may be a bit iffy for a few miles but ok afterwards.
tabetha

djleeroy

It revs smoothly while stationary and as far as i can tell, there are no air leaks that i can find...

I'm not sure where to find either the knock sensor or the MAP sensor... i'm so dumb! lol

Pain in the arse!

djleeroy

Found the knock sensor... gave it a clean.... problem remains!
MAP sensor next.... wherever it is!

cozmeister

iTrader: (1)

A Haynes comic would help you no end

Sounds like it's most likely the MAP sensor or its vacuum hose as it revs fine with no load on the engine. Most likely as soon as the load on the engine gets to a certain point, the reading it sends to the ECU is wrong, which is why there's a flatspot, as the ECU is only injecting suffiecient fuel and fiddling with the ignition to suit that incorrect reading.

Replacement's the only way to fix them.

JimmyBoy

iTrader: (1)

I too have a similar kind of problem with my ST200, it just kind of hesitates at around 4k & 5k, almost the same sort of sensation as if you drive through a big puddle, just hesitates a bit and is then off again.

As far as I can tell my IMRC is working, it opens the second butterfly at about 4k.

What I seem to find though is, it seems to drive better when it's cold, ie when I jump in it for the first time in the day, it seems to accelerate better and pull a bit harder and not really hesitate so bad. Kind of leads me to thinking it MAY have something to do with the IMRC still, as the heat from the engine may be having some adverse affect on the IMRC unit.

If you fix yours mate, let us know what the problem was!

djleeroy

The haynes manual doesn't cover the ST200 specificaly and nowhere in the index does it mention the Knock sensor or the MAP sensor, so I have no idea where to look. my local garage is useless... my sister knows more about cars and she's a hair stylist!

Does anyone know if a session on a rolling road would be a better option? The car will be 'under load' so to speak and therefore the operator would be able to see first hand what the problem feels like while driving?

Jimmyboy, if i get it sorted, the whole world will know! lol been driving me nuts!

But feel free to keep me informed of any progress you make and i'll do the same....

Cheers for the help guys,

Lee

cozmeister

iTrader: (1)

Does this help with your IMRC issue?

http://www.fordmondeo.org/wiki/index.php/Fix_IMRC

djleeroy

That was quality, thanks for the link! I might just replace the whole unit with a new one that i have just bought... better to be safe than sorry.

Thanks again bud, your a ledge'

bookwyse

I would be looking at the coil pack and the leads. These are prone to breaking down and causing the types of problems you are having.

Trust me, with a pair of 200's on the drive I have experioenced most problems with them!!

djleeroy

I have just noticed that my battery light comes on when the car is under really heavy acceleration, could this be related to the running problem? My theroy being that the alternator is on its way out and cant cope with the extra load the engine is under at about 4000rpm (the secondaries kick in thus putting on more load) and therefore giving me the power loss?

bookwyse

The battery light will be the altenator on its way out and they are a pain in the a**e to do. I have never heard of on egiving these sort of problems when it is playing up though.

djleeroy

It's been brought to my attention that this is a seperate issue that is easy to fix... ford knew about it and offered a solution. Doesn't help with my original problem though!
I'm gonna start with the coil pack as i'm convinced everything else is in good working order...