Hi, I'm having major problems with my 1.8 petrol mondeo. When I get in the car in the morning, it's all good for a while. Then it starts to cough and splutter. Won't rev over 4000, then 3500 and so on right down to 2000 revs. If I lightly touch the accelerator it will slowly speed up. Then it gradually deteriorates, and if I hit any sort of a hill, it struggles to the point of people passing me on bikes. Any heavy acceleration it just dies, and slows right down.

So far I've had, oil, oil filter, fuel filter, air filter, erg valve (I think it's called) cleaned, carb cleaner into the butterfly. And exhaust disconnected between engine and cat to see if the cat was blocked.

2 codes came up today. P0171 P1131 Any help would be amazing!!

 

http://www.obd-codes.com/p0171 (system too lean bank 1)

DTC P1131 indicates the system is correcting (or trying to...) RICH for an overly LEAN condition.

See other posts ref low fuel pressure.

Should maintain 3.8bar when key on & running.

https://passionford.com/forum/ford-m...-when-hot.html

 

Yeah had a read through your thread, found it after posting. I'll speak to my mechanic 1st thing, though I don't know how he'll test the fuel pressure, as for some reason my car doesn't have the tyre type valve at the top of the injectors.

Thanks for your reply and I'll keep everyone up to date.

 

Just thinking would it be possible for the coolant sensor to be messing the fuel feed up? Or would that happen wether the car was cold or warm??

 

Coolant sensor problems would influence the engine when cold or make the mixture rich.
I am more thinking of an aged MAF or an air leak somewhere.

What's the fuel consumption doing? The same or a lot more?

 

Fuel seems to be a little worse, tho nothing major.

Called up to the mechanics earlier, (3rd mechanic now) and he thinks it's the cat. He thinks the cat is right up at the manifold, and not where it was disconnected, at the 1st joint, at the bottom of the engine. Can anyone confirm??

Anyway, I've to ring him about 3:30 to see if he can squeeze it in this afternoon. Hope to hell he can, and gets this sorted

 

A blocked cat or pre-cat could explain the loss of power.
It does not explain why the mixture is so lean.
A extreme lean condition on the other hand could destroy the cat or pre-cat.
So even with a blocked cat or pre-cat you need to investigate further.

 

Thanks, I'll say this to him. Just a waiting game now, to see if he's correct, when he manages to get a look at it.

If the insides of the cat are removed, will it effect the emissions test??

 

Yes. It would lead to non-compliance.
Also it would lead to a fault code and EML lit.

 

I have looked at a car the same model with the same fault recently, when warm it held back losing power on WOT, the hotter it got the worse it was. When pulled over and got customer to rev car stationary it sounded just like a blocked exhaust, hissing sound and hot gases. Another garage had fitted a new cat and EGR valve.

I disconnected the exhaust both before and after the cat but the fault was still there, this led me to check fuel pressure with a gauge in-line to the feed to the fuel rail and when faulting the fuel pressure dropped to 1bar on acceleration. Strangely this car had no lean mixture fault codes at all.

 

Looks like it's the same as yours GVK. The mechanic thought there was a cat, between where I'd broke it and the manifold, there wasn't. So I'm going to get the fuel pressure tested tomorrow, then I'll try replacing the pump.

 

Lets us know how you get on.