Faulty Fuel Pressure Regulator?

[rippedoffagain]

Hi all

Some of you may have seen my other threads about my engine troubles, but as I didn't choose very descriptive titles I thought I'd try again.

On my 940 estate, 2.3 normally aspirated, I get the following aggro:

* Lambda light comes on from time to time
* random lumpiness at idle (ok most of the time then the whole car will shiver briefly)
* Smell of petrol when first starting up, which I think is coming from the exhaust end
* Starts every time, but needs to be turned over a bit more than it used to.
* Random rough running and reduction in power

From what I've read, both in replies on other threads, and on the FAQs, it seems fairly likely to be the fuel pressure regulator that's at fault.

Could it be anything else?

Someone said that sometimes when they fail, petrol leaks down the vacuum hose straight into the inlet manifold after the throttle. Is this the only way they can fail or can they pull other tricks too? If so how would I diagnose it for certain without proper gear?

Are they a nice easy job to change?

If petrol has been leaking down the vacuum hose, that would cause the engine to run rich I believe. Would that mean the cat and lambda sensor will be done for?

[rippedoffagain]

Anyone?

Oh and I have an update: I pulled off the vacuum hose after driving home tonight. I did it straight away as soon as I'd switched the engine off. There was a faint wiff of petrol, but not much. I know that if there is a smell of petrol it is supposed to mean a bust FPR, but how strong a smell to indicate this? If it is a very weak smell, is it still bust, or does it have to practically take your breath away?

[rippedoffagain]

No ideas? I'm sure someone here knows?

[minesa240x3]

Hi there,I have just spent half an hour searching my 940,740 and 240 manuals and it doesn't cover the fuel pressure valve except to say expect some fuel leakage when disconnecting it.
I would imagine that if the diaphram was leaking then the smell of petrol would be quite strong.The pressures involved in operating the valve are quite high so this would account for the running rich.
I'll keep looking,Regards Brian.

[RealEstate]

If your FPR is original, and yours looks a bit rusty, you might wish to replace it anyway.
I got my OE Bosch one from PFV.
Alternatively to test yours, you could swap it with a known good one to see if it makes any difference.
Let us know what you find,
Ben

[rippedoffagain]

Thanks for the info chaps.

My FPR is little more than a lump of iron ore. It is the single most rusty part of the whole car, so I reckon I'll change it anyway. I'm just being tight by trying to avoid spending money too hastily in case it could be something else.

Another though occurred to me tonight. When I pulled off the vacuum hose, it came off very freely. I wonder if air is getting in though it, as that would be after the MAF sensor sensor, so maybe the lambda sensor was detecting a lean mix (am I right in thinking the light comes on if the mix is too lean as well as if it is too rich?)

I'm going to chuck through some fuel system cleaner in case the injectors are sticking. When I can afford it and have the time, I'll see if Jim on here will clean my injectors properly for me.