Fuel pressure regulator

[John Halford]

I'm having reliability issues with my 1991 Torslanda (B200F - injection). Symptoms are: from start up everything is fine until I have driven half a mile. Then the engine dies. It doesn't cut out completely straight away, but lacks all power and it's impossible to keep the revs up. Then it dies.

If I wait ten minutes or so it will start but won't idle - I have to keep pumping the throttle. Eventually it seems to burst into life and I can drive away again.

A few days ago I replaced the under-car fuel filter. This has made no difference. This is my first Volvo with petrol injection and I have to confess that I don't know much about it. While on the phone to Brookhouse (ordering some unconnected parts) I asked if there was a second fuel filter but he didn't think so (not counting the one in the tank if it's still there). I asked about a metal cylinder about an inch and a half diameter and two inches long on top of the engine towards the front. This unit seems to have petrol coming in (from the under-car pump and filter?) and petrol coming out into the injector pipework. There also seems to be a small diameter (vacuum?) hose connecting to the intake manifold. What is this device? Could it have failed, and would that give the symptoms I have described?

To me, everything points to a fuel blockage of some sort.

I would be grateful for your thoughts.

[timetrip]

Originally Posted by John Halford

I'm having reliability issues with my 1991 Torslanda (B200F - injection). Symptoms are: from start up everything is fine until I have driven half a mile. Then the engine dies. It doesn't cut out completely straight away, but lacks all power and it's impossible to keep the revs up. Then it dies.

If I wait ten minutes or so it will start but won't idle - I have to keep pumping the throttle. Eventually it seems to burst into life and I can drive away again.

A few days ago I replaced the under-car fuel filter. This has made no difference. This is my first Volvo with petrol injection and I have to confess that I don't know much about it. While on the phone to Brookhouse (ordering some unconnected parts) I asked if there was a second fuel filter but he didn't think so (not counting the one in the tank if it's still there). I asked about a metal cylinder about an inch and a half diameter and two inches long on top of the engine towards the front. This unit seems to have petrol coming in (from the under-car pump and filter?) and petrol coming out into the injector pipework. There also seems to be a small diameter (vacuum?) hose connecting to the intake manifold. What is this device? Could it have failed, and would that give the symptoms I have described?

To me, everything points to a fuel blockage of some sort.

I would be grateful for your thoughts.

its the fuel pressure regulator...and i think you have 2 fuel pumps one underneath and one in tank.....any other advise ,,maybe another member can help you..

[John Halford]

Thanks timetrip. So... could the fuel pressure regulator being faulty give those symptoms? Is that the likely culprit?

[230ina245]

A faulty fuel pressure regulator can give problems. Not 100% certain it is your problem but it is easy enough to check.
The regulator works by using vacuum or pressure from the inlet manifold to operate a diaphram. If the diaphram becomes ripped or torn it ceases to function properly.
The vacuum gets to the regulator through a smallish bore pipe running from the manifold. The other thicker pipe on the regulator is a fuel pipe going to the fuel rail.
To check if the regulator is ok carefully pull the small pipe off the regulator (there is no clip on it usually).
If petrol comes out of the pipe or if it smells strongly of petrol then the diaphram is no good and another regulator is required.
The regulator cannot be dismantled in a non destructive way.
You can find the strength of the regulator stamped on it's body - usually 3 bar but some are 2.5 bar.
These cars came with only one fuel filter. The early cars had it on the bulkhead, but later ones have it under the car.
Tim

[classicswede]

It does sound like a lambda sensor issue. The ECU does not react to lambda signal until it has warmed a little and then it starts to adjust.

The FPR tends to leak fuel into the vacuum pipe connected to it as the typical mode of failure causing over rich idle

[mrredwards]

Hi Had a similar problem with my 240.Changed the fuel regulator no change.
Replaced the Coolant Temperature Sensor the one under number 3 cylinder under the manifold.Problem solved.

[John Halford]

230ina245, thanks, I pulled off the vacuum hose and all looked - and smelled - good. No petrol came out. I'll see what happens if I try with the engine running.

Classicswede, the catalytic converter has been "rodded through" and the sensor which plugs into the side has had all its wires cut. (All before I bought the car). So I don't know how the ECU ignores this, but the car has worked fine for my three years of ownership ... until a few weeks ago.

Mrredwards, thank you for that suggestion. I'll try temporarily disconnecting the temperature sensor and see what happens.

[John Halford]

Hmm. I can't actually see the coolant temp sensor - it's all obscured by inlet manifold etc. Tell me I don't have to take that off!

[Bugjam1999]

It’s a common misconception that you’ll need to remove the inlet manifold to get to the coolant sensor- you don’t. You’ll need a deep socket and only replace it with a Bosch one- the other sensors available seem to fairly quickly.

Cheers

[John Halford]

Bugjam, thanks for that. My problem is that I don't know exactly what I'm looking for or exactly where it is. There's a lot of manifold metalwork and hoses etc. in the way!