Fuel cutting out while idling

[Bonzodog]

I have an F-reg 1989 Montego estate with the carburetor 2 litre engine. The car drives fine except that it cuts out if it is left idling for about 5/10 minutes. Leave it 5/10 minutes and it will then fire up and run fine.

I have had the fuel pipe off the carb immediately after it has cut out and cranked and there is no fuel coming out so it is obviously a fuel issue.

So far as I know there is no fuel filter on this model.

Anyone any idea as to the cause of this?

[G Force]

I
Anyone any idea as to the cause of this?

Hi

Yes the problem is that the peirburg electric fuel pump fitted to your car is prone to cavitation.

The problem can be that either the fuel pump is mounted upside down or the pump is faulty.

Check the pump is fitted the correct way up (the wiring plug should be at the bottom). If the plug is at the top it is possible to spin the pump in its foam mounting. The pump is glued to the foam so you do need to use a little bit of force to release the adhesive bond.

If it is mounted the right way up then fit a new pump.

The pump is located under the car in front of the tank. You are correct about there is no serviceable fuel filter,

Cheers, G Force

[Bonzodog]

Hi G Force

I had known about the cavitation issue. I assume that what happens is that bubbles form in the fuel to the point where the pump is trying (but fails) to pump air. The pump can operate again when the bubbles settle out and the pump has unaerated fuel to pump again. Is that right?

I did check the fuel pump position. Sure enough it was fitted upside down (i.e. electrical connector at the top) but turning the pump has made no difference.

The pumps I can see online are listed for injection models, are these different? Also, does anyone do a pump with the standard connector so I don't have to chop off the connecting plug and use replacement ring connectors?

Best Regards
Richard

[Bonzodog]

Sorry, meant to add - thank you to G Force for your swift reply.
Regards, Richard

[G Force]

Hi G Force

I had known about the cavitation issue. I assume that what happens is that bubbles form in the fuel to the point where the pump is trying (but fails) to pump air. The pump can operate again when the bubbles settle out and the pump has unaerated fuel to pump again. Is that right?

Yes that's basically it, the vane type pump isn't able to pump air. Also if the pump has a faulty relief valve the pump can overheat at idle, with the excess heat exaggerating the vapourising issue.

The pumps I can see online are listed for injection models, are these different? Also, does anyone do a pump with the standard connector so I don't have to chop off the connecting plug and use replacement ring connectors?

Best Regards
Richard

Most of the pumps listed are as you say for fuel injection variants and are not suitable for your application.

I don't know if you can source the exact replacement, you may even have to go after market? The same pierburg pump was also fitted to the rover 216 carb versions and the later petrol freight rover Sherpa vans

[Bonzodog]

Just thought I would confirm that a new pump has cured the problem (thank you, G Force). I ended up going after market which I didn't like because the terminals are exposed to wet etc but I have protected them as best I can with a dab of grease and a sheathing of duct tape.

[Jeff Turbo]

Which aftermarket one did you get as my advantage seems to have the same problem?

[E_T_V]

You'll want something with an outlet pressure of 3 to 5 psi usually for the SU carb.

[Jeff Turbo]

Ahah I have one in my spares, and I've found it. Original nos too.
Works a treat now and doesn't cut out. Just been in and out of Lincoln City centre and left it idling for about 15 mins. Sorted