Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Plus 8 - Fuel Pump relay

Can anyone confirm the designation of the fuel pump relay for a 1995 Plus 8 ?

I'm thinking my car may have the wrong relay fitted.

The Lambda sensors (which are supplied from the relay) weren't energised until the ignition was turned OFF and the battery was discharging overnight as a result of this.

We altered the wiring and the problem has gone, but I've since read that the wrong relay will give exactly this issue.

12 volt relays used are usually generic mini cube shaped 12 volt 30/40 amp with internal diode protection and type B pin layout, available here. Usually 5 pin changeover type with 5th (87a) pin unused unless application requires, so allowing them to be interchanged. The lower current rating refers to the changeover contact 87a made when coil NOT energised BTW.



Thoughts are that someone fitted a type A relay despite them being far less common if even available now. They work the same and have the same pin references but pins 30 and 86 have reversed positions such that in the OE socket would make the wrong connections . Note the type B pin layout is easier to comprehend as pins 86 (+ve) and 85 (-ve) are the relay coil connections and pin 30 the power in, switched to either remaining pin.

Strongly recommend that if your "altered wiring" were to accommodate a type A relay you bin this, revert to OE socket connections and fit correct type B relay. This to save future similar issues. Important it has diode protection BTW particularly with EFI.

Thanks for that and it does explain the anomalies. Looking back through the paperwork the previous owner did have a new relay fitted some time ago. Clearly the wrong type.

Not unique to my car as I first became aware of this possibility, and the consequences, from a reference on TM. Unfortunately I can't find the thread again !

Googling the V8 fuel pump relay, the suggested replacements don't appear to have the diode fitted. The model coming up is AFU2913L

Can anyone confirm, or otherwise ?

That's the correct relay, I always have two onboard the reason being new old stock one's are prone to failure.

Bosch for me every time.
Rimmer sells them at MMC prices 70 smackers

That's great thanks. Two ordered.

Just to add, I went for original Bosch and they do have internal diodes.

As I suggested you don't have to stick to specific part numbers generally with relays, particularly as MMC have been known to fit dubious quality ones of unknown provenance. Better a quality brand and obviously to the correct spec., 40 amp being fine. Durite is such a brand even Bosch have been known to give problems, possibly cloned ones though. Good call using a diode one wherever sensitive electronics are onboard. The fact that originals didn't have such diodes highlights my points.

Thanks Richard, worth knowing about the Durite brand. £5 vs £25 or even £70 as +8Rich has pointed out.

The cost variation from various suppliers is frightening. I usually try to buy OEM, but these days that doesn't always mean much.

In a manner of speaking companies such as MMC paint themselves into a corner with generic and service parts readily available elsewhere. They are obliged to stock them but likely have poor sales due to many knowing where else to buy at realistic prices. Consequently they have huge markups to cover their stocking overheads.

When I was in the motorcycle parts business I tried to avoid marking up low turnover parts too much by writing them off against tax a.s.a.p. That way when I did sell one I would still make a fair clear profit. Re-stocking was another matter of course.

Richard, your post caused me to remember circa 50 years back, while next in the queue at my local independent s/h m/cycle dealers workshop, the owner was a keen m/cyclist himself, the guy in front of me was in need of either a jet or a float for his Amal TT carb.... the shop owner pulled out a TT carb and stripped it down to to remove the required part, and once removed he told the chap the price, to which the reply was HOW MUCH... the dealer said nothing and just began to replace the part and rebuild the carb... At which point the chap seeking the part then said OK, OK, to which the owner replied that the part was now unavailable to the intended purchaser at any price...

At the time I was in the process of re- customising my recently acquired Norton Dommie into a cafe racer whereas the previous owner had tried to make into a chopper, kinda hints at the period of time... (-: I was also a semi regular at the dealership and had always found the owner to be a fair minded chap, thus I doubt that he was likely to have overpriced the required part...