Fuel pump problem R300 After a good blat

[Billyboy]

OK looked through the archives and only 1 post for this problem, with no conclusion ☹️

 

After a lengthy blat today parked car on drive, moved other car to gain access in to garage and attempt to start the caterham.

 

NO fuel pump priming noise when ignition turned on ❗ Crancked engine and lots of spinning but no firing

 

Goes back 30 mins later ignition on Pump priming noise and hey presto..............

Goes back again and all still well pump noise and fires up. This is a first for me

 

So any thoughts please 🤔

[Billyboy]

I have just been out to the garage again and give it a try.............all fine.

 

 

[Mike Biddle]

I had a problem like that recently, on a tour in Norway, car ran fine all day, then next morning would not start.

 

With the generous assistance of other tourers the fuel pump was removed and examined, a small amount of dirt removed and it appeared to work, so we put it back in and...no go. Checked the wiring and found a loose connection, fixed that and bingo! Works a treat.

 

Now my system is totally different to yours, but the lesson is the same as always, check the simple things first!

[Billyboy]

Mike thanks for reply.

 

Have gone back to basics as always with these cars and checked the whole system from pump to fuse box, with regard to electrics. All seems to be in order.

 

What I need to know is just how these pumps fail, I mean do they just stop or is this intermittent working / failing a charicteristic of imminet failure.

 

AT the time

 

Tank was 1/4 full

Car had just been on a decent run

Car had been parked twice within the run (With no such problem re-starting)

Car had stood for 1/2 hr after long run

Car temp had dropped to about 55/60 ish deg on the temp gauge

 

I am scratching my hairless head

 

Anyone have any other ideas Please *cry*

 

Forget the health food. I need all the preservatives I can get!

[Mark Durrant]

Have you checked to see if the relay has worked loose 🤔

 

Mark D

Comp Sec

 

[Billyboy]

NO but I am now right now ❗ ❗

 

Forget the health food. I need all the preservatives I can get!

[Tom_C]

Dunno how an R300 is immobilised, but on my mems car the immob sometimes cuts the fuel pump if the car has been parked for a bit. It'll fire on the fuel left inthe rail, but then die immediately, and then takes ages to prime through. Most often happens on fuel station forecourts, which is embarrassing.

 

BTW please give generously to Bundle's Big Charity Walk for Asthma research here Ta.

 

Cheers

 

Tom

 

FH54WLX

 

see here - UPDATED again

[Billyboy]

OK so I have found all relays and checked for connection I assume the fuel pump relay is under bonnet next to MBE engine management unit checked all plugs there.

 

Now theres a point I have an imobiliser that has a loop of wire near the ignition switch, If the key ring thingy does not go near it then it stops engine I assume via cutting fuel pump power??

 

I will try that.............

[Billyboy]

Tom C

 

*thumbup*looks like you MAY have cracked it

 

Well done ❗

 

 

Forget the health food. I need all the preservatives I can get!

[Billyboy]

Thanks everyone ❗

 

bill

 

Forget the health food. I need all the preservatives I can get!

[Mark Durrant]

The relay for the ECU/fuel pump is under the dash by the fuses.

 

Mark D

Comp Sec

 

[Rob Walker]

I thought that the fuel pump relay was inclosed within the MFU ( multi function unit) this is usually mounted on the scuttle tray in the engine bay.

[DSL]

Had exactly the same, it was the Relay that had worked slightly loose. A good push & a cable tie round it, no further problems

[Billyboy]

Mark D my fuel pump relay is not under the dash, well I cant see it anyway! there is only a fuse box and all labels correspond with whats there no mention of fuel pump in that area.

 

However there is a black box next to the MBE ecu ROB WALKER that I think is the relay as it clicks when ign on and fuel pump sparks into life! This was loose and needed a push back in.

 

I am now not sure it was the immobiliser but was infact the loose connection at the relay, as I recall when there was no pump noise there was no click either.

 

However the Immobiliser does shut off the feed to the fuel pump BUT the immobiliser light flashes quicker when trying to start car without disarming it - I had not noticed this during the original problem, so I assume it now was not the immobilizer.

 

DSL good to know I am not going mad will do similar with a cable tie *thumbup*

[Billyboy]

I had thought this fault was resolved but it seems its been a failing MFU 🤔

 

BUT my question is why should it fail only after a 30 min blat and then turning ign on does not illicit a fuel pump buzz.........wait about 15 mins and NO problem.

 

I have narrowed it down to the MNU as there is no CLICK of the relay unit when restart when hot is attempted.

 

So can anyone shed a little more light upon this for me

 

bill

[Billyboy]

I am talking to myself..................cleaned up all the pins on the MFU and have gone for several runs with NO problems.

 

Could it be that??????????????????????