6 replies to this topic

[cooperspi]

1275 standard single point injection Mini (Spi)

Car starts and runs easily first time every time, but within 30 seconds you hear the familiar whine of the fuel pump slow and then stop and the car stalls.

Originally it started doing once every 20 minutes or so whilst driving. Gradually it got worse and worse until now it generally won't drive, although If I start the car over and over (ie after 3 or 4 stalls) eventually I get it running for longer periods- say 3 or 4 minutes and I sometimes get it off the drive for a quick burst. Last night I had it running well but ultimately it still cut out.

I have tried everything I can think of:

All plugs pulled apart, cleaned, WD40'd, put back together
Wires checked for splits
Any dodgy connections replaced
Inertia Switch unplugged and bridged with wire (proving its not that)
ECU removed, connections cleaned, airing cupboard over night.
MAP sensor pipes removed, cleaned, unclogged and put back
Disconnected everything other than the main circuits to eliminate any shorts (lights, stereo etc)
Tank removed, respositioned, connections cleaned.
Fresh fuel added
Injection cleaner added
All fuses removed, cleaned WD40'd and replaced
Garage heated
Heater left on inside car
Relay module tested and working. With the cover off you can see the relays working, and when the pump dies these remain on and connected.

I am confused because sometimes its better than other days.

The car has only done 50000 miles and under the bonnet is clean and all the electrics look like new still.

Any more suggestions?

By the way its a 96 so doesnt have in line fuses. No fuses are popping as a result of this problem.

Edited by cooperspi, 15 July 2008 - 12:44 PM.

[DaveRob]

Given what you have done already Id prob take a multi meter and connect it to the pump....when its running you should see the voltage at the pump.... if its going to stop within a couple of mins just leave the meter connected and see if the voltage changes when its stopped working.... this will prove if you have an intermittant fault in the pump....ie maybe its cause the pump is runnin and the windings are getting hot that the pump is failing.... if the volts stay the same its the pump going open cct.....if the voltage dissappears...( as if by magic )....then its NOT actually magic...its a fault in the circuit BEFORE the pump.

Just my thoughs

Hope this helps

Rob

[minicooper1.3i]

Oh dear.....here we go again!

Just had a load of grief myself with an intermittent fault affecting the fuel pump. It turned out ot be a dodgy connection that couldn't carry any current. Get a multi-meter and check the continuity of each part of the circuit; pump to inertia switch, switch to relay pack, etc. You'll probably have to knock up some extension wires to help with this.

As Dave says, you should definately check the voltage across the pump when it's on and off load. You can do this with the tank still in situ by making up two wires with standard male/female spade connectors on each end, and putting them inline between the existing loom and socket on the pump. The pins in the socket on the pump is the same size as standard spade connectors so by extending the loom like this you can get your meter onto the metal contacts on the other end of your temporary loom (where its connected into the existing loom).

Check out my post. Hope it's of some use.

Good luck!

[cooperspi]

Right, I've just connected an old side light bulb I had lying around across feed for the fuel pump as suggest in a previous post.

When the ignition comes come, the pump primes and the light goes on and then off with the pump (as expected). Then I start it and the light comes on again with the pump. Then the usual happens- you hear a change in the note of the fuel pump whir then it dies, and the car stalls BUT the light stays on for a second or two then goes out. It did flciker a little however.

Does this mean my fuel pump has gone?

I'm assuming as the light is on the pump has power but still dies. I'm also assuming it only goes out due to the stall when the relay will switch off the power?

This is exciting- I can feel the end of the misery i've been going through the last few months!!

[cooperspi]

Got my eye on a pump on Ebay so could do with your comments on the above!

[minicooper1.3i]

I reckon you should firstly do as I did and shove 12v straight up the loom from the inertia switch plug to the pump. Take a wire from the + on the horn to the pin on th inertia switch plug which goes to the pump (its a white + purple on my MPi, maybe different on your SPi). Then by sitting in the car, press the horn button and listen to see if the pump runs. If when you hold the horn button down continuously the pump still dies, then you've either got a knackered pump, or the earth point in the boot (at the bottom of the N/S light cluster) is crudded up. If the pump work's fine without dieing then your problem is elsewhere.

If you're got the relay pack open, then you should check the continuity across the relay contacts to make sure you are actually getting a decent supply of juice across them. They will still 'switch' when energized, but may not make a decent circuit. If the contacts look dirty or black, then give them a clean with a bit of emery cloth.

If you haven't got a multi-meter yet, then get one before splashing out on a new pump. There'll be plenty of help on here if you need any direction on using one.

Do the test I suggest above the post back your results.

Good luck!

[DaveRob]

It looks like the pump is going Open cct as the light is on with the pump not running....ie volts are their...but no pump is going....... suggest removing the pump.... or just isolating it from your circuit then supplying 12v to it seperatly..... if it dies after a few mins then the pump windings are going when the pump heats up causing an intermitant fault.....

hope this helps

Rob