6 replies to this topic

[Willowfest]

Hi all,

 

In the interests of not pouring a gallon of petrol over my Mini Equinox and setting it alight through sheer frustration, I thought I'd 

better ask the Gods of Mini Wisdom for some help 

 

I've been chasing my tail on this for a few weeks now and getting nowhere.

 

The immobiliser arms perfectly well, the alarm sets and activates as it should. Batteries have been changed in both of the two button fobs.

The immobiliser appears to disarm correctly with a click and the red light extinguishes as it should.

 

My problem is that randomly, (though more often than not at the moment) my SPI will happily crank over, but not start.

 

I read all about the immobiliser pairing to the ECU and pre-priming the fuel pump for a few seconds etc.

 

The pump wasn't priming, but the starter would crank over happy as Larry.

I temporarily wired the fuel pump directly to the battery, and cranked again... no start...

 

I spoke to Technozen Electronics, and they don't think it's an immobiliser issue (presumably because it cranks as it should?)

 

I've since discovered that if I take the cover off the relay pack, place the ignition switch to on, and manually hold down the fuel pump relay, the main relay and then the starter relay, it will

crank and start perfectly happily on the first spin. Sometimes I can let go of the relays, and it will carry on running no problem.

 

Other times, as soon as I let go of the fuel pump and main relay, it dies instantly.

 

As I mentioned, sometimes, I can cancel the immobiliser, turn the key... and hey presto, the fuel pump primes, the engine cranks and starts on the first spin!

 

It all seems so random! I'm pulling what little is left of my hair out, and any help would be really appreciated 

 

[Earwax]

Failing relay unit ?  - i think you cannot replace just a single relay (guess only) - my theory is that anything manufacturers put in a black box - it is destined for trouble.  Sorry no help but i feel your frustration.

[Willowfest]

Thanks for your reply Earwax,

 

I don't think it can be the relay unit. When it works, all of the relays work, in the correct sequence...including the master relay taking abot 10 seconds to disengage after the key is switched off.

When it fails to start, non of the relays engage at all.

I can't imagine they all fail at the same time every time? I'm thinking there has to be a common denominator somewhere.

I've tried wriggling the wiring loom and multi plugs, the fuse block looks good, with no visible corrosion or anything ... 

 

I'm stumped 

[68+86auto]

Load test the battery and connections as a start.

The voltage at the starter terminal must be above 9.6v while cranking. Low voltage can cause all kinds of issues in vehicles full of electronics and relays.

[bpirie1000]

The spi runs a vacuumed line.. these could be to blame for such issues...

 

 

Check this out also. Great insight into what is going on....

 

https://www.theminif...-functionality/

 

 

Edited by bpirie1000, Yesterday, 06:32 PM.

[sonscar]

Not familiar with mini EFI but generally the ECU supplies an earth to energised the main relay which in turn starts the others.I would unplug and check connections to the relays and ECU looking for corrosion.Check the loom especially neat places it can rub on.Examine the relay holder for corrosion and loose pins.Be methodical.Good hunting,Steve.

[FlyingScot]

Thanks for your reply Earwax,

 

I don't think it can be the relay unit. When it works, all of the relays work, in the correct sequence...including the master relay taking abot 10 seconds to disengage after the key is switched off.

When it fails to start, non of the relays engage at all.

I can't imagine they all fail at the same time every time? I'm thinking there has to be a common denominator somewhere.

I've tried wriggling the wiring loom and multi plugs, the fuse block looks good, with no visible corrosion or anything ... 

 

I'm stumped 

It's not the MFU (relay pack), the operation of this is controlled by the ECU and appears from your testing and logic to be working correctly.

 

Likewise the immobiliser is doing its job.

 

So there are several other things to check.....

 

Start with the basics - when it cranks but doesn't start check for

 

1) Fuel - removal the air cleaner unit and check that the injection unit is spraying

 

2) Spark - either remove a spark plug or use one of those inline things between the lead and the spark plug.

 

One of those isn't happening and I highly suspect you will find a spark but no fuel.

 

The crank sensor on an SPI signals to the ECU that the crank is turning, if it doesn't after a few turns it will cut fuelling to prevent a fire / fuel in the bores ( I drops the fuel pump relay).

 

So please check the fitment and connection of the crank sensor if fuelling is missing.

 

If sparks are missing check all the basic parts - leads, cap, rotor and coil

 

As  others have said of the earths and wiring - the age of these now mean that often you have to chase down internally broken wires from actuators and sensors to/from the ECU other components as sadly heat and corrosion have taken their toll.

 

 

FS