8 replies to this topic

[nomoreheroes]

Hello,

 

My 1991 SPI Cooper will turn over but it won't fire up. I've hit the limit of my abilities diagnosing this fault. But I'm now stuck and about to send in the professionals.

 

Coil, plugs, distributor cap and rotor arm all recently changed. Battery is brand new.

The fuel pump works at all times.

It has run twice since February, so the fault is intermittent (as in the fault sometimes doesn't show itself). When it runs there is no loss of performance. It either runs or it doesn't. On all cylinders, with no stuttering or hesitation. So something is stopping the ECU from doing its job. I'm currently thinking about a fault with the sensors attached to the MEMS, the crank sensor. Or a relay fault.

 

 

The internet has been pretty good. I've thoroughly read these threads:

 

http://www.theminifo...oint-injection/

 

http://www.theminifo...osition-sensor/

 

and

 

www.cantyminiclub.com/tech/miniecuproblems.doc

 

 

I did think it was the crank position sensor, but one of the threads suggests that if the fuel pump always runs, the sensor is okay.

 

So, what am I missing?

 

What can cause a car that is in good condition to just not start.

 

I would appreciate any advice you can give.

 

Thankyou.

 

Elliott.

 

 

[nomoreheroes]

N.B. I had it running at the weekend, but tried to restart it soon after for the problem to reoccur.

[hunterg30]

I would change the crank shaft sensor . Is the coolant sensor ok ? Unplug all the relays under the bonnet area and make sure all connections are clean and sound including the pegs on the relays. Can you borrow a fault code reader something like an acr4 . This will help point to where problems might be

Edited by hunterg30, 17 April 2018 - 04:44 PM.

[nomoreheroes]

Hello, I was reading that as the fuel pump works the crank sensor is should be okay? Can anyone confirm?

Also, if the cam sensor is faulty this could be the source of the problems (engine not firing up)? Is this true? Not that I can see it.

Thankyou.

Elliott.

[FlyingScot]

With the exception of the crank sensor (which stops fuelling if the motor isn’t turning) it won’t be a sensor. If it is fuelling then it isn’t the crank sensor.
What happens when it won’t start?
Is is spinning on the starter?
Is there a spark ? Is the SPi unit spraying fuel ? (Take off the air filter and look)
More likely the wiring to be honest with the age of car and intermittent nature.

FS

[FlyingScot]

No cam sensor on this.

You need a multimeter or a friend who has one to check the basics, including earths and power to the MFU (Relay pack) and ECU.
A bit of corrosion can play mayhem with these.

FS

[nomoreheroes]

I was hoping it would be something that could be easily replaced. Thankyou for the info FS. I'll take my multimeter to it again tomorrow.

 

It is spinning on the starter. I am presuming that if the pump is pumping fuel it is getting to the cylinders and the sparkplugs aren't sparking. I'll confirm the situation for both tomorrow.

 

Elliott.

Edited by nomoreheroes, 17 April 2018 - 08:16 PM.

[nomoreheroes]

Oh and the other thing that made me think component failure rather than wiring was the OFF OFF OFF ON OFF nature of the fault in that there was no faltering or degradation or hesitation in the running of the engine. And when it didn't work it really didn't work at all.

 

Elliott.

Edited by nomoreheroes, 17 April 2018 - 08:33 PM.

[nomoreheroes]

The problem quickly improved as its got warmer. I think it might have been damp maybe. Inspecting and cleaning the corrosion from the relay box and warming the ECU on the radiator, might have been the major turning point.

But I can't say what definitively fixed the problem.

Thankyou for your help.