22 replies to this topic

[mikespicooper]

1993 spi cooper 2 socket ecu runs on 3 at idle whe engine res up runs on 4.

changed spark plugs dizzy cap ht leads and all vaccum and breater hoses tighte the inlet manifold ad checked te gasket compression test all 4 cylinders the same reading....

any ideas???

thanks in advance mike.

[Miss Andrews]

I'm having a similar issue - can you let me know what the cause is when you find out. And visa versa of course

[mikespicooper]

the problem still exists but i think that it might be the valve seats of the particular cylinder but i've sent the car to a automotive electrician to check the sensors and the ecu if they are functioning correctly another point to consider is the injector or the crank position sesnor and affects the pulse of the injector at idle.....this can be happening if the flywheel is not at the correct position by meaning that they have the tendency to fly off the crank that happened to my cooper twice or if the relactor ring has slanken of the flywheel or broken or the sensor has been hitted while installing....

[Miss Andrews]

It's taken a little while but we have solved the problem with my Mini 😃

I took him to the Injection & Carburettor Clinic in Birmingham (0121 3555757). Although it didnt show on their diagnosis too,l they found the problem anyway.

It turned out that the inlet manifold bolts had come loose so more air was getting into the system on cylinders 1&2, and 3&4 then run rich. Who'd have guessed!

Tightened them up and he's back to normal!

Presumably not tightened enough after head gasket done years ago.

Good job boys!

[FlyingScot]

Miss Andrews thanks for taking the time to update your findings!
Glad your mini is "cured" and it helps all of us to explore possible causes for the faults people find.

FS

[mikespicooper]

i have done the same and also changed the manifold gasket and vacuum hoses but the problem still exists....we are up for the lambda sensor now....i will let you know.....

cheers!

[firstforward]

i have done the same and also changed the manifold gasket and vacuum hoses but the problem still exists....we are up for the lambda sensor now....i will let you know.....

cheers!

 

Why would a lambda sensor only affect 1 cylinder?

[jaydee]

Its a Single point injection, no way the injection and its sensors can cause this problem!

Investigate on the ignition and vacuum leaks (tappet clearance?).

[mikespicooper]

tappet clearance checked HT leads checked spark plugs are RN9YCC now it was running on N9YC when it came to my garage and had vacuum leaks allover the manifold.....few hours ago i contact the owner and told me that he has changed the lambda sensor but they removed the metal cover which protects the sensor from the fire in the manifold and to keep the heat inside the sensor as it is a preheated unit because it wouldn't fit in the manifold he said so they removed it and destroyed the sensor also the car won't accelerate properly and above 2000 rpm it runs on 4 cylinders....i think you must be very stupid to do that thing on a new sensor you just buy the right one for the job.....i will change the sensor with a proper one to see if this cures the problem if not then it is the valve seats and the valves that have the problem so i will remove the cylinder head....!

[minidaves]

tappet clearance or valve issue

[mikespicooper]

tapped clearance ok....if it is a valve issue then why the engine revs up and working with all 4 cylinders? in the case it was a valve or valve seat issue the valve would leak regardless the engine speed even being 6000 rpm it will still be leaking but it only runs on 3 cylinders at idle!

[xrocketengineer]

Did you replace the dizzy rotor?

[mikespicooper]

parts changed: rotor arm

                         HT leads

                         spark plugs RN9YCC

                         vacuum hoses all

                         charcoal canister and breather hoses

                         manifold gasket

                         tappet clearance checked

                         ignition timing checked

                         stepper motor indexing checked and adjusted properly

                         fuel pressure checked

                         vacuum hose to servo checked

[xrocketengineer]

When running at idle on three cylinders, do you have a spark on the HT lead for the non running cylinder?

[mikespicooper]

yes i have spark and the problem is only on cylinder no 3...