7 replies to this topic

[mininutter]

I believe the ignition is retarded on my 1996 MPI. I initaily thought it was a lose clutch and flywheel. But the vibration is the running engine not running perfectly. The vibration up the steering column is really noticable about 2000rpm(zero MPH), including the rattling dash. I can only assume the sensor and flywheel are not the way it was before doing the clutch. The reason for the disturbance been an oil leak from the crank onto the clutch. The work was carried out by a very expirienced (Not with a MPI) and trusted mechanic.

I found some forum posts about getting past 2000rpm at it all goes poo. The pickup was found dirty, cleaned and all was well. But mine feels fine under load at 3500rpm and above. Still noticable the incorrect ignition.

I cleaned the sensor which was covered in oil, but it made no difference. I don't think oil on the sensor would make much difference as I believe it only detects the magnet on the flywheel to know what position the crank is in for the ignition.

The flywheel is the orginal, just the clutch and pressure plate were replaced. What about the magnet, can that be adjusted? Can the ECU be reset? Where's my Haynes manual when i need it!!! Anyone else to the rescue? Is it time for a trip to a rover dealer? :'(

[Sprocket]

The only thing that controls the ignition timing on the MPI is the ECU. It takes a reading off the flywheel sensor to determine the rpm, it then takes a reading from the MAP sensor to determine manifold depression. The ecu uses this information and compares it to the set program to determine the ignition advance.

There are no magnets on the flywheel, the sensor is a reluctor. It changes the signal when in close proximity to metal. The missing teeth on the flywheel will produce a changing pulse that the ECU can read.

There will be no problem with the clutch you have fitted. The Injection clutch diaphragm is different to the carb ones and if they have been crossed the engine would not even try to start nevermind run.

The MPI is a wasted spark system. There is actualy two coils with in the one 'pack' spark plug 1 and 4 should be connected to the first coil and plugs 3 and 4 to the second, as th which is which i have no idea.

Ensure the plugs are the correct type NGK BPR6ES and in good working order with the correct 0.8mm gap. Check the plug leads are in good condition.

That is all you can do with the ignition system.

I, how ever believe the true origin of your problem to be fueling, the prime candidate being the Lambda sensor in the exhaust, next being the Coolant temperature sensor and next the throttle position sensor. The MPi has a cam phaze sensor reading the position of the exhaust valve on number one cylinder. If any of these sensors are faulty the ECU will go into open loop control and switch to the limp home mode. This is a set of fueling and ignition parameters that alow the engine to run but at much reduced efficiency.

The only acurate way to check the correct operation of any of the sensors is to connect the ECU to an apropriate Service tool. Using a calibrated thermometer to check the acuracy of temp sensors. Lambda sensor should be checked for voltage swing between 0.2 volts to 0.6 volts. The manifold absolute pressure sensor(MAP) can also be checked.

Other than this I am a little confused as to how you have determined the ignition timing is causing a vibration. How does the car drive, what colour are the plugs, when was the lambda sensor changed, when was the fuel filter changed??

[mininutter]

Cheers Mini Sprocket, I appreciate your time on the dark art of injection.

The vibration of the steering column was first thing I noticed. But its from the engine, its very consistent. With the increase in RPM to 2000rpm it's at it's worst, best described as retarded ignition almost missing. The car starts fine. Driving the car I did not feel a performance decrease but I really haven't done more than limp it home in fear of damage.

The car was running perfectly before the disturbance. A discussion with the mechanic revealed he did not removed the sensor, could a slight knock to the cooper pin bugger it up? When I inspected it last night it didn’t look damaged.

The car did the Italian job last year and I've been hot on the maintenance, fuel filter, air filter, spark plugs, leads etc etc. I'll go through the connections and inspect the loom before replacing the sensors. Plugs are all the same and gaps are good. A slight grey is over the plug. The Lambda is the orginal sensor. The car has been a beaut with a very smooth engine till now.

Riviera run was on the cards for the motor but I'm running out of time :'(

[mininutter]

Vibration sorted - Out of balance flywheel/diaphragm. Hammer marks on the reluctor ring too. All refitted. I reccomend to any MPI folks to buy a complete pre assembled flywheel and clutch assembly, or use a the rover tool to align the plates, or to go to a local engineers and have it balanced or as I. I used a feeler gauge to centralise the diaphragm

New problem . Kicks back when starting, hunts for idle till it stalls. Pinks under load. Guess I've disturbed a sensor? Time to refer to the SPI bible from Sir Sprocket.

[icklemini]

look again at the the ring and the crank sensor...

you local to northampton?

[mininutter]

Well done to Dave from the mini community who has got a hole in one. (And icklemini for keeping my attension in that area)

I've done some checks on the part numbers of the item supplied. The diaphragm is different on verto clutches through the production. Although I made it clear I needed an MPI post 1996 clutch assembly to a ###### on the end of the phone, I've received a pre1990 assembly.

Hopefully once I've removed and replaced the offending item from my car, I'll be having a dam good rant. What started as a vibration and is now a misfire/pinking, I can only hope its not done further damage. Major rant and supplier name may follow after inspection. But mistakes happen and I'm sure I should of doubled checked the parts supplied. Should I have to do that?

Thankyou Dave, I was just about to take off the head or replace the lambda. You really have helped. Wish I'd called you before my Holiday.


Si

[Sprocket]

Now that is interesting. It would apear that the MPI will run to a degree(missfiring on two cylinders maybe??)if the wrong clutch is fitted, You have no chance with the SPI though, noting that the MPi reluctor is 36 -4 teeth and the SPi reluctor is 36 -2 teeth. The MPi has missing teeth at 30, 60, 210 and 250 degrees. The standard non injection clutch is about 25 degrees out in relation to the injection clutch.

http://www.minispare...cle.aspx?aid=79

[mininutter]

Crazy stuff, the engine runs fine while cold, as it comes upto temperature I assume the ignition then retards, thats when the 25degree offset really hits home.

Lesson learnt. Hope I can pass that onto a telephone operator.