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Rover Vitesse 1996 - Ignition primary (waveforms) #

Posted by Alan Kane on April 20, 2012, 5:13 pm

Year of Manufacture *: 1996
Engine Size and Code *: *

This old Rover Vitesse is the pride and joy of a good trade customer. It is suffering a misfire under load. When it misfires the rev counter flicks as well.
I managed to capture it happening on the primary. Here it is below. My first thoughts are a driver fault. The 2nd and third images are freeze frames of the fault.

Opinions appreciated.

Thanks

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Re: Rover Vitesse / ign primary

Posted by James Eardley <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3143' width='330' height='300' border=0 style='border:none;'> on April 20, 2012, 10:23 pm, in reply to "Rover Vitesse / ign primary"
James Eardley

Hi Alan

I don't claim to know what may be wrong with this vehicle but I would Scope the primary volts and current and also the crank/cam signal over a decent timebase to try and get a clearer picture of what is going on.

You need to test for ecu input miss triggering/damaged signal, ecu powers and grounds and eliminate secondary components before condemning the ecu/driver.

What is the the ignition set up on this vehicle?

I would be really interested to see the primary current and voltage waveform if you have them

hth
James

Re: Rover Vitesse / ign primary

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=alankane' width='330' height='300' border=0 style='border:none;'> on April 21, 2012, 9:07 am, in reply to "Re: Rover Vitesse / ign primary"
Alan Kane - Administrator

Hi James,

Ign is dist cap, leads and a single coil with the primary in the ECU.

I did check ecu supplies and grounds, all ok.

I didn't spend much time on the trigger signals because I can see the ecu pulling the primary down which it would not do if there was a problem in this area.

The way I view the fault is that the primary is pulling down perfect but not holding. I am looking for someone to correct me on that.

I have a volt v amp trace on another laptop which I will post later.

cheers

Alan

Re: Rover Vitesse / ign primary

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=alankane' width='330' height='300' border=0 style='border:none;'> on April 21, 2012, 1:28 pm, in reply to "Re: Rover Vitesse / ign primary"
Alan Kane - Administrator

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Re: Rover Vitesse / ign primary

Posted by andyhyoung <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5148' width='330' height='300' border=0 style='border:none;'> on April 21, 2012, 8:16 pm, in reply to "Re: Rover Vitesse / ign primary"
Andrew Young

If I recall,some of these had a resistor on the rotor arm that can go open circuit.Also an internal short on the rotor can cause the ht to be dumped to ground.Can you scope the secondary ht coil and plug leads?My 25 year old Bosch Mototest machine would show a beautifull live scope picture of this.

Re: Rover Vitesse / ign primary

Posted by Andrew Clarke <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3093' width='330' height='300' border=0 style='border:none;'> on April 22, 2012, 1:30 am, in reply to "Re: Rover Vitesse / ign primary"
Andrew Clarke

I would think the fault lies in the primary control side, dwell varies way too much. To short at times to charge coil.
I'd also be checking cam/crank and I have seen poor connections do some strange things to primarys.

Re: Rover Vitesse / ign primary

Posted by Graham Bullock <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2744' width='330' height='300' border=0 style='border:none;'> on April 22, 2012, 10:29 pm, in reply to "Re: Rover Vitesse / ign primary"
Graham Bullock

If you haven't already done so I would scope the ecu earths along with the primary.
Years ago I had a fault on a test rig that was losing an earth to the amplifier intermittently, every so often instead of the amplifier switching and pulling down the primary to earth it gave a very similar scope trace as you have.

When the earths were tested with a DVM no fault was found but when tested with a scope it was clear to see every time the fault occurred the earth voltage went up, the current went down and the HT voltage reduced as the coil failed to energize correctly. Another earth bridged to the correct side of a bad connection cured the fault.

Graham

Re: Rover Vitesse / ign primary / Update

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=alankane' width='330' height='300' border=0 style='border:none;'> on June 15, 2012, 7:16 am, in reply to "Re: Rover Vitesse / ign primary"
Alan Kane - Administrator

This is back in to be fixed. I have spent some more time on this with the scope and can't fault anything besides the primary. The timing changes but it happens after the misfire and the inputs stay stable. Has to be an ECU fault, but it has had a used ecu since it was last here. Either two faulty ecu's or a faulty diagnosis.

I need to go through this pin by pin in case there is something odd happening external to the ecu. The only problem I have is that I am working with incomplete data. My oldest Rave is not old enough to cover this. Rave diagrams are listed by chassis number, this one is 213890 and its the one with just one coil/king lead rather than a coil pack with 4 leads. Anyone have the correct diags?

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