Misfire help

[QBee]

ClassiChimi said:

Well done Anthony. Before going Mbe I had the odd misfire, part of the upgrade included removing the extenders, no misfires since
I've put resistive plugs in but apparently it buggers up my neighbours free view box on his TV !
Mine does the same when motor bikes pass the house but not when running my car which seems at odds, hmm!

Having non-resistive plugs could have burgered up his TV, but not the resistive ones. Perhaps pop next door, start the car and check for yourself? He is probably quoting how it was before.

As I understand it, you need one resistive element in the system, both to stop that effect and to stop it damaging your car.
The resistive element can be plugs, extenders or leads. Plugs will have an "R" in the description if they are resistive.

I was at Donington for the first DTEC races last year, and every time the big red Sagaris went past the commentary box during qualifying, the PA system went to just crackles for about 10 seconds. The car then stopped on the circuit, with running problems. I mentioned the PA effect to Mat Smith, and he went straight over to tell them why the car was running badly - non-resistive plugs.

[castellated]

Hi,Paul

After 2 weeks of problems free mine suffered the dreaded cut out. Engine stopped but I continued rolling
and caught it. Engine alternately missfiring on multi cylinders and then surging and I persevered for about a mile.
Pulled into the side of the road switched off then on and started but running rough but quickly cleared
and I got home without further incident.

Difficult to catch with Roverguage because the laptop batteries give out before the problem occurs.

Mat Smith recently removed extenders and replaced resistive plugs during a service which included
cleaning the stepper motor.

One thing does occur, what immobilizer are you running?. Mine is Foxguard and I have recently had to have a relay changed.
Perhaps it is time to replace it.

Bruce

[blitzracing]

Paulprior said:

QBee, that's an interesting thought for my misfire issue, I have this which I fitted while looking for my slow start problem, but didn't think to look at it when I last had the misfire.

It just plugs into the cigarette lighter socket.

Blitz racing, I saw the pump cut out from my lights, probably only a second each time to get a hiccup, I didn't specifically look at the Rev counter but I would think I would notice it drop off while looking at the lights, we discussed that I can't easily measure the coil signal, but could I measure the signal from the coil to the ecu after the resistor? If so would it be measured as AC?, for the misfire maybe it's better to see a voltage, for the hiccup maybe a light to monitor just on or off?, do you know what pin this signal goes to?, is this the only signal that tells the ecu to switch the pump?
Paul

The signal goes into the ECU as a clock to time the injector pulses and control the pump ECU pin 39, white / black. The waveform is not a nice AC sine wave, so you wont get a sensible reading from a test meter of any sort. I dont recollect the voltage at the ECU once its gone through the dropper resistor, but I logged it with a data logger without blowing anything up. The problem with the data logger is it was only just fast enough to catch the pulses at idle and no more. I would think you could monitor the pulse train with a small incandescent lamp- across the coil. I doubt the emf spike you get would be long enough to burn the element out, and the bulbs brightness would simply vary a bit with RPM, but it would be good enough for a go / no go test.