Faulty Luminition.

[Bobbieslandy]

Hi,

Cylinders 2-3-4 all get a charge to the spark plug, Cyl 1 gets a charge maybe 50% of the time. with the Timing strobe fitted it looks something like flash flash flash nothing nothing flash flash. Well something like that [:D]

Anyway...... I find it strange that the luminition box of tricks has no problems firing cyl 2-3-4 but is struggling with cyl no 1.

I've checked the HT leads and they're pushed all the way in the cap and are secured tight, the chopper is ok with no damage and slices cleanly through the optic pick up. Is this normally how Luminition modules start to die? I'm reluctant to spend £100 on something which may not be at fault. We didn't cover much in the way of electronics at college so i'd have no idea how to test it.

I didn't have this problem on points, I'd like to think that's ruled out a fault with the dizzy cap and leads.

Any help fault finding on Luminition modules would be great.

Thanks!

Rob.

[bmcecosse]

It can ONLY be a problem with the dizzy cap/HT lead/spark plug connector - or the spark plug itself........... For example if the plug is contaminated with carbon/oil etc so it's effectively shorted to earth - no spark will be seen as it will run straight to earth.

[FI Spyder]

Yah, those parts are a lot less expensive than a new module and you'll have replace them eventually anyways as they have a lifespan. Problems in these parts are not always visible.


TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

[Bobbieslandy]

I see, so i guess if i've got a duff plug then the HT circuit is broken and the strobe won't pick up a charge. The leads, dizzy cap, rotor arm and plugs are less than 3 months old, looks like i'll be pulling things apart again.

Cheers guys.

[Bobbieslandy]

The ceramic part of the spark plugs has a deep red, almost purple tinge to it. I've never seen that before and they certainly weren't like that last time i took them out! a bit of reading up suggests it's because of the fuel additive, which i don't use[?]. I changed plug No 1 and the problem went away but then i adjusted the timing and the problem came back again[:(!]

while i was there i carried out a compression test.....

No 1 = 163psi
No 2 = 171psi
No 3 = 171psi
No 4 = 161psi

Are they ok?

Rob.

[Marsu]

Rob,

If you have good spark on 3 cylinders then this doesn't sound like a faulty module, but an issue with distribution of HT elec signal within the dissy.

Try another rotor button first. This was the cause of my recent sparking problems. Next, try swapping dissy cap and leads for your spare set.

Following are instructions from the manual for checking operation of the Lumenition MTK007 unit (which suits Lucas 44D)
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
Disconnect tachometer sense lead from ignition coil if applicable.
1. Set a voltmeter on a DC volts range between 15 and 60 volts.
2. Connect the positive meter lead to the minus (-) ignition coil primary terminal.
3. Connect the negative meter lead 10 engine ground.
4. Crank engine.

If the needle jumps back and forth between approximately I volt and 13 volts the ignition
system is working properly and the coil is bad or the rotor is bad.

If the needle stays at about 13 volts either the RED or BLACK wire is not making
connection to the coil primary terminals.

If the needle stays at about I volt, there may be an excessive air gap [greater than 3.2mm
(.125â€￾)] between the magnetic trigger disc and the ignition module preventing it from
switching OR the ignition module has been damaged by connecting the RED and BLACK
wires to the wrong terminals on the ignition coil.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

[Marsu]

Compression figures look good. You want no more than 10% variation between pots.

Comparing figures to others cars is always a bit subjective unless the measurements are taken using the same gauge and method.

[Bobbieslandy]

Great bit of info there Marsu, i'll have another go with it during the week. It was about time i did a full compression test, after pulling a helicoil out last time i've been a bit reluctant to.

Rob.

[Marsu]

I prefer to change all plugs as a set and at least every 3000klm.

I've never seen a pink or purple tinge to the ceramic but have sometimes seen an orange/russet discolouration, as illustrated below:


addendum
Usually only see this if I have set the mixture too lean and been running hot.

I don't use any additives and generally use premium (RON98) or RON95 when the former is not available.

[Bobbieslandy]

i'll have to post a pic Marsu, it's weird! it's actually got a vertical tidemark on the ceramic part of No 1 spark plug. It's definately red



This isn't my spark plug but the colour is identical. where the ceramic part is white (opposite side to the red) mine is a deeper red but the tide mark is in the same place. It's probably nothing but it's a new one on me!

[saabfast]

What plugs are you using? I have had probelms with NGK's before after just a few miles. Used to be one of the best but they are made in France now. If only one plug is missing I would suggest the dizzy cap (might have a hairline crack around that plug connector, try spraying in WD40) or the HT lead or plug. Swap leads around to eliminate that one.

Alan
Saab 9000 Stg 1
Saab 9000 2.3 FPT Auto
'81 TR7 DHC

[Cobber]

<font size="2"><font face="Comic Sans MS">Check your distributor shaft isn't worn and running eccentric </font id="Comic Sans MS"></font id="size2">

80'Triumph TR7, , 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
85'Alfa 90, 69'Ford F250.
76' Ford F100

[Bobbieslandy]

I'll have a mess around with it later on in the week, jobs keep creeping up on me recently. The distributor is new, first thing i'll do is change the plugs and take it from there. 3 months and the car still is'nt right.