Team MightyBoy

I posted a topic last week or so ago about my SC not sparking, i've fixed that problem and it was running fine and now its decided to die again. It's sparking still though and it's cranking, but it's jsut not starting. And yes, it does have fuel.
Im still new to the car world, but im slowly learning stuff.
Suggestions from you guys would be a great help.
Thanks, Kyle.

my MB is doing the same thing, check all your earthing and battery connections, ignition coil, leads and spark plugs.

Would you suggest putting new spark plugs in? Because i've got 4 brand new ones sitting in the packets still.

Would you suggest putting new spark plugs in? Because i've got 4 brand new ones sitting in the packets still.

Well... If you have new ones... Fit them - then that's one item you can cross off the list of possible causes.
Just make sure you check the gap is correct before you pop them in - they aren't necessarily correctly gapped from the factory!

is it sparking at the right time - triple check your ignition timing.
for an engine to run you need the 3 elements of fire -air - fuel - ignition and they have to happen in a timed sequence, Intake - Compression - Ignition - Exhaust.
Air comes naturally so if you have fuel where it needs to be & you have a healthy spark you will need to eliminate possible problems with ignition timing and compression.

has it got enough compression?

What's compression? Sorry.

Hi Kyle...
"Compression" can roughly be described as how much pressure will develop in the piston cylinder by the action of the motor running. All internal combustion engines are designed to work reliably within a certain range. If yours is not developing enough compression, then the engine is worn and will need an overhaul.
The figures you will need to meet should be somewhere in the service manual (you've got that, right? - bible for repairs to your car), and is usually measured by whipping out all the sparkplugs, then screwwing a pressure guage in the sparkplug hole, I also disconnect the high tension lead from the coil to the distributor (to be extra safe) and cranking it over.

Typically you test each cylinder in turn and should get close values to one another (say, +/- 10 psi). If the figures are low, then there are other tests you can run to help identify why they are low, but let's cross that bridge when we get there, huh?

Welcome to the fun of car maintenance matey!

Thanks Tez. I'll get someone to help me with that, i'm not too keen on the engine overhaul though!
And no, i don't have a service manual, or whatever it's called. Can i get one from a shop or something?

ha-ha i remember when i did a compression test on our old festiva, i think it was, 170psi, 110psi, 110psi, 150psi. Didn't last to long, rev it over 4000rpm, spat oily water out the back.

Hahahaha, no good, no good!

when you do a compression test make sure you test dry then put a squirt of engine oil down the plug hole and re-test this will tell you whether you are loosing compression through worn/damaged rings & bore or through the valves not seating properly. A change in value dry v wet means rings (most times) a valve leak wont show a difference.

Thanks Gadj...!

That was going to be the bit we did when we got to the bridge...

I figured getting the stuff together to get any test done would be enough for a start, but you are exactly correct with the diagnosis...

Cheers

Nice to get it right at least sometimes it helps get the confidence to try different things.
I put the F8B in my 'Boy without a manual to tell me what went where - took 2 weeks to figure the timing out & get it started. I had a little help via the forum but I did it all on my own & got 12 months of fun out of it before loosing part of a ring on No.3. I found that via compression test but lost so much compression that the wet test did not show a difference.
Life is a learning process - it doesn't stop after school.

I put the F8B in my 'Boy without a manual to tell me what went where - took 2 weeks to figure the timing out & get it started. I had a little help via the forum but I did it all on my own & got 12 months of fun out of it

That's a fair effort Gadj!

I grabbed a copy of the online manual the first day I found this site, I've printed it out in full in colour and even with that I still struggle on occassions with the various bits and pieces I've had to tackle!

Having said that, there are some areas where I think the manual is either very weak or non-existant and not much use if any.

Cheers