[Kymb0]

Still trying to identify running problems with my F5a. Does anyone know the physical difference between NGK plugs BP5ES and BP5EY?

[JrZook]

Kymb0 wrote:

Still trying to identify running problems with my F5a. Does anyone know the physical difference between NGK plugs BP5ES and BP5EY?

Standard and v-grooved center electrode. These differences will not be the cause of any poor running.

What's the running issues with your f5a?

[Kymb0]

It has never run properly. When it is running it over fuels, carbons up the plugs, miss fires. Generally runs like a dog and wouldn't get up to 60. Today my dad an old retired diesel mechanic pulled a lead off the distributor while it was coughing and farting and made the spark jump from the distributor to the lead. Suddenly it started running the best it ever has. We tested the leads and the plugs and they are all ok. It has been a long time trying to get this thing to run right. I always end up blaming the computer but everytime it ends up being something else.

[JrZook]

Did it go back to running poor once the lead was reconnected?

[Kymb0]

No It's running really well now??? My Dad (Who is getting old) said maybe it amplified the spark signal from the computer. It is still over fueling which my mechanical friend thinks relates to a faulty sensor.

[jdk81]

Lead/s might be arcing out somewhere.
Moving them may have temp solved the issue.
can still return correct ohms with a loss in shielding.

if it was missing, it would cause it all sorts of issues trying to correct the fuel.
If missing unburnt fuel and o2 go into exhaust, o2 sensor only reads the o2, and says more fuel needed.

had a jimny do this.
After a lit of looking and testing, eventually noticed one of the coil packs had a funny colour at one spot. It was arcing out through that and causing endless issues.
Once replaced it was perfect.

[atari4x4]

fire it up in the dead of night & see if you can see any spark leakage

[Kymb0]

Thanks guys. Ive been contemplating sending it away and getting a custom computer built but it sounds expensive. I will replace the leads because I havent even though they test ok. Plugs are new but end up covered in carbon. This project would have been finished five years ago if the motor ran right

[atari4x4]

sounds like JrZook needs to pay you a visit... pretty sure he still runs on pure bundy, just don't fill him up until after he's done.

as jdk81 mentioned, i'd look at throw an o2 sensor at it as well for piece of mind.

[Kymb0]

Maybe I need to throw a zook party like we used to in the old days (10 years ago)

[Scrawny]

I'm sure there's a number of us that can come and help with the drinks!

[royce]

I know the answer to this, just cant remember the details.

When you make the spark jump like that you are forcing the secondary winding of the coil to man up and provide more voltage, I cant remember what it means is stuffed though, probably the coil.

[JrZook]

royce wrote:

I cant remember what it means is stuffed though, probably the coil.

I would have said it was a faulty lead and the extra voltage built up from the secondary to jump the large gap is now sufficient to get to the plug.

When's the zook party? I should be able to drop in and give you a hand

[Kymb0]

It seems exactly how you describe it Royce. Next Sunday could be good for a get together. I could put on beer and snags and Supercheap is open up the road for parts. I would appreciate it like you wouldn't believe and it could be a laugh

[royce]

for giggles can you try opening the plug gap up to 1.1mm?