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> Confirm my theory for fixing a non-starter?, rocket surgery
wobbletop
post Aug 6 2019, 10:49 AM
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I thought I'd create a new thread instead of fouling the CanAm Mosport thread...

My 914 6 conversion died just as I got to Mosport. I could feel it stumble slightly on the last few km to the track. It's about an hour and 40 minutes of highway driving to get to the track. Temp gauge got up to about 212 and stayed.

Car stalled at the gate to the track and wouldn't start again.

Car would turn over but not catch and start. I could smell fuel from the exhaust and there was fuel in the clear fuel filter. Car would turn over, although it started getting slower and slower with the amount of cranking I was doing.

I figured I wasn't getting spark but it was tough to test in the parking lot, far from home.
Someone suggested a coil so Mark kindly brought one with him to the track, but swapping it out did nothing.

It also has a MSD6AL ignition and someone also said they go bad frequently.

Anyway, I towed it back home, pushed it into the garage, put the charger on the battery and left it for the next day.

Next day, with the charger still on it, the thing fired up right away. Turned it off, took the charger off, and it still fired up right away.

Checked the age of the battery (Optima red top) and it's older than the hills. Decided to swap the battery for a new one. The battery was old... terminal lugs were weak, and I could hear the battery bubbling internally.

So... the question is... is it just the battery?

At the side of the road, I figured if it could still crank the engine over, that the battery still should be able to provide spark, so I didn't consider just getting a new battery from CAA.

I'm thinking that maybe the MSD6AL requires more voltage to produce a spark, than the starter needs to turn over the engine, and this is why it would turn over but not start.

Can anyone with more experience with the MSD chime in and confirm this?

Should I get rid of the MSD? I like having it as it provides a soft rev limit for the engine.

Thanks for you attention,
Walter
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Superhawk996
post Aug 6 2019, 07:19 PM
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Bad battery could easily go below 9V.

The other possibility is that it technically operates but with weak spark and depending on your mixture, it might not light.

One thing to be concerned with. Since it was running then started to stumble, I'd have your alternator checked out. Make sure it is putting out proper voltage and trying to keep the battery charged.

Bad battery on it's own could be a possibility (Optima's are a mixed bag for automotive in my opinion) but you need to have the vehicle charging system checked regardless - don't assume just the battery. Don't rely on the idiot light being off as a sign of alternator health.

AGM batteries can be a bit flaky. They don't like being deeply discharged, overcharged, and don't like heat. An AGM battery in a 914 engine compartment really isn't Optima(l) pun intended. I have several of them in motorcycles and my 1991 Miata used them successfully but the battery is mounted in the trunk away from engine heat and vibration. A 914 voltage regulator being what it is (an ancient electro-mechanical device), isn't ideal for controlling AGM charge current.

https://batteryuniversity.com/learn/article...t_glass_mat_agm

There are reasons why most major automotive OEM's haven't moved to AGM's in mass production and it's not just related to cost.
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