348 with a different starting issue.

Put an other isolator. Its clear this has a bad contact problem.

 

Just bypass the isolator and use a good battery ground cable instead, along with a tender. As you probably know, every time the isolater is used you must go through the ECU re-learn process. Simple, yes, but just something to remember.

Btw, I had a '90 348 ts and currently own a '92 tb, and neither had/has an isolater.

 

Geoff, the wording of your problem is slightly different in your post on the F348/F355 sub-forum.

I don't see how a battery isolator would degrade with heat, but Wade hit on a few important factors, including grounds and Motronic ECU relearning. However, there are a lot of variables. We need to narrow things down a bit.

How does the car run generally? Was the belt service done by a Ferrari specialist?

Do you leave your battery on a trickle charger? To me, 2 or 3 (or 5 to 6) cranks to start the car from cold doesn't sound good. Do you have something to monitor voltages when you are driving (e.g. a cigarette lighter voltmeter)?

Are you getting any Check Engine lights? Do you know how to do a test on the ECUs? I don't know if the battery reset is resetting your learned parameters somehow making it easier to start the car. Did your car have time to cool down before you decided to a battery reset? When the car not completely warmed up, it runs in open loop mode using different sensors to the sensors used when the car is warm.

 

Sounds to me like the self learn in the ECU is trying to correct something and resets when switched off. A scan of the parameters when first started vs when it is hard starting should show something. Then work on what it is compensating for. That is just my guess. Power and ground should not effect it over time like OP describes.

 

It's probably not common, but I had a problem where my turn indicators hyperflashed when my F355 warmed up. It turned out to be a loose earth above one of the radiators. I was thinking maybe an engine sensor was being affected by a loose earth.

Geoff, I don't know if your Motronics ECUs have a test button (on a short wiring harness), but here is the test procedure for cars prior to OBD2:

https://www.ferrarichat.com/forum/threads/electrical-wonders.626470/#post-147365114

Have you downloaded the workshop manual yet?

If it cranks strongly, then it's probably not likely to be a battery/alternator issue. Anyway, a cigarette lighter voltmeter is a very handy diagnostic tool for these cars as I'm sure you'll get to use it in the future.

 

I agree I'd check the voltage before cranking and before and after unplugging the idolater. It does not sounds like that the issue, if the connection was bad it would be bad and the battery would not charge etc all which you can confirm with the cigarette lighter voltmeter.

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Do you have any wetness under the clutch pumpkin where the inspection plate is. Its right where the pumpkin meets the engine underneath.
When hot and you shut down, is there a rattle from the rear of the car?

 

Exactly, a MAJOR symptom of a Voith that is unbalanced do to slung grease is a hard to start when warm. Often it is accompanied by leaking triple seals, (hence the question) however simple age will cause it.
I suspect all the battery connect/disconnect bit is a red herring and unrelated. If you started it the time it started after disconnecting but did not disconnect it
I bet if would have started. I don't see them related at all.

 

Explain to me how cycling the battery cut off switch re-balances the grease in the flywheel? I am at a loss here.
It sounds to me like the engine ECU is reset on its self learn and begins the cycle of learning all over.
An SD diagnostic will be able to see all this and then maybe you can decide what it is trying to compensate for and fix that.
Again, if I am missing something, please let me know.

 

It does not, its unrelated. His starting issues is likely Voith needing repacking, Unrelated to any battery cut off.
As far as SD diagnostic, its a 348 TS....
Every 348 I know can disconnect the battery for 10 min, plug in and it fires right up. The ECU does not factor in starting as it runs on open loop tables until a) actually fired and idling and b) 02 hit 300 degrees. Then the learning begins.
My money is on Voith repack. Let's hope the NLA nylon bits are not melted.

 

Okay, I can see where the flywheel (harmonic balancer in this car) could result in hard starts, but why would cycling the battery cut off make it better for a short time? That is the connection I am missing. I just want to learn, I am not trying to dispute, just learn.

 

Sounds pretty good to me. Engine idle usually drops after warm up, so the voltage may go down a little. Also, the battery will have recovered, so won't need so much input.

 

Again it does not it's likely just a red herring. it's like patting your stomach and head at the same time and saying it keeps dinosaurs away, actually unrelated.

Is wager it is the voith. As far as the nylon blocks, look at the diagrams to see.

Also MD clutches has videos on this procedure on youtube.


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