Mondial 3.2 voltage short ?

Hello

I have a problem with my starter (most of the time, the starter does not engage and only buzz). I may have to do a rebuilt, but before I go there …

To troubleshot, I done the voltage short test and here the results

When I disconnect the ground cable from the negative side of the batterie and hook a voltmeter between the disconnected pole and my ground cable (chassis), I read 12.5v !! This mean current travel from positive side of my cables to negative (a short somewhere).

I also connected a little light, and it light up then goes almost to no light and the voltmeter show 0.5v when the light is connected.

I removed one by one my breaker to localise the short , it it is not under a breaker circuit (short was maintained).

Is this behaviour normal ? Or I really have a short somewhere ?

Here some pictures:
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Thanks in advance for your help!!





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Bonjour JspMondial

Just a wild guess:
Not having the fuses removed (that is what you refer to as breakers) a current between a disconnected pole of the battery and ground can be normal, because there are several users that can be active even with the ignition off and key removed. Think of your door lights f.e. when open.
Light bulbs are wires, thus there is a connection through them from + to - and enought to run your Voltmeter or a small light.
With everything knowingly switched off and shut, the only active user might be the Motronic of the engine.

After having pulled the fuses though, all should be dead, unless the Motronic has an internal fuse and does not go through the fuseboard.

regarding not having enough juice to start: Try to get an alternative energy source to the fat starter cable (second battery with jumper cables) and see what happens, Then at least you know if you really need a rebuild of the starter or a different problem.

Bien a vous,
Mondi Cab

 

Thanks for your reply Mondi Cab

Yes, I mean all fuses removed and everything off (door close) and still have current. In my understanding, it should not unless I have a short somewhere.

Current is really poor, but still there. With voltmeter, I read 12.5v (little lower than my fully charged batterie 12.9v). Once I connect the light, little flash , then no more light and the voltage drop to 0.5v. Remove the light and voltage rise slowly from 0.5v to 12.5v (about 20 seconds).

I’m wondering if other Mondial have the same behaviour ?


About my battery, I did a battery test and it passed . So I may try to add another source to see and let you known …





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Just tried to start with a booster and still nothing (only a buzz).

I doubt my voltage short (if there is one) is strong enough to cause that! So I will most probably have to go for a starter rebuilt job!

Let me know if any other test should be done before the rebuilt and also for the voltage short.


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Mondials commonly have an issue with the connection from the ignition key to the starter motor having too much resistance for the solenoid to work. If there is not enough current flowing, the solenoid will not engage the connection from the battery that actually runs the starter motor.

If you used a test battery in the normal location, you still have the resistance within the wiring harness. To test the starter you will need to connect the solenoid directly to power, for example with test leads. This should tell you if the problem is the starter or the wiring. Make sure the car is not in gear when you do this, as the starter motor should work whether or not the ignition is on when performing this test.

If the wiring is the problem, a relay can be installed that takes power from the batter to starter leads and uses them for the solenoid. There are several threads on this.

Using a voltmeter can be misleading, since the voltage may look good until load is applied, at which point it will drop dramatically. It is probably reasonable to have some voltage showing in the negative cable since there will always be some connected items such as the clock and probably a radio even when the ignition is off, so I'm not certain that voltage indicates a short.

Good luck with this.

 

Thanks for your reply

Just one question, if the wiring is the problem, should we work on the wiring vs to add a relay to compensate and send power directly to the solenoid ?

Note: I will read more on this subject and thanks for pointing this out.


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You can start by cleaning all the connections, which is a common recommendation for anything electrical on mondial. The connection at the starter are accessible and exposed to a lot of crud. Those between the starter and the ignition switch are difficult to access, so possibly not worth the effort

the wire gauges are frequently discussed as too small which is something you can’t really fix, or at least the relay is much simpler than pulling a new wire. This is at least somewhat confirmed by all the heat related problems with the connectors that come up

perhaps start with an inspection and cleaning and go to the relay if the cleaning helps but doesn’t entirely alleviate the problem.

I would test the starter with leads first to rule it out as the problem, then move to the cleaning, etc.

 

Remove the 12 volt signal wire from the starter solenoid, now rig a temporary wire from the battery positive to the solenoid via a switch. Close the switch and see if it works. This will prove the starter , the solenoid and the battery.
If not working you are looking at removing the starter.
The main power line from the battery to the starter also connects to the alternator so might be an idea to check that these heavy connections are clean

 

I did have 1 faulty coil and it gave the same symptoms....

 

Interesting …
The symptoms of your faulty coil was only this issue (starter only buzz and not engaging)?

Or you had other symptoms ?


Thanks all for your answers, will do all theses tests and let you know …

 

This solves a lot of starter problems:
https://www.amazon.com/Bosch-Automotive-WR1-Starter-Relay/dp/B001COAX78

I bought the kit a few years ago, not installed yet because I have had no starter problems.

Also, most if not all electrical based problems with our cars are the fuse/relay/board, even some you may not think could be caused by this area:

Start fresh:
Remove all your fuses, relays and connectors on the board. Check for burnt connector leads and replace them with gold plated 3/16" connectors and new, heavier gauge length of wire for 3" or so to get rid of the burnt part, solder AND crimp the splice and new connector. W connector is a common place for this to happen at the fuel pump circuit, but look for others, lots of posts about this. I also used to make up replacements, you can find my old ad with pics here too. Spray board and connectors with electronics cleaner, then hit it all with Deoxit. Dexoit is great stuff, use it on all connecters, switches, etc. Replace ALL your fuses and your relays, new, sealed plastic Bosch relays, pretty cheap for Ferrari parts and common. Schematic with Bosch relay numbers available here, posted buy member Afterburner. Everything will come back better, faster windows, brighter lights, etc.

Alden

 

Pics here:
https://www.ferrarichat.com/forum/threads/repair-kit-for-fuse-box-charred-w-connector.503448/
Alden