The 27 chassis earthing points on a 360...

I've been helping out to assist with fault finding of late and I am constantly finding myself repeating to check an earthing point on the car... So find attached the diagram which shows where they all are. Amazing how many faults good earths resolve on these cars.. Its because all the sensor voltages so greatly depend on reference earth's...

All the earths are circled in red... Hope you find this useful! Image Unavailable, Please Login

 

And higher resolution version here from my Google drive...
The image gets horribly scaled when uploading here..
https://drive.google.com/file/d/1-E_XJFZdYSmG8hKqYOjZrBXC7u36xEFY/view?usp=drivesdk

 

Are they vibrating loose?

I find it hard to believe they come loose after 20K miles...which seems to be the avg mlg of these cars......
what am I missing?

 

The big issue that I see is corrosion in the aluminum. When I cleaned the grounds in the engine compartment there was *some* white oxide corrosion on the outside of the chassis contacts, but wasn't bad overall. If the corrosion extends into the contact it will drive up resistance and give false readings.

 

Along with fixing grounding issues, I wonder if there can be benefits from improving the grounds? I once saw an article in a magazine on Japanese imports, where a stock, new Nissan 350Z was dyno'd, then a kit from Japan that included four, heavy gauge, high purity copper ground cables where strategically placed from the valve train to the chassis, as well as near critical sensors or ECUs. Back to back, the car gained between 5hp and 7hp depending on where the wires were placed. It was an interesting exercise, and showed that even factory grounding may be less than optimal.

 

Is there a best way to clean the corrosion? I know there are some good sprays for steel that can combat corrosion but what about the dissimilar metal condition between a steel ground terminal and an aluminum car?

 

Very helpful!

Thanks for sharing.

File Saved!

Dan

 

Just to help clarify for us US guys: These are your Chassis Ground.

Why is this important? For various reasons and here are some:

1) If you are installing a powered equipment like Stereo or Amplifier. You can power directly from the battery positive for ground return the ones circled in red are your best ground hook up.

2) If you come across some of these ground locations take a close look and if its corroded or loose - clean up the connections using wire brush, then electrical contact cleaner spray then tighten them back up snugly. Root cause of most hard to trace / hard to duplicate intermittent & malfunctions of electrical equipment are bad ground.

Dan

 

Like DeOxit ?

 

Yes, De Oxit is very good. I've used it.

I like WD-40 "Specialist" Electrical Contact Cleaner Spray" better.

Dan

 

Good enough for the lazy B...good enough for me!

 

Just to add to this te Ignition ECU's (for the Engine) also themselves require to be bolted to the chassis at the body point (normally done via a pair of 10mm socket bolts) so technically there are 29 if you include those hard points.

And yes this is all about the impact of corrosion so the most likely ones to corrode tend to be on exposed chassis areas in engine bay etc.

 

I found that out the hard way after flashing my ECU's if you remember Trev. I wanted to test them before bolting back in and car would just crank. Bolt them back in again and away she went!

 

The corrosion has to be removed .... completely. No other way. Of importance when doing so is using the proper abrasive. You do not want to leave dissimilar metal abrasive compound in the blended region. After removing corrosion and reinstalling the ground contact it might help to seal the area to keep moisture out.

 

List of mods— headers, tune, grounds.
Free hp!

 

Wend replacing all of my wire harnesses and looms and earths and grounds while doing my CS conversion, I used dielectric grease on every single plug and connection it will prevent corrosion and repel moister and make for a great connection. After over year of the CS conversion was taking place I was told several times by couple of mechanics my car may never start up again because we had replaced so much new stuff if there where any issues you never know where to start to find the bad connections my 360 started wright up on first try, I think the dielectric grease was a big help on every thing IMHO
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I had an issue with my car such that every so often, it would just shut the engine down for a second or so. The check engine light would always come on, but then everything would go back to normal, like nothing ever happened. No fault codes were ever thrown. This went on for years. It ended up being a loose rivnut for the ground point between the number 5 and the number 3 on the diagram above. A new rivnut was installed and the problem went away for almost a year. Now the problem is back. I removed the cowl and inspected both aforementioned ground points and all is secure. I just removed the two panels at the bottom of the interior firewall and checked everything. I also removed the two rain gutters and checked for loose fittings. Everything looks tight. This is SO frustrating.

 

We were instructed by Ferrari early on to fabricate and install ground wires directly from the Motronic (not its mounting bracket) to the engine in any cases of suspected engine management anomalies. Ferrari was well aware from the start grounding issues were a real possibility on an aluminum chassis.

 

Going through and fixing my grounds and adding appears to have solved 100% the problems that have been plaguing my car for 19 years.

Fried 2 ECUs
Fried 3 TCUs
Windows now working randomly
Start button randomly not working
No reverse lights

All working perfectly now. The grounds are THAT important and also potentially THAT bad on these cars.

 

Curious, when about was this? I wonder if they made changes during production to fix this as they learned more about the Aluminum chassis and corrosion.

 

Nope, never added. I think it's more related to the fact that the non-repairable by design (wire bonding using place and hold machinery with wires thinner than human hairs suspended in clear gelly like goopy like substance, a similar feel to kids slime), die substrate ECUs utilized. Yes some have managed to do simple fixes like resoldering the melted solder or failed throttle body capacitors but by and large quite throw away.

The ECUs have internally wires which are mated to the surface of the case of the ECU and most sensor and actuators are managed inside the ECUs so bad earth will cause havoc!

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Here I've circled in red the earthing points inside the ECU which are earthed to the case itself not an external earth so it really is vital to have good earthing on the ECU case. An additional earthing braided strap for example should really help improve things a lot, otherwise sensor readings can be bad.

Trevor

Sent from my CPH2145 using Tapatalk

 

In 1999 at Modena school in Maranello Ferrari started by telling us this version of Motronic was an experiment and Bosch was no longer going to use it.

 

About 2000. No, no changes. There was a protocol developed by Ferrari for checking and cleaning specific grounding locations as a 1st step in resolving many types of electronic malfunctions. Aluminum in cars is here to stay and electronics are far more relied upon every year. Its far from over.

 

So let me say, it’s awesome and appreciated that there are guys like Trev and Brian who post on this forum. Their knowledge and expertise is so valuable to the community. You both deserve free Rosso tags imo.

 

Agreed