The Automotive Thread

[csb]

You just need a better manual daily driver...

Is that a parking ticket on your hood?

 

[kevo_55]

BURN!

 

[Supe]

Somehow the fan circuit in my racecar is activating the fuel pump circuit.  The two are completely isolated with the exception that they are both connected to the main EFI harness.  The EFI manufacturer says there's no way it should be able to activate that circuit.  Now I get to start looking for shorts in the wiring harnesses

 

[Dexman PE PMP]

Is that a parking ticket on your hood?

Shipping label. That pic was from the day it was delivered in Auckland.

 

[MA_PE]

Have you seen other Camaros over there?

 

[Dexman PE PMP]

A handful, but they are not very common. I see quite a few Mustangs because they're available here. Believe it or not, I see more Lamborghinis and Aston Martins than Camaros.

 

[Supe]

Whoo!  Fixed it.  Apparently the ECU doesn't like the grounding situation without the main power harness connected, even though the tech said that shouldn't have been an issue.  Went from seeing 8V with fan on to 3V background current.  Per tech, ignition on/engine off will see 3V on that wire, not zero, so it's good to go.

Only electrocuted myself once.  Thought I flipped the main cutoff switch to off after realizing I flip flopped relay terminals.  I did not.

 

[MA_PE]

nice job.  Electrical bugs can be a real PITA.

 

[Supe]

I think it was the first time in history I actually had the patience to pull out a meter and see WTF was going on.  

 

[Flyer_PE]

Whoo!  Fixed it.  Apparently the ECU doesn't like the grounding situation without the main power harness connected, even though the tech said that shouldn't have been an issue.  Went from seeing 8V with fan on to 3V background current.  Per tech, ignition on/engine off will see 3V on that wire, not zero, so it's good to go.

Only electrocuted myself once.  Thought I flipped the main cutoff switch to off after realizing I flip flopped relay terminals.  I did not.

It's amazing how many odd things can happen as the result of a bad or misplaced ground connection.

 

[Supe]

It's amazing how many odd things can happen as the result of a bad or misplaced ground connection.

And comically enough, I am super diligent about that, because of all the problem grounding issues can cause with EFI.  So much so, that every circuit on the car has a dedicated ground that goes back to a single stud in the cabin, which then goes straight to battery negative.  Nothing is actually grounded to the chassis itself except for the engine block.  This just happened to be the ONLY ground lead not hooked up in the car, because I don't like have the computer connected during testing since small surges can fry a $2000 chunk of non-serviceable ECU.

 

[knight1fox3]

So in the end, resistance is futile. :thumbs:

 

[Supe]

Yep.  Now I get to figure out how the hell to make it all look nice and neat with velcro wire loom.  Then I get to spend 2 days trying to upload new firmware to the ECU and digital dash, neither of which are backwards compatible, so all the old log files for fuel/timing maps, etc. need to be run through some conversion tool on top of it.

 

[Road Guy]

I would just spray all the wires with that plasti dip stuff

 

[Supe]

I would just spray all the wires with that plasti dip stuff

I was temped to go with all black or all red for everything.

 

[mudpuppy]

And comically enough, I am super diligent about that, because of all the problem grounding issues can cause with EFI.  So much so, that every circuit on the car has a dedicated ground that goes back to a single stud in the cabin, which then goes straight to battery negative.  Nothing is actually grounded to the chassis itself except for the engine block.  This just happened to be the ONLY ground lead not hooked up in the car, because I don't like have the computer connected during testing since small surges can fry a $2000 chunk of non-serviceable ECU.

Whaddaya know, that ground wire actually does something!

 

[Supe]

Apparently, even though the manufacturer said it shouldn't have mattered!  I blame EE's and their stupid electrons.

 

[Dexman PE PMP]

Just don't let the magic smoke out. Everything is fixable until that smoke escapes...

 

[Supe]

Just don't let the magic smoke out. Everything is fixable until that smoke escapes...

The first ECU I had, they let the smoke out before I even got it.  Was sure glad I spent a few extra dollars to order from a super reputable guy who does R&D for the manufacturer, because they overnighted me a replacement.

 

[knight1fox3]

Rawrrrrr.....Made a purchase yesterday.

@envirotex

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