Acceptable Grounds?

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
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Southcross
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Acceptable Grounds?

Post by Southcross »

I am trying to simplify my MS wiring this weekend... is it acceptable to use a single ground bus (basically a heavy distribution block just for grounding multiple items like guages), with a single heavier gauge cable grounding at the block? or, does the MS need to have each ground wire separately grounded?
1979 Volkswagen Dasher MegaSquirted Turbo Drag Project a.k.a Mr Hanky
DonTZ125
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Re: Acceptable Grounds?

Post by DonTZ125 »

Multiple small ground wires have less inductance than a single large wire. Your ground bus may work, or there may be issues.
Southcross
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Re: Acceptable Grounds?

Post by Southcross »

arg.... I have one of those 22-pin firewall sockets from DIYAutoTune and I was hoping to not use half of the pins just for grounds :? I was also trying to get away from having multiple bundles of ground leads bolted to my head (Aesthetics), perhaps I can find a way to bolt them directly to the block or my transmission housing.
1979 Volkswagen Dasher MegaSquirted Turbo Drag Project a.k.a Mr Hanky
kjones6039
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Re: Acceptable Grounds?

Post by kjones6039 »

FWEIW.....

I use a similar bus that supplies ground and 12v for all accessories without problem. I have a heavy gauge ground to the intake manifold going to about half the buss and the rest are 12v switched.

Just my 2 cents..........

Ken
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
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Southcross
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Re: Acceptable Grounds?

Post by Southcross »

gahhhh.... I've discovered a slight discrepancy between the pin-out listed on the DIY website and my actual harness :x The pin-out listed on the website shows 6-20 gauge grounds, my harness has 2-14ga grounds.... I had planned my 22-pin socket with 6 ground wires (not including wideband and accessories). Now with my MS and wideband, that is only 4 grounds... leaving me with 2 unplanned spares and (I think) three spares (that I did plan for), a total of 5(maybe 7?) free for misc accessories now. I also determined that a few grounded items can be grounded to less sensative grounding locations (i.e. chassis instead of head) and still operate just fine.
1979 Volkswagen Dasher MegaSquirted Turbo Drag Project a.k.a Mr Hanky
Matt Cramer
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Re: Acceptable Grounds?

Post by Matt Cramer »

Sounds like you have an older version of our harness, with the six ground wires spliced to two inside the DB37.
Southcross
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Re: Acceptable Grounds?

Post by Southcross »

Matt Cramer wrote:Sounds like you have an older version of our harness, with the six ground wires spliced to two inside the DB37.
ya, thanks :P

might consider putting a note in saying just that on the website :| oh ya, and put in a note that the 22-pin connector uses 1/4-20 nuts to secure it down (not included), and a 1/4" socket to tighten/loosen the bolt that holds the two halves together 8)
1979 Volkswagen Dasher MegaSquirted Turbo Drag Project a.k.a Mr Hanky
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