Funny story.

After installing the donor engine into the MSM, I found that the ground strap which goes to the driver side shelf was missing. I wasn't sure where it hooked up, so I went over to my car to check.

It was completely disconnected from the engine on my car, just dangling there.

A few questions:
1. where should I attach it to the engine?
2. Could this cause my issue under boost?
3. on dad's MSM, any reason I can't just use an extra negative battery cable I have laying around, or do I need to use the braided cable like came factory?

Thanks gents. Getting really close to having dad's car running... I think.

 

Missing ground straps absolutely can and will cause misfires.

 

1. Anyplace on the block is best. Brackets attached to the block are second best. You just need a good connection.
2. I would think so, but defer to those with more knowledge.
3. Anything capable of carrying the current and is flexible enough to allow engine movement. Negative battery cable would be fine, if not overkill.

 

Thank you kindly, gentlemen.

Will report back, of course.

 

.

 

I'll chime in and say bare metal is best metal. Remove any paint from contact surfaces and try to get a bare metal connection. Also, dielectric grease will help keep the corrosion down on the contact points if that's an issue.

While you are chasing grounds on these cars, make sure the one that runs to the PPF is intact as well.

For the funsies, jump on the googler and look up HKS and AutoExe "Circle Earth Grounding Kits" for the Miata, I kid you not. They are sold as a performance enhancing modification to get the most out of your sensors, ignition and electrical system. Or something. Plus, you know, JDMy0 street cred and whatnot.

My 73 F-250 has a cable running from battery neg to chassis, another from battery neg to block, and another running from block to chassis. ALLTHEGROUNDS!

 

After laughing at these "grounding kits" for years, I recently actually started taking them seriously: on older cars, that have been torn apart and modified many times over, the oem grounds are often neglected or even deleted altogether. In those cases, a ton of straps all over the place actually kinda helps. I mean you can replicate the "kit" for what, 5 dollars? and it won't hurt anything

 

Ehh. I mean, like you say I'm sure it could fix some other underlying problem like omitted or damaged OEM grounds, but I wouldn't count on it to boost any sort of performance. Maybe alternator load?

Oh yeah, DIY is easy. Back in the day I made ground cables for people using heavy duty amp hookup wire and beefy ring terminals. It certainly didn't hurt anything.

 

Vaseline works as well as dielectric grease, and we all have some of that handy, right?

 

But dialectric grease does not work as well as vaseline...

 

you should make more, and sell them on here.
"Syphillis Racing earth grounding kit tacoburrito type X"

 

Purrzakly!

And no.

 

I can build you a strap. I have a bunch of 0 gauge welding cable with 3/8" ring ends. As soon as I grounded the head to the shock tower on the passenger side (removing the OEM ground strap) my saw tooth AFR readings smoothed out. I have extra, I just started replacing/bolstering all my OEM grounds.

 

Then I can ship them with vinyl stickers that say "I got syphilis, ask me how!" that you can put next to your "most disease" sticker

 

 

Thanks guys. And thanks for the offer Psyber, I just went to FLAPS and got a couple generic ground straps for $5 apiece. Will install them on both cars tonight. really hoping for first start on dad's car tonight, we will see. We're close. Then BOOSTS on mine, see if that made a difference.

 

Location?

 

Rear passenger side of PPF just in front of the rear differential. It is the main ground point where the negative battery cable from the battery hooks to the car. Scuffing with sandpaper and reassembling is easy.

 

 

Well, that seems bad.