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-   -   And my engine project begins (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/my-engine-project-begins-431150/)

2rotorkid 11-05-05 12:45 AM

this took forever to read, dDub u make rebuilding a rotary sound so pleasent, i'm to f'n scared to tear one apart yet, thats cuz im just getting into 7's.
best of luck
and i hope u take some vid. footage of it when your complete

ddub 11-05-05 12:48 AM


Originally Posted by scathcart
I can't explain it. That's why I said I don't understand. I was hoping for an explanation.

By relocated now, do you mean back to the stock position? The only thing I can think of is a very long main ground wire being undersized, or one of the MS wires being run in close proximity to a high current carrying conductor.

What was your old/new battery set-up? What changed between now and then?

Relocated as in where the passenger side storage bin used to be.

Old setup on stock ecu - Everstart battery in stock position with upgraded negative terminal wiring and upgraded grounds.

New setup with MS - Battery relocated to passenger bin, Yellowtop 51R battery, 0 gauge positive and negative wiring with 2 circuit breakers for the positive, more grounds added to some things in the engine bay.

The MS has 18 gauge ground wires coming off of it for various sensors and such. I ran 2 of these 18 gauge wires into a single 10 gauge wire for the main ground for the MS, and then another single 18 gauge ground I had left over (one sensor I didnt use and caused an extra wire to be left).

Only explaination I've gotten so far is what muythaibxr posted in this thread. It all got fixed once the ground was moved to the bellhousing instead of at the battery, and also had a shorter ground wire than before.

ddub 11-05-05 12:50 AM


Originally Posted by 2rotorkid
this took forever to read, dDub u make rebuilding a rotary sound so pleasent, i'm to f'n scared to tear one apart yet, thats cuz im just getting into 7's.
best of luck
and i hope u take some vid. footage of it when your complete

Hopefully the footage of it starting up for the first time will be tomorrow :)

scathcart 11-05-05 12:54 AM

When the MS wiring was grounded at the battery... did the MS ground go anywhere near the battery positive or negative lead?

2rotorkid 11-05-05 12:55 AM

oh i cant wait. so how long has this taken ya?

ddub 11-05-05 01:08 AM


Originally Posted by scathcart
When the MS wiring was grounded at the battery... did the MS ground go anywhere near the battery positive or negative lead?

By lead do you mean the positive and negative wires coming off the battery? Sorry for the question, just making sure you aren't using different terminology.

Anyways, it was only as close as the Negative terminal connector, went away in the opposite direction of both positive and negative wires pretty much.

ddub 11-05-05 01:10 AM


Originally Posted by 2rotorkid
oh i cant wait. so how long has this taken ya?

My FC has been down since the beginning of July basically.

But... that's mainly because I kept adding to the project. First was the engine, battery relocation, and some other misc stuff. Then it was some new manifolding as well. Then the port design changed and I wanted to go standalone so I got an MSnS. Then I had to build the harness for it. Then school started and I officially began the business program at my University so time has been limited.

I also wasn't in too much of a rush to be honest. I just got an RX8 before last summer and I've been enjoying that car a great deal as well. Of course I've missed the FC, and will thoroughly enjoy it once the break-in is over and everything is tuned.

2rotorkid 11-05-05 01:19 AM

where did u learn all of this?

ddub 11-05-05 01:19 AM

Reading, experimenting, just trying shit out.

How else are you going to learn stuff :)

coldfire 11-05-05 03:50 AM

yes, how else, heh. can't really go to school for this stuff


ok, well i would just like to say i didn't mean to start that whole discussion about the oil jet modification, even though i think some good things came from it. maybe that is why i was asking in the first place. doesn't seem to be much stuff out there on the real effects of doing oil mods, but the general ideas and consensus is that you do it if you are making a high-rpm engine. as backwards from the scientific process as it seems, saying that Racing Beat and Mazda comp uses it seems to be pretty convincing evidence, regardless of what actual facts are out there on the matter... :)

anyways, as for the electrical noise issue.
electricity is a strange creature. especially in a system like a car. my electrical engineering courses have thought me the concepts of electric theory so far, but really when you get to the real world sometimes things just don't work out.

for example, a ground is a ground is a ground, you would think, right? well unfortunately not all grounds are, er, created equal. first of all you must remember that a system like the car employs a FLOATING GROUND. this is basically just a reference to zero (nothing actual is connected to the "earth"). the general rule is that two components within this closed system must be connected to the same zero reference, and must see the same reference. sometimes it is not always easy to maintain the reference to zero isolated. like mentioned, things that INDUCE current can create unwanted noise. so you can see just from this how things can start getting screwy.

it may be the reason you see a lot of wierd stuff sometimes in car wiring, that may not make sense...for example, when wiring an SAFC you need the two grounds going to the same wire, but connecting at a certain distance apart from each other. i'm not quite sure the theory behind it, since after all it is the same actual node...

anyways, i found a little definition on wikipedia that mentions a few things on interference. it mentions shielding wire as a last resort to some ways of handling noise:
http://en.wikipedia.org/wiki/Electrical_noise

ddub 11-05-05 08:39 PM

Still not sparking even though RPM is proper...

Was testing my coils away from the MS and they don't seem to spark period. My coils might be bad, going to test them some more to make sure, but this would explain a lot.

Here's a pic because I felt like posting something. Porsches enjoy jumping FC's when battery voltage is low.

http://home.comcast.net/~rx7projects/jump.jpg

Turbo II-FB 11-14-05 03:06 AM

hye Dub what wheels are those on you're FC? BTW If I might add your paint looks goregous!

ddub 11-14-05 08:40 AM

Primax 684 16x7's

Thanks.

coldfire 11-14-05 10:57 AM

any updates??

did you get around to testing the coils? it would be wierd that they would cause the car to not start up, especially since they were working fine before.

SonicRaT 11-14-05 11:00 AM

Last I remember, he tried another and it didn't work with that either. I think that leaves it down to the connector, the wiring between the MS and the connector, the MS connector, and the MS itself.

SirCygnus 11-14-05 02:01 PM

too many variables. lol. i dont believe the coil is the problem.

SonicRaT 11-14-05 03:42 PM

That's not many at all, it's either the wires themselves are bad, the connectors, or the MS, not too bad, a lot easier than most issues RX7's have!

muythaibxr 11-14-05 04:47 PM

the MS itself worked when tested on my oscilloscope, I have vids of it :p: ...

I think he's going to bench test the MS and a leading coil/ignitor out of the car.... just to rule out the wires in between the MS and the ignitor... If I understand correctly he's just been too busy with school to do the bench test yet.

SonicRaT 11-14-05 05:03 PM

Yeah, but shipping sure can be a bugger on hardware. Does the scope tell you if the voltage/amperage/etc is proper?

ddub 11-14-05 06:51 PM

Still testing stuff.

I have the vids of Ken (muythaibxr) testing the MS also, all looks good on that end.

I should be setting up the bench test tomorrow. It'll be a car battery, CAS, leading coil, power/ground wiring to MS, and the CAS/leading coil wiring to the MS only. Very simple very short wiring, should lend to some realizations of what might be wrong.

muythaibxr 11-14-05 08:13 PM


Originally Posted by SonicRaT
Yeah, but shipping sure can be a bugger on hardware. Does the scope tell you if the voltage/amperage/etc is proper?

It shows me that I was getting a +5v square wave, which is what I'm supposed to see there.

muythaibxr 11-14-05 08:16 PM


Originally Posted by dDuB
Still testing stuff.

I have the vids of Ken (muythaibxr) testing the MS also, all looks good on that end.

I should be setting up the bench test tomorrow. It'll be a car battery, CAS, leading coil, power/ground wiring to MS, and the CAS/leading coil wiring to the MS only. Very simple very short wiring, should lend to some realizations of what might be wrong.

Cool, I'll be waiting for the results! Hopefully good ones!

Ken

theman4444 11-16-05 12:07 PM

Dang I want to hear what this problem is. I'm getting all excited!


GO dDuB!!! (Only here for the moral support...)

gerbraldy 11-16-05 01:54 PM


Originally Posted by dDuB
Still not sparking even though RPM is proper...

Was testing my coils away from the MS and they don't seem to spark period. My coils might be bad, going to test them some more to make sure, but this would explain a lot.

Here's a pic because I felt like posting something. Porsches enjoy jumping FC's when battery voltage is low.

http://home.comcast.net/~rx7projects/jump.jpg

so the porsche is the easy going economy car and the 7 is your sports car ;) ?

SonicRaT 11-16-05 02:00 PM

You forgot one key word, should be 'is your moms easy going economy car' :)


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