Icemark

well, again if they are too lame to even look at the FSM...maybe I should change it back

WAYNE88N/A

The FSM is becoming a rare thing on the net, from what I've seen lately...

Besides, that's why this forum is so entertaining- everybody learns something every now & then, that's NOT in the FSM ...

HAILERS

***************You're missing the big picture here- it's not about wire colors changing...It's about the fact that the boost sensor cannot be grounded at ANY wire on every 86 1/2 and later, because it displaces the ground potential from the rear rotor housing for all of the 5v sensors******************************************* ************************************************** *********************************************
Wayne, Wayne, Wayne (watchout, here I go again). That is just not right, what you said above. I have explicit faith in the MAZDA engineers, and those fine fellows, as a factory service bulletin, had 87 1/2 and under boost/pressure sensors rewired with an additional ground on the brown/black wire at the boost/pressure sensor.

I being the fine fellow I am, jpg'd the factory service bulletin some time ago. Even way down under, that fellow NZ ???????? knows about that rewire/additonal wire (did not help him either). The additional ground went from the brown/black wire at the boost sensor, to the thermostat housing (I think).

Aw shucks, that makes two mean spirited posts I've made today. Wayne made me do it.

Then once again I might be wrong. I guess I'll go look up that bulletin and the years involved. By the way, that particular grounding bulletin really didn't work on my 87. It took a ground on 2R(guessing right now) or whatever to fix my problem. I can make/break that extra ground and make my old problem come and go at will. It's been years now.

WAYNE88N/A

Yes, we've had this discussion already, about 6 months ago or more...

We went over the TSB, and I could have SWORN that we came to the conclusion it was only the early 86's that it applied to. Aaron (or was it Ted?)was in on it with us...

I'm just wrong with the specific production cutoff, then, NOT wrong about our boost sensors not needing an extra ground...

Sounds like you need to fix an old ground, Hailers

HAILERS

Ok. The definitive answer is in the attached jpgs

WAYNE88N/A

Umm, Hailers, that first Jpeg says air flow meter, not boost sensor...

Are you just trying to slip one past me, or did Mazda screw up the terminology?

Or did you pick the wrong page?

In any case, I don't have a problem admitting I was 1/2 a year off. The fact still remains- for the REST of our cars, adding a ground to the boost sensor will at best do nothing, and at worse make the car run like crap. The "how to" writeup did not address this, it seemed to cover all 2nd gen RX-7s and suggested that adding that boost sensor ground was a good thing, when in fact it's not. This sums up my whole beef with the writeup, and THAT is what I was trying to get fixed...

But thanks for the clarifications. I love how you can just whip a Jpeg out of your *** like that, you're going to have to show an old computer illiterate fart how to do that one of these days

HAILERS

Why Wayne, you think I'd lie, cheat and steal over a SB???????? Tsk, tsk, tsk.

The service bulletin is 404288 and issued 88/02/11.

I printed two of the three pages. The third page shows how to ground the brown/black wire to the water filler neck. If you want to see that.......purchase a service bulletin.

Since all the brown/black are tied together through mechanical splices (I posted a jpg of a mechanical splice in the past, ain't a gonna do it again because they delete 'em at will), the boost senor is a easy place to do it vs another area/sensor, like the afm, which is the real culprit..

You older, much older folk, need to enter the twenty first century with more vigor!

WAYNE88N/A

I see...

So what I gather is that either the harness splices failed, or the rear rotor housing ground was failing on the early cars...

Very interesting that Mazda wanted you to go to the engine with the ground...And...GASP...to a spot near near the alt at that...You know, the spot I've been calling the "defacto ground while running" all this time? I'm feeling vindicated, lol...

Now, these guys doing this grounding thing, you think they're grounding that boost sensor wire to the engine, or to the chassis??? There is a difference, you know...The ECU knows, anyway...

All right, we're all straight now...The guys will (hopefully) read all of this and stop trying to ground their boost sensors on all cars produced after Nov '86, and Mark fixed the archive writeup so we'll quit having to go through this every week. Woohoo, it's gonna be a good day

HAILERS

%%%%%%%%%%% Woohoo, it's gonna be a good day %%%%%%%%%%%%%%

Don't get carried away. Me, being all powerful, will decide if you have a good day or not!

Go to ALLDATA.COM and subscribe for a few pence and you too will be all powerful. Well, in South Texas anyway.

Icemark

Okay, I added the pre-nov 86 info into that grounding thread.

JamesWade2002

hey mark, have you thought of grounding yourself???!!! I heard it gets rid of hesitations.

Icemark

Careful, you already have one formal warning against you for flaming.

iceblue

Hailers, WAYNE88N/A, Icemark. Thx so much for clearing this up for evryone and all it has made to be an excelent thread and worth wile for yours and our behalfs.

Hailers is not like tossing a coin. You take the good with the bad and just shake your head b/c no matter what you know he is right. ;-) little humor.

Well it seems like we have 2 relitivly not so good grounds that tend to fail. What do you think about just going off an grounding them now? Such as the ones Hailers posted from the service bulliton release

MillerLite

i replaced the ECU and atmospheric pressure sensor with ones from the junkyard. still not getting spark from my leading coil. im just waiting on word from this guy so i can drive out and grab it from him. hopefully after the new coil i will be all set.
thanks for all the help gentlemen. i will post results, good and bad.
this is a very archiveishly good thread actually.

WAYNE88N/A

No, good 'ole Hailers screws up sometimes too, I've caught him a couple of times. He's caught me a couple more times than I've caught him, though, lol...It's like a friendly game of chess going on, and I enjoy it. I'm sure he does too. The fact that you guys get to learn something after the dust settles is just icing on the cake, so to speak.

Here is my official line on the whole grounding thing, and if you've been around a while on the forum, you'll realize that I repeat this stuff over and over...

1) Our stock grounding system, as engineered and installed by Mazda, has nothing ELECTRICAL wrong with it (the snafu with the air flow meter on the early cars notwithstanding). It is the PHYSICAL way that they grounded some of the ring terminals that's the problem. If the harness is in good shape, all you need to do is remove the terminal bolt, clean the terminal up, sand a nice little bare metal circle under it, and reinstall it. That's it...Easy...

2) Installing larger wiring in the place of the original grounds, while maintaining the same electrical pathways as OEM- I have no problem with, but again, if he harness is good, it probably won't help much. Won't hurt, though...

3) I (believe it or not) have actually installed some new ground wiring in my car, BUT, all of them are acting as bonding straps, not new ground pathways. I have a firewall to rear rotor housing strap (so the rear rotor housing ground doesn't have to flow through the rear housings and tranny mating surfaces to hit the firewall to tranny jumper), and, I have a couple of short bonders between the alt body/ UIM/ front rotor housing (because with all of the hylomar I used on the rebuild, I wasn't sure if the housing to housing conductivity was as good as it could be).

4) Housing to housing conductivity, from the alt's mounting hardware, all the way back to the tranny & starter, is very important, and often overlooked, for the performance of the ECU and fuel scheduling related systems...

iceblue

hehe I am sure there was no hostility in the tossing of the buzzer between u too but it was entertaning to read :-)

The prob with the FSB online is it is scaterd and in parts. Oh yea and im on 56k that kind of makes the pathway of the FSB online a huge hedach. Luckaly I only realy had to go through it when I was trying to find that short that you ended up finding for me.

JamesWade2002

don't mean to be stiring this thread back up, but I thought I would add some useful experinces gleaned today. Today I pulled my upper intake/dynamic chamber to clean the injecter harness ground and moved it from the top of the primary injector hold down to the rear rotor housing. I also cleaned it with sand paper and roughed up the surface of the rotor housing where it would bolt down. I also realized that because of an incorrect routing of the injector harness, I managed to plug in the wrong primary injector clip into the wrong injector, got them backwards. I don't know if that would make a difference or if the grounding change made the difference, but all hesitations that the car had, which was only a slight 3800 rpm - 4100 rpm, are now gone. car now pulls completely smooth at any rpm and any throttle setting. I also cleaned up the ground under the trailing ignitors/coils and the ground from the rear iron to firewall. Getting rid of the extra grounds cleaned up a lot of problems, I did this last year and was very happy. Non of the added grounds fixed any problems and were a waste of wiring. Once again, Wayne and Hailers are right.

MillerLite

we need a legit 'do it right' way/list of things to get rid of the dreaded 3800RPM hesitation. now what im going to do is clean up the stock grounds, and add another ON TOP of the stock grounds on engine and tranny. I am leaving off the ones i put on the pressure sensors.
Should I leave these two though?
1: From (-)terminal to under leading coil bolt to body
2: From strut mount to under trailing coil bolt
it is a grounding issue for the hesitation right?

I fixed the problems, replaced ECU, lead coil, and atmospheric pressure sensor, and all but now my car runs really lean im assuming. I started it this morning and it was blowing white gassy smoke (it was relatively cold though, id say 50F) definantly smelled like gas all around too.. All the parts i replaced were the same but the APS.. there were 4 numbers starting with a 7--- on them that were a bit different. does this matter? Or does my ECU take a few days to settle in?

MillerLite

j/ found this on another thread, im definantly shitting myself in fear now. i noticed the wires for this relay burnt to crisp and now completely forgot to fix it. after work im going to hook it back up and see if my engine runs less rich.... i hope the relay is still good though.. now this is the main ECU and engine one? its actually all the way in the front on pass. side mounted not on side wall but on front near corner. it has a black wire and a red wire and two others if im not mistaken.. possibly a brown? im not sure right now.

WAYNE88N/A

All the way in front on the passenger's side? That ain't the main relay...

Check in front of the trailing coil pack (if there are two, the front one is the starter cut relay for the alarm). On the side...

WAYNE88N/A

IF I was going to re-ground my coils (which I'm not, they've got a perfectly good ground as it is, unless your car's been submerged in the ocean for a while and the studs and mounting hardware have rusted off), I'd do it this way...

Run a bonding strap from the coil(s) body (under the attaching hardware) to the OEM chassis ground point on the left strut tower (have to dig through some tape to find it).

That's it...That was easy, now, wasn't it?

MillerLite

im just trying to get rid of hesitation... i just dont know how..

and i wasnt looking for the main relay, i was wondering what this chomped up relay is on my car! its just not a good thing, the wires are fried up to hell.

JamesWade2002

Is your injector harness grounded to the rear rotor housing? I am almost sure that must have been what did it for me, or putting the right injector harness clip on the right primary injector. I would not add any extra grounds. My car runs so good now, I don't even wanna breath on it. That is what I did which killed all hesitations, AND, the car now idles at 900 rpms while cold, and 600 rpms at initial stone cold start up, with no BAC. It did not do this before changing grounds/injector clips.

iceblue

I have no BAC but TB mod with port and polish. Mine idles at 1.2k to get best performance. at 1k if you drop off the gas it settles at like 900 but will loap down to 500 and can stall out. I wish I could get that inital drop out of it thow.

JamesWade2002

check everything. look for vacume leaks everywere including unlikely places like the lines going to the power brake mastercyclinder, caps on the back of the upper intake, and your ECU temp sensor needs to be checked out, also. This is the sensor on the back of the water pump housing with the plug that looks like an injector clip thats green. check the resistance across it, I compared it will a factory one that I had lying around and the two were very different the bad one had lots of resistance, I believe the good one I am using now had like .300 or less. I really can't remember ask Wayne88N/A. Do not buy the autozone one that is yellow, it will die in less than 6 monthes garanteed, I went through two of them. check your TPS voltage. somebody help me out here, I know there are other things that control that stuff. You don't need your BAC unless you have AC or power steering and maybe not even then, so don't listen to the nay sayers on here that say you can't run an electric fan without it, its not your problem. I'm pretty much retarded anyway and I'd have to see the car and drive it, but that is what I would check and what I went through when mine did that. That Temp sensor is critical, your engine will run super rich and be very.....um...hesistant and jumpy, if it goes bad.