ZeroStage

Hi everyone,
can anyone please tell me what is this tank in the picture...
it looks like some oil tank but it's allmost empty and i can't find any information about it..

(sorry for the picture... it was taken when i bought the car and it's the only one i have.. i'll try to take a better one later)

and by the way.. i have anothe problem, my car is esitating when i'm reaching 4k rpm.. and sometimes it doesn't even pass that rotation with me flooring it... it's just like if it has some kind of fuel cut or something like that...
i know it can be tons of things but can anyone give an idea of what is causing this? i have this problem for about one year now and i've already changed lots of stuff but the problem comes back everytime...

Thanks.

clokker

iTrader: (2)

That tank is the cold start assist reservoir.
Mazda recommends removing it and forgetting that they ever designed/installed the system.

ZeroStage

wow... i wasn't expecting an answer like that... lol are you sure?
because now that you talk of it... there are only a few 7's with this reservoir...

farberio

iTrader: (7)

The system is useless but you don't have to remove it, it will sit there and do nothing all day long if thats what you wish.

As for your other problem, you should be looking at. (In no particular order)
1. Stuck Aux or 5/6th ports
2. Bad Grounds
3. Clogged Cat

HAILERS

It's the reservoir for the Sub-Zero Start system.

A Factory Service Bulletin recommended removing it decades ago. But, leaving it in place hurts nothing.

You car looks like a early 86-87 car. There was a service bulletin put out by Mazda addressing hesitation on the early models. You can read that bulletin at AllData.com.....for a price. The bulletin identified the problem as one related to the AFM and inadequate grounding. So what they did was add an additional ground wire at the Boost sensors brown/black ground wire. Why the boost sensor???? Because all the sensors ground wires are spliced together inside the EM harness and that was the easiest place to add a gnd. The AFM elect plug has a rubber boot over the wires and that would have made a mess adding a extra gnd wire.

IF you look at your boost sensor wires, and you find that you already have two brown/black wires going into the same socket, then that *correction* has already been done. Adding another won't do much good.

And for all ignorant peckerwoods, even though this is a non turbo car, Mazda calls the sensor a Boost sensor and not a Pressure sensor. See the manuals and parts fische.

As for hesitation, splicing in another ground wire to the three/four ground wires near the ECU has corrected hesitiation problems. The ECU grounds run from the ECU to the top of the rear rotor housing on a series four. But, if one follows the gnd wires from the plug up the harness about four inches, you will find a couple of them spliced together. You would solder in a new wire there and terminated the other end at a place like the studs that hold the ECU BRACKET in place to the chassis.

You would make sure you did not splice into the 02 wires center conductor which is BLACK and in the same area mentioned above. The 02 wire is a shielded cable with black center conductor.

Go the FUEL AND EMISSIONS page in the FREE online FSM, and you will find in the CONTROL UNIT pages, the pinouts for each wire, including GROUND wires.

ZeroStage

thx a lot guys i'm going to check out the things you said...
about the reservoire i'll later think about removing or keeping it...

HAILERS yes it's a 86 FC, i bought the car about 2 years ago, this car came from canada to portugal and i bought it here to an old man who had it stoped at his garage... but the last year i've had problems one after another and this one is really making me crazy!

ZeroStage

I was searching the internet with the topics you guys said and i found out this site:

http://www.aaroncake.net/rx-7/tech1.htm

I think this are the topics you were talking about but can you please confirm if this is what i need to do?

-How To Test The 5th and 6th Ports
-Cleaning The 5th And 6th Ports
-Proper RX-7 Grounding Proceedures

Thanks.

S4GXL

not to hijack this but why is the cold assist bad? mines still there and i may be needing to start the car in below zero weather. is it completely useless? i dont even know if the cold start assist is even working but i plan on filling that tank up this winter unless someone says dont do it with proof.

clokker

iTrader: (2)

The only "proof" i can offer is two Colorado winters with no starting issues in extreme cold and no sub-zero assist installed.

HAILERS

Yes. Not cold start. SUB-ZERO START SYSTEM. Frankly I've forgotten what fluid is put in there. Anti freeze perhaps. There was a post on this forum once upon a time as to what the fluid WAS. MAZDA had a REASON for removing it.

Cold Start refers to another thing, like the water thermowax, fast idle cam/stuff. See FSM. FUEL AND EMISSIONS SECTION.

OWNER: look at the rear aux actuator. See the small hose that feeds it? It come from the split air pipe. Well take that hose off and attach a long piece of vacuum hose to it and blow like the dickens into it. The actuators should start to retract. OR take a shop air hose and apply air pressure to that metal nipple that feeds the actuators. They should retract all the way inwards. IF they don't, then you have problems. Nothing that can't be overcome. It takes only about five psi on the outside to make them retract. I've used quite a bit more than that and have not ruined them.

OR, shove downwards on the actuator linkage with your fingers/thumb, and they should go inward. IF so the actuators and sleeves are good. BUT a air leak at the gaskets b/t the actuators and intake can cause them to not work with the exhaust backpressure, or if one of the two banjo bolts is loose, that can make them leak airpressure and not work.

Try Cakes grounds and when that does not work......write back.

ZeroStage

Well,
i've already started cheking the grounding of the car and the ECU ground looks like this:

and the main battery ground and the drivers shock tower ground are also in bad shape...
as for the 5th and 6th ports...
i've asked a friend of mine to rev the car as i was seeing if they move but they didn't...
but when i aplied a bit of pressure with my fingers the moved so my question is... are they not supposed to move with the car stoped or is it due to what HAILERS said:

"IF so the actuators and sleeves are good. BUT a air leak at the gaskets b/t the actuators and intake can cause them to not work with the exhaust backpressure, or if one of the two banjo bolts is loose, that can make them leak airpressure and not work.
"

??

farberio

iTrader: (7)

I am pretty sure on S4 cars the actuators will only open when there is a load on the car, thus you will not see them open when the car is not moving. You can throw some griese on there and drive around, if the griese moves then you know the ports opened.

ZeroStage

well the look like they are working because of the marks on the actuators but sinse i didn't saw it moving i thought there was already a problem... in that case i'll first check the grounds and then with everithing in it's place i''l give it a spin with some grease!

Thanks

HAILERS

************************************************** ************************************************** ************************************************** ****************************************

Sorry to say. that is NOT a ECU ground. It's probably one of the most insignificant ground points on the car. Just my humble opinion.

The ECU grounds are located under the dynamic chamber and are bolted to the rear ROTOR housing. Just to the left of centerline.

ZeroStage

hmm... are you sure?? because this was the only one i've seen in the rear rotor housing... maybe i've mistaken the wire but i think this was the one referred on the site i posted above...
can you pls explain me were the dinamic chamber is located because some terms i just can't understand and this is one of them...

ZeroStage

nevermind my previous post... i've already seen what that is... do i need to remove that to reach the ECU ground?

ZeroStage

Finaly i found the ECU ground

It's this one right?

And since i've removed everything i'm going to send the injectors to be cleaned!
tomorrow i think i'll have the grounding part done... also the admission will be cleaned. let's hope this works

HAILERS

I think you have it. Should be two black wires on a *ring* terminal.

You can download the FSM, factory service manual, from this site. The FUEL AND EMISSIONS section would do the most good.

Someone attached this jpg some time ago, and it shows the ECU grounds.

ZeroStage

Thanks HAILERS,

I've already downloaded the FSM.

Let's hope this works!

ZeroStage

Hi guys, this is taking more time that i expected but it's not stoped... :P

I think that this are the wires from the boost sensor and there is only one that is brown and has a black stripe
can you please confirm if this is it:


If so than this is the one that i should cut and solder another wire to make another ground right?

while i was cheking out other stuff on the car i found out that one of this hoses was cut... it's cut at the oil injector but i'm not finding a way to remove the remaining piece that is still in the injector... is it me that am not making enough force to remove it or it really should not be removed?
once again sorry for the noob question... =X

ZeroStage