The harness is easy enough to change and more than likely the problem. Just bite the bullet and get a new unhacked harness. And if that dont fix it well the rest of the stuff is easy to test and replace.

 

Ya I agree too. Thing has me at a dead end right now ill give you alittle more detailed info and see what you think. The car is an 86 rx7 base model,been working on it for 11yrs. I like the car alot probably would never get rid off it.the original engine froze the block and I came by a engine for 200$. It had a 13b carburated engine in it for 5-8 years so about all the fuel injection wiring and sensors ended up going. Then I ended up 3 months ago changing it out to the 88 turbo. And pretty much starting from scrap with the injection componets. It doesnt have the knock conrtol box on it or the atmoshperic psi sensor in it right now. I put a new n318 pressure sensor new high impediance injectors all new filters and new afm. The engine has about 60,000 miles.the radiator is for a different year i liked that cap on it. I bought the engine from japan. The car didnt cut out when I first drove it but started doing it verry quickly more and more. The engine sat for a very long time so everything on it is oxodized and coroded.I checked all the solenoid valves and they all work good. The variable resistor is off a 88 n/a. The car takes a bit to start in the morning... think it might be cuz I need a new bettery.Once it starts it idles fine till it warms up, a month ago it was idling great then quit idling. When its warmed up it starts with no problem. Right now the car is running good but when it get up to 4000 rpm the secondarys click on great but the one on the rear will stay on for a bit then quit clicking for a while.I checked them with a stethoscope and thats the only one with a problem. I have no clue really how to troubleshoot the secondaries.

 

If you want some more info or pics let me know. I appreciate the advice and am starting to figure out whats wrong with it.

 

Im gonna look around for a harness probably ebay.But till I get one clean the grounds see if that helps till I find a new harness. the cars are hard to come by at a junk yard exspettialy a turbo one. Does it have to been exactly for an 88 s4? Do you think I can take it out and take it to a wiring repair shop and have it fixed if i cant find one?

 

Thank you for pointing out this error, I mixed up the information for S4 and S5 Euro-spec cars. So I went through all 3 catalogs again and documented everything as follows, including date of introduction and appropriate supercession information for every EFI 13B prior to the FD's introduction. The only ones missing are the Euro-spec First Gens as I do not have a catalog for them yet.

N304: NA-spec GSL-SE (All)
N306: J-spec HB Cosmo (9/1983 to End of Production)

N318: J-spec S4 (9/1985-1/1/1987, superceeded by N319)
N319: J-spec S4 Automatics (1/1/1987-6/1/1987)
N322: Euro-spec S4 NA (All)
N326: NA-spec S4 NA (9/1985-6/1/1987, superceeded by N327)
N327: NA-spec S4 NA Automatic (6/1/1987 to End of Production)
N332: NA-spec S4T2 (up to 6/1/1987, superceeded by N333)
N333: NA-spec S4T2 (6/1/1987 to End of Production)
N338: NA-spec S4 Vert (All)
N340: J-spec S4 (6/1/1987 to End of Production)
N341: J-spec S4 Cabriolet (All)
N344: Euro-spec S4T2 (All)

N350: CALI-spec S5NA Coupe (All but 1992)
N351: NA-spec S5NA Coupe (All but 1992)
N352: CALI-spec S5NA Vert (All but 1992)
N353: NA-spec S5NA Vert (All but 1992)

N370: NA-spec S5T2 (All)
N374: J-spec S5 (All)
N380: Euro-spec S5T2 (All)

N3B1: NA-spec S5NA Vert (1992 model, 4/1/1991 to End of Production)
N3B3: CALI-spec S5NA Vert (1992 model, 4/1/1991 to End of Production)

N390: JC Eunos Cosmo 13B (All)
NF01: JC Eunos Cosmo 20B (All)

 

I cleaned all the grounds this morning, made no difference.I figure it propably would be best just to get new wiring harness and ecu. Im sure it will fix the problem. Thanks for the help. Does anybody know what type of ecu I should get for it, Its an 88 turbo II all the sensors are n318.

 

I'd recommend just getting a whole new S4 NA harness. They are much easier to install on a TII swap then making a TII harness work in a NA chassis. You have to re-pin something like 3 wires.

Start making sweet sweet love to the EFI FSM pages that identify each harness pin out. Compare them between NA and TII, and you'll see how easy using the NA harness will be. While doing this, use a mutlimeter to identify each plug and label them. You can also check for impedance. Anything over 3-5ohms(these are 20 year old harnesses) of resistance and there may be an issue in that wire.

I personally recommend changing the wiring path of the harness at this time. I routed mine along the firewall and under the UIM instead of in front of it and near the turbo. The turbo will cook the harness over time.

https://www.rx7club.com/2nd-generati...5/#post8808739

As long as you don't have a hacked up harness, you couldn't have put in the wrong impedance injectors. The high and low Imp injectors have centered and offset notches so you can't put the wrong ones in.

You can tell if it's low impedance by the resistor box.
It's in the bottom left in this picture.
It's stock location will be under the air filter. I relocated mine.


There's a LOT of extra crap that can be removed from the harness.
I personally don't run any of the solenoid stuff or BAC. The FPR solenoid didn't change a thing for me so I removed it later on.

The only one you may need is the S4 twin scroll if you stay S4 turbo.

To make sure, you need
S4 TII AFM (Assume it was clarified S4 TII)
S4 TII ECU (which you have)
S4 TII Boost sensor (?)

A walbro fuel pump is a safe upgrade. Why chance a new turbo engine on an aging NA pump when a single fuel issue can mean blown engine?

Getting the injectors professionally cleaned is a good idea too.

 

Thanks, im gonna start on it tomorrow hopefully all goes well. Did you use the n/a afm meter wire? does the turbo II afm and map sensor wire in the same as a n/a?

 

Yeah, the pinout and wiring for boost sensor,maf,tps,etc are all the same.

The only things different are the non essential things like boost gauge/volt meter, ps switch, knock box.

Also, add a local ground to the boost sensor. Tee into the ground right at the sensor plug and connect it to the strut tower. There's an old TSB about doing this to help get rid of the 3800 rpm hesitation.

 

Thanks im gonna have to start working on it.the boost sensor for a 88 shoud have the wires colors have brown, brown/white, brown/back and black/white? wich one do i put and extra ground on ?

 

Im not sure if the colors i put are right going by memory at the moment.

 

FIRST AND FOREMOST.
DO NOT FOLLOW COLORS!!!!!!!!!!!!
They're a good indicator but never definitive.
Use a multimeter and verify the pins. I made this mistake once and swapped a power and ground wire because a new plug used different colors.

Like said before, they are pretty consistent on the S4 harness but that does mean it's corr4ect 100% of the time.

I'm not going to tell you the color because you need to find it the correct way.

 

I would appreiciate if you would help me verify the wires are correct before I start. Im not sure if I have them conected right. for an 88 turboII. my boost sensor has brn, brn/wht, blck/white and brn/blck. the variable resistor has blck/wht, brn black and grn/blck. Please correct me if they are wrong

 

disregard that last message i was typing didnt see you sent another message

 

So in the fsm does it show how to use a multimeter to check that the wires are correct, I have a haynes one and a chilton would those work too?? is it by the ohms or the volts that you look for on the wire?

 

I aprreciate the good advice, feelling confident that im gonna be able to get it done fairly easy thanks. So when I use the mutimeter what am i checking for? is it the ohms, volts or something else. I have two manuels a haynes and a chilton and have the fsm downlaoded? do those show you what your checking for and how how much the multimeter should say??

 

Have seen the color thing first hand, especially with the AFM wiring.


Also we can't teach you how to become an electrician. Why don't you just measure continuity to the ecu plug or to ground for wire verification? If it's over your head I recommend having someone experienced do it....if you want your car to run correctly :] If you had done that in the beginning this thread wouldn't exist.

 

Im pretty sure I can do it , so check for continuity? do the manuels tell you how much continuity they should have? Just wanna make sure im doing it right...

 

I said continuity, not resistance.

and it's spelled "manual"

 

do haynes or chilton manual tell you how much continuity or should I look for something online that says?

 

Most harbor freight cheap multimeters have a continuity option on them.
It will be blank or infinity when the two prongs aren't electrically connected. If connected, it will usually show how many ohms it's at.

The reason why I say a few ohms isn't bad is also due to your physical connected(probe/clips) can be not fully on and cause some resistance.

Also, I use a sharpie and actually mark each of the wires with their pin outs for ease of id'ing them.
Like in this

 

Ok thanks gonna have to go pick one up.Its either blank or infinity not a crertain amount?

 

thanks for the pic. The splices i have will make the ohms higher? Will it mess up the reading that its sending to the ecu?

 

Thanks im sure my stuff is hooked up wrong, I just used wire colors hooking them up. im gonna go get a multimeter and do it the right way you were saying.

 

Happy new year, might it bring luck to you and your car!