I have a S4 13b NA powered offroad buggy that has some wiring issues. I beleive i have an injector that isn't firing properly. This was diagnosed by a local shop who replaced it to no effect and then told me it was a bad ECU, which then i replaced, to no effect!!! I think all my problems are coming from the harness that i cut and spliced when building the buggy. This problem has been driving me crazy. So i am at the point of either rewiring the buggy from scratch or going with a aftermarket ECU that has a harness with it (like Microtech). any input would be appreciated especially if you have a modified wiring diagram that shows what i can delete from the stocker.

 

Well, all the injectors need to fire is the 12V feed from either the EGI relay or resistor block (depending on year) and the wire back to the ECU. It would help if you provide some description on how you set up the harness.

 

i used the stock 86 rx7 harness. i had to cut and splice in a few places to make the rear mounted set up reach, and in other places i just folded the harness over on its self and zip tied it together. I must admit that fuel injection is not a strong point for me, i understand the basics but to trouble shoot it... well i have a hard time. Essentially the wiring to the injector is Mazda factory with an extension soldered in. the wire has full continuity but the resistance is a little high?? (as per the shop i took it to). to be perfectly honest the wiring is a rats nest once taken out of its binding. there is so much redundancy in it, because half the original systems and circuits are gone.

 

can you bring up any codes? the extension you added to the harness shouldnt have any impact on it at all unless you got some wires screwed when you did it. it would be more suspect that you removed to many circuits. recheck all your extensions and if you had a list of what you removed and how it might be easier to help you figure it out. It is strange that only the one injector has an issue though.

 

I built the buggy in 2000 and then sold it to my borther in law. Now i have it back again and to be honest, i am having a hard time remembering what exactly i did when building, i do know we got rid of anything to do with emmissions, the air pump, AC, . I will take some pictures and post them. I do not have access to any type of code reader.

 

OK. I'd suggest getting a copy of the Haynes manual and FSM (from the FAQ) and then trimming the fat off the wiring harness. From memory, all you need to make the engine run are the injectors, resistors (if equipped), AFM, IAT, CLT, TPS, pressure sensor, coils and CAS. Almost all of that stuff is located on the emissions (EFI) harness. The CAS and coil wiring are in the engine and front harness.

With the wiring diagram, unloom the harness and take out all the emission stuff. Then power the ECU by just feeding 12V (though a switch) to the appropriate wire (see diagram). I've used this setup when putting stock 13Bs into other cars and it works well.

 

OK i am feeling a little stupid, I cant seem to find the abbreviation section i know that i have been there before. how do i get there?? I have a haynes manual and it has been invaluable so far. I appreciate your help as i dont know a lot about fuel injection. I will be on vacation for a week and then i am going to dig into the harness.

 

There's a sticky thread w/ abbreviations here: https://www.rx7club.com/showthread.php?t=782434.

Some that Aaron mentioned that aren't listed in that thread:
IAT = Intake Air Temperature Sensor
CLT = I'm guessing he means the coolant temp sensor, but I've never seen it abbreviated like this.

Also, the abbreviations for the various harnesses in the FSM or Haynes wiring diagrams are as follows:

Emissions harness = EM
Engine harness = E
Front harness = F

There are more (listed in the FSM), but these are the big three. Any wire shown in the wiring diagrams will have these abbreviations listed to show what harness it is on.

 

OK i have my haynes wiring diagram blown up and ready to go. can some one give me a COMPLETE list of sensors and/or circits that i need. I am ready to rip into it!!

 

OK i am a complete retard. i can't seem to post a new tread??? Am i locked out because i am new or am i just not looking in the right place? ANY help would be appreciated

 

sometimes i post and they dont get them. just repost and hope they didn t get ur first one. show us a pic or ur buggy. i have 84 300zx that were going to turn into a buggy.

 

my friends dad makes custom buggies since the 70's. i think hes used a few rotarys

 

The frame is made from 2" polished stainless tubing. 13b NA S4 engine and a 091 Bus tranny. Beefed up beetle suspension. lots of odds and ends off different cars from the junk yard to complete. When it ran well it was a kick in the pants. I am not sure of the weight but i can lift the front tires off the ground without any help (although it wont wheel stand under power?)

 

In the New Members forums, all new threads are moderated so you won't see them unless approved.

In the other forums, just hit the "New Thread" button.

I believe I have already posted this list in this thread.

 

o so ur saying that if my post wasnt brought up then that i shouldnt ask again? that maybe my question wasnt questiony enough? just dont want any mods mad at me cause i didnt realize that. sry if i alrdy have....