Dan_Gerlach

I bought an 85 GSL-SE (13b)in the fall. When I bought it, I was told it needed a fuel pump and some ignition components. (The owner's dad cut the coils out of the car so owner couldn't drive it.)

I put in a new fuel pump, and wired in ignition coils (from a 12a car, but that doesn't matter, does it?) However, when hooking up the coils, there is a mystery wire in the harness. It looks like a coaxial cable- there is a black wire, and then there are strands of wire around that, and a gray sheath around these strands.

I have spark, fuel is getting to the head, but I don't think that the injectors are functioning when I crank the car. I read that if there is no trailing spark, the fuel pump will not work. My question is, does that gray "coaxial cable" trigger a sensor to see if there is trailing spark, and because it is not hooked up, prevent the injectors from functioning? Also, where does that gray wire connect (and if this is not its function, what DOES it do)? And if that gray cable is not the culprit, any ideas on why the car isn't starting?

Thanks

Dan
85 GSL-SE
Milwaukee, WI

2fast2rotar

Need a pic!!!

The car will not run well with no secondary ingnition.

And I do NOT think that the GSL-SE use the same coils as the GS and GSL. But I'm not positive.

As for the cable... we really need pics...

trochoid

iTrader: (6)

Welcome to the forum. Just you don't hate it when PO's do that kind of crap. The shielded wire is for the O2 sensor, should have a green connector.

In my sig line is a link to the online FSMs, and other rotary related material. Download whatever you need and start reading. You'll need the 85 FSM. Sec. 4B covers your model engine. Read up, follow the troubleshooting guide, holler when you get stuck or have a question.
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..Coils are the same.

Rx-7Doctor

iTrader: (13)

Coils are all the same on 1st gens.
What do you mean by fuel is getting to the head?

Fuel pump should not be coming on until you crank the engine.

You also need to check for spark to both the leading and trailing plugs.

Dan_Gerlach

I undid the hose going to the rotors, and when I cranked the car, a friend saw fuel coming out of the hose.

All 4 spark plugs fired, I had them resting on top of the engine and cranked (no fuel was spitting out of the spark plug holes, so no gas would ignite while I was trying it), and all the plugs fired.

Will try to post pictures tonight or tomorrow!

2fast2rotar

Try your timing.

The dizzy might be turned 180 degrees out or even 90.

If you got spark and gas, it has to be timing or no compression.

Did you do a compression test??

85 FB

^ The engine will run even with bad/no compression. There won't be any power to it, but it'll run.

Dan - do show us a picture of that cable you're talking about.

2fast2rotar

My car jammed an apex seal and it wouldnt crank at all...

85 FB

A jammed apex seal and a busted up one (no more sealing) are two different things.

You said no compression, you didn't specify how there is no compression. Usually, when someone says "no compression" it's because the apex seal has worn down beyond specs and sealing ability. Or just broke into pieces and there is no seal period. If it's anything but jamming up that rotor, which you didn't say originally, the motor will still fire up. Just have a very bad idle and no power.

Dan_Gerlach

The compression is ok, I made sure to check that. Could my problem just be that the fuel pressure is not high enough, even though there is SOME pressure? I also read that the injectors will not function without a signal of trailing spark. Where is that sensor, and where is it wired in to sense the trailing spark?

I'm still pretty new at car stuff (especially rx7's), so forgive my ignorance- how do I check/adjust the timing?

The mystery wire is the gray wire- I think it's the O2 sensor. Another dumb question- how do I upload a picture? No matter what I do, it says its bigger than the 100/250 kb limit.

djessence

you can size down your pics (compress) using office file editor or something like that if you have office 03 or vista.

OR you can use a third party like photobuck.com and post the links

Dan_Gerlach

I think I was sort of vague in my last couple posts.

Here's everything I know, as specific as possible.

The fuel pump is new.
There is fuel in the tank (mixed w/ 2 gallons of new gas).
When I crank the car (with the inlet hose off) fuel comes out of the hose.
There is spark for all 4 plugs.

However, after trying to start the car, I pulled the plugs, but the plugs were not wet. This makes me think that the fuel is not being injected into the rotors. I know its possible (but doesn't seem very likely) that BOTH injectors are shot. I have the Mazda manual, and it says "check that continuity is presemnt in wire from trailing coil neg. terminal to U terminal in control unit connector." Could this be my mystery wire?

The mystery wire is the gray one resting on my finger.

Rx-7Doctor

iTrader: (13)

Can't tell where that wire is in relation to anything. Need a better view. Where is the wire coming from?
Need to see where that gray wire starts from.

Dan_Gerlach

The wire is coming from the harness, and location-wise, is right near the ignition coils and the battery.

I hope these pictures are more helpful- it looks like a wire within a wire- there is a black sheath, surrounded by braided strands of wire, and this is covered by the gray sheath.

Rx-7Doctor

iTrader: (13)

Need a larger view of the surrounding area including the fusible link area. Get a wide view please. I can't place that wire?

Kentetsu

Check your fuses. I believe there is an engine control fuse that can blow and keep the injectors from firing, but not really sure due to my limited experinces with the SE models...

trochoid

iTrader: (6)

Best advice I can offer at this point is to sit down with the wiring diagram in the FSM and strart tracing wires to see what's there and what isn't. If that shielded wire is tied in with/close to the coil wires, it doesn't belong there. As I stated before, the only shielded wire is for the O2 sensor and it's black, not gray. The O2sensor is not needed for starting or running.

Test the 2 fusible links on the strut tower. Iirc, one of them is for the injectors. You can use a long piece of vacuum hose or a mechanics stethoscope to listen for the injectors clicking during cranking, or use a noid light.

Dan_Gerlach

Hey all, I did get it to start.

For those who are interested, it turns out that the inside wire (in the black sheath) in the gray "mystery wire" needed to be connected to the negative terminal of the trailing ignition coil. (I'm not sure where the outside wire connects, yet)

Thank you to all who posted advice- I really appreciated it, and I'm sure I will have a lot more questions pretty soon!