Tech Question
 

Hi guys,

So I will be converting my 86 gxl this weekend to a set of 48 dco webers (thanks to 13btoy!) And will also be using the 81-85 dist. with ignitors, I had a question about the role of ignitors with the distributor..I will explain what has been explained to me about how all this works, and if I'm wrong could someone set me straight?

From what i understand, the distributor is spinning around, something on or connected to the distributor sends a signal to the ignitor to "set off" the coil, the coil then sends high current to the distributor, and when the rotor passes the contact it creates a high voltage spike which is sent to spark plug and spark occurs..(bear in mind I don't know the technical term for everything, I can guess but I'd rather be vague than use the wrong term and confuse someone with my question). As for the coil, it always has 12v applied to it, and when it is not sending high current to the dist., it is somewhat charging itself right? So essentially the coil is being "discharged" or commanded to send high current 4 times per rotation right, once for each plug? I am asking all this to understand how to hook my ignitors up this weekend..

Also I have read the 2nd gen coil direct fire technique used by many members here in the 1st gen section. Since I already have a second gen, I figured I could go this route and save the money I'd have to spend on coils anyways! If I understand this mod correctly, are you guys using the ignitor to fire the 2nd gen coil straight to the plugs? Thus bypassing the part where the coil sends high current to the distributor? And also, is the main reason this is popular thanks to the fact that the second gen coils have two outputs for plugs? Sorry for the questions if they're stupid, but the searches I have done are just how to hook it up and I'd like to understand it before I fry it all. I appreciate your time guys!

Hey guys, one more question to add on to this, for those doing the direct fire swap with second gen coils, is it all right to use either coil to fire my leading spark? Is it necessary to use the leading coil from an fc? Only asking because I suspect my stock leading coil is taking a crap on me, but the trailing is fine! Thanks guys,

Must use the leading 2nd gen coil, the trailing one will not work for the leading. To wire up the the 1st gen dizzy, follow the wiring diagram in the 85 FSM. As for how to run the 2nd gen coil, there are links in the FAQs on how to wire it up. You will not be able to use the 2nd gen trailing coil on the trailing because it's switched by the ecu to fire for the correct rotor, which gets it's signal from the cas. You will need a single 1st gen coil for trailing.

Since you're going carb and tossing the maf, you will need to make some wiring changes for the fuel pump to work. The way the FI system is set up, through the fuel pump relay, the pump comes on when the key is in the start position, once it's turned to the run position, the relay gets it's signal for the pump from the maf door being open. If there is no signal to the ecu from the maf, the pump shuts off.

There are a couple of ways around this, one is to bypass the relay, the other is to install a jumper wire on one of the green plug connectors in the engine bay. I recommend downloading the FSM for 85 and 86. The link to the online FSMs is in my sig line.

At this time I'm going to assume you know what you need to do to bring your fuel pressure down to the 4.5 psi that's needed for the Weber. As a side note, since you will most likely still be using the FI pump, all new fuel hose and clamps need to be FI rated.
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I had a feeling you might respond! Thanks for the advice, as far as fuel regulation goes, I have a mallory fpr, so that should work well, I had forgotten about the fuel pump shutting off, I am familiar with what do for that though. As for wiring the dist, thanks for the link! As I'm pretty ignorant to 1st gen rx-7's, weren't the 85's fuel injected, or only the 85 gsl-se? Also, did they use a distributor instead of a cas like the 2nd gen cars? Thanks again for the help! I'll keep you guys updated on the install, I should have it all installed tomorrow, so hopefully I can try and fire it up later tomorrow or sunday!

Gus

84-85 offfered the Se and they were fI. All 1st gens used a dist.

Wow that fsm is great! I need to find one for the second gen online:) I think I am learning more from the wiring diagrams in the fsm than I am in my circuits class at the moment! Anyways, thanks for the advice, and I'll keep you guys updated on my progress. Thanks!

Gus