Hey Guys, my RX-4 engine has decided to take a crap o me recently....no I didn't blow it, it just became very hard to start once fully warmed up and seemed to be mis-firing when really on the throttle.

No I figured it must be the ignition, either the points were scuzzy or screwed. But it has very good spark. It only seems to have trouble starting when warm. Another thing is that once your on the throttle higher in the rpm's it would mis-fire and back fire a couple times on me. I pulled the plugs and they seem to be dry and dark coloured.

I figured it might have been starving for fuel, but even spraying gas right into the carb wont get it to start.

Is it possible for there to be ignition once the plugs are out and weak spark once everything is back together again?

Its confusing me! haha

Thanks guys

 

Sounds like bad side seals and/or missing chrome. Could also be a clogged exhaust. I had similar problems in my REPU. It didn't want to start when hot and had problems with ppower at higher RPM.

I tried the REPU's engine in a project car with a small single exhaust and the engine really came alive. It turned out it was a combination of things. There was infact missing chrome. Lots of it. (or lack there of lol) The side seals were fair. The REPU had a really crappy exhaust built by a noob. Just the simple change of exhaust systems imrpoved the engine's runability noticeably. It would start quickly, even when fully warmed up.

Both vehicles had DLIDFIS based on 1st gen RX-7 ignition parts. If I were you, I'd at least consider a 1st gen electronic distributor upgrade. Then move on to a direct fire ignition upgrade of your choice. I installed DLIDFIS and a Racing Beat single pipe exhaust in my bro's RX-4 wagon. Ran like a raped ape. Didn't handle like one though.

Edit: see here.
https://www.rx7club.com/forum/attach...d=203221&stc=1

 

as an old lawnmower man, when hot starting is aproblem, look to the condenser. I am thinking of placing the dizzy from an rx7 in mt 73 rx3 wagon. bob

 

Thanks Jeff, I know that the motor is good and I built a full mandrel bent SS exhaust for it when I put it on the road a couple weeks ago, so there shouldn't be any restrictions.
Could you show me a wiring diagram of how to wire up the 12A distributor and ignitors? I have a rough I idea, but I'd rather do it right the first time lol.

 

What diameter is that exhaust? If it's too big it will kill velocity and power. My REPU had a dual pipe 2.5 exhaust. Excessively oversized. The project car had a 1 7/8" (will soon be replaced with a full 2" OD single exhaust with Racing Beat pipe and the same old Rotary Engineering glasspack as it currently has).

Look here for a diagram.
http://www.geocities.com/cd23c/dlidfis.html

 

Hello

I am by no means a mechanic however I do own a 74 RX4 Coupe. i also have the OE shop manual, parts book, emmissions book, and power steering book sent to me by a Mazda Canada contact. If there are any pages in these that might help you I'd be glad to copy and fax them over.

Back to me not being a mechanic, could it be an emissions control issue you have? I had the reverse on mine and it had trouble on low RPM or while iddle it would shake and eventually choke and die. Turns out the deceleration control unit and its vacuum wasn't working well. But this sounds like nothing to do with ypur issue. Again, I am no mechanic. Mine has the 13B in it, original not rebuilt or modified.

Let me know if you need and pages off the manual. I also no a Rotary pro here in Quebec, I will see if I email him your questions what he says. He is not on this forum.

Regards

Max

 

Hello R.P.M.

Have you done a compression test? that might be a good starting point, after a

basic tune up ofcourse.


Check RR site, Kevin got a tech articles section that might help you,

http://www.rotaryresurrection.com/1s..._symptoms.html!


I hope it help!

Andre

 

Ok, LOL I figured out what it is....spun rotor bearing! Thats whats making it hard to start when its warm.

Oh well, now its time to build a motor