Hello RX7 forum,
My car has taken a drastic turn for the worse starting this morning. I'm hoping I didn't blow an engine.

Car is a 1988 n/a 5-speed. Only mods are emissions removal (cat, air pump, and ACV).

Stalled it twice getting out of the driveway this morning. Made it through town ok but when I got on the highway power started dropping, wouldn't go over 50 in 5th. When I had to stop for a light and the light turned green I figured out that I still could make good power over 4000 RPM. the higher the RPM the better. Not quite like normal but like 90% of normal. Car barely holds a steady speed in 4th and 5th gear. Can drive 70 in 3rd no problem.

Recent work:
Replaced uim, lim and plenum gaskets a month and a half ago along with the omp, omp lines and omp injectors (omp pump was leaking out the side). Have been using 1qt premix per tank since then. Also sent fuel injectors to witchhunter performance to have them cleaned (engine would flood when turned off).

After all the work it ran better than it ever has until this morning.

I would like to know if there's an easy way to see if the primaries are stuck without tearing the uim off when I get home tonight. Or if there is a particular sensor/sensors that would cause this issue.

 

I would start out with a compression check to be safe, it kind've sounds like you have a dead rotor

Does it sound different rolling over to start it?

A plugged fuel filter & sock are another likely issue
Bad plugs
Bad wires
Bad fuel pump

Theres more things that could cause it, but a compression and spark check are easy, and pretty much free tests

 

Only one primary injector firing? Or both not so well? Sounds like a fueling issue before secondary kick in to me.

 

Well I hope for my wallets sake its not a dead rotor eh. I had a hard enough time with it this afternoon that I had it towed to the only place in town that works on rotaries.

It starts just fine cold and hot but it stalls after 3-5 sec if you don't give it any gas. I didn't have enough feet to keep it running thru all the stop lights on the way home.

 

Sounds like a problem related to the AFM or circuit opening relay. Jumpering the fuel check connector would be something to try.

 

I recently spent two days working on a friend's '88 N/A FC that wouldn't run below 2,500rpm. It was a vacuum leak below one of the primary injectors. It ran fine above 3k, made ok power, but wouldn't run near idle. After fixing the vac. leak, it ran just fine. I used a propane torch with 2ft of rubber hose on it to find the vacuum leak since I couldn't get the torch head near the leak... Good luck.

 

Funny thing about the FC, runs better with emissions in rather than out. I was getting all kinds of strange problems until I went in and replaced all the vacuum hoses with 100% silicone ones. The project took days and I broke a solenoid in the process trying to get the rubber aged to plastic factory hose off. Then I found out my Purge-Control-Valve was fubar. I recall around 72 hours of hard labor taking the whole intake system out and removing all the hoses. Also the 6 port injection system needed cleaning badly.

I did see a guy at my mechanics shop who just stripped everything but the bare minimum off of his FD and it ran cherry. Mess around with the Throttle Positioning Sensor and that screw on the top of the (Edit) Intake Manifold enough and you will get some sort of result.

 

Possible faulty TPS... May be worth getting an ohm meter out at making sure there no dead spots. Free and easy.