So I just bought this car yesterday from a guy I know very well and we both know it has a few problems, just not sure how to fix them. I'm not new to forced induction, but this is the first rotary I have owned/worked on and I am definitely not familiar with it. The mods that I know of on the car are: Greddy intercooler piping kit w/ front mount intercooler, 4" turbo back exhaust, and hks blow off valve.

The first problem is that the idle is rough at times and sits around 1300 - 1700 rpm whether its cold or at norm op temp. But as soon as I put it in gear with my foot on the clutch, it drops down to 900 - 1000. My friend replaced all the vac lines with blue colored line, so I know all the lines "I can see" have been replaced. Do I need to pull out the vac line routing diagram and start routing the lines from scratch?

The second problem occurred while doing a post purchase test run on the highway from a stand still. I got up to 6000 rpm in third and slowed down to 110 km/h. And as soon as I slowed down to 110, I could smell fuel vapor coming in through the hvac system. I pulled over, shut off the car, got out my flash light, and couldn't see any gas or wet spots in the engine bay and the fuel smell was gone. . I also noticed that the pull from the turbo's fades away around 6000 rpm in second and third gears. Could the turbo's cutting out also be caused by a vac leak?

The third problem is that if I release the clutch with any aggression at all when I shift while driving, I can hear a clunking/banging sound in the rear end of the car. But nice smooth shifting and the sounds never happen. I suspect the differential mounting bushings need to be replaced and/or universal joints in the drive shaft.

Any thoughts or info would be a great help!

 

Take a good check under the hood before you go tearing off in that car!
It's always good to know that you have checked it out thoroughly before you Rod the Crap out of it!
Fuel smell.?..Rx7's are known for that,but as I said,look it over.

 

So the fuel smell isn't something to worry about if I can't find a leak? And I got the day off work tomorrow, so it will be a full day of inspection/photo shoot with my FD.

 

Well when I come inside from driving my Fc,I can get lit on fire...lol!
I smell like Fuel!
..I'm not saying that in your case.I am saying Check it out.You don't know if it is just the Nature of the beast or a slight leak..Your car is new,so It's best to give it a Good going over and acquaint yourself with it.
You can get to the point later that you can identify bolts and say where and what they are used for!..(Useless in life but useful when you own a Rotary..lol!)

 

Did some inspections on the rear end, under the engine, and in the engine bay up top. I found some interesting things.

Two or three of the metal vacuum lines underneath the intake manifold were unhooked and found a kinked one under the intake where the throttle plate is. The differential mounting bushing on the drivers side rear upper area of the differential is definitely worn. The rubber material has pulled away from the metal ring encasing it; and has rub marks 1'' long in a vertical motion showing some serious up and down movement where there should be very little. Found several wiring harness plugs with nothing connected, looks like the a/c lines and condenser were removed at one time. I can push up on the rear wheels and compress the rear shocks quite easily when the car is lifted on a hoist and the rear shocks also have signs of oil leaking from them.

I'm still not sure what is causing the banging sounds in the rear end when I let the clutch out aggressively while driving , but I can definitely hear the rear shocks banging when I go over rough spots in the road. And I found all the fuel lines and checked them for leaks, found none, thank goodness!! I suspect the one kinked vac line under the throttle plate and the unhooked vacuum lines to be the problem with my boost cutout at 6000 rpm and high idle.

I have quite a few pics, with descriptions, of the stuff I found in my album titled: Interesting inspection finds.

 

Found out why my fd never warmed up in the morning before work. Someone spliced a wire to ground on the cooling fan relay #1 so the fans would turn on whenever the key is in the run position. Disconnected the splice and the cooling system functions normally now and it only takes 10 minutes idling in -15 C weather to get half way to norm op temp.

Went for a rip on the highway after the car was at norm op temp for 15 minutes. And the results were surprising. Had boost all the way to 7000 rpm with no sputters, bucks, or coughs from the engine!! I am even more confused about why I had low/no boost at 6000 rpm problems before. Maybe its because the car sat for two months before I bought it. And now the sleepy valves and solenoids have awakened. What ever the reason, Im going to run another "test lap" tomorrow after work. Hopefully I will have the same, or better, results. Wish me luck!!

 

Went for two test runs today, one a norm op temp and the other half way to norm op temp. On the coldest of the two, I noticed that the car sputtered a bit and the boost slightly faded away at 6000 rpm. The second run at norm op temp, the car had no sputtering and boosted all through my shifts @ 7000 rpm. So the problem seems to be when the engine is not warmed up all the way. I'm guessing a dirty valve in one of the vac line solenoids may be the problem or I just need to clean some things.

 

I bought mine thinking it was rebuilt 1700 miles ago and... it blows up 2 days later..

 

Finally got a boost gauge installed, and it seems that my fd only boosts 2 psi when its cold. haven't done a hot run yet.