adrock3217

Well if the 5/6th ports are wired open, it would be revving higher in the upper RPM then down low. Seems kinda strange. Nothing to do with trans if it did it in neutral as well...have him make sure the ports are correctly wired open.

Turbo7MN

On an S5, the port actuators should be fully pushed out if I remember correctly, maybe he got confused with the S4 and wired them shut?

Keep in mind that the actuators are supposed to open at around 3500-4000 RPM. When my car's 5th/6th port actuation system wasn't working I had no trouble redlining it in neutral. My vote is still on VDI or something else.

fast90rx7

If you had no trouble redlining in neutral why do you still think it is something with VDI?? And you also said that they open up at 3500-4000 rpm.. Why is this car having trouble at 6000 rpm? Just a thought but maybe the 5/6th ports are not all the way open?? Maybe only half way?

Icemark

VDI and aux ports only work under load.

But the Aux ports and VDI are two different things.

Think of the aux ports (or sometimes called 5th/6th ports) as extra valves opening on a DOHC piston engine (like your SHO), and VDI as different cam shaft timing (like a VTEC honda or Toyota VVVTC sort of). As you learn more about rotary engines, you will also see the aux port change intake time as well, but that is another story and I didn't really want to mention it as it sounds like you are already way confused on operation.

Two radically different things.

To me it sounds like a couple of things.

#1 no air pump. This pretty much kills the engine. The Aux ports won't work, the VDI won't work. Wiring them both open kills the low end power (everything under 4K RPM is gone making it a true dog). Leaving them closed will limit the high end rev to about 5500-6000 RPM.

#2 the walbro. If it is one for the Turbo (as most inexperienced non turbo tuners will put in) then there is radically too much gas at above 5K making it run like a rich pig and further lowing engine output. The absolute last thing you want on a non turbo is more gas above 5K RPM. They are all ready pig rich at that RPM.

#3 the tranny... using a Turbo tranny just adds extra weight that is not needed, but will have 0 effect on the way the engine runs. Gearing is almost close enough to be considered identical to a non turbo.

#4 spark plugs ... if the condition of the spark plugs or spark plug wiring is poor; then that too will limit the upper range RPM.

edit: FYI VDI: FYI: Aux ports= a single port in each rotor that opens around 3800-3850 on non turbo 13B '84-'91 models, that allows both intake timing and amount to change when the engine is under load.

BLKTOPTRVL

I once parked my Vert for around 5 months while I drove my new FD almost constantly.

When I started driving the vert again, it had a lot of trouble getting to redline. When it started running bad, I would always back out out the gas.

After a while, I decided to 'push through' to see what would happen. So, getting onto the freeway, I would rev the **** out of it. When it started to slow, I would just keep my foot in it.

After a few trips past 5K it was back to normal. I've always been told by service dept. people that the engine needs to redline every once in a while.

coldfire

iTrader: (1)

i have driven around with 6pi and VDI not operational and i can still rev to redline.
icemark mentioned it about the fuel and spark, and i have to say it is most likely to be a fuel/spark problem.
it could be the engine getting too rich, but i think either the spark plugs or the coils may not be working properly, causing ignition break up at the upper RPM range. so check 2 things:

- spark plugs
- ignition coils

fast90rx7

Geeze you are very knowledgeable. Fist off thanks for helping me out! And no im not confused on the operation of a rotary but it is just everything else that im getting confused about. Like 5/6th ports, and VDI. I am starting to figure out what it all is. But as of right now I think that I have got all the info I can at this point. And right now I can't do anything else but just get the car and go from there. Do you guys think that I should put the airpump back in it?? Also why do ppl remove these if they are so vauleable, in low end torque?? And sence the motor is still bogging down even in nuteal and having no load on it, I think you maybe right with the fuel pump or spark idea. I have known about the problems with putting to big of a pump in a car that doesn't need it from my SHO. So I guess at this point I will get the car and just go from there. Im sure once I get the car I will start this thread back up.

Thanks for all your help everyone!!

Turbo7MN

I wouldn't bother putting the airpump back in, just run the 5th/6th ports and VDI off an electric airpump and RPM switch. It'll save weight and engine bay space, and it will open at the same RPM every time no matter what. People wire the ports open because they are ignorant (no offense) and probably too lazy to do it the correct way. If you don't push your car into the high RPM's all the time, you're probably better off just leaving them shut. I spent about a year with stuck 5th/6th ports and the car was still just fine for everyday driving. Wiring the ports open is a pretty stupid idea in my opinion.

Your best shot is probably the fuel pump.

-Darren

Rancid7

check your ignition system , i once had this problem and a loose spark plug wire was the cause . Hope this helps .

fast90rx7

Ok ok this is the last thing I am confused about now. Can you or someone else explain to me, how the air pump works?? A diagrame would be really good to. But im just confused on the operation of the airpump. I get what it does, I just don't get how it works.

Turbo7MN

It blows air. Seriously. It's main purpose is to blow air into the exhaust system for emissions reasons, but on S5's it also operates the 5th/6th ports and VDI. If you want a diagram, look up the FSM.

http://www.teamfc3s.org/main/factory...ual/1989_1991/

It should be in section 4A

fast90rx7

I talked to the owner again, and he said that the old owner (that was his friend) had the same revving problem that it has now. I asked him if it had the fuel pump in it that is has now. He said yes. So im almost positive that it is the fuel pump causing the problem. Now do I have to put in a stock fuel pump, or can I just put in a pressure regulator to big the pressure down?

Turbo7MN

I'd put in a stock one first, just because they are cheap and common and you should be able to tell right away. I have a spare one laying around my garage, but I have no idea if it works. Ideally, you should get a Walbro that is designed for the N/A.

fast90rx7

Well once I learn more about rx's and stuff, I think im gona buy a TII motor with a blown Apex seal. I also happen to know someone with one. And ill get it rebuilt with 3mm apex seals, and do some kind of P&P. Im not sure how big yet. But anyway ill do that and put in the motor, ECU, Harness, ect. So that is why I want to keep the pump in if possible. I mean worse comes to worse, ill just throw in a stock pump and just keep the walbro until I turbo it.

Icemark

A blown Apex seal generally means you will be replacing half the motor.

You may wish to find something that is not blown and just has high miles or try a crap shoot like a Jspec for rebuilding.

fast90rx7

well I have a friend who bought a motor for his Gen II. He got the motor and put it in his car. When he started it, it blew alot of oil. So he told the company that he bought it from, which was one of those Jap inporters. And they are giving him a Gen III TT motor in place of the old one. So I was just thinking about getting the old one. What would be the problem with this?