So I recently bought an 89 rx7. But the car was in rough shape. Someone how the guy before me managed to swap in an s4 motor because the s5 was blown. He did not swap harness or ecu. The problem is though that I can't give the car mroe then a 1/3 throttle or it dies right out. Other then that I could drive it all day long. I did get the blown s5 motor and also picked up a parts 87 that runs and drives. Would it be better to swap over everything off the s5 onto the s4 block. Or just swap over the engine harness/ interior harness/ and ecu off the parts car????

 

what OMP is on the motor? what tps? might just need to plug in an s5 omp and tuck it away somewhere...

 

Well I am new to a rotary, first time I have ever actually worked on one. Where would I find out what type of omp is on it. As for the tps I am pretty shure it is off the old s5 motor

 

Looking directly at the front of the motor, where the main pulley is on the front cover, look to the left of it. Their'll be a little object bolted to the side of the front cover with 4 tiny tubes coming out of it. If it has a metal rod on it, its a S4(86-88 model), if it has wires for electrical coming out of it, its a S5(89-91).

 

An S5 TPS will have 2 plungers, while an S4 will have only 1.

 

so I took a peak at that and saw that it wasn't mechanical, but electrical...but I wanted to be on the safe side and called the guy I had bought the car from. The car has an s5 oil pump on it. It also has an s5 maf which got me thinking. The s5 maf was a sensor, while the s4 maf had a flap that would open up more depending on the throttle if I am correct. So could this also mess the motor up??

 

No, an S5 AFM (a MAF is not the same thing) has a cone that moves, while the S4 AFM has a door instead. Both work in similar ways. The electronics need to match the ECU, and from the sound of it, they do.

 

maybe sounds like a fuel delivery issue to me.... But im a noob to rotary

 

Well I am starting to think that it may be a fuel issue as well...I have another set of injectors lying around so I may try to put those in...but I just got the original motor that was in the car. It was rebuilt by atkins rotary, and the warrenty sticker is still on the eshaft unbroken, so I am going to give them a call and c if maybe I can get it rebuilt for free and put it back in the car

 

If you don't have a confirmed mileage of whats on the motor or any papers for it, I don't think they will. Give the PO a call and ask him if he/she still has the papers for the rebuild.

 

You should do a simple test of the TPS before swapping injectors. I don't have much faith that a different set of injectors will do anything. Your problem sounds more like a dead spot in the range of one of the TPS plungers.

Go here for testing info: http://howto.globalvicinity.com/gv_w...i=58&co=1&vi=1

Also, try pressing the plungers in with your finger, while the engine idles. Engine speed should increase steadily, as they move in. Or at least that's how it works on S4s.

 

Hey thanks I am going to check the TPS and see what happens. I will let you know what I find out.

 

so I checked the tps today and I saw that it had two plungers. This would mean that it is an s5 tps on the car so all the electronics match up. Also the bottom plunger registered fine, and so did the top plunger. but when I pushed the top plunger in by hand nothing would happen to engine speed?? Not quit sure what this would indicate. Decided that I am going to keep the s4 block in the car and put on all the s5 externals though. ie) intake manifolds and those good things and just park it for a few weeks

 

sell the motor out of your parts car and get an S5 T2.lol. I'll even let you put my T2 tranny in if you can buy the rear end too. Stop trying to use that S4 motor and make it easy on yourself. we could probably finish the swap in a weekend if you just want to put an N/A s5 motor in. depends on how much help we can get.

 

^^^^^^ that fc looks better than any fd ive seen except for the semi-gay body kit and wing.Hmmmm,,,I need a fd front clip

 

Johnsgxl- indeed, but the rear needs to be a little more rounded as well. I was thinking of doing an FD wide body kit on my FC so I could use the wide body rear quarters and blend it into my body lines. IDK. lot of fab work, I wonder if I'd have to mod the front radiator/ light surround area because the FD goes lower in the front I think. I'd have to swap to the FD headlights and housings too. with all that work, might as well fab in the FD rear tails and do a full conversion.lol.