Hi guys,

This is my first thread on Rx7club and hope to get help from you. I've an 93 RX7 FD3S with twin HKS turbocharge. It's not running right at this time. The proplem started when the wasgate got stick and kept opened. I think because of over boost. Now the engine works rough and it seems only one rotor is working. I checked all hoses for leakage but all are ok. I notice that the intake manifold has two sound, vacuum and pressuer it the same time. It's look like that one rotor has cracked! Please check out this video guys. Thanks

 

..can you say Engine replacement?

 

The video doesn't want to load, but from your description it sounds like you may have run lean and detonated. Get a compression check done. You're looking for 3 relatively even pulses on each rotor. If not, as mysterstix suggested, a rebuild is in your future.

 

Thanks guys. I found a JDM FD3S 13b from eBay in case for replacement, the left rotor compression is 125 but the right one is about 73. Is that normal or both should be the same?

 

Both should be about the same psi. The back is low. i think 80 PSI is as low as u can go. The front rotor on the other hand is just fine

 

Hmmmm - that does sound nasty. Get back to us with those numbers on compression.

Or - are the plugs fireing well on each rotor. Its worth a checkings - though that sound & your description of a lean out does not give me confidence that its anything but an expensive fix.

All the best - Rusty

 

It's toast. Compression check it to confirm. As stated, 75 is extremely low, look for something with each rotor above 100.

 

Thanks for reply guys. Rusty, all plugs works fine, the spark are blue color.

I already disassemble the engine and all Apex seals looks like new. I don't know if the seal on the side of the rotor let the compression go out through the intake! There's no sign of any cracks on the rotary housing. Please any troubleshooting to figure out what's going on?

Thanks

 

I think the problem will be solve. It's the Apex seal. When it was fixed on the rotor it doesn't show any sign of damage, but after removed, The seal already broken. See the pic.




Thanks everybody for taking time to reply. I really appreciate your help.

 

The seal broken the idle have up down up down ?

 

I don't think so. If the RPM goes up and down it seems from the idle control valve.

 

I'm having this same issue but I just got a new atkins motor installed by rotary doctor less than 7k miles ago. I was told it might be a harness or sensor issue? Possible or is this a common problem??

 

^ Bump