Nisaja

Hey guys. I apologise if this is in the wrong section. Couldn't find a "help" section.

I finally got time to work on the car. Most of it is done now.



You guys might remember me from my old posts. For reference, these were the problems I had - https://www.rx7club.com/new-member-r...tions-1145863/



Car is a 97 JDM FD.



I did a lot on the car. Checked the CEL codes by hooking up an LED to the diagnostic port. Replaced the turbos. New plugs. Checked the rats nest. No vaccum leaks. Checked all solenoids. They work.



Now there are no CELs.



Problem - sometimes under load, and after a few mins of driving, the car doesn't rev past 6000rpm. It's like a rev limiter. But it's fairly smooth. It doesn't jerk.



Revs all the way to 8000rpm in neutral.



Put the car on a Dyno and it only made 160whp.



We tried a Link ECU, and then it worked fine!



What could this be? Could it be the cat? The JDM cars have a downpipe, so there's no front cat, but the second cat is still there.



I would love to go catless and just eliminate that headache but I read somewhere that without a cat, the car could boost more and damage the engine. Is that true? My car is stock.



Thanks a lot!

Trinityevo13

iTrader: (1)

Hey Nisaja,

I had a similar situation with my JDM FD as well, only thing I wasn't passing 3000 - 3,500RPMs. I did a lot of changes similar to what you did, plugs, coils, injectors, vacuum leak tests, you name it I probably did it.

Here is what worked for me. Pulled the rats nest and tossed it as far away from the car as I could. Got a Rywire harness made to spec and swapped out my old engine harness. Ran a Apexi Power FC with a midpipe and tuned the car. Never looked back since, car revs all the way thru to redline, no issues, been running solid now for the past two years with multiple tuning sessions.

If there is the slightest leak in the vacuum system or a simple electrical system fault in the harness it will cause issues. Maybe one of the solenoids are bad. I did find multiple issues on my old harness that I would never have seen unless I removed the entire harness. These cars are very old as is and things like the vacuum system and harness tend to be the culprit.
I can only share my experience and tell you what worked for me, hope this helps to point you in the right direction.

Cheers

nycgps

iTrader: (4)

U need to first check the ECU, there are times that it's simply the ECU went bad. I seen so many Rx7 did that

after that, check the fuel pump speed relay (the one by very front of the car). Short the diag connector see if it solves the problem

and as Trinityevo13 point out, the Emission harness (that's what it's called) on top of the engine could cause all kinds of weirdness issue as well, and it's a PITA to check, but I seen a couple of FDs went back to normal AFTER I replaced the harness with new, that's even after the harness checked out and it looks like it's completely fine.

Nisaja

Thanks a lot for the replies guys. We spent the next few days diagnosing the car.

We plugged in a power FC and found a few more fault codes. Turns out one of the solenoids weren't working. Fixed it and now the car revs all the way to 8000rpm under load.

I bought my 7 with a bunch of issues so I never got to experience it properly. Now, for the first time, I got to drive a working RX7, and a stock sequential at that. Amazing feeling. The power delivery is so smooth. I'm super happy. There is a small rubbing sound coming from the rear suspension. But that's nothing major. I should be able to get it fixed at a local shop.

Thanks for the responses guys.

Trinityevo13

iTrader: (1)

Awesome, glad to hear man. Enjoy the car !! Until you are ready to upgrade lol !! Safe travels!!

Cheers