JAlfano

iTrader: (3)

Hi guys I am very new to the rotary world. I bought a 93 fd earlier this year and spent some time on the obvious things. Fluids, fixing up the interior ect.

Car has been driving fine until a couple days ago I would say like 25% of the time when I shift to 3rd I will accelerate and around 3k to 3.2k the car jerks alot and then it feels like turbo kicks in and smoothes out.

Any insight on this?

FFWD_FD

That's the 3k rpm bucking issue. I'm not sure what the real fix for it, some say it has to do with grounding. Some folks just replace the ecu with a pfc and it seems to go away. The pfc isn't a fix, it's more of a band aide covering up some unknown issue with the car.

Do a search for 3k rpm bucking and you'll see a lot of discussion on it.

tt7hvn

iTrader: (5)

^Agreed.

However, the 3k hesitation issue is only present on the stock ECU. Everyone that has upgraded to the PFC or other aftermarket ECU has never experienced it.

So, that being said, an upgraded ECU isn't a band aide to the issue, it IS the fix.

JAlfano

iTrader: (3)

That leads to my next question. Obviously the pfc is the ecu of choice because it's ease of tuning plus the commander can act as a boost controller plus other functons. However I really like the greddy profec boost controller. Are there any good plug and play ecu that match well with this? Perhaps aem's?

FFWD_FD

I run the pfc with a Profec type-s and it works perfectly.

JAlfano

iTrader: (3)

Isn't the commander and profec a bit redundant together?

FFWD_FD

I wanted on the fly, hi/low boost switchability. With the pfc commander, I couldn't drive and hit a button to get hi/low boost. So the profec type-s is perfect for me. Also the pfc controlling boost limits you to the stock twins using the stock solenoids. So an aftermarket b/c will be more adaptable to any turbos if I want to change it out to go single.

ArmitageGVR4

iTrader: (13)

Just a thought, you don't know for sure your bucking problem is the standard 3k rpm stumble. It could be a number of things including vacuum leaks, failing solenoids, etc. It's also unusual that it only happens 25% of the time.

Here's something you can try for free first: clean all your grounds and make sure the ECU is also well-grounded. Some people report this can diminish or eliminate the 3k rpm stumble.

wstrohm

I'll post this link once again just for drill:

See posts 42, 47, 53, etc. on this link... others are interesting, too:

https://www.rx7club.com/3rd-generati...-127905/page2/

arghx

iTrader: (3)

The PFC can switch to a different boost setting with a couple presses of a button when it's set up. It also works fine with 3 port solenoids for stock twins or single turbo. I have posted extensively on this.

FFWD_FD

At the time when I was setting up my car, I wasn't too keen on all the features of the pfc, so a ebc was much easier for me to set up.