93 FD, new ported engine, non seq, all mods, PFC.

Getting stuttering around 6k WOT. Just stumbles plus the car feels slow as ****. It started doing this lately, really feels slow at WOT, but feels really good at 1/4-1/2 throttle. Um any thoughts? Need anymore info.. let me know.

 

Go to the diagnosis connector, hook GND and TEN pin together and watch the check engine light. Report codes.

Codes are given in a sort of morse code way.

Example:
LONG blink, LONG blink, short blink, short blink, short blink would be code 23. Long blinks are the first digit, short blinks are the second.

Jeff

 

Using a POWER FC... that doesn't fly anymore.

 

Did you just add the PFC? Maybe your car is now running too rich. How old are the plugs?

 

PFC has been on the car.. the car is running too rich, though one night it ran flawlessly and didn't break up, then the same night it started having the problem.

-Plugs are new. I've gone through all the simple crap... thinking it might be a bad ignition coil low tension harness, or bad ground?

 

Plugs foul really easy....

 

Could be a ground problem. It does'nt hurt to have an extra gound anyway.

 

check teh plugs, if its a high rpm thing it could easily be your plugs or mayeb u are just runing really rich

 

plugs they'll foul in 30 sec.especially when rich

 

plugs are still good, i'm thinking its a ground issue.. i do have an extra ground that i used, but i might have a bad ground somewhere.. i'll check it this weekend.

 

How old and what type of plug wires are you using? When this happened to me, a simple change out of the wires solved all the problems.

 

Plugged wires solved my problem.

 

I had the same problem after I added an upgraded fuel pump. I got hesitation above 5k rpm at WOT. I figured that I was running too rich. Since I am running an M2 stage 3 ecu, non-programmable, I had no way of leaning out my fuel mixture. I ended up buying and installing an HKS twin power ignitionn amp. The car works much better now. I think the increased spark duration is doing a better job of buring more of the fuel...Try it out.

 

using Magnecor wires, so they are kinda new, also i've tried the HKS twin power, didn't solve the problem. I think it might be the harness, yet i haven't had time to mess with it yet.

 

I have the same issue. I'm still working on it. I got new plugs and new wires with the same result. I have new ignition coils i have yet to install. I'm working on getting a new ignition harness. I'm hoping one of these things will solve the problem.

 

What size plugs are you using? Maybe your ignition is not hot enough?

 

Is your PFC tuned? Most likely you are just running too rich and/or have dirty plugs. Check your ignition wires and coils just in case.

Wade

 

Did stubling start after opening the car up? If so you probably popped off the Map sensor Hose.

 

MAP sensor is hooked up.. i can tell when thats not on.. lol.

The PFC isn't tuned exactly, but it was able to make pulls before. I'm running BUR9EQ non platinums all around, i've tried the HKS box, and i don't have any emissions equipment anymore. Everything is blocked off.

This is a simple engine bay.. 3 vacuum lines.. no emmissions. So i'm a little confused on to why. i never have enough time to mess with it, but i'm sure it might be the harness.. it is 10 years old and baked.

 

I had a similar thread recently, and someone posted a link to the following thread:
https://www.rx7club.com/forum/showth...threadid=70779

It is suggested, that the 93 harnesses had a problem that will make them miss. The thread has a picture of the old (with ground) and new (without ground) harness. Last weekend, I changed the coils and harness, but unfortunately, haven't been able to run the car yet, because I'm waiting for UPS to bring my a new turbo control solenoid this afternoon.

Anyway, the part number of the harness is N3A3-18-05Z, and they're $57.04 at Mazdaformance.

Good luck,

 

Sounds like ignition to me, Hi RPM breakup. You tried replacin the plugs and wires?

 

I've got the exact same issue. I'm changing out the plugs and wires this week. I'm running extremely rich so that's what I attribute it too. I'll let you know if it fixes the problem.