RXfiles

Hi guys,

I'm new to the Rotary world, I own an American FD3S for 3 years now.

The engine keeps cutting around 5-6-7k rpm in 2-3-4 gear. In neutral, it doesn't cut at all.

I run 10 psi with an Apexi Power FC with a few bolt-ons like a BOV, a 3.5 inch exhaust, hi flow cat, PFS SMIC.

Previous owner told me to install only trailing spark plugs which I did.

My wideband (Innovate Motorsports) doesn't show any signs of fuel cut/too rich/whatever.

Here's a video showing exactly what it does :

Fast forward to 0:13 , 0:27 , 1:13.



Thank you for your precious help!

Mark

ReddRex7

iTrader: (4)

What's the mileage on the car? I would check plug wires for arcing under load, also check coils for carbon tracking. Have you checked the other 2 plugs yet?

RXfiles

Car has 189k miles, motor itself has around 20k miles. My spark plugs are one year old. Spark plugs wire are MSD but I dont know how old they are, they were on the car when I bought it.

Can it be coilpack ?

ReddRex7

iTrader: (4)

It's really hard to get a good look at the coils without the UIM off but I had somewhat of the same issue, but when I checked the coils found carbon tracking coming from one if the post terminals across the side of one of the coils(looks like a white line/crack) on a black coil unit. Swapped it out and bam! No more problem for me. I would check them if you haven't yet.

RXfiles

I will definitly do that , thank you!

rx3sum

As you are new to rotaries and its having issues in boost id take it to a pro.
Dont mean to sound harsh but its too easy to pop a motor with issues in boost.
If you are willing to risk the engine keep persevering.
Does the PFC have a boost cut?
You mentioned previous owner told you "to install trailing plugs only"im guessing you just changed them and the leading is wired as normal.

RXfiles

Yep... The leading are wired as normal.
I said I'm new to Rotary but I'm also new to mechanic world... Now you say that, I realize that changing the spark plugs without changing the wiring doesnt make sense at all.

It is winter here so I won't have my answer before May. But I will start with putting normal spark plugs. If it's my only problem, I will facepalm hard.

Thanks Rx3sum

legatia

What kind of a boost controller do you use? This looks very much like fuel cut due to overboosting (boosting over the limit set in PFC will cause fuel cut).

What is the boost pressure set to in PFC, and also what does the boost gauge read when you are hitting what looks to be fuel cut?

RXfiles

Everything is electronically set at 10psi on my Apexi Power FC and on my Apexi AVC-R.

From what I can remember when the cut happens, the boost gauge falls to 0 and if I continue to accelerate the boost gauge goes back and forth from 0 to 10 every cut.

96fd3s

I agree - it looks very similar to a fuel cut issue I was having recently.

Your minimum boost may be too high, so you may need to remove the pills in the wastegate line or drill out the nipple if you have newer turbos. (and install a manual boost controller or needle valve to regulate the boost)

I may have misunderstood - but you should really run all 4 spark plugs if your not already!

I recently changed the plugs, wires, oil, filter, check valves, coolant, vacuum lines and re-did all the grounding points on my FD trying to fix my problem.
In the end drilling out the restriction in the wastegate nipple, and adding a needle valve was what fixed it for me.

EDIT; I dont believe your electronic boost controllers can control your boost properly if your minimum boost is too high or is creeping to fuel cut limits. The only way to fix is to remove restriction to the wastegate or port your wastegate. (or tune it out with your ECU, i run a stock ECU so i dont have that option)

legatia

Are you reading boost from the commander display? If the map sensor is a bit off it's calibration it might read higher boost than your avc-r unit.

RXfiles

I can read 10psi on my boost gauge and the same boost pressure from my avc-r and commander.

What i don't understand is that I'm boosting an almost stock boost pressure 10psi. How could it be a boost problem ?

Thanks for your replies guys

Tem120

iTrader: (5)

I'm pretty sure the PO ment to change them all to trailing , as in use trailing plugs in all 4 spots . normally my leading foul up quicker then my trailing . so I dont see why he would say to only swap the trailing .

Also 1 year old ? my plugs last a couple months LOL . but then again I do alot of City driving so its at idle alot which is rich.

RXfiles

Ok maybe I didnt choose the right words. I did replace all fours plugs by trailing plugs. Also yes they are one year old, I hardly do 800 miles per year so they are not new but close to it.

rx3sum

Try setting the boost controller to 8 psi and see how it runs.