Hello,

1992 FD3S
Simplified Sequential
HKS V Mount
Twin Power
PFC
Intakes & Exhaust
Air Pump and emissions delete
OMP delete

I started to troubleshoot a no secondary boost issue and ended up going down the rabbit hole of while since I’m in there. I ended up taking off both intake manifolds, turbos, and everything to get to them.

I replaced all of my solenoids and did a vac hose job. I got the injectors flow tested, cleaned and installed a new FPD. I also ported my wastegate.

I got the car running and it idles fine on start but occasionally will die after touching the throttle. I don’t know how to describe it but it doesn’t have clean power under load. When I get under boost the car will act very unusual. Sometimes it stalls out and sometimes it will have a bad idle hunt from 2000-3000 that will continue until I turn the car off. The symptoms are inconsistent and that hasn’t made it easy to troubleshoot. I haven’t done an official compression test but, during my deflooding procedure I didn’t notice an uneven compression stroke and the engine has less than 5000 miles since a rebuild.

I have checked
MAP, TPS voltage, VAC line routing, Injectors stuck closed, FPR, sensors on PFC, spark plugs, new gas, engine grounds, and just smoke tested the intake.

I’m nearly given up. I live on Oahu and I haven’t found any rotary specialty mechanics. And I know the saying. If it ran before you touched it and now it doesn’t it’s gotta be something you did. I’m trying hard to find it but I haven’t had any luck. It could probably use a tune but it should definitely run comfortably without one.

 

The thing with what you have is people don't typically consider the possibility that they assembled something wrong or didn't install a seal/gasket properly or at all or did not replace something that should have been replaced......

With what you've done, there is a million+1 things that could be wrong. It may not be the answer you want but going backwards and methodically working your way forward will be the solution here. The community will walk you through it but it will be based on a lot of assumptions.

If you've already reset the power fc and did the idle relearn, then it would be advised to tear everything back down and triple check that everything you did is correct and that everything is plugged in correctly. It's really easy to swap the fuel and water temp connectors.

 

Have you sucked in an air filter element? Check if any of your intake pipes re collapsing under load.

Perhaps try a substitute PFC. There could be issues with the mapping of your ecu, i.e. If it was tuned to a different set-up

I don't see a CAS check on your list.

Also did you check if coils are in spec?

Perhaps replace the coil harness with new.

You have the correct coil harness right?


I don't see an ISC check on your list either.

 

Did you mix up your injector plugs?

 

Thanks for the reply’s.

I have triple checked my injectors, red secondary on top and purple primary on the bottom. And verified the harness and plugs are working to the ecu.

I took out my IAC and put 12v to it and it would open and close respectively.

I haven’t touched my CAS but if I it was bad or not functioning correctly I don’t think my car would start.

As for the ignition coils I haven’t checked the resistance yet. My mindset was it simply wouldn’t go bad from sitting in my garage, but I wouldn’t count out anything now. I’d assume I’m using the correct harness since I didn’t do anything but disconnect it and before it was running well.

I have been running the stock map on the PFC and reset it and all it did was give me some idle hunt. I also threw in a different pfc and it gave it a worse idle hunt so I just put the original back in.


The intake tubes are all metal and the intake filters aren’t sucked in.

 

I ordered a new ignition harness because why not, it’s probably not helping me.

 

Out of curiosity, how should the ignition harness be oriented in the car. Short lead in the back (firewall) or towards the front of the car?

 

I think I just had my eureka moment.
My car is oriented like the picture. I'm 99% sure that's wrong and it should be White T1 Black L Blue T2. I will let you know how to runs after I swap it over.

 

Check the colours of the wires vs the wiring diagram.

 

You replaced a coil harness with a 30 year old one? Nengun sell brand new for about US$75.

Ask them for "N3A3-18-05Z " before they get sold out.

 

yep it’s backwards. Holy moly.

and as far as the new harness I ordered a new one not an old one but if this works I might cancel that order and just pray I don’t need to open my hood for awhile.

 

FSM recommends changing the plug leads annually and the coil harness every five years.

I replaced mine and it got rid of some stalling i was getting on decel.

My starter harness is likely aging out as well. Have a new one on back order from Nengun.

The reason I said check the actual wire colours is that it seems the wiring diagrams were changed from year to year and looking just at the schematic might cause some confusion.

 

Took it out and got one pull in and it started surging more than a normal pfc idle hunt.

smoke tested it no leaks. Weird right?

turned out to be my primary throttle plates weren’t closing.

 

What was the cause of that?

Also if you have a pic of the coil harness grounding point, it would be helpful to see it. The FSM is not specific.

Do you have an AFR gauge installed?

 

I don’t have a pic right now. My ground is in the middle on the coil mounting bracket, sanded all the mating surfaces. The car feels so much better after swapping the harness around. It’s not constantly misfiring anymore lol.

Just gotta fix a leaking secondary turbo exit gasket leak now. No AFR, it’s on my list of things to buy.