I have been trying to help my Friend on his S14 Swap. I know it is RWD, but Maybe yall will have an idea.

We Are using the JDM Ecu in the 95 240SX 5 speed. The motor is a 98. First night we got it started we took it for a drive. Greddy 3"DP, APEXi Dual cansiter N1, Greddy FMIC, Generic cone filter and stock boost. We drove it easy at first and then got on it. The damn thing was quick as hell. Much quicker than I expected. I think Mid 13's with a good launch is easially possable. We took it home and went to bed. The next day he hooked up the Turbo timer, Tach, Speedo, cleaned up some of the wiring mess. Well after that we took it for a drive. The TACH worked, as did the turbo timer. THe speedo did not work as of yet. Now under boost it falls on its face. It feels like misfire to me. We re-grounded the mass air meter, no help. If you stay out of boost it will go all the way to fuel cut (long and hard process with the fast spooling s14 turbo) AS soon as you get into boost it starts popping and wont accelerate. If you get on it at 2000 rpm it will accelerate in boost to till about 3500-4000 then it starts crapping out. It seems like misfire to me. It has a AFC on it. You can lean the hell out of it or richen it out a lot but nothing helps. You can richen it to the point that when it starts bogging down it will send flames out the exhaust.

What could it be. We are starting to think the coils might be having issues. We will know tonight. We changed the plugs also...

Thanks for the help..

Danny

Ouch! I think you are detonating. You burnt up your plugs. Sounds exactly like what happened to my car when a vacuum line T'ed off my FPR got a vacuum leak. All the boost leaked out of it at like 4 psi, and I detonated like crazy. Burned 3 out of the 4 plugs. LUckily the SR20DE is bulletproof. Replace the plugs and you should be ok. It's sputtering and stuff right now because the spark is blowing out. If not getting into boost, it would run perfect. So find the vacuum leak, replace the plugs, and be thankful your motor dind't blow up. Get rid of the AFC and JDM ECU which is tuned for 100+ octane, whatever the hell Japan uses. Get a JWT ECU.



Terrin
92 SE-R

The plugs are fine. I know what burnt plugs feel like.. The car has 116 octane in there right now (dont ask) So I DONT think it is detonating...

PLENTY of people run the JDM ECU's without a problem. I am in no way putting down JWT, just saying the JDM Ecu works..

Danny

Well, it can't hurt to check. *** that sounds exactly like my symptoms. Ohwell. Good luck.


Terrin
92 SE-R

Pulling the plugs and regapping them wouldn't be a bad idea. I wouldn't necessarily just trust your senses to it. Things I would check:

Plugs
Wires (Make sure they aren't covered in oil, it can cause crossfire)
Cap
Rotor
Plugged Fuel filter
Faulty Fuel Pump

Perhaps that AFC is "fighting" with the ecu. Can you disconnect the AFC and let the car run on its stock JDM map?

Going to check all that. New 255lph fuel pump, new fuel filter, No real wires as they are Coil on plug design... Already tried to bypass the AFC and nothing different..

Danny

Danny
Call Chris at SR20 Development. 619-69-TURBO he can help you. I'm lost here. I thought maybe the MAF sensor ground. Check for a vacuum leak though. That could be the culpit too.
Travis

Did you check the plugs? if it ran fine last night you might have the timing to advanced and lost an electrode on a spark plug I have done that....also check your intake piping my crimped up underboost and would cause my car too hit a wall under boost....or another thing that happen to me your wastegate rod could have fallen off so much shit you have to go through ....

Checked and replaced the plugs. They were fine but replaced them to make sure. They looked like a good burn pattern. Not Chalky white and not sooty black.

Crimped up?

Wastgate rod is on and works. It would not go into boost otherwise.

Danny

Danny....... I might be able to check it out this Sun......

did you happen to recheck all the wiring?, I did quite a bit of it when I was putting it together, but it was all done on the basis of being temporary, it still needs to be propelry soldered, the owner did some of it himself im sure he did a good job but the way it was done doesnt allow for anything to be moved around...... have you tried moving the ECU around to see if it has an effect?

haha, i had the exact same problem.

it was from my intercooler hose couplings popping open on full boost. it would feel fine, then positive manifold pressure would be enough to pop open one of my IC couplings. the turbo would injest 200+ HP worth of air, and shoot it out the hole in the piping. the Flow meter, meanwhile, would "see" 200+hp worth of air, and add the respective fuel. the thing would then run like ass. backfiring, and the car would feel like it was decelerating under boost. the plugs ended up black.

check and tighten all couplings with a ratchet, and make sure your TB seal isnt leaking.

also, the inlet pipe could be crushing if it is made out of rubber.

I had that same problem and it wasn't the plugs turned out the be the Plug Wires, I replaced them with some NGKs and haven't had the problem since, but I'm still going to get an aftermarket ignition for some more spark, but ultimately what my problem may have been simply that I was maxing out my injectors.

I have been trying to help my Friend on his S14 Swap. I know it is RWD, but Maybe yall will have an idea.

We Are using the JDM Ecu in the 95 240SX 5 speed. The motor is a 98. First night we got it started we took it for a drive. Greddy 3"DP, APEXi Dual cansiter N1, Greddy FMIC, Generic cone filter and stock boost. We drove it easy at first and then got on it. The damn thing was quick as hell. Much quicker than I expected. I think Mid 13's with a good launch is easially possable. We took it home and went to bed. The next day he hooked up the Turbo timer, Tach, Speedo, cleaned up some of the wiring mess. Well after that we took it for a drive. The TACH worked, as did the turbo timer. THe speedo did not work as of yet. Now under boost it falls on its face. It feels like misfire to me. We re-grounded the mass air meter, no help. If you stay out of boost it will go all the way to fuel cut (long and hard process with the fast spooling s14 turbo) AS soon as you get into boost it starts popping and wont accelerate. If you get on it at 2000 rpm it will accelerate in boost to till about 3500-4000 then it starts crapping out. It seems like misfire to me. It has a AFC on it. You can lean the hell out of it or richen it out a lot but nothing helps. You can richen it to the point that when it starts bogging down it will send flames out the exhaust.

What could it be. We are starting to think the coils might be having issues. We will know tonight. We changed the plugs also...

Thanks for the help..

Danny


hey i know rhis is kind of old but i was wondering if u solved the problem as my pulsar swap in my 91 sentra is doin the same thing now after a year. was wondering if u could let me know if u fixed it and how.

.......

I'm with hotshtSR20, I had the exact same thing happen to me, hit positive pressure, car starts missing BAD, let off runs normal. Turns out 1 clamp was loose (still there) but loose, idled and ran great until slightest boost... then just what you described!

im only running stock boost, and i have 370's.

I FOUND MY PROBLEM. turned out that my fuel pressure was 100psi at idle!!!!!!!shit. my fuel pressure could go up but wouldnt go down with the nissmo adjustable fuel pressure regulator. turns out there was a blockage in the return line in the tank. now *** it runs like a monster. MUAHAUHAUHAUa