ok so my car just started running horrible today very bad skip so i got some new plugs (long over due) also checked my wires and coils all test good but when i start the car it only runs on one rotor ( can take both front rotor wires off and car runs like when they are hooked up. does anyone know of any injector problems ?? i.e this is a jspec s5 TII

 

If you are running on one rotor, then chances are you are blown or in limp mode. Pull the plugs and the egi fuse, have someone crank the car, and feel for pulses from the spark plug holes.

 

Check for spark at the rotor that isn't running. If your coils are sending out spark, and your getting fuel, check compression. It will most likely reveal a blown rotor if the two previous test passed.

 

compression test! start from there.

 

what ecu? if its a non chipped n374 thats ur problem. idk if it just all the sudden or what

 

I just spent the last 6 months chasing the same symptom in my 88. Turns out the cat was clogged. Do you still have the original exhaust on the car?

 

Cats have nothing to do with the engine running on one rotor,,it is an electrical Snafu,
as he is Done a Jspec swap and the ECU's are Finicky when doing a swap.
I "think" he needs the N370???.( I hope I am right on that Number,I am an S4 TII guy myself.)

 

I don't know too much about the one rotor thing. But my car was skipping really bad too, and some time when I go high rpm, the car won't let me accerlerate even if I press down the pedal! And all of a sudden it would go. I still have this problem sometimes, and I think it's the injectors. But don't take my word for it,

 

ok ive done a compression check 90 psi on all rotor faces on both housing have checked spark at the plug and i have it. it is a chipped n374 and i have straight pipe on so no cat or restrictions. ive also checked the injectors them self they click when power and ground are applied have good injector pulse and resistance of injectors are within spec. once again the reason i think its runnning on one rotor is while at idle it skips really bad and i can take off leading and trailing #1 wires and the car does not change if i take trailing or leading #2 wire off car dies. thanks for all replies

 

Well if you have compression, and you have spark, and you have fuel, the rotor will be firing up properly. I suggest since you already verified compression that you double check the spark and fueling (checking spark with a spark test plug). Just because the injectors click when when power is applied directly doesn't mean the ECU injector drivers are working properly or that there is a problem in the wiring or the injectors are completely clogged.

 

ive checked wiring to injectors i have good continuity and like i said i got good injector pulse. any chance that this could be a turbo problem ? i do have a bit of shaft play. guess ill check to make sure injector is not clogged

 

ok so after getting car all back together its running alot better but there is still a very noticeable misfire below 2k rpm once above 2k mis is not very noticeable and is not causing bucking or anything under a load only when below 2k rpm anyone have any ideas ??

 

Set your timing?
Replace your plugs.

 

ok so i have checked timing and its timed properly new plugs and wires. only thing that concerns me is my boost guage is reading 20-25 in hg instead of the usual 30in hg but i have smoke tested the intake system and cant find any leaks ?

 

if i can't verify that a rotor is getting fuel that easily i don't see how so many people on this forum can claim that they are....

how did you verify that it is getting fuel?

spark
compression
fuel

one of these things is missing regardless of what you are saying to us.

30"Hg idling is physically impossible also, but it could be an indicator that you did the compression test incorrectly.

 

i pulled the fuel rail then cranked the engine and looked for the injectors to spray which they did(only primary injectors). Tested spark with an inline spark tester and also pulled plug and visually saw all spark plugs fire. Did the compression test with a matco compression tester all bounced to 90 psi and i know its physically impossible to have 30in hg but i was just noteing the change in my guage readings (was reading 30in hg at idle before the mis started)

 

are you sure they all bounced evenly to 90psi? it is very fast and easy to miss an uneven bounce indicating a chipped apex seal which will result in basically the car running on one rotor.

 

ill double check the compression but i wouldnt say that its running on one rotor anymore think i took care of that. now the problem is an obvious mis at idle not so obvious once past 2k rpm but still there. if it did have a chipped apex seal wouldnt it be smoking real bad ?

 

nope

 

afm, boost sensor, knock sensor. maybe the coils are fucked up. thats the main reason i would stray from a n374. some times they work some times they don't. i would look for a n370 and just plug her in. the rear rortor not fireing sounds like a classic n374 problem. who chipped ur ecu? does it still have the little black box?

 

since when was a N374 having a classic issue of not firing the rear rotor? classic in your one case?

coils fail in pairs and either would be hardly noticable with a dead tach(dead trailing coils) or the car wouldn't start(dead leading coils)
the pressure sensor doesn't affect idle(they also rarely go bad but they can have ground/reference voltage issues)
the AFM would not allow the car to be drivable but it could idle
knock sensor has 0 relevance on these cars, it is there to make the engineers feel better about having some sort of knock safety device in place even though it does basically nothing..

if it at least has a somewhat steady idle and is running better now, perhaps you just have a vacuum leak left to deal with or timing way off. set the TPS, then your idle below 1k RPMs then check your timing. lastly spray around the engine with carburetor cleaner while seeing if the idle smooths out, just be careful spraying around the exhaust and spark plugs.

 

it does idle but not smoothly. i checked the timing and its at 5degrees atc. also it seems like the car is idleing lower than usual (i figured cuz the misfire). guess next step is tps any suggestions on best way to test ?