Very odd misfire RB20DET

[G-Man127]

Alrighty,

So I have an RB20DET powered Cefiro, and recently it just started running on two Cylinders... it seems that only 1 and 3 are firing, however all other coilpacks when pulled out and tested are definitely making a solid spark.

I have tried new MAF, Igniter, ECU, Coilpacks, Insulating with RTV, wiring, everything seems to be okay. However the car struggles to idle and is making lots of loud popping and running phenomenally rich.

No codes have been thrown, spark plugs are all new, no vacuum leaks, everything seems to be okay? The car honestly ran fine a couple weeks ago, I pushed it outside and it hasn't ran properly since!!!

This has got me incredibly frustrated and obviously I want the car to work!
Please give me any insight towards the problem, it would be much appreciated.

Thanks!

[Cooked Rice]

check the MAF and the piping

[epp01]

Originally posted by G-Man127
Very odd misfire RB20DET

Misfires in RB20's aren't odd, they're common lol. :rofl:

[S13_Ryan]

Originally posted by epp01


Misfires in RB20's aren't odd, they're common lol. :rofl:

great contribution to a thread from a guy whos looking for a bit of help. GTFO newb:whipped:

[Nissan_Fanboy]

Is your compression and everything fine?
Does it run, and what RPM does it misfire? Just all the time?

o2 Sensor?

[JTC180]

Do you have a air fuel controller thats messing with anything? Is your FPR working?

[sr20s14zenki]

Have you tryed another ecu? Maybe you have a short somewhere in your harness. Is your ignitor well grounded? How do your plugs look, really wet? take your coilpacks all out and check for spark one by one. If you have spark on all 6 look towards injectrion next.

Also, a bad boost leak will cause these symptoms.


and yes, a bad maf as well

[G-Man127]

Hm,

yeah Ive basically tried everything listed. Im not sure if the injectors are bad or not. Is there a way to test them?

Thanks!

[zieg]

Easiest way to check em would probably be to pull the fuel rail off, and crank the thing, while having someone watch them to see if they are firing. You could also remove them and take them somewhere to get cleaned and flowtested. That'll uncover any problems with them and they're probably due for a cleaning anyhow.

[badatusrnames]

PTU gone bad?

[sr20s14zenki]

Originally posted by ZiG-87
Easiest way to check em would probably be to pull the fuel rail off, and crank the thing, while having someone watch them to see if they are firing. You could also remove them and take them somewhere to get cleaned and flowtested. That'll uncover any problems with them and they're probably due for a cleaning anyhow.


Only one problem with removing the rail. you need to hold the injectors on, so you would need 3 people's hands in there. LOL, the fuel pressure will blow the injectors right out of there.

put the end of a screwdriver to the injector body, put the other end to your ear and press it against your ear. Get a friend to crank, you will hear a rythmic ticking.

[Primer_Drift]

Originally posted by ZiG-87
Easiest way to check em would probably be to pull the fuel rail off, and crank the thing, while having someone watch them to see if they are firing..

I lol'd at this..

Better yet, do this near an ignition source for increased awesomeness.

I concur with sr20s14zenki's posts, also if it seems like it is "running phenomenally rich" it would indicate that the cylinders are indeed getting fuel.. if you've checked for spark then you can rule out the coil packs.. so an ignition timing issue would be the most likely culprit. I would test the camshaft position sensor and wiring to the ecu.