need help with RB20det power loss after 5k rpm....suggestions on diagnoses

[blues14]

Ok, heres the deal. I have an s14 rb20det 5spd. the car runs perfect up to 5k rpm, and the the power curve just dies. The boost gauge stays at 10psi, I just installed a new z32 fuel filter, and the car has a walbro 255 fuel pump that was installed at the time of the swap. (i never saw it so hopefully its in there) I am on the auto ecu (i swapped from auto to manual) and i thought that was my problem, but i just got done using my friends MINES mt ecu and although power improved up to 5k rpm, it still had the high end problem. I used the ecu diagnosis and it gave code 55- all ok and then i did the O2 ecu test and it blinked once, which i believe indicates lean. Could one of the coils be missing at High rpm? could the walbro be giving me trouble? maybe timing? How should I go About diagnosing this problem?

[Carl H]

well start simple check timing,plugs, charge piping, hoses and electrical connections.then go thru the systems one by one, try some injector cleaner like seafoam that may help.also if you are on the auto ecu there is a wire on the ecu that needs to be grounded so the ecu will run normaly.also it could be your tach is reading wrong and you are at 6k instead because power dies off on a stock rb20 at around 6k.

[blues14]

how about the coils, how can i test them?

[IslandBoy]

I had a similar problem. I did all those same checks and still nothing. My problem ended up being my injectors. They were dirty. You would have to take them out and clean them individually. I tried using an injector cleaner in my tank and it never worked. My car works good now but the only problem i have now is that 5th gear runs up to 6500rpm and shuts off. I need to cut this rev limitor. Any Ideas?

[mmatl16]

what the hell are you doing at 6500 in fifth. thats pretty fast

[wawazat8402]

IslandBoy, was yours an RB20 as well? My RB25 just started doing this as well.

[unstable240]

I was having the same problem with mine until I got a Z32 MAF. Now it pulls hard to 8000 on. I was noticing on the stock MAF that it was having problems with the reading at high RPM's, but now it is smooth all the way.

[blues14]

maf, good suggestion. you know , my injectors are hella loud (ticky) is that normal?