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egg-less
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348 Posts
Discussion Starter · #1 ·
Thanks to Joe at Rosen Autosport (and someone else in Richmond with the same problem I had), my months-long idle problem with my NX2K is fixed!!! :)

First:
All of my emissions crap (EGR, IAC, crackcase breather(?)) have been disconnected for years with no problems.

Second, what I changed that DIDN'T help:

ALL vacuum lines
PCV valve
Cleaned throttle body
O2 sensor
Fuel filter
Coolant temp. sensor
Fuel pressure regulator
Checked MAF ground (OK)
Checked throttle position sensor (OK)
Exhaust cam changed to be in sync with crank and intake cam (it was 1 tooth of from 4 years ago!)

Finally, the Fix:

A F*CKING FUSE!!!!

That's right! The Electronics (B) fuse in the in-dash fuse box was blown. That's the 3rd fuse from the bottom on the left side. Apparently, it controls the electrical circuit that the O2 sensor and a couple of other sensors are on. Basically, these sensors were off line to the ECU when the fuse is blown, so the ECU runs in limp mode.

Now, the cold idle is perfect, warm idle is perfect, AND it doesn't smell like a Lawn-Boy! Since I replaced all the other stuff (above), and replaced the fuse, my NX is running as strong as it ever has, all the way up to 7700 RPM!!! WOOOOHOOOO!!!!!!

SO, to all of you who have had idle problems with your SR20 lately, and I know there are a few that have posted here, check that pesky little 50 cent fuse...

Question: What kind of HP/trq should I expect with these mods?
CAI, 1st gen. Stillen header, Borla exhaust, lightweight flywheel, UR pulleys, JWT ECU
 

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egg-less
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348 Posts
Discussion Starter · #3 ·
No, I was there yesterday, when Stiletto and silversx were there. I'll be dynoing next week sometime, and I will post it here.
 

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Registered
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1,147 Posts
ah ha!! well, it's prolly better that you fixed the prob b4 you did the dyno. i would've felt bad if both NX's had lesser #'s than my little SEL!!

oh BTW, those roads SUCK in that part of town! if i had fillings, they would've surely fallen out!! :D
 

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egg-less
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348 Posts
Discussion Starter · #5 ·
HA!!!! Even running in limp mode, it STILL probably had more power than your lowly...er...little SEL!!! J/K

Hmmmm, maybe I'll do 2 dyno runs; one without the fuse, and one with, just to see what the difference is...

And yes, in the old part of town, the roads are almost as bad as the roads in St. Paul/Minneapolis. I would NEVER run 17's up North.
 

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Army Boosted
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565 Posts
I just want to thank you AKNAPP for posting this solution to your idle problem. Reason I'm grateful is because my ecu was throwing up an AICV code and an O2 sensor circuit code (9 long 1 short) after installing brand new components...I was pulling my hair all day. After searching and reading about the fuse, went outside and proceeded to pull the blown sucker out, replaced it and viola! Now just to fix a vacuum leak and we're good to go. Great job!
 

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sellout
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1,000 Posts
Ok, but fuses do not wear out, it blew for a reason. I wonder why.
 

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I have the same problem as you did, except my fuses are alright. My idle at this time is at 1700rpm (30ish °F), but when it was 0°F it reached 2900rpm. Sometimes after some start ups it goes down and after a long run it idles 800rpm.

What could be the problem? I've checked the engine codes and the only one coming out is the 55 (everything is alright).

Also, I would think my O2 sensor is shot, because when very cold after 2 minutes the idle was getting up to 2500 then dropping instantly to 1500 then rising up again at 2500 and so on...
 

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my fues are all good and I still have idle problems
 

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lee_harvey said:
always check the easiest things first. i wouldve never thought about a fuse until last though. thanks for posting the fix tho.

I have checked all the easy things, and still no go :(
 

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mhmmm
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1,263 Posts
i have this EXACT same problem.. but i havent checked that fuse... i will check it tommorow when its day time.. i tried adjusting the idle and stuff like that but it wouldnt go.. im also throwing a code but im lazy and cant get to the ecu to pull them, my vaccum lines are fine..

djisnx2000 said:
I have the same problem as you did, except my fuses are alright. My idle at this time is at 1700rpm (30ish °F), but when it was 0°F it reached 2900rpm. Sometimes after some start ups it goes down and after a long run it idles 800rpm.

What could be the problem? I've checked the engine codes and the only one coming out is the 55 (everything is alright).

Also, I would think my O2 sensor is shot, because when very cold after 2 minutes the idle was getting up to 2500 then dropping instantly to 1500 then rising up again at 2500 and so on...
 

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Just tried it. My Engine Electrical B fuse didnt look like it was in the best shape plus on each prong it looked slightly fried. So I put the spare 10a fuse in there but i havent driven it yet since my clutch has crapped out on me. Could this be the reason that my revs dropped when i used power steering, used power brakes and such? They dont seem to be dropping now...I dont know, i still have to get a voltage tester on my TPS to make sure its set right.
 

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have you tried adjusting that black plastic screw next to the oil filter? You can reach it from the side where the pulley's run. Sometimes it's full of dust and just needs some turning. I think it's the IAAC valve adjuster if not mistaken. My revs also used to drop when braking etc. now it's 100%
 

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sweet, believe it or not. I had a list of replacement parts to fix my studdering and idle problem that totaled over $150 2 02 sensors plug wires cap and rotor lol.. went out and sure enough my fuse was blown.. started it up fixed the idle, and the revs climb cleanly again! w00t!
 
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