L20E running issues

[mark105]

so ive had this thing a while now and me and the old man just cant make it idle right.

 

 

as far as i can tell with my limited knowledge on these engine this is what i can see as my 4 problems as none of these pipes went anywhere when i got it.

 

1. im not even sure if this inlet is even supposed to be here or if it is where it goes or what it does.

2. there is a little pipe here under the throttle body which i dont know where this goes

3. this was blocked off also and im 100% sure i need this but once again i have no idea where this goes either

4. i dont know what goes on here either but at current have the big pipe from the EGR/idle valves hooked up on it but i dont know where that pipe goes either.

 

i can also see 1 and 3 being quite important as they do huge things to the engine when running and they are tampered with.

 

also adjusting the screw on the AFM for air by pass make no different at all and the previous owner had take the throttle body butterfly stop screw right out also so im not sure where a good position for this is either.

 

should also point out that the current setup is 1,2,3 pipes are blocked off and 4 is hooked up as shown.

 

at current the only way we have figured out to slow it down is to take either pipe 1 or 3 off and let a certain amount of air in (too much and the engine just dies) and adjust the idle speed with the throttle butterfly stop screw.

 

pipes 3 and 4 make no difference as they are not big enough to let in enough air to slow it down any rate.

 

also could the short length of pipe from the manifold to the AFM be the cause? to much increased air flow through the AFM? as im almost certain when i looked in the R30 book at the library that pipe was over twice as long.

 

 

 

1. is this the idle control valve? and shouldnt it speed up if we take its plug off as it would close? because you can take it on and off and it does nothing.

 

2. also what can i just plain out remove cause its just boring old emissions crap? like there is a breather from the bottom of the manifold to the crank case and then it goes back again from the rocker cover to the throttle body. can i just block the bottom one to the crank case and put the top one to a catch tank n stop all that black crap getting in my manifold?

 

3. the last bit whats all this stuff? more emissions stuff then can be chucked out?

 

also if any one can tell me what else apart from what ive asked about i can just take off as its just fuel emissions stuff that isn't needed would be good.

[OlderThanMe]

I just have a breather on my valve cover... but you will have more bad smell in the cabin.

 

Whenever you get bored and stick an L28 in there I'll be interested in that crankshaft... LOL

[Guest TeamNissan]

I would buy a manual if I were you, the you'll have all the answers you need.

[mark105]

ok i went to the library and photocopied the sections i needed.

 

tho im still confused on 1 point, whether air is supposed to be allowed to suck into my manifold from the P.C.V valve which comes from the crank case or not.

 

cause at current it does. and the book says this.

 

Checking and replacing P.C.V valve

1. remove hose from pcv valve and block hose with plug.

2. start engine and run at idle

3. check pcv valve. if the valve is working a hissing noise will be heard as air passed through the valve and a strong vacuum should be felt immediately when a finger is placed over the valve inlet. if not replace with a new one.

 

now in the trouble shooting section it says this

 

engine idles to fast

check for manifold vacuum leaks, including at pcv valve, dipstick and oil filler cap seals.

 

now im confused by this, top part says there is supposed to be a vacuum leak and the bottom bit says there isn't supposed to be.

[mark105]

ok ive gone over the whole thing, manifold, electrics everything and found that when running the ECU led goes solid at idle.

 

which from this post http://forums.hybridz.org/showpost.php?p=759377&postcount=2 tells me my O2 sensor isnt working properly as it should be flashing like it is at warm up.

 

i have replaced the O2 sensor already, that was the first thing i did months back.

 

what happens is its fine at cold start but once it comes off cold start it kicks up in the RPM and the ECU led goes from flashing to solidly lit. ive tested the AFM, TPS and temp sensors as per my manual and they test as ok.

 

 

something is telling it the wrong information but i dont know what. i need ideas here?

 

also i replaced the O2 sensor with generic one as i couldnt get a nissan one, could this be a problem?