I need help! Really high idle

[articzap]

I finally have got my CA swap started. Everything from what I can tell is hooked up properly.

The problem I'm having is this. I'll start the car. It will stumble around idle wise and seem like its missing. Then after a couple of seconds it'll rev up 2000 RPM range and stay there. From there it'll get up 2500 RPM. And on this last attempt it made it to 3000 RPM. If I try to rev it, it just starts to choke up and wants to die out. If I slowly give it gas I can get a 500 RPM increase before it starts to break up.

I have a Walbro 255lph fuel pump. Stock injectors. Synapse fuel pressure regulator. My fuel pressure gauge is showing right around 30 psi. Seems a little low I know but I doubt thats causing my high idle, or maybe it is?

My car has been down for 2 months trying to get this swap to run and now I just want to drive the damn thing! Please someone help me!

EDIT: Once the car hits the 3000 RPM mark the temp gauge will be reading normal operating temps. I can then rev the engine without it breaking up.

Pulled codes and came up with 55.

Modified by articzap at 3:07 PM 6/28/2008
Modified by articzap at 10:10 AM 6/29/2008

[float_6969]

vac leak on the intake side of the manifold. Check the brake booster line and the booster itself. Also try crimping the line to the idle control valves, they may be stuck open. Get some starting fluid and start spraying it on every vac line, gasket, etc that you can see. Becareful not to get it near the exhaust mani, as it WILL combust easily.

[articzap]

I'm really thinking its a stuck cold idle control valve. I ditched the elbow piece that coolant flows through that sits behind it so I don't think its closing and slowing the idle down.

I'll try crimping that line tomorrow morning.

[float_6969]

That coolant line doesn't have anything to do with the function of that valve. It's heated internally and is wired in with the fuel pump. They're infamous for sticking open/closed, so it's quite possible. it's failed.

Not one of Nissan's greatest idea's...

[articzap]

Does anyone know the part number after I test it tomorrow and if its failed? Is it something I could steal off of my KA24E?

[float_6969]

IIRC, the only one I found that was the same was one off of an SE-R Sentra. Most of them bolt straight to the mani and don't have 2 hose connections.

[articzap]

Ok heres what I've tried and whats happened. If I plug the air line going from the intercooler piping to just the cold idle valve under the throttle body, there is no chance. If I crimp the line closed for all of the idle control valves right at the intercooler piping, my idle drops drastically. So I then went to the idle screw. (the 10mm bolt by the idle valve) I turned that all the way in so it let in as little air as possible. The idle drop but still stayed high. If I crimped it went down a lot. This leads me to believe that the valve that says ACC on it has failed letting to much air in. Does that ACC valve not control idle when the A/C is on? I do not have A/C in my car so to me its useless if thats what its really for. I need ideas so the idle will bump down.

When it starts also it stays low in the RPM range and just kind of bumps around, sounds like its camed or missing until it goes up RPMs by itself. Giving it throttle when its stumbling helps some but just makes it break up. It'll be at around 500-600 RPM when its stumbling. What could be causing this? Maybe my fuel pressure set to low being at 30 psi?

Thanks for the help.

[articzap]

I cleaned the ACC and ICV perfectly with carb cleaner. Hooked it backed up and it continued to idle high. WTF

My dad comes out and grabs the throttle body and twist it back and it idled perfectly. When I modded the throttle body for the SOHC throttle cable, I didn't put tension on the throttle return spring.

Now my only issue is bogging when you give it gas when its cold.

[zmannz]

If its doing that from idle when cold, you just don't have the temp sensor in the throttle body working right to read temp from the coolant, I believe. We are having this problem here, and I don't have the coolant going to that spot on the tb. Once this car is up to temp though, it runs just fine.

[articzap]

I think part of the stumbling problem is the extra piping from the FMIC. I'm going to try to tune it out with SAFC and see how it goes.

[articzap]

Ok the stumbling was from the low fuel pressure. Its at 35 psi now and runs sooooo much better. I think i need 2 or 3 more psi for it run just a bit better.

The Nismo mounts are producing some vibrations. Not sure if thats normal or not.

Now the next big question, from 2.5k till about 4k it stumbles in boost. It wants to go but it won't. Almost like a fuel cut/spark blow out. I tried adding more fuel via SAFC but that made it worse. What can I do to correct this? My butterflies are hooked up to a straight vac/boost source. Ordering those parts this week.

[zmannz]

Do you have a wideband a/f meter? At least a gauge of some sort to show your air/fuel?

[ca18detgabby]

how fresh are your coil packs? are your plugs still good with the over fueling issues you were having?

with the extra vibrations I would check out the ignitor and see if it hadnt shaken loose a bit.

still need to check to verify for vac issues..... they love to hide.

[articzap]

No vac issues.

Its possible plugs could be fooled but it pulls like a raped date after 4k with no hesitation.

I'll pull the plugs tomorrow after work and check them.

For A/F gauge I got my Apexi' turbo timer. I know its not a wide band but I don't have money for a wide band quite yet.

Its running rich because theres some black some and I'm shooting fireballs between 2-3 shift.

You think pulling some fuel with SAFC would solve the hesitation? I'm not sure what causes it between 2.5k-4k ish.

[busteds13]

this may not help, but remember to reset your ECU so it can make adjustments for the stuff you replace/changemine used to misfire right about where youre describing 3000rpm, i got a new drop in resistor, and that kinda fixed things a bit, and your fuel should be 36.4PSI( i think)thats satick >Stickies<

[mod_mastaz]

If it's running super rich, look at the coolant temp sensor. It sounds like it only runs good only when it's warmed up. Most nissans/japanese ECUs are reliant on the coolant temp sensor and if they are broken, it'll dump loads of fuel due to it being in limp mode then it'll run fine after it warms up. As for your idle issues, try to find the real problem and fix everything else before you mess with the SAFC. The SAFC is for tuning, not fixing ECU problems due to faulty sensors or other issues.

[articzap]

Car runs fine when cold now. I figured out all of my issues. Fuel pressure is set to about 37-38 psi. I think I'm running slightly rich because of the extra volume that the Walbro 255 lph pushes.

If I stay in vaccum until 4k it accerlates fine. Its because of the ghetto rigged butterfly valves being hooked to back of the intake manifold. I'm going to look for a pump/solenoid this weekend at the junkyard.

[mod_mastaz]

Ah ok cool. Is that 38psi with the car off or idling? Reason being is that the fuel pressure should be set at approximately 37 psi at atmospheric pressure. If you're idling, then it's going to have vacuum on the FPR and it will read lower.

[articzap]

37 idling. It runs the best on that setting!

[articzap]

what plugs are you running?? i know the rb's only like a certain heat range of plug or they run like **** when they start boosting. what does the ca have for stock fuel injectors? 270cc's?? maybe u should go back to the stock fuel pump for now??? are u recurcing the bov? or are u correcting it with the safc?

NGK copper's heat range 7. Stock 370cc top feeds. Yes I'm recircing. I'm confident my hesistations will go away when I get my butterflies hooked back up.

Want a ride? Maybe we can meet up this week.

[articzap]

Well I think my spark plugs are shot. I'm getting a rough idle. Makes the car shake. Motor sounds like its running perfect. No back firing what so ever. Its running a tad rich, which is what makes me thing the plugs are gummed up. The car still pulls amazing in boost.

In coralation to this problem, I have my SAFC hooked up to my knock sensor. Now I do NOT trust SAFC to be reading true knock, but every warm up cycle it seems to read more and more knock. No knock is audible. Timing is set to 13 degrees roughly. Its where it was from factory so thats what I left it at.

My fuel pressure as stated before is about 38 psi. I may try pulling a pound or two of fuel. My Apexi' turbo timer has my A/F coming in at 14.3 - 13.9. Despite a lot of black smoke coming out the back.

[articzap]

Well I pulled my plugs. They look perfect. Could actually use a bit more fuel just to be safe. So this got me thinking, why was it getting a shake. I start checking my mounts which proved to be solid. Then I look at my crank pulley and other accessories. Nothing was wrong there. Then I noticed it. A broken fan blade. Time to get my Civic half radiator fan mounted. I hope this solves all of my issues.