Dual intake idle problem

[300zxAng]

I recently converted from a single intake to a dual maf intake with the Selin kit. Once I start the car it idles perfect while cold but once warmed up after a minute the idle gets unstable. It sounds like there is a misfire or big vaccum leak. The car drives fine and has power but the idle is bouncy and low. It only happens when the car is warmed up. Sometimes when I come to a stop while driving it actually shuts off. The vacuum on my gauge reads really low as well. I double checked the connections. No codes on the ecu. I have a eprom tune for dual maf. Selin is set on average. Does anybody have a idea what this can be?

[twinturbozxtacy]

Only things that would cause the vacc to drop is a leak after the throttle bodies. Maybe a hose popped off or came loose. If it wasn't reading low before check all the areas and hoses you were messing around in. Maybe a recirc valve hose.

[300zxAng]

I'll check again for all connections. Thanks a lot I guess it's a big vac leak I might have to do a smoke leak test. I'll report back thanks again.

[twinturbozxtacy]

Doesn't have to be that big, a small hose like the one on the fpr can cause a big drop in vac

[300zxAng]

I have z1 bovs that I recirculated back to the intake track after I realized it was pointless to have open bovs. is there anything wrong with that ? That could have a effect on the idle ?

[twinturbozxtacy]

which bovs? the z1 rfl? i dont see that being a problem, in fact most problems are when they are vented so you should be good there. and NO it wont alter your idle if they are recirculated. now if they were vented and were not closing all the way, they sure could.

if it idles when its cold but once its warm starts acting up i would look into the coolant temp sensor.

[300zxAng]

Ok thanks that makes sense they are recirculated so shouldn't be a problem and they function good. I'm not sure which ones they are I forgot. I tried the brake cleaner meathod to find a leak I can't find any but I'm going to leak test it. I also changed the coolant temp sensor and CAS recently.

[nissanfreak12]

Do a boost leak test, that is one of the best ways to test for leaks. I found leaks I didn't know I had.

[300zxAng]

I'm doing the vac leak test and i hear a hissing coming from mid engine area I sprayed everything down with soap water looking for leaks/bubbles on hoses but I found nothing but I hear it loud. Sounds like it's under the manifold engine area. Anybody have any tips or a guess as to what can be leaking?

[ThisIsSparTTa]

You're going to have to do more investigation. Have you replaced your injectors? You could have a pinched o-ring.

[300zxAng]

I have 740cc injectors that I recently put it and it ran perfectly with a single intake. Once I switched to dual intake and maf on average mode with the EPROM for dual intake it idles fine once the car is started and is cold but after a minute Once it warms up it's like a switch is flicked and idle begins to die. It's like the car is leaning out at idle. It drives fine but when I come to stops it wants to die out and shut off if I don't keep on the throttle. I never had this problem with the single intake so I'm confused

[ThisIsSparTTa]

Silly question...you did get your ECU reflashed for the Dual Intake, right? Also, you could test for a leak at the injectors by spraying starter fluid around them, if it changes the rev's/idle then you have a leak. Maybe you didn't get your injector fully seated and its leaking under certain conditions. If you actually have some kind of leak, the dual intake might just be a red herring, try not to focus entirely on that.

[twinturbozxtacy]

possibly the intake mani gasket, have you deleted the water lines and such under the intake? also the injector orings like sparta said. the selin would make things worse if you already had an issue. before it was metering air from one side. NOW its metering from both so any issues would be amplified.

[nissanfreak12]

The Selin translator, you don't need an ECU reflash-

What MAF are you using? Is it the N62? Where did you get it? Was the Selin kit new or used?

Think about it, if the only thing you changed was the single to dual, your problem may lie in that area. Granted, it could amplify the issue like twinturbozxtacy said, but go back to a single and see if you have it. Eliminate the obvious first.

[twinturbozxtacy]

How did you make out bro? I doubt it's the Selin but if it were I do have the email reciepts from czp and the packing list invoice if that's the real issue. Let me know man you are not thy far from me, only 30 bucks in gas lol!(45 in the z give or take!)

[300zxAng]

Hey guys thanks a lot for your input I appreciate the help. Problem solves the Selin is fine and working properly. Turned out that I ordered my eprom from specialty z. My eprom consist of 5speed TT 740cc deatshwerks 93octane dual intake. I realized my car was leaning out at idle passed 18.0 on my AEM gauge. I called up specialty z and Greg told me that he tunes for 740cc NISMO* injectors not my brand which is deatshwerks. He sent me another eprom with the correct AFR in the mail and it runs perfect. He's really good with customer service and took his time out to help. I'm actually going to buy a nistune now and get it dunno tunes so if anyone has one for sale let me know lol. Once again thanks guys and do buy from specialty z their service and products are awesome.

[twinturbozxtacy]

glad to hear it!

[NolimitZ32]

Greg is the beezneez man, glad to hear you got it sorted.