Well we (me and Nismo3112) installed the 00VI on my car today, everything went smoothly, the EGR is blocked off temperarly, and all plumbing was rerouted.. After installation, we went for a drive, and we noticed there was a sort of erratic idle. When at a stop light, in neutral, the it would idle at ~1500 RPM's.. A few seconds later it would come back down to normal. Also whenever the idle would be at normal speed (650rpm), the idle would dip a few hundred RPM's, but it didn't stall once.. Driveability is fine, except for the idle.. Anyone have any ideas? BTW, the IACV is mounted on an adapter plate, with a hose routed to the IM, nothing else was adjusted..

 

All IACV wires in? Vaccum leak?

 

All the IACV wires were plugged in. We took the car out for a 2nd drive, this time the CEL came on, but the code is for now unknown (possibly EGR related), but the erratic idle SEEMED to have gone away.. Could this be the ECU adjusting?

 

yea from what i understand if the ecu will re-learn the air-flow after the ecu has been reset. Could be the case since you blocked off the egr port.

 

What size hose did you run from the IACV to the IM? If it is too small then it will resist air flow a bit, and the response time of the IACV will slow down, resulting in oscillations in idle speed.

You can reduce or even eliminate the oscillations by opening the throttle plate a bit with the throttle adjuster screw on the throttle body, which will allow more air into the engine at idle so that the IACV doesn't need to supply as much air to maintain a steady idle speed.

Use the idle air adjuster screw at the IACV to bring down the idle speed if it gets too high after opening the throttle plate. You have to find a happy medium using the throttle adjuster and the idle air screws.

 

The inner diameter of the IACV>IM hose is 1/2 inch.. Is that too small?

 

Would the weird idle explain why the car is more aggressive? When I leave it in "D", the car moves forward faster than when I had the DE manifold on.

~THT

P.S. If you can't tell, Nismo did most of the work lol

 

I would think that would be large enough to not have problems.

 

Pulled codes:

P0325 - Knock sensor
P0734 - 4th gear ratio incorrect
P1105 - Fuel/air meter

I bugged the local Nissan techs about the problem and they said to check out the TPS for the second code and to check the vaccum lines for the third. We all agree that the KS code is being caused by the third one.

~THT

 

Did you ever fix this?

 

Yep; Idle is now normal at 650rpms. I'm not sure what exactly the problem was because I changed a couple things simultaneously. I re-routed the FPR vaccum hose so it was no longer dependent on a T fitting (has it's own source now) and I also completely blocked off the EGR system. It was probably the FPR though.

 

A sticking egr valve that won't close all the way will give you idle problems. Blocking off the egr would have fixed that.

 

How would someone go about "blocking off" the egr, temporarily, to see if that is indeed causing a problem with the idle? On a usim 4th gen?

 

You can get some thick gasket material and make a egr tube gasket but without the central hole. The gasket will go in between the egr guide tube and the intake manifold at the rear of the IM near the IACV.

 

sorry for the newb ques, the gasses out the egr are cool right?

 

no, EGR gasses are hot.

 

Here's a hint,

EGR

EXHAUST GAS recirculation

 

lol. car looks nice Nismo. Lovin the projectors, but i think i like the 3.5 a little bit more. Cant wait to install my VI this weekend. Hey, THT and Nismo3112, would you guys mind pm'ing me your numbers in case we run into some rough spots while doing the install?

 

You got PM.........