The Worst thing ever.

[Qdemption]

O.k., I am prepared to admit the biggest sin in all the land of Q45's.

Are you ready?

I monkeyed with the throttle cables.

This apparently is the biggest No-No. And I did it. It was last april and my car had just began suffering from a dirty MAF connection. I didn't know of NICO, nor did I respect the amount of precision that is put into an automobile of this caliber.

It happened so long ago that I don't remember exactly what I did, I just remember doing it.

At the time, I was unaware of the actual problem with my car. It was just kinda like a trial and error thing. I wanted to see what affected the cars idle. I was in college, broke as a joke, so a trip to a dealership was out of the question.

So my previous experience working on a '53 Chevy Bel-Air and a '68 Chevy Pickup led me to believe I could correct this malfuntion just by tinkering with the throttle cables.

Well, see cars made a long time ago, they are not like cars today. This was my tragic flaw. Thinking that the same principles applied.

I have looked in the FSM and they say to secure the locknut and adjust middle throttle drum free end play to 0mm. And to adjust throttle drum play to 1 to 3mm. But the accelerator cable there isn't really a setting.

I have been carrying this secret with me since the begining. I stumbled upon a Q45tech thread describing how this is something you don't EVER want to touch. Well, I touched it.

Am I toast? Is it over? How bad is it? Please, please, tell me I am worrying about the wrong thing. Could I be perhaps mistaken and the nuts I adjusted are easily repositioned?

You know they say the first step is admitting that you are in denial. But shouldn't it really be admitting that you are in denial about being in denial?? Regardless, I am in denial no longer and am prepared to face the consequences. Be gentle.....

[elwesso]

I would re-adjust it so that when you have the throttle undone it is just past taugt... IE its loose but you odnt have to move it far and it will be tight.....

WHen the accelerator is all the way down there should be just a TINY bit of extra you can take the throttle plate.. Im talking less than a mm...

Same for the accelerator, just make sure they are slightly loose, but not that much...

IT wont be perfect but wiht some trial and error you should be able to get it no problem.....

[elwesso]

Like the manual says, there should be 1mm or so of play...

what I would do (assuming you need to loosen), just undo the bolt closest to you (front) and then get it where it needs to be, then adjust the rear one...

Simple, but somtehign that you shouldnt have played with to begin with!!!

[Qdemption]

Thank God, Wes. I don't want to get too excited, but hearing that makes me feel a bit better.

BTW, your pass side valve cover write up was dead on. Helped out a lot. You were right, it was easier than the drivers side, just more disconnecting of wires.

What happened to your website link??

[elwesso]

http://infiniti.home.insightbb.com/

I did the writeup on the drivers side, didnt do the pass side yet!!! It was hte one I emailed you... Jeff williams did the passenger side, i dont know if he did a writeup on it.....

[Q45tech]

A greater sin is the adjustment of the screws on the throttle body or adjusting the CAS/TPS by eye.

But I am one to speak considering my 2.5 turn out trick on the IAC screw.

[Qdemption]

See that I did not do. Thank goodness my attention span is that of golden retriever, cause I probably would have started messin with those screws as well.

No kidding though, I just did your IAC trick. I had read one of your previous posts and the range given was 2.5-3.5 turns. I did 3 and 1/4 turns. It took about 4 plus turns to get it back all the way, so it probably needed it.

[Q451990]

Yeah... I messed with the cables once too. One thing you need to do is make sure the car has been fully warmed up so that you're getting a true closed position to set the cables... I tried to re-set mine with the car cold and had them tight when it was closed with the fast idle cam holding the throttle body open some. Made for a really high idle. Definately not rocket science (like the TB screws or TPS) just set them with a little slack with the car fully warmed.

Heath

[Qdemption]

Thanks for the tip Heath.

Do the cables contract a little bit when the car is warm? Or was it just a matter of having the engine running to properly determine the correct positioning?

[Q45tech]

Everything interacts: the amount of air flowing under a CLEAN closed throttle body should allow maybe 450-500 rpms, the amount of air bypassing the IAC [the idle screw] should allow another 100 rpms, and then the 10-15% duty cylce of the IAC should allow another 100 rpms..........650-700 rpms.

When the AC is on the IAC duty cyle bumps up to 25% to maintain the idle. Turn the steering and it adds 10%, turn all the electric loads on and it adds 10%.........WHAT ever is necessary to maintain the idle speed under varying engine loads.

By definition idle is ZERO EXTRA horsepower just enough to overcome the loads.......otherwise the speed would increase slowly.

When you are cruising at 60-80 mph the IAC may be up to 70-85%,, so when you suddenly remove the throttle opening the IAC percentage drops slowly and progressively to avoid a stall. Just enough below the rpm to allow some engine braking to slow your speed yet not too much to stall.

A dirty throttle body or a dirty IAC bypass tube or thus a misadjusted bypass screw or even a dirty IAC valve throws things out of range and the IAC may not have enough air range at cruise even wide open 100% duty cycle to make for smooth lift throttle........rpms drop to fast when you let off it risking a stall, usually just funky and not smooth.

We see IAC counts at 40-50% not 10-15% at idle all the time as they come in for 60k service...........the bypass screw has usually been cranked out [beyond the 2.5-3.5 turns from bottom] to maintain idle speed.

[Q451990]

Do the cables contract a little bit when the car is warm? Or was it just a matter of having the engine running to properly determine the correct positioning?

The throttle body has a "fast idle cam" that holds the throttle open slightly when it's cold. Only after the car is fully warmed up can the throttle body close completely. It doesn't need to be running when you set the cables, just warmed up recently. If you set the cables when it's cold, they'll continue to hold the throttle body open some even after the car has warmed up, even though the fast idle cam has retracted...

Heath