VG30DETT Idle Questions

[SirjiC]

Hi, First time Z owner and love it so far. 1994 300zx ttI've had the car for about a month. So Far I've put on a borla catback UR Pulley set, JWT Filter turbo timer and Boost Controller. All this was in anticipation of a Jwt Chip. But I've stopped b/c the idle is not were i like it. IE steady as a rock. Am I expecting too much out of a 123k car. The Idle is high. I brought it down from 900-1000 rpms to 750 by adjusting the AAC valve screw. I think that a mech was trying to hide the rough idle by raising it, k can't get it below 750 by kosher means. I Cleaned and adjusted the TPS to .5V exactly and they are shown as closed on the compy. Check as many vacuum lines that i could get, i did install the Boost controller after all and found all kinds of lil gremlins hiding down ther. The WG solenoid Valves are properly isolated no vacuum leaks there. cleaned and replaced two of six injector harness. 1 was absent, had the wire crimped to the injector and the other one had exposed wires, retaped the harness better. Changed the sparkplugs with OEM NGK's against the dudes harassing me over and over to get some iridium who knows what cuz it'll give me more power i dunno. Well this leaves me at my question. Though it may seem advantageous to start randomly replacing crap on the engine, it does not fit my morals and wallet. Does anyone have any resource for this engine specifically to start trouble shooting. I think i did some of the more obbious items already. But now I am ready to start trouble shooting from scratch. O2 sensors are switching b/w lean and rich correctly 5 times i think it is in 5 secs or something like that. I plan on cleaning out the AAC valve 2morrow, is this advisable or is there a TSB on that item. I believe there is one for the PTU right. Well, sorry to seem analrententive about my engine but I would like to have the engine purring before i put the chip in. oh, btw the engine runs fine under load and while driving which is leading me to believe that it is some kind of engine control system like the egr or iav or opp or some other funky acronym. If you have any insight into a proper course of action short of rebuild lol please feel free to throw ur ten cents in. P.S. I have read the rest of the board(no not all of it but searched rough idle) and was hoping to find vg30dett specific info. Thnx

[Ill give u a head start]

i think 750 is just about right... i have owned 3 z32's and all idled at about 750 rpm.

[SirjiC]

K 750 is cool, even thought i put the adjuster screw all the way in, (normal?) now but I can feel the Engine idling in the drivers seat, not good right. Could the transmission or engine mounts be culprits? cuz, i dunno, I've driven a 92 tt b4 and i couldn't feel the engine. I put a rig of particle board on the intake and pressurized the entire intake system to see if i could hear a leak and found nothing so, vacuum is def not culprit. I just reviewed the vacuum line layout from the manual and everything looks correct sans the WG valve soleniod which has been isolated. I'm out of ideas. I've read something about the valves being dirty on some other threads about the silvias but not the z32 en1 experience this?? Thanks for looking

[Wetmyson]

i can feel mine idle in the drivers seat to 'CAUSE IT'S A BEAST. actually, my old house shakes when it's idling in my driveway.

i think you're right to be suspicious though. in one of my auto mechanics classes my teacher said that you should never have to play with an idle screw unless someone has already messed with it, the symptoms usually have a cause...unfortunately i don't remember what he said about causes lol. sorry.

[SirjiC]

LMAO nice plug about your beast there, Unfortunately my Z is not to beast status. Any info on the valve thingy? En1 changed heads out? what did it run ya(bottom line) I saw some heads for 200 a piece reman. Thanks.

[Srowlands]

Have you checked to make sure your running at 15 degrees on timing and not zero? Just thinking of some backyard mechanic freaking out and adjusting it to zero. Have you run a good fuel cleaner through it? Have you checked plugs and ground wires?

[Srowlands]

If you think you have bad valves do a compression test.