weird idle issues.. help!

Reply Subscribe

Thread Tools

Search this Thread

01-02-2004, 10:32 PM

jon93PGT

Guest

Posts: n/a

weird idle issues.. help!

Hey guys...

Ok, here's the deal...

82 ZX non turbo, spd... runs well, but lately, its doing some weird stuff...

Sometimes when its started, the idle fluctuates up and down from like 500-1200 for a couple of minutes until it settles out. The weird thing is that it only does this after its been driven for a while. For instance, today, I drove it for about 30 miles and then started it again, and it did it... But, drove it again later tonight (about 26 miles) and decided to test it. Tried to shut it off, only let it sit for a few seconds and restart, and the idle was fine... Sooo, it only does it after its been ran for a while and then let sit for about 10 minutes or so... At least thats the most I can tell..

Timing? Car has been running fine for about 20000 miles, with just minor things.. Tune up stuff has all been replaced... Sooo, I'm thinking its something to do with the disty, timing or the vacuum timing adjust mechanism.. I'm not a Z junkie...

Any ideas.. ???

Also, is Icice out there?? You are the only local Z owner I know that could fix it.. Any others in the bay area CA that care to help...?? I can provide a shop or deliver the car.. Your choice... Thanks guys...

01-03-2004, 10:14 AM

lifegrddude

Externally Wastegated

Join Date: Oct 2001

Location: San Diego

Posts: 1,220

Do you have a boost gauge you have access to? you can use the vacuum side of it to see if you have a leak. No fuel leaks or anything right? At first I was thinking vapor lock, but then again it is winter time... Hope other people can give better advice.
John 82ZXT

01-03-2004, 11:27 AM

AllmyZs

Guest

Posts: n/a

Yoiu also might want to check you temp sensor in the block . If it is malfunctioning it will make the car act funny, Like thinking it is cold then hot which would explain the idle issues.
Hope this helps some.

01-06-2004, 01:19 PM

jon93PGT

Guest

Posts: n/a

anyone local to me care to fix it for some cash or trade work??

let me know..

01-10-2004, 03:21 PM

jamest_corvel

Guest

Posts: n/a

My 82 280ZX 2+2 started to do exactly the same thing too. I am so frustrated. Not sure what to do from here too.

01-10-2004, 03:31 PM

AllmyZs

Guest

Posts: n/a

When my 78Z did this I had to replace the AFM. ANd give it new plugs cause they had fouled in only 500 miles. Once I replaced the AFM the plugs havent fouled since. I only drive 10k miles on a set of plugs. But when I remove them they look good. I just dont like my car breaking on me.

01-11-2004, 10:13 PM

jon93PGT

Guest

Posts: n/a

hmm...I have another possible idea...

head gasket...

The car has been giving the low coolant alarm and this weekend my girlfriend noticed it running hot.. or so she thought... she said the heat smelled funny (like coolant) and there was a lot of steam coming off the hood...but yet the temp gauge read normal...

soo..my question is... what should the compression numbers be for a Z with around 170K on it... not well maintained, until just recently (15K or so)....

gonna do a compression check when I see her next...

thanks in advance guys...

01-12-2004, 08:34 AM

Bleach

The Evil Twin

Join Date: Mar 2001

Location: Seattle, WA

Posts: 9,296

I did a compression test on my 82 ZX. (8.8:1 stock) at 199,000 miles it had 179 to 181 psi on all six! Very nice.

I tested a friend's 280Z with about 260,000 miles which is a slightly lower compression engine to begin with. Her's had 120-125 on all six. If all six cylinders are close to the same compression and are somewhere from 130 to 170 psi then you're ok.

01-12-2004, 08:58 AM

jamest_corvel

Guest

Posts: n/a

my 280ZX 2+2 read 180 psi average on all cylinder. And it has 145k miles so far.

02-14-2004, 06:56 PM

#10

phoneman1

Guest

Posts: n/a

Thought I would throw this out, I had a Idle problem it would start and Idle at around 950, right where I like it, then when it got a little heated up, say to normal range, it would idle down for around a minute or so then back up, up/down/up/down. Later I installed a small vacuum gauge under hood for troubleshooting . and I started watching it when this idle thing started happening, well idle would reach 18/19 then bamo it droped down to 15 and idle went with it, after many hours of troubleshooting (many). I found the Valve cover cap didnt have a gasket of any kind at all, plastic or otherwise, missing in action. apparently when ever the vacuum reached a certain amount , it was just enough to over come a plastic to metal cap seal, once the pressure got back up to 18 it started it again. took some rubber and cut out a seal and slipped over threads on cap, and presto, smooth,smooth idle.

But thats probably not your problem.
Charles

02-28-2004, 07:07 PM

#11

justun ross

Guest

Posts: n/a

i think i know your problem

Quote:

Originally Posted by jon93PGT

ok, it sounds like your air flow meter. they will make your car rev up and down while ideling. also 79-83 models had a problem(once the car got older) with the throttle position switch. sorta. where the harness plugs into the throttle position switch there is a rubber dust and water cover, like a little boot. the boot gets old and dry rots, water or condensation runs down the wire and drips into the plug. to find out if it's a problem, when it's acting up, cut the car off, unplug the TPS, spray the connectors real good with WD40, plug your TPS back up, start the car and WA-LA! if it's fixed, you were getting water in the plug. to make sure it doesn't happen again, fill the female side of the plug(the TPS side)with vaseline or dielectric compound(NOTHING CONDUCTIVE!!!)plug it back up and rub some silicone over the boot to seal it and keep the moisture out. let me know! justun ross p.s. does anyone reading this know what WD40 stands for?

03-05-2004, 01:10 PM

#12

smartman3000

Registered User

Join Date: Dec 2003

Location: Rockford, IL

Posts: 56

Water displacer-40, It was the inventor's 40th attempt at the spray, and that was his codename.

Whenever I start my car up, it suddenly goes to 1800 rpm and stays there. I'm thinking it may be a bad regulator.

03-08-2004, 05:50 AM

#13

jon93PGT

Guest

Posts: n/a

Quote:

Originally Posted by justun ross

Justun-

damn, thanks for hte advice. I'll check it out.. I'm not sure if that is it, but i will try... I also haven't checked this post very often, so I'll try and stay up to date a little more... Also, does anyone know how to make the headlight check go away? I had to run new wires for the pass side. well, I tapped into those for the drivers side, and it worked great, but the car still thinks the drivers headlight is unplugged... Any way to short the pins in the connector so it thinks its working?

03-08-2004, 09:15 AM

#14

justun ross

Guest

Posts: n/a

wd40

Quote:

Originally Posted by smartman3000

smartman, in 12 years i never met anyone who knew that answer. i use to make lunch money betting people on that one. you are exactly right. when i repped in the autoparts industry i found out what wd40 stood for. the sad thing is a lot of people don't even know it displaces water they just think it's a penetrant. GOOD SHOW!!!!! justun ross

03-10-2004, 10:20 PM

#15

TheeZ

Coming to understand "Z"

Join Date: Mar 2003

Location: Cal Poly, SLO

Posts: 60

ey i gota prob!

mmm I duno if my prob is related to what you guys are talkin about, but here goes: Ok start the car, first hit on the starter runs perfect. All the driving time after that is flawless. Then, I turn it off when I arrive somewhere. So the engine is hot. Run in the store or something, comeback out 5- 30 min later (when the engine is still warm) I have trouble... When I try and start it, it gives me trouble, lots of turns and the engine doesn't start. After a minute or so of trying (not holding the starter, but a few long tries) it starts up. Then when I accelerate (normal driving) the engine has a hard time revving then at about 2500rpm it backfires out the intake like its coughin up something then clears up and finishes the rev. Then does it in the next gear at bout the same rpm. After about 5 min of battling it out everything clears up and she runs flawlessly again, unless I turn it off! Whats up?! I can start it first try when its 25 degrees outside, but when its warmed up it gives me trouble?? I'm stumped... AFM maybe?? anyone had this problem? HELP MEH!

03-11-2004, 06:14 AM

#16

chrisc0623

Guest

Posts: n/a

I had a problem close to this last fall. The car ran fine cold but went to hell after it was warmed up. My problem turned out to be the oil pressure switch. The oil warms up, starts to thin some and poof the pressure falls. My 83 zx n/a has the shut down feature. The oils pressure drops and the fuel pump shuts off. My gauge never showed no presure (around 30 psi or so) new switch and great pressure. Never had the problem again. If I were you I would slap a new pressure switch in it, could be a simple solution for what seems like a big problem. Takes 2 mins. and about 20 bucks to do. Oh yeah a 14mm wrench too.