High idle after running.. Some questions

[-=Jeff=-]

I did some searching on here, but I need to be verified..

with key on, not running, secondary pump runs every 30 secs for about 10 secs maybe..

When I start the car the it idles around 700 rpm.. if I drive it a short bit it will not drop below 100 it seems.

Can the secondary vacuum lines be a cause of the higher idle? Primary map is connected fine, as is fuel regulator. I took the vacuum hose off the driver side of plenum and blew air in it.. that is okay.. I know there are probably more I need to look at any spots more then others?

I need to put my scanner on it and check the IAC steps and such too, but I did not have time tonight.

just trying to see what I need to look at, I really don't want to pull the plenum but if I have to I will.

[tccrab]

Jeff:

Had a similar problem on my '90, turned out to be a vacuum leak.
On mine it was the funky PVC two hose connector just behind and under the throttle body on the drivers side. If it's not *EXACTLY* in the right position it leaks.
I had a heck of a time getting mine to seal, I swore that if it ever gave me problems again I'd replace the f*ing thing with fuel hose and hose clamps.

Have you tried tapping the throttle after the car comes to a stop? If that kicks the idle down then I'd say it's more likely in the throttle body. If the primary throttle body blade doesn't close all the way it'll cause idle problems. The mechanism might be gummed up a little and need a little WD40.

Good luck!

TomC

[-=Jeff=-]

Jeff:

Had a similar problem on my '90, turned out to be a vacuum leak.
On mine it was the funky PVC two hose connector just behind and under the throttle body on the drivers side. If it's not *EXACTLY* in the right position it leaks.
I had a heck of a time getting mine to seal, I swore that if it ever gave me problems again I'd replace the f*ing thing with fuel hose and hose clamps.

Have you tried tapping the throttle after the car comes to a stop? If that kicks the idle down then I'd say it's more likely in the throttle body. If the primary throttle body blade doesn't close all the way it'll cause idle problems. The mechanism might be gummed up a little and need a little WD40.

Good luck!

TomC

Tom, Yes I check ed the TB tapping it, it did not help. that 2 PCV hose connector was replaced before I got it, the hose are both individual but I will lok at theat too.

I also will reset the IAC and see if that helps.

[GrayZ]

Hey, Jeff,

i get the same damn feeling, i just don't run anymore.
I'm walking at every chance.
Am I in the right post?
where the hell am i ?

[-=Jeff=-]

Hey, Jeff,

i get the same damn feeling, i just don't run anymore.
I'm walking at every chance.
Am I in the right post?
where the hell am i ?
LMAO..

where are you? you are HERE!!!

LOL

[XfireZ51]

Jeff,

You'll want to look at the IAC counts. I adjusted the MinAir on mine to the point where the throttle stop barely touches the throttle body. My idle is around 800rpm. I have been getting a slight surging which had me suspecting a vacuum leak but I think I have been able to smooth it out modifying the timing and VE at idle.
Did you check line from secondary pump to under the plenum? Does it hold vacuum?
See what MAP is at idle.
Lgaff started his up and then did the IAC adjust and he says his idles fine now.

This is where having the Ostrich really helps. I sat in the garage yesterday and played with the cal with motor running. I made successive changes to the Prop Gains and downloaded bin. Worked great. I could immediately see which direction I needed to make changes in without running back and forth to the eraser/burner. :dancing :mrgreen:

[-=Jeff=-]

Did you check line from secondary pump to under the plenum? Does it hold vacuum?

According to this:
http://zr1netregistry.com/forum/showpost.php?p=23457&postcount=6

and This:
http://zr1netregistry.com/forum/showpost.php?p=23475&postcount=10

that were found in this thread:
http://zr1netregistry.com/forum/showthread.php?t=3912&highlight=high+idle

leads me to understand that it is not an issues with the secondary system

My Secondary pump runs for a few seconds, then shuts off for a few then repeats..

As I said, I need to see what the scanner shows, but i will try the IAC reset first.. Start simple. I question it being a vacuum leak because when I start it the idle is fine, after the motor is running and I drive it a short bit the idle is high.

If there is a vacuum leak it will be there when I start the car too, so I would never see the lower idle.

I am unable to do too much right now though, my radiator is leaking too, found that yesterday. Pass Tank is Bulging athough there are no stress cracks yet leaking on front and back..

Good thing I have a spare

[-=Jeff=-]

Okay.. Tried IAC trick.. no change

all Hoses seem good as far as I can tell.

BUT.... the PCV Vales were very loose, theat 2 to 1 rubber piece was loose on all 3 holes.. I uses a hose clmap for it on the tube to the front of the Plenum. for the 2 PCV valves I used a zip tie to keep them together wrpped top and bottom.. will that work.. don't know

started it again and it did drop to abot 1000 on the tach (need to connect the scan tool though)

the vacuum line from the bottom of the air horn goes to where? all other vacuum lines I blew into and all seem good

[Jeffvette]

Jeff, for giggles, go get a vinyl 3 ring binder and slap the flat surface over the air horn inlet. See if it dies.

[-=Jeff=-]

Jeff, for giggles, go get a vinyl 3 ring binder and slap the flat surface over the air horn inlet. See if it dies.

YEah I will get to that.. maybe tomorrow.. I did find the PCV boot ( the Y piece) was basically falling off and loose

[tomtom72]

This is just a fwiw from the peanut gallery.

we have sooo many vac connections that it's a nightmare. I bought new 90 els from the I/H's, new F connector @ PCV tops, and new reg hose & MAP hose. The double connector @ the lower left TB was loose too.

I replaced what I could buy, and zip tied the TB double connector. I also did the update on the PROM from GM....net result was great for about two & a half yrs.....now the GM F connector is loose as chit again & the idle is starting to do a bit of up & down.

After all my bs, my point is even with new rubber this stuff seems to go soft in a hurry & back to square one. How to keep the rubber from softening, and or how to revive the soft rubber are the keys to all these small additive vac leaks? I clean the oil out of the PCV system on a regular basis and still it's a loosing battle.

JMHO, when people had turntables to play records......yea I'm that old!....the most common problem with all of them was a part called the Idler Wheel. A combo of rubber molded to a metal wheel. The common trick was to use iso-propyl alcohol as a reviving agent to firm up the soft rubber. We used to soak the wheels in the soloution for a day, and presto...firm rubber again. I'm gonna try it & see what happens on the old stuff, I saved all the BG/OEM parts as spares.:redface:

Sorry to be sooo long about this!:o

[32valvZ]

I realize this may not wok for the PCV boots or other parts in the PCV system. (it might though) However, when I pulled my plenum, I noticed a few loose vacume connections where the rubber boots met with the hard plastic lines. I used black silicone as a sealer and it seemes to work pretty well. I let it sit for a long time while waiting for parts to fully cure. I havent had any issues "yet".
:cheers:

[-=Jeff=-]

thanks for the tips guys.. I was thinking about it last night too.. specifically that 'F' connector for the PCV.. Since I know my 90 with NEVER be NCRS, I might find something else, at the local ACE, then use some old PCV hose from my 89 (if I still have some) and create something better. I know the PCV on my 89 would not get that loose, but there are many different factors between the 2 motors.

I also have the Latest MEMCAL Binary file to change as the PROM in the car was the older mask with the VERY high IAC count settings.. The Newer Mask will probably help too

[-=Jeff=-]

I Found that my PROM even though it was a 'Tuner' PROM, still used the early base BCC so I had a later BCC Bin file and changed the fan turn on and burned it to try.

Starts up at 1500 rpm and drops off quickly to around 800 I think.. hard to tell with the GM Accurate Tach :rolleyes:

[XfireZ51]

Jeff,

We should try putting a 92 stock bin on your chip and see how it works.

[bldavis11]

Did you guys ever get this sorted out?

[-=Jeff=-]

Did you guys ever get this sorted out?

Yeah I think I am good.. combination of the having the early MEMCAL and the 'F' boot being loose on the PCV..

I will drive it around the block tomorrow to verify..