high idle when cold & CEL

Decipha · Post by **Decipha** » Mon Nov 19, 2007 6:56 pm

hey all, long time no post, i have a 95 3100 v6 with auto trany, last week i was driving normal at about 35mph and my check engine light came on, first time i ever seen the light so it kind of shocked me but the car still seemed to drive fine, no noticeable loss in performance or odd happenings. Since then every time I start the car in the mornings the car idles high (hangs at about 3k) then once the car is warmed up I have to turn the key off and restart it, then it'll idle fine (about 750), if I don't turn the key off and restart the car it'll stay up there at about 3k until I shut it off. Anyone have any ideas?

Money pit Beretta · Post by **Money pit Beretta** » Mon Nov 19, 2007 10:04 pm

Can you put a scanner or code reader on it? Most auto parts stores will do it for free. Have you lost anything like the speedo or heater/air con controls?

Jeff P · Post by **Jeff P** » Mon Nov 19, 2007 10:37 pm

My first guesses would be throttle position sensor or idle air control valve, but definitely see if you can get it scanned.

Decipha · Post by **Decipha** » Tue Nov 20, 2007 5:56 am

yeah i used to work at speedee i got it scanned came back with a throttle position sensor error, yet when i attached a new throttle position sensor we had laying around on a spare t/b it didn't give me any fluctuating reading on the realtime readout on the scanner, the master tech there said the computer is probably kaput

this really sucks, when i had my other 2 berettas i had 3 spare 3100 ecu's laying around, now that i got rid of them i don't have any, go figure, guess i gotta go to the yard and find a spare

i'll post back with the results

Money pit Beretta · Post by **Money pit Beretta** » Tue Nov 20, 2007 7:12 pm

There have been a few people with this same problem in the past months. I still have a spare to cover my butt if it happens to me again. Good to hear that there is nothing else wrong.

88*Beretta · Post by **88*Beretta** » Sun Dec 02, 2007 10:53 pm

(Decipha @ Nov. 19 2007,17:56)QUOTEevery time I start the car... idles high (hangs at about 3k)...warmed up I have to turn the key off and restart it, then it'll idle fine (about 750), if I don't turn the key off...about 3k until I shut it off.
Stuck IAC valve....when key is turned off, IAC resets itself.

Computer controls idle RPM via IAC.

Computer looks at other factors (voltage, AC on/off, etc) to adjust base RPM, but IAC controls idle via computer.

Decipha · Post by **Decipha** » Sat Sep 13, 2008 12:20 am

I finally figured out the problem with the car today!

I figured it wouldn't hurt to check my throttle position sensor to see what it was reading... as i pulled the connector off i noticed one of the wires was paper thin.

after feeling on the wire i realised that the wire was corroded completely away inside the insulation. It wasn't visible unless you cut away at the insulation. Anyway, I pulled about 4 inches of insulation away to finally hit wire, i have no clue where the wire could have gone it just simple vanished. I'm thinking maybe somwhere in the wire it was stressed and that caused it to pull somewhere else.

anyway a simple splice and tape job fixed the check engine light so now all is well. I'm hoping maybe I get some of my gas mileage back.

Money pit Beretta · Post by **Money pit Beretta** » Mon Sep 15, 2008 7:51 pm

Good that it was a cheap fix. A few months ago I lost the TPS on my new Beretta. Wow, I was way off, sorry.

Decipha · Post by **Decipha** » Sat Sep 20, 2008 8:01 pm

not a problem money pit i really did appreciate your response, i don't know if you noticed but this was an ongoing problem

since i've gotten the check engine light off I've been doing some supporting mods on the beretta to try to get a little better gas mileage.

i removed the air silencer and change my thermostat that was shot
next i'll be changing my cat and removing my muffler for a better flowing exhaust.

Money pit Beretta · Post by **Money pit Beretta** » Mon Sep 22, 2008 7:47 pm

A new cat always helps, the stock ones have been on there too long and most of the time they are not good anymore. On the muffler I'd just get one with better flow than the stock. That may keep the cops off you. The intake resonator will help build power, but you could get a CAI and put a K&N on it(that would help alot + the new exhaust). I'm happy when I can help, but support is sometimes just as good.

Decipha · Post by **Decipha** » Thu Oct 09, 2008 8:42 pm

what do you mean by the intake resonator? I'm refering to that restrictive little pipe that has the water catch on it and clips on the air filter box.

you saying to put it back on? car runs better without and i've actually picked up a couple mpgs

Money pit Beretta · Post by **Money pit Beretta** » Thu Oct 09, 2008 10:24 pm

Well, that was it, the little pipe that is. It is set up to cut down on the noise that engine makes when pulling air in. That noise can slow down the air flow and a small amount of power is lost(they can be set up for low or top end power,what ever GM thought the engine needed). I can tell you that a Cold Air Intake doesn't have one, though they could use one if someone would just build them with one. No, you don't need to have it. If you are thinking of getting a CAI I can give you some info on them. Wait, I now have a 95 3100 and I didn't see a resonator on my car. Where was it? You have a Z-26 right? That may be why I don't have one.

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