Idle Problem

I own a 1996 buick riviera. I just purchased it during the summer and now that it is winter around my area i notice when I start my car up the idle increases to about 2500 rmp. I let the car warm up but the idle does not come down. I am forced to shut the car of because I dont want to ram it into gear. When I do this I start the car back up and because its warm it idles at 1 rmp like it would normally. My brother works at canadian tire and we check for vacum leaks and there was nothing so we installed a new Idle air control motor. But nothing. I was wondering if anyone had this problem before. If not im forced to take it into the dealership to use their computers to scan and see whats going on here but that will cost a fortune... Please help a brother out lol thanks.

Are you getting a "Service Engine Soon" light ?

No nothing at all

I would have said a bad IAC, but you guys changed that.
Have you tried doing the simple things, like spray cleaning the Mass Air Flow sensor with MAF Cleaner. Don't use anything but MAF cleaner or you'll ruin it.
I'm not saying this will fix it but there are some things you can try before paying the $$$ to a shop.
Other people on here might have some better suggestions than me, so hang on.

BTW, Welcome to the site.

My brother said he cleaned that as well. Its weird like when i start it up I now put it into reverse quickly before it has a chance to rev up too high. But then it drives itself pretty much. Like when Im at a stop light ill have to hold on the breaks because it will want to take off and is reving at 1800 rmp and when i let go it drives itself up the street. But once it gets warm ill come to a complete stop and all of a sudden the idle will drop and it will idle at a normal speed.

And thanks for the welcome by the way hahah Ill get some pics up soon

What was it like during the summer?

Albertj

It was perfect at start up was just under 1000 rpm never had any idle issues until it started to get cold outside

How about something as simple as a bad coolant temp sensor.?
I don't know if that will make it Rev as high as your experiencing.
Maybe someone else has some input / experience with that.

Has anyone adjusted the throttle cable? Tampering with the adjustment could cause the symptoms you're describing.

Well if it was the throttle cable wouldnt it rev high in the summer as well?

If it's been happening since summer, I guess that's not it. I thought maybe some one had recently made some adjustments, and that might explain it.

my money is on a faulty coolant temp sensor.

YoungIke8732 wrote:

It was perfect at start up was just under 1000 rpm never had any idle issues until it started to get cold outside

1000 RPM after warm-up is *high* for the Riv. Maybe the throttle cable idea has some merit. Maybe somethign was replaced before you got the car and throttle cable was not properly adjusted.

Wonder if someone reset your "base idle" before you got the car?

I think Rick's onto something with the coolant sensor.

I also think you're in for some hard-headed, systematic troubleshooting.

Albertj

Hey Guys!

I found this Group because of this same problem in my '95 Supercharged. It idles cazy as hell at morning start-ups and evens idles down and cut off. The Service Engine Light is on but before I throw myself at the mercy of the Dealer (should I say, Pusher?) I would appreciate any help.

I'll post some pics soon.

Hard4unot2 wrote:

Hey Guys!

I found this Group because of this same problem in my '95 Supercharged. It idles cazy as hell at morning start-ups and evens idles down and cut off. The Service Engine Light is on but before I throw myself at the mercy of the Dealer (should I say, Pusher?) I would appreciate any help.

I'll post some pics soon.

Service Engine Soon light indicates an emissions-related problem - you have to get a code reader or have someone pull the codes and work from there.

Most dealers will 'check and advise' for less than $100.

Most AutoZone stores will read the codes for free.

Albertj

Thanks Addict - will the emissions related problem likely effect the cold weather starting?

Absolutely could.
But you need to know what the code(s) are that they find and report back here with those code numbers or if the repair suggested by the dealership is within your means, have it done.
Someone with a 95 can assist you with describing the codes if you don't already have a set of Manuals for the car.
If you plan on keeping the car, I highly recommend you look on EBay Motors, Parts and Accessories, Manuals and find a good used set for your car. They are invaluable and relatively inexpensive used.

Thanks Guys... the Dealer $100 diagnosis goes towards the price of repair... I'm gonna go for it! Was just checking out Woodgrain Dash Kits....NOICE!

Just a stab in the dark but it sounds like the throttle position sensor to me. If you step on the gas when it's revving high quick a few times, does it knock the idle down to normal?

I dont understand why a faulty coolant temp sensor would make it rev so high and where would that be located?

YoungIke8732 wrote:

I dont understand why a faulty coolant temp sensor would make it rev so high and where would that be located?

I agree, i don't know if a faulty coolant temp sensor can some how cause a very high idle.
The sensor is in the thermostat housing.

GMFreak8 wrote:

Just a stab in the dark but it sounds like the throttle position sensor to me. If you step on the gas when it's revving high quick a few times, does it knock the idle down to normal?

I'd take a stab at that as well.
But hopefully he'll get good service at the dealership and not get screwed.
As we all know the 95 is unique.

If the temp gauge on the dash works, it's not the ECT sensor...

Theoretically, any bad sensor or device should throw a code... First, I would double-check every vacuum line on the car (try squeezing the rubber ones closed with pliers where they connect to the engine, remove & cap the port for the plastic ones.) After that I would be awfully suspicious of the IAC, even without a code... An IAC that was stuck over 80% open would rev the engine to 2500 - I did it yesterday.

As to the stepping on the gas, I have to do that to keep it running...the idle goes up and down when starting cold. I did find me a $18.00 keyless remoteon e-bay, thanks to you guys but I'm afraid the only logical recourse for me is to take it to the dealer...at least I can sue them if they mess it up! I'm sure It'll coost me dearly but other than that the car really seems Mint.

Another thought though... I have begun to hear a noise coming from the passenger side of the engine when I'm warming the engine up and the outside temp display goes bright and dim causing a layman like myself to think Generator or somthing in the "charging system"... it slams into reverse also after the long warm up so I checked the Transaxle fluid (good) and heard the noise more pronounced coming from around the belts... I've also been told a possible loose engine mount... you're right, Rick... I hope the dealer don't screw me!