high idle in park but not in drive?

Hi,

I have a 95 sc riv with about 106k on it. I noticed that the idle is a little high while it is in park (around 1100rpm) but while in drive it drops down to around 600rpm. I first thought it was a vaccum problem and check every little rubber connection(there are a ton) and replaced the bad cracked out ones. This did nothing to solve my issue. Has anyone run into this issue before? I am at a loss as was a mechanic i took it too.


Also, I have never driven a supercharged v6 before and it feels to me like mine should have more power than it does? Do you guys have any tips on getting a little more performance? I have changed wires, plugs, 1 coil pack(previous one went bad) and changed the SC oil which was a royal pain! I think i may be a little picky with the performance of my riv as i drove a GMC Sonoma with a 350 stuffed in it before this car. The car does not act funny (stall, stumble etc) I just feel like it should be a little more....performance.

I have been reading on this forum for a little while and you guys seem great. Anything you guys can suggest would be great! Thank you in advance

Switz

Hey Switz, welcome to the forum. A quick answer to your questions might be the coolant temperature sensor if it only happens when the car is cold. I had a similar problem and the guys here helped me figure it out. Its a copper plug with an electrical connection that threads into the block right below the T-stat housing.

dswitzer9865 wrote:

Hi,

I have a 95 sc riv with about 106k on it. I noticed that the idle is a little high while it is in park (around 1100rpm) but while in drive it drops down to around 600rpm. I first thought it was a vaccum problem and check every little rubber connection(there are a ton) and replaced the bad cracked out ones. This did nothing to solve my issue. Has anyone run into this issue before? I am at a loss as was a mechanic i took it too.

1100 sounds about right for cold idle.

Does you car have A/C or did the previous owmer (PO) install a "delete pulley?"

What temperature is ypur car's engine when fully warm, and what is the idle speed then? best way to check is with scanner (for your car, GM's Tech I or Tech II for instance). It will read the temp sensors directly. Might be your problem is the coolant temp sensor. The Riv has several temp sensors, IIRC the sensor for the dash gauge is different. However... what does the dash temp gauge read when car is warmed up?

dswitzer9865 wrote:

Also, I have never driven a supercharged v6 before and it feels to me like mine should have more power than it does? Do you guys have any tips on getting a little more performance? I have changed wires, plugs, 1 coil pack(previous one went bad) and changed the SC oil which was a royal pain! I think i may be a little picky with the performance of my riv as i drove a GMC Sonoma with a 350 stuffed in it before this car. The car does not act funny (stall, stumble etc) I just feel like it should be a little more....performance.

The Riv weighs less, and its SC engine (L67) has less torque (280 ftlb) than any 1992 or later versions of the venerable 350 (LT1). Starting in 1992 that engine (LT1) built factory at 325 ftlb and up.

dswitzer9865 wrote:

I have been reading on this forum for a little while and you guys seem great. Anything you guys can suggest would be great! Thank you in advance

Switz

Suggest you get a factory repair manual set and a scanner (not code reader) - I use Alex Peper's "CarCode" with my laptop and one of Peper's dongles, it reads all the sendors, reads and resets trouble codes, shows fuel trims etc. The books are usually pretty cheap on eBay. I appreciate all the help I've gotten on this board, and try to contribute. Hopefully you will too.

Albertj

thanks for the reply guys,

It has the high idle when it is warm also. It runs at 205 all warmed up. Yes it does have the AC..everything is stock nothing has really been messed with. The thing is- cold or warm it does the same thing--while in park its 1100 and pulled into drive its 600. The 500 or so difference is what bothers me somewhat, id expect to see like 100 or 200 change.

I feel like if the 95 didnt have the forbidden 1.5 obd I could have had this figured out a long time ago. Also whats up with Haynes not making a book for this model Riv?

dswitzer9865 wrote:

thanks for the reply guys,

It has the high idle when it is warm also. It runs at 205 all warmed up. Yes it does have the AC..everything is stock nothing has really been messed with. The thing is- cold or warm it does the same thing--while in park its 1100 and pulled into drive its 600. The 500 or so difference is what bothers me somewhat, id expect to see like 100 or 200 change.

I feel like if the 95 didnt have the forbidden 1.5 obd I could have had this figured out a long time ago. Also whats up with Haynes not making a book for this model Riv?

Haynes makes manuals depending on how many of a vehicle model are registered and vehicle age. Riv is OK on age but registrations are too low, I forget what their number is. You can get some insights on the engine from the BOP FWD Full-size haynes covering similar years -- BUT for about the same money you can usually get a for-the-RIv factory manual set off eBay.

The Riv's OBD 1.5 is just the OBD 1 wired thru an OBD 2 connector - if you search on the web you should find more detail; if you search on this site you will find postings telling what scanners will work (theres more than one) other than the factory scanners. You shoud be able to get a Tech 1 pretty reasonable off eBay if you want one.

Albertj

While our cars have a PCM that keeps the idle RPM within a narrow range regardless of gear, and this is sounding much like an old, non-computerized car that drops a lot of RPM when in gear... how about a stuck Idle Air Control (IAC)?

Right, I will try to check out your guys suggestions and try to obtain the manuals and scanners sometime when $$$$ comes available.

Has anyone else had trouble with the factory paint just chipping away? My riv is the basic white (not the pearl) and the trunk lid has a decent size flake gone and a small spot right behind the sunroof. I have heard somethings about the primer Buick used back then has bad and didnt let the paint stick all that well

Also, when i bought the car the lower Riviera symbols behind the doors were missing the a. All it says is Rivier.......Weird right? They are the gold signature edition ones and i havnt had lucky finding any? Are those badges glued on there? Would i have to heat them up and scrap them off to replace them?

dswitzer9865 wrote:

Also, when i bought the car the lower Riviera symbols behind the doors were missing the a. All it says is Rivier.......Weird right? They are the gold signature edition ones and i havnt had lucky finding any? Are those badges glued on there? Would i have to heat them up and scrap them off to replace them?

Yes...

Welcome to another of their dumber ideas. Not only did they make our Riviera script out of thin plastic, they changed they actual 'typeface'! It's narrower than the older Riviera script, without a blackout backing, and the tail of the 'a' sticks out farther while the 'a' itself is not a complete, closed loop. I broke the end off of one of my regular chrome ones while washing it by hand...

Finding gold ones would probably take forever, and the dealers have probably obsoleted the chrome ones too. You might be able to find some on the Net at one of the companies that buys out obsolete GM stock, or in a wrecking yard... Check this section of our site:
https://rivperformance.editboard.com/parts-wanted-f23/discount-gm-parts-sources-t488-30.htm?highlight=parts+source

PS - I had an actual body shop replace that script of mine (when new ones were still $20 from the dealer) and he scratched the hell out of the clear coat. I would think that someone like 3M makes an adhesive remover/dissolver for this job...

Eldo wrote:

dswitzer9865 wrote:

Also, when i bought the car the lower Riviera symbols behind the doors were missing the a. All it says is Rivier.......Weird right? They are the gold signature edition ones and i havnt had lucky finding any? Are those badges glued on there? Would i have to heat them up and scrap them off to replace them?

Yes...

Welcome to another of their dumber ideas. Not only did they make our Riviera script out of thin plastic, they changed they actual 'typeface'! It's narrower than the older Riviera script, without a blackout backing, and the tail of the 'a' sticks out farther while the 'a' itself is not a complete, closed loop. I broke the end off of one of my regular chrome ones while washing it by hand...

Finding gold ones would probably take forever, and the dealers have probably obsoleted the chrome ones too. You might be able to find some on the Net at one of the companies that buys out obsolete GM stock, or in a wrecking yard... Check this section of our site:
https://rivperformance.editboard.com/parts-wanted-f23/discount-gm-parts-sources-t488-30.htm?highlight=parts+source

PS - I had an actual body shop replace that script of mine (when new ones were still $20 from the dealer) and he scratched the hell out of the clear coat. I would think that someone like 3M makes an adhesive remover/dissolver for this job...

to your PS - body shop screwed up unfortunately. The script is backed with 3m foam tape, removal without scratching requires using a piece of wire with the ends wrapped around a couple small dowels for handles - slip the wire behind the script and pull back and forth, holding the wire somewhat away from the car's finish... essentially you saw the foam tape apart. Then remove the remaining foam tape w/GooGone (takes patience) or one of the proprietary solvents bodyshops get. I mean, I was not involved in your car's body work but I'm sorry they messed it up, it's not impossible to do it without scratching but it does admittedly take a little finesse.

I am not involved in the following link either - but for those of you who want one at the moment (see date of this post) there's a seller on eBay who has 3 for sale, $15/ea or best offer LINK.

Albertj

albertj wrote:

I am not involved in the following link either - but for those of you who want one at the moment (see date of this post) there's a seller on eBay who has 3 for sale, $15/ea or best offer LINK.

Albertj

These are used, so some kind of new adhesive will be necessary, but I say take the easy & cheap way out and GO MAN, GO!!