new to site, need help rough idle

[14mins]

New guy here wanting to pick the brians of experts. I have a 87 GN all stock with the exception of a k an N air filter. The car has a 114,000 thousand miles. I have owned this car since 1990 when it had 40,000 miles. It has suffered from rough idle from day one!

On startup in the mornings it will rev to 3000 rpm and drop back to 800, rev up to 3000 drop back, rev up, drop back. Sometimes it dies and has to be restarted. It is like the car is loading up, chocking. It will finally idle at 1000 rpm when warm, but no lower or it sometimes dies at lights, stop signs etc. The car runs pretty well, other than the rough idle. I have had the car to 3 different dealerships in the last 10 years with no luck! I finally got frustated with it and parked it 3 years ago. Walking by it in the garge ever day was driving me nuts. So i cleaned it up, changed the oil,filters, hoses and belts, plugs. It still idles bad. I WANT to cure this problem! Thank in advance for the help.

 

[striker_29]

Man you need a scantool to set the iac. I'll bet doughnuts to dollars that is your problem. Well after 3 yrs you no doubt have some other issues. But check out www.gnttype.org and do a search for iac reset. Also check the tps, just do a search for that too. Try that and see what happens. Good luck and hth.

 

[striker_29]

Here is Iac reset:

http://www.gnttype.org/techarea/faq/IACreset.html

And here is Tps adjustment procedure:

http://www.gnttype.org/techarea/maintenance/TPS.html


HTH

 

[salvageV6]

What chip is in the car?

 

[14mins]

Salvage- stock chip in the car.

Thanks for this round of advise, and i hope that this works, but the dealers could never figure it out. If and when i get this going i plan to add a chip. At this point i have more plans than money, but i am going to do what is needed. The car is cleaner than most that i have seen. It has been garage kept. No dings,scratches. The paint is dull, the interior is in great shape except the grey velour in the middle of the drivers seat. I know that you guys know more than the dealerships. Thanks

 

[14mins]

striker_29- thanks for the links. I printed them off. I will try to find a shop this week to do the adjustments. Are those haynes manuals they sell at pep boys, auto zone any good.

 

[TurboJim]

You more likely than not need a chip recalibration. Thr factory puts the car in closed loop with a lean target air/fuel ration too quickly. This causes the rolling you describe. If you feather it for a couple minutes, its fine right?

 

[dconnor]

Aledo is just west of Fort Worth isn't it? Try hooking up with the DFW area Buick club, there are a lot of experienced Tubo Regal guys up there.

www.lspbc.org

I know you've already stated that you got started on a tune up, but be sure to check out the Spring Cleaning guide at www.gnttype.org , it gives some pretty good TR specific advice.

Doug C.

 

[tim87tr]

14mins, I had the same problem when I got my stocker a couple years ago. One thing I noticed is your comment about the dealerships. All they do is check for codes and ask what the syptoms are. Their service manual leads them through a diagnosis in a flow chart based on that. I know, I have a service manual. Yes, they have general mechanical knowledge and occasional someone there will have specific TR knowlege, but most likely NOT.

What I'm trying to say is read up on the links and advice everyone gave you. You can do most all the work yourself. You will thank yourself in the long run. There may be a local TR guy to help you out, and not sure where you're at in Texas, but a TR specific shop is located down there also. Along with a couple of gurus on this board I can think of off the top of my head.

Answer Testa's question and follow his advice, he will have you fixed up in a flash. I guess my point is to learn something about your car. I had no mechanical experience and have found doing the work very rewarding. A good place to start learning and doing your work is spring cleaning: http://www.gnttype.org/maint/basics.html
That's where I started a year ago. Sounds like you are on your way to learning the car with the work you have already done. Like striker29 said, a scan tool (Scanmaster) will help you learn more about your car.

 

[14mins]

TURBO Jim- Yes i have to feather the gas pedal.

Dconner- I am going to check with the clubs that i can locate.

tim87tr- I spent hours reading on this site last night. Now i am convinced that my car suffers from many ailments. LOL
I printed off a lot of things to do. The intercooler has never been cleaned. I can handle that. Did some reading on scan tools. I know that i will need to buy one and a used laptop. That will be a long frustating process, but to get it right it will be worth it in the longrun.

I probably need to upgrade the fuel pump, add a regulator, get quaility wires, clean the intercooler, replace the mass air hose, etc. I want to get it running to good condition, learn the ropes and start modding with my son down the road for a project.

What is a good chip to get? I do not want to run more than super unleaded for a while. Do i need a 160 T-stat?

Last night i bought a egr valve and installed it. It ran worse so i put the factory back on with a new gasket. (The old gasket was blown on a part of it) Should i buy a new GM? Should i get a new GM o2 sensor. The mass air flow sensor was replaced with a gm at 75,000 miles (114,000 now) and the coil pack at 85,000. I do not mind changing these kind of things now to be saving a little trouble in the near future. This car is going to stay with me for many,many years to come. Thanks for all the advise guys!

 

[tim87tr]

Originally posted by 14mins
tim87tr- I spent hours reading on this site last night. Now i am convinced that my car suffers from many ailments. LOL
I printed off a lot of things to do. The intercooler has never been cleaned. I can handle that. Did some reading on scan tools. I know that i will need to buy one and a used laptop. That will be a long frustating process, but to get it right it will be worth it in the longrun.

I probably need to upgrade the fuel pump, add a regulator, get quaility wires, clean the intercooler, replace the mass air hose, etc. I want to get it running to good condition, learn the ropes and start modding with my son down the road for a project.

What is a good chip to get? I do not want to run more than super unleaded for a while. Do i need a 160 T-stat?
[/B]

There is about a one year learning curve on these cars, I think. That is about how long I have been working on mine.

Definitely the fuel pump and hotwire kit first if you have a stock one in it. I just installed this setup, it was good:
http://www.racetronix.com/Racetronix-Buick_Single_Fuel_Pump_Kit.html

A fuel guage at the end of the fuel rail will show you the fp at WOT. An adj regulator can be set to around 42 to 45 lb static, line off, and you can run the braided fuel line and guage under your wiper to check the fp at WOT. Should be ie: 42 static + 15 lb boost = 57 at WOT. The stock fp would not put out this much (car runs lean) and that gives you engine knock, detonation, in high gear when the engine is under more load. The detonation hurts the crank bearings.

A scan tool such as scanmaster (no laptop), will show you the knock retard, how much the ecm is retarding the timing. You tune for 0, but can have 3 to 5 on a shift point.

ALWAYS run as high of octane in these cars as possible. Even 91 octane will give you a lot of knock unless you want to drive around with 10 to 12 maximum boost. There is an adj arm on the wastegate actuator on the turbo to adjust boost. Looser is less boost, tighter is more (Be careful). You really need an aftermarket boost gauge to read for best accuracy, the LED in the dash is sometimes not too accurate.

Yes, change the plugs, wires, and wait on the coil pack for now to see how it runs. Cleaning the IC will keep oil blowby from the turbo from going into your intake, which increases knock. The 160 T helps with a cooler engine and is an easy and fairly cheap mod.

Lots of good chips. Testa, Precision, Red Armstrong, Jay Carter, etc, you can't go wrong. Also, I would use the AC purple wire O2 sensor. It is about $35 dollars.

 

[salvageV6]

1. Buy the factory service manual best $70 you will spend on the car.

2. 160 stat.

3. Fuel system upgrades, pump + hotwire + filter

4. 93 street chip I like Ramchargers or Reds others named will also work fine I'm sure.

5. 1 or 2 gallons of Xylene in under a half tank of gas to clean the injectors.

6. Spring cleaning including top engine cleaner.

That oughta keep ya busy!

 

[14mins]

salvagev6- xylene as in paint department of hardware store?
What do you mean by top engine cleaner? Sorry to sound dumb, don't want to screw up. I am looking foreward to getting the ball rolling. I am not to mechanical but i have most tools and some common sense.

Scanmaster or laptop? where can i find scanmaster?

I can allready see the $$$ dropping out of the wallet. I do not mind, i am excited just want to get it right. The dealerships made me gun shy. More than 800 was spent on this rough idle in the past.

Keep the ideas coming please, i plan to get going hot and heavy this week end.

 

[timothydog]

...And so it begins

Welcome to the dark side 14mins!

A few simple things that you might not know about yet:

There is a breather line going from your passenger side valve cover to the inlet bell of your turbo. Pull that line off and cap the hole on the turbo (leave the breather plugged into the valve cover). This is where tons of oil gets sucked into your system. YUK!

Also, remove the small coolant lines going to and from your throttle body and loop them back to themselves. This is just excess heat you don't need.

(here is a link about top engine cleaner too:
http://www.gnttype.org/techarea/maintenance/cleaner.html ) I used a product called SeaFoam last time. Worked great.

Good luck!

 

[salvageV6]

GM top engine cleaner available at most if not all GM parts counters. Just follow the instructions and do a search on this site for tons of information.

Spring cleaning on gnttype.org is the way to go.

So is the service manual!

 

[BLACK6PACK]

As mentioned before, DO NOT TAKE THE CAR TO A DEALERSHIP!!!

The scanmaster is very good and doesn't require a laptop. You can get it from Ramchargers, Cottons, and several other vendors that advertise on this board.

I knew very little about tuning cars when I bought mine 4 years ago. Not much has changed but I can do most of the work myself now. If you have a problem, get on this board ask questions and just watch the info pour in.

 

[14mins]

Timithydog-thanks for the tips. I have blocked off the breather line many years ago when i put the k an N air filter on. Did not know about the other.

Black6pack-thanks for the names.

My budy with a paint and body shop told me i can use his name to get parts at a discount. I am going to order more parts today. Last week i totaly cleaned her up from top to bottom, replaced the window drain molding, door moldings and a few trim pieces. tHE valve covers were leaking, did that. I am going to get the spring cleaning parts and lock myself in the garage this week end.

Last year i bought a yamaha raptor atv and got on a web site like this looking for a little help. Well this year the motor was sent to Trinity racing for port,polish,valves,springs,hi-comp piston etc. Then i needed new shocks,graphics,handlebars,riding gear,etc.I can see where i am headed with the TR. I hope my wife does not lock the computer on me.

 

[BLACK6PACK]

And you think the ATV got expensive!!!

Actually you can get a lot out of these cars for a small amount of money. Once you get all the basics done, and start to get the feel for the scanmaster, the best $300 you can spend is on an alky kit. Its easy to tune and only takes about an hour to install.

 

[14mins]

Picked up a few more parts for the car today. Went looking for a screw in fuel pressure guage, could not find one locally. Picked up a boush 02 sensor. Good or bad? going to the dealer tommorow so i can get the ac part. Did the water line at the throtle body today. Going to put on a upper radator hose and t-stat tonight. And add the xlene tonight. Thanks

 

[tim87tr]

From reading on the TR's a lot and talking with owners, I think more people go with the AC purple wire O2. But the Bousch will work and people swear by them too. Here is a link to a fp gauge with a braided line and T tap for the end of the fuel rail.
http://www.jaysgn.com/inst.html#inst2
You can look at the vendor index on gnttype.org also.