New joiner 87 Idle problems

[Sevy14]

Hey folks just picked up an 87 GN with about 40k Miles on it. Been sitting a bit. Starts reasonable well. Idles well but high for about 45 seconds then drop really low and eventually stalls. Changed plugs and wires and just today added new air intake with MAF translater. Figured that might help but still doing same. While under hood added a manual boost control. And now Service engine soon light on but was not on before. Guidance anyone?

 

[John Larkin]

There are alot of things that go into these cars running well. It starts with having all the sensors in spec and working properly. Do you have a scan tool that can help you know how these all are functioning? Once you have this figured out, then it is a good time to consider what chip you have.

 

[erikelvis]

Any idea on chip?

My T was having horrible idle probs for a while. Switched from an older chip to a new one from turbotweak and it got much better. I believe he cuts out open loop running. That wasn’t the only prob though. Had to replace some vacuum lines and currently replacing the maf with a ls1.

 

[Sevy14]

Stock

 

[Sevy14]

Any idea on chip?

My T was having horrible idle probs for a while. Switched from an older chip to a new one from turbotweak and it got much better. I believe he cuts out open loop running. That wasn’t the only prob though. Had to replace some vacuum lines and currently replacing the maf with a ls1.

I just switched to the ls1 as well.

 

[Sevy14]

I just switched to the ls1 as well.

And Stock chip

 

[TurboTGuy]

First, check for vacuum leaks on all lines.

Stock as in the '87 chip?

If so, buy a new chip from Turbo Tweak. Gasoline formulations are much, much different today than they were back then.

 

[Sevy14]

First, check for vacuum leaks on all lines.

Stock as in the '87 chip?

If so, buy a new chip from Turbo Tweak. Gasoline formulations are much, much different today than they were back then.

Yip stock 87. Will check for vacuum leaks. Is a good place to start at the top? As in the plenum down?

 

[erikelvis]

Yip stock 87. Will check for vacuum leaks. Is a good place to start at the top? As in the plenum down?

My vacuum block had a few offenders. I smoked the car and found a leak between the maf and turbo. At some point someone replaced the pcv hose with fuel line and that was collapsing. I mean if you don’t know how old the vacuum lines are just replace them all.

 

[Chuck Leeper]

Fresh gas and filter?
Fuel psi?
Fresh O2 sensor.
Plugged up cat?
Cracked headers?

 

[TIMINATOR]

Places to check, in no particular order:
Throttle body to plenum
Plenum to manifold
Vacuum block on top of T Body
Dirty or bad IAC
Bad O2 sensor
Bad computer/water temp sender
Bad TPS
All sender connections
Intake manifold to heads
Injector O rings to intake
Bad fuel regulator, fuel pump, or filter
Old fuel?
Bad alternator, regulator, wire to battery
Any and ALL grounds!
Trouble codes?
Don't fixate on vacuum leaks, lots of things can mimic that.
These are all things you should check before driving a car that's been setting, especially under boost!
There are more things too that I probably forgot, but ya gotta start somewhere.
Trouble codes and fuel pressure first, then use a 2 or 3' piece of hose to listen around while someone keeps it running.
Then wiggle test wires and connectors.
TIMINATOR

 

[hensleyt]

without TPS and IAC numbers where do you start?
fuel presume very important too.
Looking for the obvious is important, ECU will do its best to keep it running, but all the numbers must be in proper + - <> zone
scan master should be your first pursues
Today what is your intention with this new turbo Buick?
Spring cleaning is just getting the basics right OE chip is not the best place but it should start idle and perform good under 10 psi (light causing )
and after that ,when you have decided where you and this Buicks new relationship is going to go then you order a chip.

 

[John Larkin]

Everything you bought was not wasted - all usable upgrades. Fullthrottlespeed.com or turbotweak.com has scan tools, 3 different kinds but all will work depending on what you like. Everybody is priced the same on them.

 

[Sevy14]

Hi folks got the scanmaster2.0. All sensors seem in line but have a low and hi MAF trouble codes. Rough up and down idle then smooths out somewhat after it warms up a bit. Give it a bit of throttle and it is rough and not responsive. Vacuum seems ok, no leaks. Have installed MAF set at 0-0 for LS1 with translator. Going one step at a time so I'm thinking going through the fuel system and Chip next. Thoughts anyone? Thanks

 

[THensley]

good move, chip and fuel system good place to start.
Go to Turbo Tweak for your one stop shopping experience
Get a chip and matching injectors , fuel pump, and hot-wire, new fuel pressure regulator.
May seem like a long list but all these work together. I would call this a Baby step or one step at a time.

 

[John Larkin]

Unplug the ECM power behind the battery, let the ECM reset for 30 seconds, then try again.