OBD 1 and 2

[another Todd]

Looking a a neighbors buick my son wants. 1994 LaSabre 3.8. Engine label says OBD1 compliant. Diagnostic connector is OBD2 style. OBD2 scanner will not link, but OBD1 cable will not plug in. Has some issues, with idle randomly going to about 2500 RPM (guess, no tach) within 1 minute or so from a cold start. If I shut it off and start it up, it is normal again (like microsoft windows

) It's not registered so I cannot drive it around. Any ideas?

 

[The_Jeff]

It's a hybrid.

You may need an older OBD-I scan tool (like a SUN?) with proper dongle connector.

Sounds like a wonky TPS. If you got a scan tool to connect it might not help the diagnosis; didn't on my saturn. No codes, no funny data stream readings.

The TPS logic typically says at 1% throttle, open the idle air passage for "dashpot duty" blowing hydrocarbons out.

If the pot goes bad, it can sometimes read 1% and others 0%. But a restart of the computer resets to zero.

You could redneck it by unplugging various sensors until it idles right.

I would also look in the vicinity of the MAF for trouble.

 

[another Todd]

I looked on other forums and apparently a lot of Buicks have this issue, and you cannot jumper it like a obd 1 or read it like a obd 2, it takes a tech 2 scasnner. I am going to pass on the car, it has too many issues.

 

[artificialist]

Yeah, some 1994 and 1995 GM cars had an OBD-II port that sent OBDI code. You don't have to have a GM Tech-II, many mechanics have a scan tool that can read your car's diagnostics.

What a bummer that you can't buy a low cost scanner to do this kind of job.

That in mind, what a pain.