Hi,
Here's my situation:
87GN 49K miles, overall runs well but has an annoying slightly rough idle. Off idle car runs great. I'd like to smooth out the idle and would rather troubleshoot it rather than just replace parts.
Running turbolink my reading appear to be in the norms compared to other readings I've seen here. But I've noticed lots of malf. codes when idling. These do not stay on just pop in then go off. To name a few I've seen 55, 51, 45, 44, 43, 34, 33, 32, 24, 22. I get no codes while driving. Is this normal? Or is it some kind of bad ground or low voltage thing?
Fuel Pressure w/vac off is 38psi and Vacuum is 15inhg? are these normal for a stock GN. Also has a new O2 sensor.
I plan on installing a new fuel pump and adjustable regulator to get the pressure up to the recommended 45psi.
Any thoughts about the turbolink readings and how to smooth out the idle?
Thanks,
Ray
Common reasons for the readings:
- Number 1 cause is grounding ... the cars are getting to be 14 years old and all sorts of funny little grounding problems from wiring getting brittle, corrosion, etc.
- Loose connection of the connector from TurboLink to the ALDL connector
- Ground of the ALDL connector weak
- Power inverter transmitting voltage out through the parallel port (as noise)
- Fan relay is "chattering" causing noise in the wiring harness (might explain why it happens at idle, since that's when the fan is kicking on and off)
- Loose/corroded connections at the ECM
- Chip not properly seated in the socket of the ECM (loose enough to vibrate loose)
As far as the idle goes, it would be worth it to reset the IAC/min idle air setting, up the fuel pressure to about 43 psi, and make sure it has fresh plugs and wires.
15 in/Hg is normal for a stock cam and good intake sealing.
Thanks Ken for the info....
Since the car basically runs fine I couldn't believe all those sensors were bad or misadjusted. BTW, I really enjoy your product and being able to see and review all the data. I'm a computer geek by trade as well as a retired USAF aircraft avionics technician and I hate looking at something that isn't working right and having to guess at what might be cuasing the problem. Information and knowledge is power!
So here's my follow-up questions:
1. Is there a good resource that defines all the grounds and gives their location?
2. Is the power inverter you mentioned in #4 the power inverter to powere the laptop? If so, I run mine on battery, can this cause the same thing?
3. Assuming it is parallel port feedback, is there any filter that can be added?
Thanks,
Ray
Ray, the shop manual has an electrical section that I use more than anything else in it.
It is a pain in the neck to assemble the Regal pertinent stuff out of the 70 lbs of paper you receive after ordering one (you get the entire Buick line) but I don't know how you can be serious about working on them without one....
Another resource:
http://www.gnttype.org/techarea/electrical/electricpage.html
especially:
http://www.gnttype.org/techarea/electrical/grounds.html
http://www.gnttype.org/techarea/electrical/wiring.html
If you are using the laptop battery, then strike #2
Shouldn't be any feedback if you aren't using an inverter, so I'd start looking at grounding and the fan relay.
Thanks guys.....I think I'll check some grounds tomorrow. I am truly impressed with this sites personal help and information resources!
Ray
Another thing that may be your "gremlin" is your chip programming....right Ken? I've got a new chip and ever since I've put it in, while the car runs just fine, I've got frames on TL that have error codes. But the frames before and after are clear and my SES light never comes on. I think I've gotten a few of the ones you list. Things like MAT temp too high, fuel pump voltage low....all sorts of stuff that make NO sense. From what Ken told me, it's not causing any real problems, but you should check the chip and see whose it is, ie who makes it, BGC,( I know for sure) add a special code which makes a Scanmaster able to access the data faster than the normal rate, and that is what causes TL and a few other tuning programs to see "gremlins". You should be able to get ahold of them and have them send you another chip without the code in it, (when you can get around to it, still haven't verified and changed mine Ken.
)...good luck, Scott