auto_editor

1989 Custom Cruisers like mine could be optioned so as to have a "Driver Command" or some such fancy name for an additional bank of idiot lights.

I know with OBD-II systems they can just plug in a tester and read about the reason(s) the check engine light [it actually says "SERVICE ENGINE SOON"] came on.

I was cruising along and the light came on just long enough to scare the hell out of me (around 20 seconds), then went off all without an apparent reason (i.e. bad engine noise, drop in power, etc.).

Modern "Oh Sh*t!" lights come on in different ways, each symbolizing a varying degree of scariness: on for a few seconds, no biggie; on for a while, not good; and flashing, BAIL OUT!

I have no idea what systems are hooked into this light, what parts affect its coming on, and what it actually means. There's no "data port" to plug a tool into and no mention in my factory B-Body manual or owner's manual that says anything beyond, "When your Service Engine Soon light comes on, service your engine soon."

Any ideas?...

Lady72nRob71

Time to pull the troublecodes...

If you want to do that yourself, here is how:
http://tlentz.oldsgmail.com/howto.html#Computer

This should apply to your wagon, as it is the same ol' 307 CCC...

If you do not wish to do this, your local parts store might have a scan tool to use (if it works on those older systems). They will scan it and give you a printout of what could be wrong.
The computer plug is to the left of the ashtray under the dash on the g-bodies, but could differ on the wagon.

Report back the code(s) and we will take it from there.

auto_editor

My Firefox browser went nuts when I tried to follow that link:

"This web page at tlentz.oldsgmail.com has been reported as an attack page and has been blocked based on your security preferences.

Attack pages try to install programs that steal private information, use your computer to attack others, or damage your system.

Some attack pages intentionally distribute harmful software, but many are compromised without the knowledge or permission of their owners."

Might that info be on ANOTHER web page?...

Lady72nRob71

Funny, as my work firewall said the same thing today but it worked last week just fine...

I had been going to that (and other member sites in that domain) for well over 10 years now. It is/was a VERY informative site, not sure what happened to it now (or if it was mistakingly MISflagged as bad...)
I am a member on oldsgmail.com, so if I hear the probelm and solution, I will post it.
I had copied that link from a previous post I made last month since I could not access it today.

Anyway, here is the info that I copied from it long ago, just in case it went down:

Pulling the computer codes:
When the "Check Engine" light comes on, it means you should open the hoodand check the engine. Yup, that's an engine all right :-) Now what?

Don't waste your money on one of the "scanners" from the parts store. A full fledged diagnostic machine is another matter, but a paperclip can accomplish all that the parts store scanners can.

• Under the radio by the driver's right knee you'll see a connector with two rows of pins. That is the ALDL (Assembly Line Diagnostic Link) connector.Pin A is in the upper right-hand corner (as you're looking at it), PinB is right beside it.
• Bend a paper clip or small piece of wire into a U shape and insert it into both pins A and B so that they are connected together.
• Turn the ignition switch to the ON position, but don't start the car.
• You'll see the "Check Engine" (or "Service Engine Soon" on some models) light flash some codes.
• Error codes are two digits, and the light flashes out the first digit, pauses, and then the second digit. It will repeat each code two more times (total of three) before displaying the next one. The first and last code will always be a code 12 (flash, pause, flash, flash, long pause, repeat). This code is normal and means that no tach signals are making it to the computer (because the engine isn't started). If you don't get a code 12, something is wrong with your jumper or your computer.
• Make a note of any codes that come up and look them up on the chart. Hereis a chart listing the computer error codes. It is in Microsoft Word 6.0/95format. I recommend printing out this chart and keeping it in your glove box along with an official GM diagnostic paper clip. Shrink it to 1/4 pagesize and then laminate or coat with clear tape and it'll last a while. The chart says what each code is and some common causes. From there it's your call whether the problem is serious enough to keep driving the car or not, and how urgently service is required. Troubleshooting each code is beyond the scope of this web site and if you need to do so you should either get a manual (Factory, Haynes or Chilton's) or take it to a mechanic who can do further diagnostics on a diagnostic scope.
• Remember to remove the jumper before running the car.
• If you think you've fixed a problem and need to clear the existing computer error codes, just disconnect the battery (for a few seconds is plenty) and reconnect it.

CCC System Trouble Codes

To pull codes, jumper pins A and B on the ALDL connector (upper right) and turn ignition switch to run position.

Code Circuit or System Probable Cause
12 No tach signal to ECM This code will flash whenever the diagnostic terminal is grounded with the ignition turned On and the engine not
running. If additional trouble codes are stored in the ECM they will appear after this code has flashed three times. If
this code appears while the engine is running, no reference pulses from the distributor are reaching the ECM.
13 Oxygen sensor Circuit Check for a sticking or misadjusted throttle position sensor. Check the wiring and connectors from the oxygen sensor.
Replace the oxygen sensor.
14 Coolant sensor/high temp If the engine is experiencing overheating problems the problem must be rectified before continuing. Check all wiring
and connectors associated with the coolant temperature sensor. Replace the coolant temperature sensor.
15 Cooland sensor/low temp See above, then check the wiring connections at the ECM
21 Throttle position sensor/high Check for a sticking or misadjusted TPS plunger. Check all wiring and connections between the TPS and the ECM.
Adjust or replace the TPS.
22 Throttle position sensor/low Check the TPS adjustment. Check the ECM connector. Replace the TPS.
23 Mixture control solenoid The mixture control solenoid is open or grounded.
24 Vehicle speed sensor A fault in this circuit should be indicated only when the vehicle is in motion. Disregard Code 24 if it is set when the
drive wheels are not turning. Check the connections at the ECM. Check the TPS setting.
32 BARO circuit low Barometric pressure sensor circuit low.
33 MAP Sensor Check the vacuum hoses from the MAP sensor. Check the electrical connections at the ECM. Replace MAP sensor.
34 Vacuum sensor or MAP sensor Code 34 will set when the signal voltage from the MAP sensor is too low. Instead the ECM will substitute a fixed MAP
value and use the TPS to control fuel delivery. Replace the MAP Sensor.
35 ISC valve Idle Speed Contro error. Replace the ISC.
41 EST circuit No distributor reference pulses to the ECM at specified engine vacuum.
42 Electronic Spark Timing Electronic Spark Timing bypass circuit or EST circuit is grounded or open. A bad HEI module can cause this code.
43 Electronic spark control unit The ESC retard signal has been on for too long or the system has failed a functional check.
44 Lean Exhaust Check the ECM wiring connections, particularly terminals 15 and 8. Check for vacuum leakage at the carb base
gasket, vacuum hoses or the intake manifold gasket. Replace the oxygen sensor.
45 Rich Exhaust Check the evaporative charcoal cansiter and it’s components for the presence of fuel. Replace the oxygen sensor.
51 PROM or MEM-CAL Make sure that the PROm or MEM-CAL is properly installed in the ECM. Replace the PROM or MEM-CAL.
52 CALPAK Check the CALPAK to insure proper installation. Replace the CALPAK.
53 EGR Valve Exhaust Gas Recirculation valve vacuum sensor has received improper EGR vacuum.
54 M/C solenoid The mixture control solenoid voltage is high at the ECM because of a shorted M/C solenoid circuit and/or faulty ECM.
55 ECM Be sure that the ECM ground connections are tight. If they are, replace the ECM.

Component replacement may not cure the problem in all cases where recommended. For this reason, you may want to seek professional advice before purchasing replacement parts.

OLD SKL 69

Thanks Rob! I saved it to my computer, I figure it will come in handy with the Delta I just got.

Lady72nRob71

And BTW, the OIL light is the "OH SH*T" light!

To you, the Check engine light is just the "F*** you" light.
To the repair shop, the Check engine light is the "Gimme all your money" light...

auto_editor

My "oil" light actually reads "OIL/CHOKE," though it's never referred to as having ANYTHING to do with the choke in any of my manuals (even that WORDING isn't mentioned). On my drive home from where I purchased her that oil light was flickering while driving and steady on at idle. I put a quart of oil in and it went away (for a while).

I got a discount on her as the guy who sold her to me thought the oil pan gasket was leaking (she dripped oil steadily), and he didn't want to incur the cost of repair. Turns out there was a fat crack in the oil sender unit, and once that was replaced, the oil loss--or most of it--stopped.

But a NEW mystery has taken its place: After driving for a while--mostly on the freeway--as you slow to a stop (on an off-ramp, for example) her idle gets lumpy and the oil light flickers. The second you give her gas, though, it goes out and the engine purrs like a kitten.

This can keep happening after the initial stop for a few minutes, but after that she behaves like she did before the long drive.

WHY???

It's just spooky enough to make me want to drive on surface streets alone, as she doesn't act up at all "in-town" no matter how long the drive is.

Is engine-heat related? The oil pump? Martians? Throw me a clue here, people!

Drew

[Oh, where are my manners. Thanks VERY much for the code info. Judging by the parameters of those codes I can think of several that could have likely caused the light, though nearly all of them aren't--as you said--"Oh Sh*t!" issues...]

Lady72nRob71

Sounds like you are losing oil pressure when the idle gets lumpy. Kinda normal, depending what the RPM drops to. Switch closes below 4psi. Need to get that lump fixed.
Maybe install a mechanical oil gage temporarily so you can see what is going on.

None of the 307s in '86 used the choke light, as it was for the 3.8 V6 only.
If your 89 307 has little pipes coming out of the choke housing on the carb, then the light is for oil only in that year, too.
GM probably had plans to add electric choke to the 307's but never got around to it, or perhaps the stardard ones were found to be reliable enough!

Rickman48

Exacty the same used to happen to my '86 GP 2+2 w/ a 305!
Cruising down the x-way after about 15 miles - it'd come on!
I'd put it in neutral, turn the key off, [at 65] turn it back on, and put it back in gear - stayed off for the rest of the trip, anyway!

auto_editor

I don't know if this shows anything but it's really cold outside and I can't re-shoot it until tomorrow. Anyway, here's the choke/carb topside overall:



And here's a closer (and clearer) version:



You can only see the little figure-8 fitting (top/far left) that connects the spring-loaded rod to the choke "butterfly".

I don't think it's "computer controlled" or anything, but it might be. I'll get better pics tomorrow. But even if you have a "hunch" now, it'd be good for me to hear it as I have been putting off a long-ish drive for almost two weeks now.

[My son knocked my rearview mirror off the windshield with his head while climbing into the car. The glass is fine--aside from some remaining adhesive--so Safelite will re-attach it for free so long as I go to them. But they're a half-hour's-worth of freeway driving away.]

Drew

Lady72nRob71

You will have to pull the air cleaner up to look at the choke mechanism (on RIGHT hand side) - there will be a round black cover.........

oldcutlass

Well to start with I believe you have a pcv / and or vacuum leak with a bit of blowby thrown in!!!! The pic of the air cleaner and carb is that before the engine was warmed up??