Check Engine?

[MR. BUICK '72]

Here's the problem, almost every time I start the car the check engine light stays on. I let the car warm up a little to see if it goes away and it doesn't. But as soon as I put in drive it turns off. Can anyone tell me why this is? Is it a serious problem?
Any imput would be greatly appriciated. Thanks in advance.

 

[1badTTA]

Nobody will be able ot give you much help unless you pull the code. You can use a paperclip and short 2 pins on the ALDL to get the check engine light to flash the code. The instructions are on gnttype.org or in any service manual along with the malfunction codes. Once you get the code and look it up, post back if you still haven't been able to solve the problem.

 

[b4black]

You're oxygen sensor is probably on it's way out. That's the only sensor I know of that will turn itself off. My truck does this too when it idles, it's on, when I drive, it goes out.


This applies to NA 3.8 as well:

1981-1983 COMPUTER COMMAND CONTROL - Since 1981 (1980 in CA), the Turbo V6 has used a Computer Command Control System (CCC) to control many engine functions. The Electronic Control Module (ECM) monitors and controls various systems that effect vehicle performance. The ECM can recognize some operational problems and alert the driver through the "CHECK ENGINE" light. A SCAN tool can be connected to the computer by using the ALDL port under the dash. The tool will display the output of various sensors (Oxygen, RPM, etc.) and display trouble codes. The codes can also be retrieve by grounding the test terminals on the ALDL port with a jumper (wire or paper clip). Do not buy "code readers", they just fancy (and very expensive) jumpers. This tech page from the Turbo Regal Web Site will explain more: GN/GNX/T-Type Malfunction Codes Codes for Carb/Turbo cars can be found here: 1981/83 ECM CODES

gnttype page
1981-83 ECM codes

 

[MR. BUICK '72]

I want to thank you both for the info. I'm going to try this tomorrow.

Thanks

 

[MR. BUICK '72]

Well, I did the non-scan diagnostic and came up with two trouble codes. I have a Chiltons manual that list and defines these codes. This is what I got.


Code 24; Vehicle Speed Sensor (VSS) circut. The car
must opreate up to 5 min. before this
code will show.


Code 44; Lean oxygen sensor indication. The engine
must run 5 min. in closed loop (oxygen
sensor adjusting carb mixture) as part
throttle and under road load (drive car)
before this code will show.


So what now? Change oxegen sensor and what else?

Thanks for any and all your help.

 

[b4black]

The VSS code is an odd one to get. I would try clearing the ECM's memory by disconnecting the battery for about a minute, then reconnect and see which codes return.

For the 44, I'd start by changing the sensor.

 

[turbofish38]

On the SFI cars you can set a code 24 by power braking(with out breaking the tires loose) for at least 5 seconds. Sometimes revving the engine(rod bearing test?) does this too although the NSS has to show the car is in gear. This might also apply to a NA?

Eric Fisher

 

[MR. BUICK '72]

Well Eric , I don't belive I attempted to do either to cause the code 24 to show but thanks for your responce.


Rich, thanks again for your advice, I'll clear the ECM and see what happens. Although, since the diagnostic, the check engine light dosen't remain on. Is this normal or did something happen?

 

[MR. BUICK '72]

I disconnected the battery for a few minutes to clear ECM. Then reconnected and performed diagnostic. Now the only code I'm getting is 12. Would it be best to change the oxygen sensor anyway?

 

[b4black]

Sorry, I forgot one detail. After disconneting the battery, you'll need to drive around for a while to get the errors to happen again. Some codes could have happened a long time ago and were a one time glitch (this could be the VSS code). Others are chronic and will return. Next time you see the check engine light, check the codes.

Most likely the oxygen sensor code will return. Even if not, it might be worthwhile to change it as the O2 sensor gets lazy. A marginal sensor will not set the code, but not perform well either. A good O2 sensor is important for performance, fuel mileage and emissions.


My truck is doing the same thing. I'm waiting until spring though to change it. Sensors that haven't been changed before can be tough to get out.

 

[MR. BUICK '72]

Well it's been a few days since I disconnected the battery and have been driving around. The check engine light is back on again. I had the chance today to do a scan and came up with one code this time, 24.

Rich I know you said it was a rare code to pop up but this is the second time. Is it bad? What can I do?


Thanks

 

[b4black]

The VSS is located behind the speedometer. You would need to remove the instrument cluster to get at it.

Looking at the shop manual, it looks like a misadjusted park/neutral swicth will cause problems. Do your reverse lights turn on and off like they should? The first step is to place a volatge meter accross the P/N switch terminals and see if the volatge changes between N and D. The ECM may be thinking the car is in neutral when it's in drive.



A couple of thngs you may want to invest in are a 1982 Regal Shop Manual (the '83 is a BIG loose leaf mess) and a OTC Monitor 3, 4, 85 or 2000 scan tool. You can find these cheap on ebay.