Idiot light question

[White Lincoln]

On my Cougar's OBD1, if you get an intermittent Check Engine light, does the code stay or does it get cleared when the light goes off? I have yet to check my codes. I thought I would ask this first since I think I still have a code for rich fuel.

I will be driving around doing errands, not running the car hard, keeping the speed, etc, etc and the light will come on after a while. Sometimes it will clear on the way home, other times it does not. But it is never there when I start the car cold.

 

[theterminator93]

It should store it in memory. If you ground the STI on the DLC under the hood, it will blink the code(s) stored for you via the light.

More: https://forum.birdcats.com/threads/obd-i-self-tests.775/

 

[White Lincoln]

That is interesting! That is the first I have heard of that. Thanks Term!

 

[White Lincoln]

Turned out to be the same code I have had for a long time. 137 / 173 - O2 too rich. It was interesting that light went on today and the car was rather sluggish. Once the light went off, it got its pep back. And that was full AC in heavy traffic. Other than that, the car is running great and a joy to drive.

 

[Grog6]

Datalogging is the only way to find those problems. See what changes when it sets the code.
Have you ever seafoamed this car? If not, start there. On Lazarus, my process was to do it every spring.
Seafoam intake,change oil,air filter every spring,and inspect everything.; and do O2 sensors, plugs, wires and coolant every 3 years.

 

[White Lincoln]

Datalogging is the only way to find those problems. See what changes when it sets the code.
Have you ever seafoamed this car? If not, start there. On Lazarus, my process was to do it every spring.
Seafoam intake,change oil,air filter every spring,and inspect everything.; and do O2 sensors, plugs, wires and coolant every 3 years.

I did run seafoam once. Don't remember how long ago. I still have the special long curved tube you put inside the throttle body. Is this like pouring water down a carb to burn off carbon?

Thanks Grog.

 

[theterminator93]

I don't know that there's a way to log live data from an OBD-I EEC-IV...

Try running the KOEO and KOER diagnostic tests, sometimes they can be quite helpful.

 

[Grog6]

Once again, I think everything is a 96 4.6, lol
Odb1 sucked; my firebird was odb1, and after I rebuilt it, I never got it running well; adjusting the timing was off either in the morning or afternoon, but needed a distributor turn either time.

 

[White Lincoln]

I don't know that there's a way to log live data from an OBD-I EEC-IV...

Try running the KOEO and KOER diagnostic tests, sometimes they can be quite helpful.

I am using my Snap-On MT-2500, ran both KOEO and KOER and same error, 137-173. Sorry, OBD1 kinda sucks compared to OBD2.

 

[White Lincoln]

Once again, I think everything is a 96 4.6, lol
Odb1 sucked; my firebird was odb1, and after I rebuilt it, I never got it running well; adjusting the timing was off either in the morning or afternoon, but needed a distributor turn either time.

That really sucks. One other thing I can think of, and I mentioned this before is that I have gas fume smell from the canister. Sometimes bad, sometimes very faint. Which says there is excess fuel somewhere. The smell could be the A/C right at the same area of the canister (front passenger side, headlight / air intake area). I did replace almost the whole A/C unit a year or so ago. I should not have any leaks and it still works great!

 

[Grog6]

Gas smell near the airbox is usually the fuel vapor lines to the charcoal canister.

 

[White Lincoln]

Gas smell near the airbox is usually the fuel vapor lines to the charcoal canister.

Correct. But does that mean it is clogged and needs to be replaced after 30 years? Or is this normal? I wish I could describe the smell better.

I wondered if I had a vacuum leak there and part of my issue with running rich. I sprayed brake cleaner around that area, but the engine did not change any.

 

[Kidd-7]

Potentially still a leak. If I'm correct the EVAP only pulls fumes in when hot and maybe some other criteria. So if the EVAP valves were closed when you sprayed brake clean it may not have sucked any into the intake.

 

[Grog6]

Brake cleaner is not good for that; it'll eat your maf. the cheap stuff is a chlorinated solvent. crc isn't. propane or starting fluid won't.

 

[White Lincoln]

Brake cleaner is not good for that; it'll eat your maf.

I have only used MAF cleaner on my MAF. I have never sprayed brake cleaner into the intake, just around the vacuum lines.

 

[White Lincoln]

Potentially still a leak. If I'm correct the EVAP only pulls fumes in when hot and maybe some other criteria. So if the EVAP valves were closed when you sprayed brake clean it may not have sucked any into the intake.

Good to know, thank you.