CEL / Climate Control Issues

[limey284]

I have two issues with myJ30t that you guys may be able to help me with.

1. My CEL is on. I had the codes read at a local shop and they could not find a code. They reset the system and the light went away. I drove the car the next and light came back on. Any ideas of what may be causing this? Maybe oxygen sensor? I run on 87 Octane Gas. Should I switch to 93? Will this fix the problem?

2. My climate control is working but does not seem to keep the temperature accurate. The only way to get heat is to turn it to 85 degrees. Cold air seems to work at 75 degrees but keeps cooling the car. It appears that a temperaure sensor maybe bad. Has anyone experienced this problem before?

Any help would be greatly appreciated.

Thanks.

[DominickJ30]

First of all, yes teh 87 gas can make the light go off.

Tank up on 93 and take it out on the highway, should clear the light.

The climate control I dont quite understand you.

What is the temp outside when you try to do this? Do you make it 85 manually or do you push the "auto" or "econ" button?

[limey284]

Thanks for the quick reply.

I'll try the higher octane gas.

The climate control is definitely weird. When its cold outside the interior of car will not heat up unless the temp is set to 85 degrees. If it is setup at 83 degrees I will get a little bit of heat to begin with but then the system will switch to cool air. It appears that system is thinking it is warmer inside the car than it actually is.

Again, thanks for the response.

[Defiant]

I wasn't aware a sub-octane gas could trip a CEL.

Make sure your coolant is full. When cold, pull the radiator cap on the engine and look.

[elwesso]

I wasn't aware a sub-octane gas could trip a CEL.

Make sure your coolant is full. When cold, pull the radiator cap on the engine and look.

i agree

Since when does the car know what kind of gas you run??? There are no sensors on board for ignorant owners!!!!

[DominickJ30]

Since when does the car know what kind of gas you run???

I dont even know where to begin...

[elwesso]

I dont even know where to begin...

fair enough, ill start! Ill go ahead and spell this out..

According to the service manual for the J30 (OBDI), there are 11 codes that will throw a CEL.... In order: MAF, coolant temp sensor, VSS, ECU, EGR function, O2 sensors (L and R), EGR temp sensor, TPS, injector leak, and injector circuits....

Right away we can eliminate all but the o2 sensors.. The knock sensors wouldnt throw a code even if they were retarding the timing, they only throw codes if the circuti is bad... Plus KS wont throw a CEL!!!!!!!!!!!!!! So thats out. The o2 sensors work the same way, in that the only way they throw a code is if the circuit is either shorted or open (really high or low voltage), not if its throwing a goofy signal... Which is why we replace our o2 sensors, because they will still be functioning according to the ECU, but we know theyre bad because we're not getting the fuel economy we should...

None of those is directly related to what kind of gas you run!!! Im not making this up or trying to pull the wool over anyones eyes, im just saying, thats how it is! if somehow you get a CEL and by chance the CEL goes away after putting in premium after running regular, then its gotta be luck or something... Because your car isnt gonna throw a CEL!

Even with the OBDII with the car in question, there wouldnt be any code for fuel.... Or anything even related to that...

So, im all ears if you can come back and tell me how the ECU knows if you run a lower than premium octane! The ECU is made for people who know they should run premium but think its stupid... Thus, for most people they probably wont notice much difference by running regular, even though the car is detonating and the knock sensors are retarding the timing...

now that we got that taken care of, to the original poster.......

For the CEL:

Thats really weird that it wouldnt pick up a code.... Did it give a P0000??? IF it didnt, that means it wasnt communicating properly to the cars' on board computer. Anytime the CEL comes on, it STORES it in memory, even if the light goes out!!!! I would take the car to autozone for a free test, maybe they can get the codes to come out??

Anyway, it does kinda sound like an o2 sensor.. Usually that is what the problem would be, at least on OBDI...

For the climate control....you can do the self diagnosis and make sure the modes are all working... If you think you can do it yourself (just pressing buttons on the climate controller thing), ill post it up!!!

[DominickJ30]

How do you know if he has an obd1 or 2?

First thing first. What year is the car??

[limey284]

The year of my J30 is 1997 with a build date of 10/1996

[elwesso]

How do you know if he has an obd1 or 2?

First thing first. What year is the car??

using my psychedelic powers.... No, actually i just clicked on his profile.