92 LC running rich (High CO and HC) failed emissions...

[CJ the man]

Check your throttle position sensor. I can see where it might think your throttle was further open than it really is, and dump a ton of fuel in there.
You might want to use a meter and go through the whole range of throttle positions. You might have a bad spot in the middle or something.
Good Luck!

Thanks, I did have a dead spot in the old TPS sensor, but I replaced it about a month ago... It tests per the FSM now too... Had to adjust it when I put it in so it should be fine.

cheers

 

[CJ the man]

Ok... so here's where I'm at. It turns out the code 51 is thrown by hitting the throttle or turning on the ac or putting the shifter in anything other than park or N. This is normal I have concluded. I did some more research on it and Toyota uses this same code on other vehicles. Well that's good.... So I don't think my ECU is the issue anymore. Anyways, I know the forum regulars are probably sick of me by now but I really need to get this damned thing fixed. I'm getting about 7 or 8 mpg. I have inspected every damn part that the ECU senses to control the operating parameters. The damn thing just keeps running rich and I don't know why. I can say that it runs better now that I replaced a few parts and did the timing but It's not 100%. I should supposedly get like 12mpg with this beast. I am about to throw in the towel... Anyone have any ideas?

My throttle body is pretty bad... I know i need to clean it, its on the list of things to do... I just keep thinking that there is something so simple going on and I am just too blind to see it. Can anyone tell me some things to check that could give me some hints as to what is wrong with this time vampire of a car?

Thanks,

CJ

 

[jonheld]

There should NEVER be any CEL illumination under ANY circumstances while the engine is running. If you're getting a code, then there is a failing part or something is adjusted outside its normal operating window. The ECU is spitting back the information with a code.

Some time ago, I posted a complete list of items with OEM part numbers and procedures that should be part of a baseline tune-up. I need to know EXACTLY what you did so far on that list.

This engine and all its electronics including the EFI system and ECU are 1987 technology. There is no magic here.

 

[CJ the man]

There should NEVER be any CEL illumination under ANY circumstances while the engine is running. If you're getting a code, then there is a failing part or something is adjusted outside its normal operating window. The ECU is spitting back the information with a code.

Some time ago, I posted a complete list of items with OEM part numbers and procedures that should be part of a baseline tune-up. I need to know EXACTLY what you did so far on that list.

This engine and all its electronics including the EFI system and ECU are 1987 technology. There is no magic here.

Mr. Held, are you sure about that? From my understanding this code (51) is suppost to illuminate when you have (terminals TE1 and E1 jumped together) AND (turn on the ac OR press the accel OR take the car out of N/Park). This code is to tell the technician "Hey! youre running richer than you should be if youre trying to run diagnostics ya idiot!" or maybe im the idiot and im completely wrong.... But i have found another thread that was for a camary (i believe) and thats what it said... same code, same name, same conditions... which makes sense.

If you could try it yourself that would solve the issue right now!!! Tell me if you get the code when the above conditions are met!!!
Then you can tell me what a moron I am again! Ha! jk jk

as far as the parts I replaced so far:

TPS sensor (had a dead spot in the middle)
O2 sensors
Thermostat (was stuck open)
Exhaust gaskets
Spark Plugs
Spark Plug wires
Dizzy cap
Rotor
Thermo time switch
air filter

Things I have checked and are ok:
MAF or the other name... i forget
Coolant temp sensor
Coolant temp sender (I assume it works cuz the gauge does)
TPS operation (the whole feeler gauge thing)
Fuel Pressure
Compression
IAC valve
Did the timing
Cold start Injector
Ran a bg44k through the tank too

Things I know that need to be replaced:
Brake booster (dont worry i plugged the vacuum leak)
That speed sensor thing for the cruise control that mounts to the drivers side of the tranny
Window washing fluid pump for the rear
Probably the cats
Like to get a new FPR Because pressure is a bit higher than Id like it to be
Like to get a new FPD for good measure
Sunroof glass
Need to clean the intake too, that thing is nasty

So Mr. Held, is this list good enough for ya? Or do you have a link to that list you were talking about? I cant seem to find it on my thread.

Thanks

CJ

 

[jonheld]

You wrote, "It turns out the code 51 is thrown by hitting the throttle or turning on the ac or putting the shifter in anything other than park or N. This is normal I have concluded."

You neglected to mention that you were in ECU test mode. I therefore assumed you meant that a certain CEL code under normal operating conditions is "normal".
I have never attempted to look for a code while the engine is running as that is not specified in the FSM to my knowledge.
All trouble codes listed in the FSM assume that the motor is off and the key in in the ON position.
Shorting TE1 and E1 while the engine is running disables the ECU from auto correcting the ignition timing.

I do not see a valve adjustment on this list. It makes a significant difference in power and economy and the FSM wants it done every 15K miles. If your valves haven't been adjusted in a while, it would be worth looking into.

 

[CJ the man]

Held, do you have any documentation on this procedure that I wont have to pay 70 bucks for?

Thanks

CJ

 

[CJ the man]

Just pulled off the valve cover after letting it idle for about 20 and there is a s*** ton of gas in the oil... WTF?! Im guessing this might be why the thing gets like 7-8 mpg...

I am going to adjust the valves anyway but this is the first time I have noticed this... any ideas?

 

[angerhater]

it may be a bad wire or plug..... a non full burn will leave oxygen in the exhaust which will make the ecu send more fuel to burn up the extra oxygen...check your plugs for a wet cylinder(fuel/ not water) ....

 

[CJ the man]

Still failing emissions... running super rich... Noticed that the egr had a crap load of black soot in it... also another thing i think might be overlooked is that I hear constant clicking intermittently from the frontmost vsv in the line of 3.

Can anyone tell me how to fully check the egr system? or provide a link to it?

 

[CJ the man]

I may have found the culprit... I got the wild idea that if I measured vf1 and started bangin around on s*** in the engine compartment and the ecu, I could see if anything would change the voltage output. Sure enough, the efi main relay was shorted or something, if i banged it, the engine would almost die and the output voltage would go ape s***. So here's what I learned....

Before, the voltage would stay at .06 V with an occasional brief output of 2.25 V, then it would fall back to .06 V... Even with the engine warm

Now, the engine will start cold at .06 V, and then 2.25 V after warm up. Most of the time the output will go up to 3.5 V while I'm revving the engine or it will stay at 2.25. BUT NO MORE CONSTANT .06 V!!!

I got the new relay from advance auto for 35 bucks.. not a bad price for something to cause this much mayhem...

I also looked at the output of the o2's and it fluctuates rapidly between .1 and .9 volts like i read from the manual it should... they used to stay at .9 to .97 V all the time...

So I believe my bangin' around has paid off... to be sure I will retest at the emissions place next Saturday and let you guys know.

Here's some interesting info BTW...

http://alflash.com.ua/vf1.htm

 

[Timpanogos Slim]

Good luck! There's also a known issue with poor contact conductivity on the EFI relay. sometimes it's mechanical (socket slipped down), sometimes it's chemical - hit with a good contact cleaner (like CAIG deoxit (radioshack or electronic supply store or CAIG's website)) and insert/remove/insert/remove several times.

 

[AZ 80]

CJ, mine was running rich (smell raw gas at exhaust, and emissions were borderline , previously much better) it was intermittently stumbling with, lack of ability to accelerate.
I have replaced the fuel pump and sock.
done a tune up, Replaced plug wires, distributor cap, rotor, plugs, and the intake hose!!!!
Changed the fuel filter, twice.
I ran BK44, Chevron Techroline, and Seafoam thru the gas tank many times.
Replaced all the vacuum hoses.
Replaced the TPS and the Air Idle valve motor.
Then I replaced the throttle cable, and accelerator cable.
That same day I cleaned the MAF and really sprayed the throttle body heavy. I then stated the engine. Ran it, then shut it off and sprayed with the throttle plate wide open. (I used MAF Cleaner) Ran it again. After that day my milage shot up to 14mpg highway!! (up from 11mpg), the acceleration was like new. With the new throttle cable the shifts were smooth and aggressive. It ran the best it had for years. Not one stutter, skip or stumble. At first I thought it was the new cables being freer and not sticking.
One month later it stumbled again, a few times. so I cleaned the Throttle body again and the problem went away again. I believe the problem lies with a dirty throttle body. I am going to pull mine off this next week and really work it over. Then clean the EGR port in the intake manifold as well. I wish you luck. My 2 cents.

 

[StewartP]

Running Rich

Hi everyone, FZJ80 has been running a bit rich using extra fuel. So I went to check my o2 sensor (There is only one the the Aussie model) through the diagnostic port under the bonnet. I was receiving a 12-14 volt reading in my multi-meter. This cant be right can it?

I isolated the o2 sensor from the ecu and it seemed to operate normally (have yet to test with lpg) followed the wire back to the ecu and removed from the ecu and the high voltage disappeared.
Hoping someone can give me some where to look, have searched the forums tirelessly and still nothing.
Could it be possible the ecu has failed? No fault codes have been produced, the only code I get is 21.

Help please!

 

[StewartP]

Ok, I now look like a fool, I thought code 21 was for no codes, but after researching again, I find out that its for o2 sensor.
So is it normal to have a high voltage on the diagnosis plug when the o2 sensor goes faulty? is what is coming out of the o2 sensor a + or a - voltage? a little confused.

 

[family 80]

hey guys just bought my first lc and she's running real rich at idle anyway you can see and smell it so planning on 02 and maybe egr to start. im also from co so have to get through emissions to plate her. so curious after the main relay yours went through the emissions and started running leaner would love to hear some recommendations before I start on this thing but really looking forward to building a cool trail rig out of her thanks