Doom86

13 - Oxygen sensor signal problem or loss

15 - coolant sensor low temperature fault

21 - TPS voltage high

44 - Oxygen sensor lean error

These are what i am getting when i check my error codes. Ive done some work over the last few weeks and just wondered if i should reset and drive then check the codes again? there is still a check engine light that comes on during driving, after its been running a few minutes.

But i did have a gasket leaking where the thermostat is, which was fixed. And also it was bogging down bad when you were WOT, which as been corrected. There was also fuel leaking from the fuel filter, which was fixed. And the radiator fan was also not working and has been fixed (we just ran the wire so it would turn on with the car).

My temperature gauge doesnt work, its always stuck as far up as it will go, even when the car is off.

Im not sure exactly what all these error codes indicate so any help here would be great.

Trickster

Taking care of the code 21 will possibly take care of your code 13 and 44. Your code 15 is a possible bad sensor or wiring. Disconnect the battery to clear the codes and then drive it at normal conditions to see if any codes pop back up and then check to see what they are. If the Coolant temp sending unit is connected and you still have the problem with the gage, check the wiring and replace the sending unit if neccessary.

Doom86

Thanks Trixter.. I took a nice "country drive" (which is almost impossible NOT to do around here.. ) after resetting it by unhooking the battery for a minute and the check engine light didnt come on one time during my 20-30 minute cruise.. Strange.. This light has been coming on for the last 2-3 years.

I've done a big tune-up on it over time, so maybe that helped. I just dont understand why the engine light quit coming on while driving just from resetting it.

Doom86

I meant to ask, where can i find the "Coolant temp sending unit".. Im guessing this is why the radiator fan wasnt working as well.

Doom86

sorry for so many post's.. I searched and found you saying this, Trixter: Is it a green wire as well? i read that too..

Trickster

here is a picture of it, it is located between the #1 & #3 sparkplug slightly above them in the head. You might have to feel around for it since it is a little hard to see. There will be a single green wire with a slide over connector for it. No, the sending unit itself would not have any effect on the coolant fans, that would be the coolant temp sensor. The reason the SES light kept coming on is because the previous codes had not been cleared from the computer.

Doom86

I think i found it, its just under the manifolds, right? Theres 3 green wires running into a wire guard then one splits off leading to the sending unit. sound correct?

The old/cheap plastic harness crumbled in my fingers when i was checking it. Its connected though, it spins around freely it seems.

the guage is reading an "off the scale" temperature, its up as far as it will go, and always stays there.

You think the sensor is not working properly? im guessing thats a pain in the rear to change?

Trickster

Yes the sending unit is probably the problem here and no it is not a PITA to replace. Just move fast to put the new one in because when you take the old one out you will start to lose coolant since it is in the water jacket area.

five7kid

iTrader: (14)

Let's be clear about "coolant temperture" devices: There are 3.

1) "Coolant Temperature Sensor", or CTS. This is what feeds information to the computer, and the only one that can cause a trouble code 15. It is located on the thermostat housing.

2) Coolant Temperature Sender". It provides the signal for the temperature gage. It is located in the driver's side head. It provides a variable resistance to ground, decreasing resistance when temperature rises. If you take the wire off of the sensor and short it to ground, the temp gage should go to full scale. However, if the gage sits at full scale when the ignition is off, it's probably a stuck gage, not a problem with the sender.

3) "Radiator Fan Switch". Located in the passenger side head. When the coolant gets up to the preset temperature, it provides a ground to complete the circuit to the radiator fan relay, turning on the radiator fan.

All three of these are independant. The only thing they have in common is they all sit in a bath of coolant.

Trickster

If he has the dual fan set-up, then that coolant fan switch in the passenger side head serves only as the secondary fan switch. If he has the single fan set-up, then what five7kid says would apply. Also if he is running the 350 TPI (not sure about the TPI since he didn't specify) the Coolant Temperature Sensor would be mounted in the front of the intake manifold below the throttle body.

Doom86

Its carbureted and a single fan radiator.

Driving it today the SES light came on and it was error 21 again. Now its time to find out how to adjust the TPS voltage, i have not a clue what it is, or where it is.

Doom86

I need some advice here, because im working on a "2 kids in diapers" budget.. so bear with me

Would it be more cost effective to replace or adjust the TPS? I dont have the hex tool to adjust it. If i just replace the sensor do i need the tool? Will the new sensor more then likely be working in the right voltage range, with out adjustment? If i need to adjust it all i have is a analog multimeter, with .25, 1, 10, 25+, ranges. Some people say you "need digital", which i dont understand.

The code 15 is back. I was checking out the coolant temp sensor and it isnt in good shape, i think its due for a replacement aswell.

five7kid

iTrader: (14)

It will need adjustment, even if new.

I haven't had to replace a TPS yet, must be especially lucky.

five7kid

iTrader: (14)

Just wait until it's a "2 kids in college" budget...

Doom86

Many thanks five7kid.

I dont even want to think about them going to college yet! whew.... $$$

What i'll try first then is adjusting and if that doesnt work i'll replace it.

Well first, really, i need to check the voltage. I've already read about how it should fluctuate smoothly from ~.48 to ~5 volts (some people say ~4) going to WOT. But my volt meter seemed to have died on me today, i tried new batteries but i couldnt get more then a 2 volt reading from my car battery.

Is the "anti-tamper" plate the little circle plate on the top of the carb, directly above the TPS?

Another question; to remove the "anti-tamper" plate i drill a small hole in it, drive a screw in the drilled hole and yank the plate out by the screw?

Thanks again you all.. This website is a gold mine of knowledge.

Doom86

could someone answer the above questions about TPS adjusting? its a quadrajet, probably the one that was originally in it.


"Is the "anti-tamper" plate the little circle plate on the top of the carb, directly above the TPS?

Another question; to remove the "anti-tamper" plate i drill a small hole in it, drive a screw in the drilled hole and yank the plate out by the screw? "

Trickster

Yes that is the anti-tamper plug and it can be removed by punching a hole in it with a sharp pick or ice pick and pried out.

Doom86

I finally got a new volt meter and i checked the voltage of the TPS with the high-idle off and the engine off but with the ignition turned to "on" and i got a reading of 2.5 volts with no throttle. Opening the throttle to full only made the voltage go to 2.7.

With the wire-harness unhooked from the TPS sensor its giving me a reading of 4.x (dont rember exactly) at no throttle. Should the voltage read the same that it does when the harness is hooked up?

Im thinking that it would be a waste of time to try and adjust it since the voltage isnt even going up much at all and is so high above what it should be at no throttle. Replacing it makes more sense. Does this sound right?

Doom86

help anyone?

five7kid

iTrader: (14)

It's either sticking, or FUBAR.

Sounds like disassembly is in order at least, and probably replacement.