GLHS Power Loss Light On

[cqlink]

Just starting to learn about the electrical system in my car ('86 GLHS). Picked it up from the shipper today and noticed the "Power Loss" light is on.

Can anyone tell me what this means and what impact it has on the car?

The only insight I can provide is the car runs fine. Boost seems a little weak (but I wasn't pressing it) and the previous owner just changed batteries.

I'll try doing a search in the interim.

Thanks

[cqlink]

OK...Looks like I'll need to do the "key dance" and get the codes.

This was the 80s version of the "check engine" light?

[NAJ]

Let us know what code(s) are present

[cqlink]

Just received word from previous owner that he had codes checked and one code was the "Charge Temp Sensor." He mentioned the location is above or behind the two-piece intake.

Can anyone let me know what this is and how to go about replacing? Does anyone have a source for the part?

The previous owner suggested going with a new Nippandenso alternator too. That would seem like the easiest and first thing to check and replace. Would that be the best alternator to use or are there better options. Does anyone have a PN or part source for a good alternator?

I'm going to double check the codes this morning to see if there's anything else.

Thanks!

[cqlink]

Hi again.

Just pulled the codes: 15, 23, 55

If 55 is similar to to the other Chrysler's I've owned, this signifys the end of the code sequence.

Any tips as to what the 15 and 23 mean and how to fix would be appreciated.

Thanks!

[NAJ]

15 is Vehicle Speed Sensor Circuit
23 is Charge Temp Sensor Circuit
55 is End of Message

Does the speedometer work? The wiring from the speed sensor splits to the cluster and the engine controller. If the speedometer works the sensor is probably fine and there is a wiring problem from the sensor to the controller, if the speedometer is operating the sensor or wiring may be at fault.
Chrysler wants you to use a scanner, if you do not have access to a scanner the wiring will have to be checked by hand with an ohmmeter for opens or short.
According to Alldata your ACT sensor is located on the back side of the valve cover next to the detonation sensor(single wire). It is a 2 wire connector.
Very simple to diagnoise, unplug the connector and with the key on probe the 2 terminals with a voltmeter, you should read 5 volts, if so replace the sensor, if not post back.
Let me know what wiring, info you need.

[cqlink]

Thanks NAJ!!!

If I'm reading correctly, I have to check two things:

1) Code 15 = Speed Sensor or sensor wiring to the engine controller

2) Code 23 = Unplug connector and check for 5V. If I don't see 5V -- replace CT sensor?

As this is my first GLHS, I haven't had a chance to get under the hood and I'm not sure if my service manuals cover the 86S. Where is the engine controller?

Do you know of any part sources if I need to replce the sensors?

I plan on getting into it a little tonight and hit it hard on the weekend.

Thanks again!

[cqlink]

Also, the speedo works fine!

[NAJ]

#2 is incorrect, if 5 volts are present the wiring and controller are good.
The controller sends out 5 volts and it checks to see what comes back on the signal return line and by that it determines intake air temp, the ACT sensor is a thermistor, the hotter it gets the lower the resistance becomes. When you check with the connector unplugged there is no resistance so your reading should be 5 volts.
Coolant Temp Sensor operates the same way. Also MAP and TPS, they are variable resistors (3 wire) with a 5 volt reference, signal line and signal return line, but you still check the 5 volt reference and signal return(ground) the same way.
If the speedometer works it is more than likely a wiring problem, either an open, short to ground or short to power, also check the connector thoroughly to be sure the terminals are not damged/broken in the connector.
You have 2 controllers, the power module that is located underhood by the battery and the logic module that is located behind the R/S kick panel inside the car.
I do not know if the sensor is available aftermarket, I usually just check Autozone/Advanced Auto(parts america)/Napa online and look up my own parts.
You would have to call your local dealer to see if it is available thru Mopar, if they say it is not get the part #.
If you need the system wiring let me know, I can post it in your thread or e-mail it to you and you can print it out.

[cqlink]

Thanks for the quick response. If you can post the system wiring here, I'd like to check it out. You can also send to Messina57@comcast.net. Whatever's easier.

You've given me a good place to start!

[NAJ]

I will post the wiring in your thread, you will have it this afternoon.

[NAJ]

[NAJ]

[cqlink]

Thanks again for the help RAJ. A few other questions...

1) My RPM gage just died. Is this related?

2) I took a quick look behind the valve cover to see if I could find the wires you referred to but all I could see initially was a a harness back there. Didn't have much time to lift it up and see what was underneath. Am I in the right place?

3) While you may have mentioned it, am I tracing the wires back to the logic module or the power mod? I did see a nest of wires poking out from behind the kick plate. Not sure what the previous mechanics were working on but it looks like a mess. Guessing those wires will need to be checked soon.

Thanks again!

[NAJ]

Not sure where the ACT Sensor is located on an 86, I can only go by what Alldata shows.
They say rear center of engine above fuel rail.
Chances are the tach problem is not related, it is common for the tach's to stop working or work erratically, usually a problem with a cracked solder joint on the circuit board.