No DTC codes listed. One thing I noticed is Bank2 O2 appears to be dropping in and out. On the A/C data I can't really tell if it's integrated, as I'm not sure what data is null returns from the PCM.

 

Downloaded the file. You did a good job.

Preliminary look shows no activity of any kind on the A/C sensors/parameters. I would say they have the aftermarket A/C set up independently. A/C request and A/C clutch never indicate they are operational. A/C pressure and temperature are based on the fact there is nothing attached to the PCM. The absence of the sensor presents infinite resistance or very high voltage to the pins on the PCM, and the numbers displayed are based on the scalar for those very high values.

What are you looking at that seems to indicate the B2 O2 sensor is "dropping out"?

At idle, the PCM uses Cell 16 to store the long term fuel trims. the left bank (B1) is adding 18% extra fuel. The right bank (B2) is adding 12.5% extra fuel. That is the response to a perceived lean condition. I need more time to look at things in more detail.

 

I also took a look,, the ST trims look OK but the LT trims show lean as Fred mentioned. The B2 O2 looks good as the ST trims stay between 128 and low 130's. Do not know why the LT''s are reading so lean. Maybe a reset to 128 reset and start over may give more info. I agree the A/C does not look like it's integrated into the PCM. A/C temp at 20*, pressure at -13 PSI, pressure sensor at 0.02 volts,clutch off and no A/C request from the dash switch. The High and Low A/C pipes are not stock, mixer valve is not stock looks like a total homemade setup. Are those green wires hooked to a high side pressure switch in your pic, if so does the blue wire from the relay go to the compressor clutch. That may be where to start.

 

I also have a gutted cat, so not certain how that plays into the O2 reading.

On the AC I'll have to find out where to expect to measure voltage when given the AC command from the HVAC console switch. I'll inspect those two switches/relays on my passenger side shock tower more closely and see what I can determine. I've removed and replaced them already years ago by exact part number. I'll trace them down and see where each is going.

I purchased the vehicle in 1998 and it had the aftermarket AC in it already.

 

Cat, or absence thereof, does not affect anything at all in OBD-1. PCM has no way to tell if it’s there.or if it’s working.

Have you checked fuel pressure? Any chance there is air bypassing the MAF sensor? Any exhaust leaks before the O2 sensors?

 

I do have varnished fuel in the tank that's being diluted by premium gas. I have a new fuel filter but I haven't swapped it yet. I had the fuel pump swapped in 2009 and when they dropped the tank I suspect they broke something because I never get a hiss at the gas cap when I take it off. I'm gonna replace the gas cap tomorrow and see if that helps, the one that is on there is old and the seal is cracking. Also, near the EVAP canister system on the drivers side rear wheel well has strong smell of fuel. I've been thinking of pulling the tire again, and the panel, and looking at all the lines that connect to the charcoal canister.

When they swapped my fuel pump, they didn't do something correctly with the float cause my fuel gauge is all over the place. I suspect I'll be dropping the rear end and pulling the gas tank to clean, inspect, and install an new fuel pump and sensor. I won't cut a hole in the hatch.

edit: ps - I also discovered I have an exhaust manifold gasket leak on the passenger side that diminishes as the vehicle heats up and has had a few heating and cooling cycles from being driven.

 

I'm not sure what that is those 2 Green wires connect to, if that's high or low pressure switch. There is a single Blue wire that goes down to the compressor. I can't get voltage to that wire. It goes to the bottom terminal on the inboard switch mounted on the passenger strut tower.

 

Eric, looks like you have a lot going on.... when you get back to the A/C..... you can take a look at page "6E3-A-8 5.7L (VIN P) 5.7" in the 1994 Service manual volume 2 that you downloaded from one of the previous posts. You s/b able to grab the +12 volts A/C switch on from the dash on the Dark Green/White wire going to PCM connector 'B' pin B1. Page 8A-64-0 of vol 2 has the switch schematic. This will tell you if the switch is wired up Ok W/O digging inside the dash. Page 6E3-A-13 has the PCM connector pin-out for reference. From then on you need to figure out how those relays are wired. Do you have a gauge to make sure you have 134A in the system prior to kicking the compressor on.

 

Yeah it's a restore job and no longer a daily driver. I'm just slowly going through the vehicle.

I don't think that the AC is integrated with the PCM but I'll look. I'm suspecting those wire locations to be empty. This is an aftermarket AC install cause the 1LE didn't come with AC from the factory. I have to find out where the wires from the HVAC control panel enter the engine bay, and also need to find the low pressure and high pressure switches. I've measure 12VDC (was actually 13VDC) on the 2 top center terminals on the relays mounted to the shock tower. However, wherever those relays get their grounds from to energize and route voltage down to the compressor I haven't determined yet.

 

No, don't have a gauge yet. I had the vehicle serviced by midas in 2012 and it holds refrigerant. Haven't checked it since then but I will. I could be wrong but 15yrs ago I wanna say a shop "jumped" or "shorted" the low pressure switch and that made the compressor come on but I could be wrong.

I'm still documenting where all my components are and drawing a schematic. The relays I think have it drawn on the side as well so I'll include that. Getting their coils to energize is the big question.

 

Anyone know what these components are on this AC system?


Two pin connector, and hard soldered line out the top that goes into the airbox.

Other end of the hard line coming off the component.

A copper line from this sensor and also goes down into the airbox.

Under AC return? Where it goes into the airbox.

 

I found out the one on the bottom is a thermal expansion valve.

 

The first one appears to be an evaporator temperature sensor.

now I have to find the high and low pressure switches.