2seater

Unfortunately, the other items are an unknown. I have been looking at the "E" body parts book for Buick so I cannot tell in the Olds part bears any relation to the Buick. The BCM number listed, 16137994, is listed as a remanufactured controller. There is also a part listed as the calibrator memory for BCM, 16155458. I don't know where that might lead at this point.

I suspect you will need a junkyard replacement BCM with the Prom from a 1991 Reatta. Is the BCM good and just needs the PROM? A replacement PROM will display the donors mileage and information.

I must admit I have lost track of what the overall issues are with this car. Well, if you have no ECM codes, and you have fuel pressure, then it is likely a spark problem, which will not set a code. It is strange the 042 went away because it still sounds like it has that problem. The next thing to try is run the engine with the MAF sensor unplugged. It may run better or worse, but we are looking for a change. What does ED01, the TPS sensor read at idle?,

I read through the diagnostic section of the FSM looking for failure to enter diagnostics and both relevant pages indicate to replace the climate panel. These are quick photos from the 1990 FSM. The diagnostic tree under #3 indicates replace panel if diagnostics won’t engage and the text on the next page, Chart “C” indicates the panel should be replaced if it displays normal information but will not enter diagnostics proper.

In a perfect world, known good replacement modules would be on hand, BCM and Climate Control panel. Unless there is a wire or wires out of action, A head scratcher.

What does the climate control screen look like in normal operation? Does it display fan speed, inside/outside temperature, air flow indicators etc..?

It would seem it is either the climate control or a BCM issue. The contacts in the climate panel is not uncommon but to stick part way into diagnostic is unusual.

The ECM energizes the fuel pump relay both for priming and for running. The prime we all know is to get enough fuel for the engine to start but when the ECM sees the pulsed signals from the ICM, it re-energizes the fuel pump relay. The switch in the oil pressure sender is a backup to the ECM control and connects directly to the fuel pump bypassing the relay.

Does it still fail to go past Ec? when you press Fan Up? You can read codes but not actual sensor data if that issue still exists.

Something doesn't look right here. The engine should not need to be running to get into diagnostic mode, only key on. But that is beside the point, since it appears the engine was running with indicated oil pressure and rpm visible, and yet the HVAC panel was blank and dark? I don't have my car home to confirm exactly what it should look like at the moment before getting into the ECM sensor displays. Can anyone confirm?? Regarding the cleaning of the HVAC panel. The contacts are inside the little gray buttons. It is similar to cleaning phone button pads or remotes for tv's and such. Everything runs on very low voltages so it doesn't take much. The most common failure mode of the buttons is the ability to raise or lower temperature, but even if it doesn't cure the problem, it eliminates one possible cause. The diagnostic displays are a function of the BCM.

If the HVAC panel is blank, there is more diagnostic information missing. Information is located in the HVAC panel as well as the buttons to change function. Something is amiss in that area. Oil pressure doesn't look too healthy for almost 2k rpm but the pressure sender is a known problem item.

Does the odometer reading work normally when not in diagnostics? That reading is a function of the BCM so ??? I was just looking at the photos again and I notice with the engine apparently running, the HVAC control panel is dark? It should be displaying something if ignition is on.

One other function that can't be accessed is the clear code function.

I cannot think of any reason your diagnostic system doesn't engage except the fan control button doesn't make good enough contact?? If that doesn't work, you are missing a lot of valuable and handy information. Maybe Padgett has a clue?

It should be less than one volt when closed but if the arm on the sensor has not engaged the drive pin on the throttle shaft correctly, it may be stuck at full voltage? If I am understanding correctly, you can access the diagnostics, since it shows an ECM code in the above photo, but the fan control doesn't work to get beyond the Ec? point, correct? That means you cannot step through the various sensor data readings??

It sounds like you could have two separate issues. If all the controls on the Climate Control panel do not work, it probably needs to be cleaned. The contacts inside get dirty over time and cleaning the contacts almost always restores functionality. See here Reatta Owners Journal - How To Clean 1990 Climate Control Panel Use the diagnostic function to read the TPS voltage. ED01 is the TPS and it should read .38-.42 volts at idle position and over 4.0 volts at full throttle. Of course the Climate panel must be operational to use the onboard systems. Edit: Codes that are active will not clear and the TPS needs to be adjusted when it is being installed.

That must be a BCM code, b132 is the oil pressure sender.

The pressure drop is normal as it references vacuum in the intake manifold. If you blip the throttle the pressure should spike upwards in response. 042 is the code for poor communication between the ECM and ICM. The ECM tries to take over the operational ignition timing after the engine starts and there is a problem with that. On a 1990 there is a short harness on the front of the engine that connects the ICM to a connection on top of the engine behind the power steering pump. Disconnect and examine the plug at the ICM looking for corrosion or backed out pins. Hopefully just removing, contact cleaner spray and reassembly may help. Same for the plugs on the ECM, specifically the black 32 pin one. The diagnostic chart is page 8D52 and 8D53 of the FSM.

I have never removed the transaxle on a Reatta, but I have removed the engine numerous times. Once the two items are separated, the torque converter simply slides out of the transaxle bellhousing. It is not fastened in any way but the drive notches (dogs) must be engaged inside the transaxle before bolting the two items back together. There are no new seals or fittings required regarding the torque converter itself. The three torque converter to flex plate fastener bolts are the first thing removed and the last thing installed.

I have no issue with the Allante mixed in here.

I would check with Jim Finn to see about a complete replacement line. There are three plastic lines connected to the fuel tank, 3/8"fuel pressure line, 5/16" fuel return and 1/4" vapor line to the charcoal cannister. Fabricating your own line seems pretty similar to patching it, but it is unusual to get "knicks" in the plastic line?? My $.02

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Opinion only, but I kept mine R12 when I replaced the compressor, (leaking oil). It still had some charge and worked minimally, so I didn't have quite the same dilemma you do. I was able to find a local shop that still had the equipment to recycle R12 but that is getting harder to do. Yes, R12 costs more, but, it isn't like the quantity needed is vast, especially if factored against the other changes required for 134a. I purchased all my parts from Rock Auto, compressor, condenser, accumulator and the correct oil and an o-ring kit. I would think the system will need to be flushed at the very least due to the mismatched fluids used. As long as the system will hold a deep vacuum for an extended period it can be refilled with R12. The shops I know won't do so unless the system is sound, as it should be, since that is illegal.

Correction to previous; yes the year is in the title😞 This sounds similar to what happened with Daves, ironically also an 88, when the crank sensor was loose in the bracket. Terrible behavior but not a constant.

You didn't mention what year Reatta, but do you know how to access the onboard diagnostics? Is the check engine light on?? Is the ICM and coil pack new or salvage yard and is it the correct package? I know that may be a silly question but there are similar setups for some other GM V6's that may not function correctly.