OCDan

I think we're just going to sell the car. Aside from not having a TPS, the engine runs well. Being in the PNW, hopefully we'll find some interest. Thanks to azdave and SuspiciousPizza for your advice.

Darn! SuspiciousPizza suggested looking for a throttle body, which would probably come with TPS. I've been using the search terms: EA82 SPFI throttle body on eBay and Craigslist, but suspect that there are better terms I could use, for example specific models and years. I don't have any knowledge of which Subaru models/years had engines that are close enough to what's in my 1987 SPFI GL-10 wagon, to have a compatible throttle body. I would appreciate any advice on that front.

Would the replacement throttle body need to have come from the same vehicle, an 87 GL-10 wagon with the EA82 SPFI engine? Or could it come from other years/models?

Well, no luck finding anyone parting out a SPFI 1987 GL-10. Also came up empty on wrecking yards. I was about to order another Hitachi SERA484-2 from PartsGeek, but fortunately checked their return policy. It is very strict when it comes to electrical parts. I chatted with a rep and asked about the return policy on this part. From that conversation: "If your part fails, we will issue you an RMA number to return the product. Faulty parts and improperly installed parts return decisions are left up to the manufacturers’ rules and regulations . We process the return for you by accepting the part and then forward the part directly to the manufacturer for final approval. In this case, this part is returnable as long as it is due to an error whereby the incorrect part was delivered, or similar cases. Returns are not accepted in cases involving warranties or returns due to electrical failure of the part, or because it burned out due to an electrical failure in the vehicle, or similar cases." Ugh! So back to the drawing board...

I have not done that, but good point. I'll do that. Thanks!

Thanks for the update. It appears that for me, my only option will be to order a second TPS from PartsGeek and test it very thoroughly with a temporary connection to the connector, before cutting wires to replace the connector.

On that photo in my last post, the discoloration on the tabs resulted when I removed the solder to separate them. Regarding the SERA484-10, I was looking at the image here. It appears that the rotation of the throttle would need be opposite of what we need.

Bummer! I tried very carefully to dismantle the failed TPS from PartsGeek. Unfortunately, while drilling out the rivets holding the circuit board to the base, the circuit board cracked in 3 places. It seems surprisingly fragile. Other than the cracks, I don't see any places where the carbon trace is broken. Nor any sign of heat damage.

My electronics skills are pretty basic. So I really appreciate the suggestions. I just checked for continuity across all possible pairings of the R, G and B tabs, on the inside of the module. It's open on all of them. As expected, when the contact on the idle switch is closed, LG to B shows continuity. I'll go ahead and open it up and let you know what I find. Crossing my fingers that the SERA484-10 can be adapted for our application!

Thanks for your reply azdave! No, the connection stays open through the whole sweep. Thanks for the offer to bench test it. What would that involve? Just wondering if, with guidance, it's something I could do. The FSM Fuel Pump Circuit diagram contains this section on the TPS. Presumably, the new TPS circuit is the same... I do have a good multimeter. Thanks again!

I have a 1987 GL-10 which I haven’t been using and decided to gift it to a friend in need of an inexpensive vehicle. I’m helping him resolve some issues with it. It’s getting a 31 code. The TPS is the 4-wire type. Without going into detail, the original TPS was irreparably damaged during removal. Based on information posted here https://www.ultimatesubaru.org/forum/topic/153231-1987-subaru-gl-throttle-position-sensor-help/?do=findComment&comment=1283981 I located and purchased this: https://www.partsgeek.com/dpq5225-isuzu-i-mark-throttle-position-sensor.html with part description “Throttle Position Sensor - 1989 Isuzu i Mark - Walker 1272-06053178” This is what it looks like: And internally: Box label: Prior to cutting any wires, I checked resistance as described in the EA82 FSM: And measurements were within specs. So, I took a leap of faith and cut the wires on this new TPS and on the engine side connectors and soldered in a new connector on each side. I installed the TPS and double-checked the resistance on the TPS pins and everything was still within specs. So, I went ahead and connected the TPS to the engine side connector, reinstalled the components and belts which had been removed to gain access to the TPS screws. The engine started on the first attempt and was running smoothly. After it had been running for a few minutes, the RPMs suddenly jumped from around 1000 to around 2000. At some point, the CEL came on. I looked at the ECM light to see that it was blinking 31 again. I pulled the connector to check the resistance on the TPS. There was no longer any continuity at all on any of the pins, regardless of the throttle position. At this point, I don’t know if the part just failed due to some defect, or if it was somehow damaged by some condition when the engine was running. Regardless, it can’t be returned to PartsGeek, due to my having cut off the original connector. I’m fairly certain that I matched wires correctly between the 2 sides. The engine side harness wires have the following functions: I measured the voltage on the red and it is 5 volts. Red goes to red, black to black, green on the engine side to white on the TPS side and blue/green to blue, for the idle switch. I’m hoping someone might have some ideas on how I can troubleshoot this. Can you think of any scenario which could have caused the new TPS to fail? Without knowing, I’m reluctant to plunk down another $210. If I do go that route, I’ll temporarily use its existing connector with alligator clips on its tabs. That way, if it doesn’t work, I could return it. I would appreciate any advice!

Cleaning and lubricating the slide pins seems to have solved the problem. Thanks for your help!

Yes, I did check for bearing play and there was none. I did as you suggested with a wood block. Both pistons did extend and make contact with the pad. Could insufficient lubrication in the plungers be the cause of what is happening?

I've owned the vehicle for 6 months. Almost 1 year ago, previous owner had a shop replace front left wheel bearing as well as left and right calipers, pads and rotors. A couple of months ago, I replaced the front right wheel bearing. Suddenly yesterday, we started getting a grinding sound from the front drivers side. It mainly happens when braking and it isn't constant. It also happens occasionally when not applying the brakes. When it does happen, it feels as if the brakes are being applied lightly. I've pulled off the wheel and removed the caliper assembly and rotor. I did not find any debris or damage to the rotor. Nothing unusual with the brake pads, plenty of life remaining, with uniform thickness end-to-end and side-to-side. I did notice that one of the two pistons in the caliper was extended approximately .25" more than the other. Also, on one of the plunger rods, the little protective boot was not attached at the outer end, and the grease inside is pretty dry and dirty. I'll clean them up and put new grease on them. I would appreciate your advice.

Thanks to both of you for the information!