davepak

Well @el_freddo I haven't declared it dead. But I thought I'd give it more time and adjustments to see if I can pinpoint something else now that I fitted a new fuel pressure regulator. Ill clean up the MAF again.Oh and regarding those fuel lines...I had taken them all out and blew compressed air on all of them including that weird fuel separator! On that note, Im curious to see if I run the car without the fuel cap and check whether there is hesitation under load or not then... Hmm

@1 Lucky Texan @idosubaru I have replaced the fuel pressure regulator with an aftermarket one with a gauge. I set it to (+/-) 65 psi based on the FSM that indicates a "discharge pressure of 61-71 psi" for a MPFI. I noticed some sort of improvement, but marginally. At one point only I stepped on the gas and it launched forward nicely. Then I went for a longer ride and again it stumbled. My foot is down on the pedal, but the car is showing 500 rpm or less. But it doesnt die, it doesnt fall back. Then it picks up again and it goes forward. Like a WAVE. Which is why I suspected the fuel pressure regulator failing to maintain the fuel demands, or even the fuel pump unable to meet the requirements. Both are new now. And the problem remains. I have canceled the appointment for the yearly inspection as I dont think it will drive steadily. Ill try @1 Lucky Texan method of squirting some starting fluid through the air duct tomorrow I tend to think now about the MAF, whether it is faulty somehow. But the thing is, at idle it remains totally steady, no surging, no waves of up and down idling, it doesnt die.I have to MAFs no changes when interchanging them. Transmission wise..ATF is fine and I hear the gearbox working, changing gears, kicking down, downshifting.. (Just in case, reaching out for a mechanic is just out of the question) No money for that and even worse, no qualified mechanic that knows about this particular type of EA82. Again, I wish it was an SPFI or carbureted. I had both types before. It was a start up and drive-away affair. This one is a "start-up (if it does) and see what's wrong now"

Interesting point. Ill try it later on on the field test. Surely will tell me a lot about the transmission's behavior!

Its just so weird! When revved up, the engine goes smooth, then on the next revved up it sputters, and then it just like "dies" while still somehow turning. It doesnt die completely, it just seems to be running on air. Then it picks up. The problem is, when engaged in gear, eventhough it seems to be smooth, it initially drives, then it goes down to like 600 rpm, not moving forward nor backwards, like "suspended" suddenly it picks up and it goes. It does that mostly going uphill (Under load I'd say?) I've replaced the fuel pump for another brand new one. No noticeable changes. I suspect. Well I suspect firstly that it is haunted. Secondly, I suspect issues with the air/fuel mixture somehow. The thing is, all those systems are fine, in the sense that they operate. It seems as if there needs to be such a precise calibration that becomes unattainable. Ive got sort of a deadline. On friday I have to take it to a mandatory yearly inspection (its overdue for 6 months already) I hope it even drives there. There are a lot of hills there and Im worried Id be going to a certain headache thinking itll let me stranded. Ive got no more budget for any other major repairs. The car is almost worthless even if it was running fine. No way Id hire a tow truck to take it there either, basically, if the car cant even get to its inspection..it means is not road-worthy. Ill do a field test later on today. Next call of action would be to be sold for parts.

@1 Lucky Texan this was a grear suggestion, I had left the transmission unattended sort of speak. But I checked the ATF fluid and its full. Somehow I thought of this as plausible place to check. I checked the differential oil and it shows HALF mark. Although I don’t think the differential oil has much to do with the stalling going uphill. I would think low ATF pressure will have a negative effect. So I continue to scratch my head!

@idosubaruI have just came back from the garage and: The car starts up right away, steady on 1000 rpm until engine warm-up. And it stays there. I have set up the idle at 1000 rpm as it seems to be "happier" there. I can though set it at 800, 850, 900, 950 it wanted to. I'm sure the car is running better now because: 1. It didn’t run before. 2. It now runs steady, there is no clanking or knocking. 3. It used to stall and die right away. 4. All major sensors have been replaced or tested. I have now tested the throttle position switch following the FSM. Where the contact points must indicate resistance or not based on the movement of the throttle. It passed the test. I have just now placed another brand new pump. And it worked. The only thing with the now 3 fuel pumps I have is that they kind of "whine" all three pumps whine and it is annoying and kind of loud. It's bothersome in the passenger cabin because you can hear that "whiiineee". I have checked the fuel pressure regulator and there is no wetness on the vacuum line. I have massaged the wiring near all sensors and no changes in engine behavior were noticed. I'm guessing after all it is an old super-sensitive (and sensor-laden car) that struggles to reach standard operation due to its own convoluted complicated arrangement. Oh and its the infamous Automatic 3 Speed Gearbox (as if all other issues weren't enough) I wish it was a simple carbureted one. Less wires, just start and go.. **sigh**

So this is where I am now with the car. I replaced the fuel pump for an aftermarket one, can't say I see much difference in fact the aftermarket seems to whine more than the stock one. But it works. I checked the fuel pressure regulator and as @idosubaru mentioned, I checked the vacuum hose for fuel wetness, it was dry. I adjusted the igntion timing to the dot! The procedure included removing the vacuum hose from the distributor, removing the wiring connector for the distributor too, engine warm at 800 rpm and setting it at + - 25 degrees BTDC. And I got it dead on. I cleaned and tested the fast idle solenoid too. I inspected vacuum hoses and main air hose for cracks or leaks. None found. The car has got an impressive idle and smoothness. BUT When going uphill it boggs down. It is almost comic, because say my foot is on the gas pedal and the car is just bogging at 600 rpm, neither going forward nor falling back just "stuck" there clearly struggling, as if "something" is missing preventing it from ever going "free." Then, at one point it clears, RPMs pick up and it goes. Im really scratching my head with this! And again, I notice that when I am going uphill, that's when the struggling starts, I have to wait, keep the pedal on and wait until it "clears." Another thing is that this happens under load, when I have the car on idle, parked and I depressed the gas pedal, it runs fine, in other occasions it sputters a bit but generally runs smooth. However, when I actually drive it and I have to go uphill, bam! It won't go smoothly, stalls, boggs and only after a while it clears. Any suggestions based on these symptoms? Thanks!

This is an area I haven't worked much on, but I had bought an aftermarket fuel pump and an adjustable pressure regulator, the plan is to fit both of them and see if this solves this hesitation problem. What I've noticed is that the car is working smooth and at some point when hitting the gas it sputters and it "drowns" so I have to stop the car, keep the gas until it picks up again, as if it had a carbbed engine and there was dirt that needed to be passed through.. @idosubaruyou mentioned to check if the vacuum hose was wet.. Meaning "fuel wet" where the pressure regulator might be faulty?

I had an old GL SPFI... that thing ran without any issues. Engine leaked, all battered up, but it ran. In fact, I kept THAT car's fuel pump, and I fitted it on the XT. I wonder if the pump struggles to meet the demands on the XT now. Also I saw mentioned about the fast idle solenoid..could that be a culprit somehow?

Good idea, I actually brought one fuel pump from abroad. I'll replace it next week.

Thanks a lot Bennie! It's a big improvement no doubt. But.. There is hesitation.. Bogging, sputtering mainly under load. I'm suspecting the fuel pump. It has the fuel pump of an old EA82 SPFI I used to have. I wonder if the fuel pump fails to meet the demands of a MPFI..? I'm checking in fact posts on USMB to see if someone has had the same issues..

**Happier update! ** Well, it looks like the FrankenSubaru is alive. These are the latest updates : -I got the new ECU a remanufactured unit by Standard of Canada. -Following advise, I changed the oil and also flushed the cooling system and replaced it with ready mix Coolant. -I completed a brand new wiring installation for the radiator fans. This included fixing the auxiliary fan (for the AC circuit) and the wiring for a main fan with a separate relay, yet both share the same signal from the thermo switch, making them start simultaneously but fed from different sources. They work spot on, by the way, the thermo switch is for a Hyundai that opens at lower temperature than the standard Subaru switch boiling hot head gasket killers! -I found injector #4 leaking again. It was working but there was a leak around its base. FGS! So I got another injector from the junkyard. This one worked fine. -I found green corrosion on the connector of the throttle position switch. I cleaned it both connector and leads. And did the same for the MAF's connector and leads. With these fixes done the car started right away and to a somewhat smooth operation. So I worked on: -Idle adjustments, this was really a PITA, that included swapping a MAF, throttle cable adjustment, idle screw adjustment, ignition timing, new rotor and distributor cap. -Next is a second "field test", as I went for a spin around the block and noticed that dreaded hesitation and sputtering when going uphill. At this point it SEEMS better and more stable at idle, and when ramming the gas. Early conclusions: I'm yet to really know what was the real problem in the first place. I went through so many systems and so many fixes, that I just wonder if this car is so sensitive, complicated and badly aged, that it developed all these problems. After all tests I'm overdue to take it for the mandatory yearly inspection so it's street legal. That'll be next week most likely. Early thanks to all the great USMB members that helped me out! Special thanks to @idosubaru @DaveT @naru2 @john in KY I'll post more updates soon

** Sad update ** After trying the result wasn't good. The car started for some time but then Harness on Injector #4 SMOKED. Injector #4 is now leaking the pressure of the fuel pump. The car died. I tried again and then I heard an awful clank from the engine. I tried a few times and now it won't start, actually, it won't turn. Maybe a valve? Maybe I'm actually not sure. I might be declaring this project a totally fried XT.

Happy holidays to you all! @idosubaru @john in KY @DaveT @el_freddo @naru2 This is where I am now : I fixed the alternator's wiring by adding the line labeled "S" that stands for "voltage sense" this was cut and left on the side. I reattached the wires I had cut suspecting they were shorted. These wires were all fine all along. I prepared 4 new injector harnesses by cutting the old ones and soldering the new ones then using heat shrink on their solder joints. I fired it up. It started. But with a clanking noise, I let it run for a good 10 minutes. And then I noticed it smoothed out, at first it was like a wave, it would run ckanky then I would hear the typical EA82 purring. In the end it really seem it got a lot better. I noticed injector #4 still leaks fuel, but at a lower rate. When putting a long screw driver it sounded as if that injector 4 was clicking. The computer (damaged after a short when attempting to find the injector pulses) works good enough to run the ignition and distribution and in fact, it gave me code 42. Very clear 4 long pulses and 2 quick ones. Reading about it, it is related to "Injector" stuck open or closed. Which makes all the sense considering all the issues with injector 4. Perhaps that injector is faulty despite thought of being fine otherwise. However, reading on USBM, someone mentioned that code 42 refers to "Idle Switch" this would be consistent with the car's behaviour now. After the auxiliary air valve was released of keeping the idle still, the car couldn't maintain an idle any longer. The suspicion now is that the pin in the ECU that controls the iddle switch is fried. (Most expected) With all this, I'm calling it a massive improvement! The next actions include an oil and filter change, a swap and test of the injector #4. Waiting for the new ECU that is on its way. And fixing the relays for the radiator fans. Yes, I eliminated the fan clutch and placed 2 radiator fans. However I need a separate relay for the now main fan. It drags too much current for the current auxiliary radiator fan. I'll keep the updates coming

The rubbed / torn wire is position "A" from the alternator to fusible link #4 (1.25). And it was strangled by position "L" that heads to the "Charge" indicator on the digital meter out of the alternator. Might not be a culprit but for sure does not look good. I found wire "S" that heads to fusible link #2 (0.85) from the alternator is disconnected. I will fix the connector properly the next time I have a chance.

This is where I am at the moment. @john in KY @el_freddo @DaveT @idosubaru Checking all wires in the engine bay. I found a torn exposed wire related to the alternator and a couple of "orphan" wires. At one point the car blew the fusible link perhaps associated to the starter or the alternator. So the fault could be there. Even the alternator could be the culprit, it could be shorted somehow now that I think about it. The injector harnesses look fine although I will put new harnesses and verify that they aren't shorting each other afterwards.

You know what @idosubaru Im gonna have to take your offering on that diagram as I dont see it exactly as you described it. I'll PM

Got it. Will take it from there. I'll post the updates

Yes. The FSM I've got them all. I'm looking at "injector connector" and their colors and designations. I'm once again suspecting something in these wirings. Perhaps a not known wire that affects the injectors and might be affecting the feed of the battery from the fusible link. I have injector harnesses and plenty of wiring. The plan is to fabricate a new section for the injectors while checking the wires running along those wires. Maybe the fast idle solenoid, maybe the positive feeds from the battery.. Thanks for the input once again. I feel I'm gonna get this darn issue one way or the other!

Hmm this is something to consider then. My plan is to open up all the wiring from the injectors to the main engine connector and inspect them. The section from ECU to the main engine connector was fine. And Ohm tested. I figure is more likely that from the injectors (including the harnesses) to the main connector there could be a problem since this section is widely exposed to wear and tear. I know about the file limits. *sigh* so I tend to convert the pics to very low resolution to say 110 kb and the like. Otherwise it wouldn't let me upload anything!

The next thing I will do (probably after the holidays) is to redo the entire wiring from the engine that feeds into the engine connector number one. That'll be injectors, thermosensor, oil pressure, radiator fan etc. I'm beginning to suspect the culprit might be associated with the live B+12V coming from the fusible link that feeds all injectors but somehow it is shorting with the injector #4 ECU pulse. This could answer a fusible link that kept blowing a while ago and I thought it was the alternator circuit. I reason this now as I have seen that the wires from ECU to the engine bay are fine despite being under a smelly carpet and after having tested them for circuit and resistance.

Yes, Ill try that, especially now that I have seen the location of the ECU pins for the injectors

Gotcha! Yes, Ill run some more tests this week..have no choice

I wonder now whether the pairing of the injectors differs from the location of the cylinders. I mean this: Location of cylinders: Front 1. 3. Of Engine 2. 4. Fire batching by injectors?? 1 + 3 2 + 4 If this were to be true, perhaps the contact /resistance in Ohms I'm seeing between ECU wires for injectors #3 and #4 is somehow normal, maybe this means there is a contact between them (#3 and #4) while #1 and #2 are "closed" and the ECU opens these signals in pairs, but not by cylinder location (as I've thought) but by batch firing order instead? Therefore keeping for example : injector #1 and #3 closed while injectors #2 and #4 are "open" / "touching" as part of the firing signals the ECU sends? What do you think @idosubaru @naru2 @john in KY @DaveT @el_freddo