Thesatelliteguy Posted November 7, 2014 Share Posted November 7, 2014 1990 legacy ej22 from an automotatic trans. installed in a 69' VW baja bug using stock computer. 1. At 100% throttle the engine just kind of studders, like its not getting the right fuel/air ratio or bad spark timing. It does this at any rpm or engine temp. If i lay into the trottle its fine until i get the pedal to the floor. 2. It starts right up in the morning but idles high, about 3000 rpm, then slowly comes down to about 1000rpm. After that, if i just barely tap the throttle it shoots back up to 3000rpm then slowly comes back down to 1000rpm. It only does this when cold. After running for about 1 min. it stops. 3. I noticed that i can pinch the idle control valve hose completely shut and it still idles. Im a mechanically inclined individual, i just know very little about subarus right now. Quote Link to comment Share on other sites More sharing options...
Twitch de la Brat Posted November 7, 2014 Share Posted November 7, 2014 Failing Throttle Position Sensor Nasty vacuum leak somewhere ECU not told it's not hooked to an automatic any more (there's a simple pin grounding procedure to fix this) Failing MAF Curse of the undead Subaru? Twitch Quote Link to comment Share on other sites More sharing options...
MilesFox Posted November 7, 2014 Share Posted November 7, 2014 Depending on how complete the harness is, the engine needs to see a VSS signal to rev out past 4500 rpm. The IAC is probably not seeing a signal from the engine temp sensor. If this were in its original car, the fans would run constantly if there were no input from the ECU temp sensor. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 7, 2014 Share Posted November 7, 2014 The high idle indicates a vacuum leak. Spray around the manifold with some throttle body cleaner to see if it changes the idle. When the idle changes you found where the leak is. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted November 7, 2014 Share Posted November 7, 2014 Depending on how complete the harness is, the engine needs to see a VSS signal to rev out past 4500 rpm. Good guess but not applicable to the 90 computer. The rev limit w/ no VSS began in 95 with the OBD II computers....(one reason I like the OBD I for swaps) 1 Quote Link to comment Share on other sites More sharing options...
Thesatelliteguy Posted November 7, 2014 Author Share Posted November 7, 2014 1. I tested the tps with back probes on the connector. It read 4.27-4.30 volts with the throttle closed and 0.69-0.71 volts open. These numbers are backwards from what the haynes manuel says, but i read a post somewhere online that said the older tps read that way. I got a reference voltage of 5.15. Do these numbers look off to you? 2. Dam, i hate vacuum leaks 3. I already grounded that pin to let the ECU know its not an automatic any more. It did change that problem but it still idles high. It might be a cursed car. The legacy had some codes before i pulled the motor out of it. a knock sensor and a MAF code. Thanks for your help 1 Quote Link to comment Share on other sites More sharing options...
Twitch de la Brat Posted November 8, 2014 Share Posted November 8, 2014 1. I tested the tps with back probes on the connector. It read 4.27-4.30 volts with the throttle closed and 0.69-0.71 volts open. These numbers are backwards from what the haynes manuel says, but i read a post somewhere online that said the older tps read that way. I got a reference voltage of 5.15. Do these numbers look off to you? 2. Dam, i hate vacuum leaks 3. I already grounded that pin to let the ECU know its not an automatic any more. It did change that problem but it still idles high. It might be a cursed car. The legacy had some codes before i pulled the motor out of it. a knock sensor and a MAF code. Thanks for your help Check your MAF if it already had the code for it. Also, is your intake clean? All of it, not just the manifold... Twitch Quote Link to comment Share on other sites More sharing options...
Thesatelliteguy Posted November 8, 2014 Author Share Posted November 8, 2014 I replaced the MAF with a junk yard one about a month after I got it running in the bug. It cleared the code and ran just fine. I pulled the throttle body and cleaned it real well. Even got that bypas that is cast into the TB that let's air past the throttle butterfly. When I put it back together, that's when the high idle issue came about. I blamed it on me messing with the TPS (I took it off to see what it looks like) but I'm pretty sure I set it back in the same spot. According to the chiltons manule at least. The inside of the manifold was a little dirty. I was planning on taking the manifold off to weld up some holes on it that will never be used and clean and test the fuel injectors at the same time. Quote Link to comment Share on other sites More sharing options...
Twitch de la Brat Posted November 8, 2014 Share Posted November 8, 2014 What did you clean it with? And that bypass is your idle air control valve housing; so if it got chemical soaked it may be malfunctioning, causing your weird idle issues. Do you have a spare ecu to drop in and test? Twitch Quote Link to comment Share on other sites More sharing options...
Thesatelliteguy Posted November 8, 2014 Author Share Posted November 8, 2014 i cleaned the TB with B-12 chemtool and the IAC with sea foam. The bypass i am refering to is inside the TB. I dont have a spare ecu but the local junk yard has a few subies right now. Should i get one and if so, what do i look for to get the same ecu? i heard they are very specific. Quote Link to comment Share on other sites More sharing options...
mikaleda Posted November 8, 2014 Share Posted November 8, 2014 quote name="Thesatelliteguy" post="1257657" timestamp="1415478014"] i cleaned the TB with B-12 chemtool and the IAC with sea foam. The bypass i am refering to is inside the TB. I dont have a spare ecu but the local junk yard has a few subies right now. Should i get one and if so, what do i look for to get the same ecu? i heard they are very specific. You want another auto ecu From the same year range so the injectors operate properly. And are you referring to the coolant bypass on the throttle body? Quote Link to comment Share on other sites More sharing options...
Gloyale Posted November 9, 2014 Share Posted November 9, 2014 He means the small port inside the throttle bore. ECU....you just need any 90,91 Automatic....or any 92-94 Auto or Manual ECU from a legacy. Probably not the issue though... I would adjust TPS to baseline first...so the idle switch is actually closed and making contact to ground when idle........Then reset or replace the IAC. 1 Quote Link to comment Share on other sites More sharing options...
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