idosubaru Posted July 24, 2008 Share Posted July 24, 2008 1988 XT (NON TURBO) starts and idles very low, stalls some times. all the injectors are pulsing swapped coils - spark looks good fresh gas timing belts were checked multiple times. i've checked the firing order a bunch of times - 1-3-2-4 for firing order - i've seen it said that the "#1 under the distributor should point at the brake master cylinder"......and that is when....when the flywheel is set to 0 or what? is that using the timing marks...0,10,20 on the flywheel? Link to comment Share on other sites More sharing options...
Frank B Posted July 24, 2008 Share Posted July 24, 2008 It could also be the IAC, Idle Air Control solenoid. Try spraying some carb cleaner in it. If not, remove it and soak the hard parts, not the electrical parts of course, in carb cleaner. There's a screw on the throttle body that adjust the air for idle, it looks like a big set screw. Link to comment Share on other sites More sharing options...
idosubaru Posted July 24, 2008 Author Share Posted July 24, 2008 okay, - the idle air controllers are cleanable too. i've done that a zillion times on XT6's but they're a bit different. i don't think that's it, but i can't say why i think that! i'll give it a cleaning. the idle "isn't supposed to be adjusted", right? i'll save that until last unless that's considerable reasonable practice. Link to comment Share on other sites More sharing options...
Gloyale Posted July 24, 2008 Share Posted July 24, 2008 okay, - the idle air controllers are cleanable too. i've done that a zillion times on XT6's but they're a bit different. i don't think that's it, but i can't say why i think that! i'll give it a cleaning. the idle "isn't supposed to be adjusted", right? i'll save that until last unless that's considerable reasonable practice. You can adjust the idle. Just not using the throttle stopper screw. There is an actual idle adjustment screw. There is a flathead screw located on the top/almost center of the Throttle body. Recessed down in a hole. IIRC turning it CounterClockwise will raise the idle. Check page 3 of section 2-7 *Fuel Injection* in the FSM for a diagrham There is also a fast idle adjusment (to raise or lower cold/ AC idle) it is a similar screw, smaller, and on the under side of the throttle body, near the Fast Idle Solenoid. Link to comment Share on other sites More sharing options...
idosubaru Posted July 24, 2008 Author Share Posted July 24, 2008 There is a flathead screw located on the top/almost center of the Throttle body. Recessed down in a hole. IIRC turning it CounterClockwise will raise the idle.oh great, i've seen that. should the throttle plate always be fully closed at idle, that was always my assumption - that's what the IAC is for. a good running engine should never need adjusted right? i did a motor and intake swap so maybe that has something to do with it. Link to comment Share on other sites More sharing options...
Gloyale Posted July 24, 2008 Share Posted July 24, 2008 oh great, i've seen that. should the throttle plate always be fully closed at idle, that was always my assumption - that's what the IAC is for. a good running engine should never need adjusted right? i did a motor and intake swap so maybe that has something to do with it. The throttle stopper is tuned and set to the excact airflow of the engine it was originlly installed on. Only real problem with adjusting it is that you can end up with you're throttle plate wedging closed, and then bending to release. Otherwise if it's open too far you;ll just get a high idle, and the TPS will be off unless you adjust it. Most FI systems, if they do have an idle adjustment, use an air passage type adjustment, rather than a traditional *throttle adjusment* Link to comment Share on other sites More sharing options...
McDave Posted July 24, 2008 Share Posted July 24, 2008 You shouldn't need to adjust anything, the iac motor just isn't working. Same thing probably happened to it as what happened to the fuel pump. Died due to non use. Try tapping lightly on the electrical end of the iac while the engine is running. That may free up the brushes in the iac motor. Link to comment Share on other sites More sharing options...
idosubaru Posted July 24, 2008 Author Share Posted July 24, 2008 thanks Gloyale. Same thing probably happened to it as what happened to the fuel pump. Died due to non use. Try tapping lightly on the electrical end of the iac while the engine is running. That may free up the brushes in the iac motor. good call dave, i'll do that while i'm cleaning it out. will check this stuff out tonight. Link to comment Share on other sites More sharing options...
idosubaru Posted July 26, 2008 Author Share Posted July 26, 2008 this turned out to be interesting. carb cleaner made a noticeable difference in idle so it was obviously a leak. it seemed to make the biggest different right at the intake manifold/fuel manifold juncture. in other words not the gasket where the head meets the intake manifold, but above that a couple inches where the intake manifold meets the fuel rail manifold. it's typically left together as an assembly but it is two parts. awesome, easy fix! i already had those gaskets anyway. wrong! keeping in mind this car was all bolted together with no known obvious issues and ran fine.....look what fell off when i unbolted the intake manifold. the chunk circled used to be in the rectangular area, it was completely cracked off and just fell off when i took the manifold off. so that was my intake manifold leak. Link to comment Share on other sites More sharing options...
McDave Posted July 26, 2008 Share Posted July 26, 2008 That's odd. An intake leak usually causes high idle, but then that is a pretty big leak! Is it the intake that's broke or the head? Car been in a wreck? Edit: I'm guessing it's the lower half of the intake that's broke? Bummer. Link to comment Share on other sites More sharing options...
Gloyale Posted July 27, 2008 Share Posted July 27, 2008 Whoa! That is a pretty bad intake leak. Good news is you might be able to order just that pice from Subaru. Link to comment Share on other sites More sharing options...
Frank B Posted July 27, 2008 Share Posted July 27, 2008 When it's bolted down, it's not that big of a leak, just a crack. Can you weld aluminum? Got some JB weld untill you find that piece to replace it? Or do you not need this car on a daily basis. Link to comment Share on other sites More sharing options...
idosubaru Posted July 27, 2008 Author Share Posted July 27, 2008 When it's bolted down, it's not that big of a leak, just a crack. i was kind of worried about that too, thinking could that really cause it to run bad? but it did rev up with carb cleaner sprayed in the engine bay so i'm hopeful it helps. Can you weld aluminum? Got some JB weld untill you find that piece to replace it?Or do you not need this car on a daily basis. no JB Weld, i'm not convinced that stuff is good long term for automotive fixes. thanks for the suggestions guys, i had it fixed right away. i had another manifold in the garage so no sweat. i saved it in case i ever feel like welding it up. should be an easy weld, though i can't weld aluminum so i'll have a shop do it if i ever need it. Link to comment Share on other sites More sharing options...
idosubaru Posted July 27, 2008 Author Share Posted July 27, 2008 Is it the intake that's broke or the head? Car been in a wreck? Edit: I'm guessing it's the lower half of the intake that's broke? Bummer. it was the lower intake manifold, the head was fine...or i THINK so!!! never wrecked. i had that intake shipped...it either came on a JDM engine i ordered or from an intake i bought from USMB or ebay, so i'm guessing maybe in transit. or i did something to it and didn't know it. Link to comment Share on other sites More sharing options...
Gloyale Posted July 27, 2008 Share Posted July 27, 2008 ........., so i'm guessing maybe in transit. or i did something to it and didn't know it. Maybe not you, but perhaps someone way overtightened the bolt on that edge. I notice if you were to draw a line through the bolt hole and the center of the intake port, the fracture points would lie on a chord perpendicular to that line. Almost, but not quite. i.e. the pivot line created by the force of that bolt. Link to comment Share on other sites More sharing options...
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