idosubaru Posted July 25, 2007 Share Posted July 25, 2007 Friend of mine has a 1992 Loyale. recently the RPM's will shoot up when he first starts it. it will often stall when he hits the gas, like it's flooded. once the car is warm it doesn't do it any more. is this an Auxilliary Air Valve issue? i'll be visiting him next week fortunately so give me some pointers for when i'm down there. i'm not familiar with the AAV set up since my XT6 is different. should i be looking to replace that valve? Link to comment Share on other sites More sharing options...
idosubaru Posted July 25, 2007 Author Share Posted July 25, 2007 does this have an AAV and IAC or just one or the other? i've seen mention of both when searching so not sure if people are interchanging the terminology or both are present. if i unplug the CTS should the car still run, just as a check? that it goes away once it's warmed up seems like a very important clue. Link to comment Share on other sites More sharing options...
zyewdall Posted July 25, 2007 Share Posted July 25, 2007 I think it's normal for the engine rpm to be pretty high when it's first started cold -- because the choke is on -- not a mechanical choke any more, but a computer implemented one. My SPFI GL will idle at 2500rpm or more for a minute or more when it's cold, but then slows down as it warms up. What it doesn't do is bog if you try to drive it before it warms up. And, if you rev it with the gas pedal, it'll change to idling lower -- like resetting an automatic choke by hitting the gas. Have you cleaned the MAF? I noticed that I did have a hesitation on mine before I did that -- though that didn't seem to vary based on temperature. EDIT -- by cold, I mean a sub freezing day. On a 60 degree day, it might idle at only 1500 for a little while before going back to 800rpm idle. Z Link to comment Share on other sites More sharing options...
Gloyale Posted July 25, 2007 Share Posted July 25, 2007 does this have an AAV and IAC or just one or the other? i've seen mention of both when searching so not sure if people are interchanging the terminology or both are present. if i unplug the CTS should the car still run, just as a check? that it goes away once it's warmed up seems like a very important clue. SPFI has IAC. MPFI has AAV like you're ER27 Link to comment Share on other sites More sharing options...
idosubaru Posted July 25, 2007 Author Share Posted July 25, 2007 MPFI has AAV like you're ER27 ER27 has an IAC. what's the difference between the two? i realize the idle could be higher and then lower as it warms. but the problem is if he hits the gas the car stalls and it's idling abnormally high...so something isn't right. he's 3 hours away so i can't look at it until this weekend. just happens i'll be in his area anyway and will see him this weekend, so i'd like as much info as possibly when i get there. Link to comment Share on other sites More sharing options...
subyrally Posted July 25, 2007 Share Posted July 25, 2007 the fuel injected engines have both an idle air control valve and an auxilury air valve. the iac valve is usually on the throttle body and the aav is on top of the thermostat. it sounds like the aav though, there is a bi-metal coil inside the aav that is heated by the coolant in the thermostat housing. when the coil heats up, it heats unevenly and acts like a switch to let in more or less air through the valve. also might not be a bad idea to make sure that the hoses arent cracked and that the throttle and intake are clean. might want to get that car a seafoam treatment, couldnt hurt. Link to comment Share on other sites More sharing options...
Gloyale Posted July 26, 2007 Share Posted July 26, 2007 the fuel injected engines have both an idle air control valve and an auxilury air valve. the iac valve is usually on the throttle body and the aav is on top of the thermostat. Not so. SPFI engines have IAC (Techincally called Air Control Valve by Fuji). MPFI 4cyl engines have an AAV and do not have a IAC in the throttle body.. And XT6 (er27) has what's techinacally called the By-pass Air Control Valve. Altough it is largely similar to the SPFI's IAC set-up. IAC and the By-pass valves are controled, at variable rates, by the ECU to regulate the idle for load and tempature conditions. It can change the amount of air passed through for idling very quickly. The AAV setup starts open when cold and then slowly closes as tempature rises. It is not controled by the ECU in relation to anything other than temp, and reacts very slowly. In our case here, I think our poster has a IAC. And it may be dirty or malfunctioning. Hook up a voltmeter to the Black/white wire going to it and test for Voltage with ignition on. should be 12v Again test for voltage but on the white wire. There should be less than 1v at start-up, and more than 10v after about a minute. repeat this test if it fails, this time at pin 45, GR wire at the ECU, to find if it is a harness issue. All that good? Now test the IAC itself by measuring resistance across the 2 terminals. Should be less than 100 ohms. Resistance between either terminal and body ground should be greater than 1M ohms(infinite, no continuity) Link to comment Share on other sites More sharing options...
subyrally Posted July 26, 2007 Share Posted July 26, 2007 dont know about the spfi engines, but i know that the ea82t's that i have came with both, the iac is on the back side of the throttle and the aav is ontop of the thermostat. i ran into a problem with that when i mounted the xt6 throttle body onto a regular xt manifold. the xt6 throttle didnt have the iac valve and the car would stall out when i ran with that set up. Link to comment Share on other sites More sharing options...
Gloyale Posted July 26, 2007 Share Posted July 26, 2007 dont know about the spfi engines, but i know that the ea82t's that i have came with both, the iac is on the back side of the throttle and the aav is on top of the thermostat. That's the fast idle solenoid. It's not the same as the IAC on the SPFI. Link to comment Share on other sites More sharing options...
idosubaru Posted July 26, 2007 Author Share Posted July 26, 2007 Hook up a voltmeter to the Black/white wire going to it and test for Voltage with ignition on. should be 12v Again test for voltage but on the white wire. There should be less than 1v at start-up, and more than 10v after about a minute. repeat this test if it fails, this time at pin 45, GR wire at the ECU, to find if it is a harness issue. All that good? Now test the IAC itself by measuring resistance across the 2 terminals. Should be less than 100 ohms. Resistance between either terminal and body ground should be greater than 1M ohms(infinite, no continuity) excellent, thanks. what does it look like and where is it located? Link to comment Share on other sites More sharing options...
daeron Posted July 26, 2007 Share Posted July 26, 2007 the IAC (judging from what I am reading in the current "my xt6 wont run" thread) functions essentially the same on the loyale SPFI setup as it does on the XT6.. By that I simply mean, if its a problem that, on an XT6, would have you thinking IAC, then yes, its likely the same here. The IAC is mounted on the front side of the throttle body, the solenoid body that activates it is integral with the assembly and juts off to the left in this image, and the open tube pointing upwards just in front of the TB is the air inlet for the hose from the snorkel. the plug is laying on top of a vacuum hose below the manifold. No AAV on the SPFI. Link to comment Share on other sites More sharing options...
idosubaru Posted July 26, 2007 Author Share Posted July 26, 2007 excellent pictures, that helps a ton since i haven't worked on nearly as many SPFI as others. he's got a spare parts car or two so hopefully we can test stuff with my meter and swap if necessary. Link to comment Share on other sites More sharing options...
daeron Posted July 26, 2007 Share Posted July 26, 2007 excellent pictures, that helps a ton since i haven't worked on nearly as many SPFI as others. he's got a spare parts car or two so hopefully we can test stuff with my meter and swap if necessary. The IAC is simple to test with a battery and maybe some jumper wires to make the needed connections. I took a whole buttload of great photos when I did my head job.. I had planned on doing a detailed, step by step from soup to nuts to indicate exactly how easy it was, and demonstrate proper shop procedure in keeping lifters, rocker arms etc in order... ..but I forgot my camera on assembly day, Doh!! Link to comment Share on other sites More sharing options...
hooziewhatsit Posted July 26, 2007 Share Posted July 26, 2007 just a few days ago I lubed up my IAC solenoid (again). To do this, I removed the two small screws holding the solenoid to the valve, sprayed some cleaner into it, then some silicon lubricant, actuated it a few times with jumper wires to the battery, and put it back on. Got rid of my hesitation problems off idle when cold. The solenoid is the brass looking tube with a black end cap, with wires going to it in that picture. If the power steering is in the way of the valve, I've used vice-grips to break the 4 bolts loose to get it off to soak in cleaner. Kinda sounds like the valve is sticking open when it first starts (high RPMs), then closing after he hits the gas (and then stalling). Cleaning it could definitely help. -Dave Link to comment Share on other sites More sharing options...
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