New AIC opens all the way>???

[saab900turboguy]

When I start the car in the morning it will rev high like the choke is on and then it will idle perfectly at 900 when it warms up. doesn't matter whether its hot cold etc. outside. If I drive the car for a few minutes if I go to park, the 1500 RPM idle is back. Shut the car off and turn it right back on NORMAL IDLE!!!! Everytime this happens. Doesn't matter how long I drive it for if it sits and I don't move idle will stay the same, it would Idle at 900 rpm ALL DAY if i don't move the car. Then I drive around the block and come back 1500 rpm. Shut the car off and turn it on normal idle. Drive to china and back same thing.

What I did do was check all vaccuum leaks, BRAND NEW AIC 230 bucks, changed out the TPS sensor and adjusted everyway from sunday. Throttle plate is clean and everything is the way it should be I believe. I also have a NEW NTC sensor as well.

NOW))))!)!)!)!)!) I figured out that if I squeeze the AIC hose the idle will adjust, so for some reason when I drive it the AIC opens all the way up. Its brand new and the last one did it too. So i probably didn't need a new one but o well piece of mind. So why does it do this??? The AIC opens up, could the wires be backwards or does it not matter?

[saab900turboguy]

Its 1990 SPG.

The throttle plate is deffinetly closing all the way. I switched AMM same thing.

I have a wideband A/F gauge and when i have a 900 rpm idle it does go from rich to lean rich to lean while it wanders about 50 rpm or so.

I sprayed carb cleaner all over the place and no change> I was hoping to at least find some sort of high rev but nothing.

I also have a new o2 sensor as well so I don't think that is the problem either.

No check engine light.

[saab900turboguy]

UPDATE!!!!!!

It could be the o2 Sensor i believe, with the way the AF ratio swings when it is at a normalish idle. My down pipe broke last week where my external wastegate pipe meets the flange so it wouldn't boost and I had a huge exhaust leak and it was backfiring in the downpipe. Then when I had it welded to be fixed i DID NOT remove the o2 sensor from the pipe so I may have ruined it. Its the only thing that changed from before the break till after.

But will a bad o2 sensor tell the AIC to stay open after a short drive?

[BionicBanana]

Not to threadjack but I have been having this exact same problem. The only difference with mine is that if it's sunny outside and the temp is atleast 75+ degrees my car will run perfect, although once the sun goes away and it cools down the idle jumps back up to 1500+ RPM's. It makes it impossible to engine break because the throttle stays open, very unsafe for winter driving. Sometimes a blip of the throttle drops it back down to 800ish RPM's but most of the time it doesn't help.

I can put the car in 4th gear driving about 35mph along a straightaway, take my foot off the gas and my car will literally drive itself and travel without losing speed.

I have cleaned the AIC, throttle body, and all intake hoses without any luck.

Also, my car takes about 10 minutes to warm up from a cold start no matter the temperature. The temp gauge will be about half way once fully warmed up, but once I start driving (even on really hot days) the temp gauge will drop to less than 1/4 and the problem begins.

[saab900turboguy]

That sounds like a bad NTC sensor. It has a blue plug and is right under the intake manifold inbetween the middle two runners. If it is bad it won't read right making the car think it is in constant "choke" keeping the rpm high. Search for testing NTC sensor. I can't remember what the resistance should be hot and cold. so if the car heats up and the resistance is to far outta wack thats your problem. If its warm out and the car runs well might be giving it just enough heat to keep it running right. But if its cool out it might put it outta wack just enough.

I fixed my issue it was deffiently the o2 sensor. Went and got a new one today.

[peva]

From memory the NTC is about 2500Ω cold and about 300Ω hot. If you disconnect the NTC plug the ECU defaults to somewhere in the middle simulating a warmish engine.

[BionicBanana]

Cleaned off the NTC plug and connection and all electronics coming from the coolant tank yesterday and the problem did NOT occur on the way to work this morning (raining and cooler than yesterday too, problem usually happens in this kind of weather). My temp gauge was still very low, but it was idling correctly. I'll be picking up batteries for my tester and I'll see what it's at when I'm home

[saab900turboguy]

My problem is actually not solved. New ntc, o2, swapped amm and tps with good parts and I get a 200-300 rpm wobble at idle and stalling when I push the clutch in so I obviously have a vacuum leak somewhere. I didnt think I did. I pinched all my lines to no avail. I have a new bypass valve as well but I will unplug it and plug the holes when I get home.

I need to.check the intercooler pipes but its a maze with the.fmic setup I have. Can I juwt plug the amm directly to the intake with my filter to eliminate that area? Or will it cause all kinds of issues?

[scantar]

Just a thought, but try spraying carb cleaner around your PCV valve. Or if you have a spare one, swap it out.

[saab900turboguy]

I pinched all those lines and it did nothing. But I have sprayed alot of carb cleaner juat about everywhere but on that so we will see.

If I can put the amm directly on the TB and eliminate my intercooler set up as an issue that would be a huge advantage, then I don't hace to get all duty on the wet ground today.

[saab900turboguy]

Ok i put the AMM directly on the throttle body and no change still a reving idle. Its only 200-300 rpm. BUT if i push the clutch in while moving the car will stall, it will try to catch but just stall everytime.

When there is a vaccuum hose on the bypass valve and the engine is running, are you suppose to be able to blow air through it? Or should it be closed?