Trouble staying started when engine is cool

[Shaggy]

I have a 1990 legacy l 2.2 na. It recently has been having trouble staying started after engine cools down. When I start it up it revs up to 1500 then it just dies. If I give it some gas it will stay going, I will hold for about at 1000 rpms for a little bit then let go it will catch it's seof before it dies then it will idle at around 300 rpms sometimes it will even idle as low as 100. But as it warms up the rpms build very slowly until it idles perfect at around 6-800 rpms.

[94.GT.Wagon]

Idle air control valve? That's just a wild ass guess, I'm sure someone who knows something will chime in, but if it were me I'd start by looking at the IAC,

[Legacy777]

Does it only exhibit this issue when the engine is cold from sitting overnight? Does it do it if the engine is warm, or sits for a couple hours?

[Shaggy]

Yes it does after the engine has been sitting for a coue of hours, but it does it worse when it sits overnight. Thnak u I will check out the iac. Any help is appreciated.

[Legacy777]

I would suggest replacing your coolant temp sensor.

[tturnpaw]

engine temp sensor and iac. this sounds like a situation where cleaning the iac wont work. like my ej22 swap.

does it throw any codes?

[Shaggy]

I'm going tommorow to have my brother run the obd on it so I will know tommorow if there are any codes. I don't have a ton of money but I'm gonna shop around for those sensors Thanks for all the help I love my durbaru. I'm gonna start a build thread soon, I don't plan on doin anything to crazy but we'll see wut I get around too.

Should I take the iac off and clean it, do u think that would help. I've had a couple of worthy mechanics that are family friends tell me that it sounds like my fuel pump, but they didn't check my car out it was in conversation. I don't have a ton of money but I have plenty of time and patience and I love my car so I'm willing to do whatever I need too.

[Legacy777]

I'd recommend getting OEM sensors. I'd only suggest replacing the coolant temp sensor. It's about $20 from www.subarugenuineparts.com

[Shaggy]

Alright. Thank u, I'm going to buy it right now. I was wondering if the the sensor is the on that sits Down behind the alternator? I was asking because I noticed that that sensor leeks a little bit, but it looks like oil. If this isn't the one can anyone tell which sensor that one is?

[94.GT.Wagon]

The one behind the alternator is the oil pressure sending unit. The temp sensor is on the crossover pipe, accessible from the passenger side and behind the intake manifold.

[Shaggy]

Ok. Thank you i think I'm going to replace both of those. I appreciate all the help guys. So does my car...

[Shaggy]

So I replaced the oil pressure sensor, coolant temp sensor and cleaned the iac. I didn't take it off and get every nook and cranny but I cleaned it up to where it was nice and clean with a rag and carb cleaner and my idle went up to 1800. So i adjusted the throttle until it idled at 800. I let my car cool down and it started this time without me giving it any gas but it idled down at 1-200 rpms, it also spudders like it's missing everyonce in a while. But not constantly. it built up it's rpms faster than it did before but it still isn't starting completly right. Should I take the iac off and clean every little spot out of there?

[Shaggy]

So I started my car this morning and still the same thing. It won't start unless I give it some gas then it idles realy low but the idle builds back up to where it's suposed to be. Can anyone help me, I realy appreciate all the info so far. Thnx

[Legacy777]

Try resetting the ECU. If the long term fuel trims were set with data from a bad sensor that could throw things off.

You can pull fuse 14, EGI/TCU for about 30 min to an hour.

I don't recall if I asked this, but is this a manual or automatic trans car?

[Shaggy]

I'll try pulling the fuse to reset the computer. It's a manual. Thnx again

[Legacy777]

The manual trans cars have a different style IAC valve, which can be a little more tempermental. So removing it and cleaning it more thoroughly may help. Be careful with removing everything, there is a spring on one end and it can spring out and may make it difficult to put back together if you didn't see how it went together.

[Shaggy]

Resetting the computer helped a little but not much still same symptoms. Is there anything else I could check? When I have my lights off and no accesories it wants to start better but if I have my lights on it definately won't start unless I give it some gas. after my car warms up When I turn my lights on my idle drops from 800 to 5 or 600 rpms and doesn't pick it's self back up. if I turn my lights on after I just started the car it makes the engine die or start spuddering( sounds like it's missing)Could this posibly be my battery. It's only a year old but I just replaced my alternator because mine was starting to go out. Could my battery be the reason why my car doesn't start right? I also noticed after I cleaned the iac the rpms built up faster after I started it. I'm going to take the iac off and clean it after I get a new gasket for it.

[Legacy777]

When your lights go on, they create an electrical load, which causes more parasitic load on the engine from the alternator. The engine is supposed to compensate for this via the IAC valve.

So again I would probably recommend checking the IAC valve.

I'd also suggest checking the voltage output of the alternator to make sure it's working correctly.

[Shaggy]

I just recently replaced the alternator so I will make sure that i take off the iac and make it look new again. Thnx again for all the help.