88 Gl Wagon - Help troubleshooting cold idle issues?

[stratman977]

I have been working on an 88 GL wagon. Its main issue is that it doesn't want to idle when especially when cold and then it also stalls when pulling out until its warmed up. I really need to fix the stalling cause its a safety issue.

 

Its an auto, 4wd, single range, ea82.

 

I just recently put all new seals in the engine, water pump, thermostat, timing belt, tensioners, plugs, wires, cap, rotor, coil, pcv valve, air filter, coolant temperature sensor (tx96). I also checked the timing with the test connector together and it seemed like it was set maybe on 21 degrees so I bumped the distributor just a little. I checked the rpm with the pickup on my multimeter when I set the timing and it was averaging around 720 rpm to 750 rpm. The idle screw is about 1.5 turns out, and the throttle position is showing contact on the top terminals when the throttle is closed.

 

I had 5 or 6 codes and I'm down to 3 now. 24, 34, and 51. I bought a used idle air control valve and put that in and it made no difference so I tested the old and the new with a  power probe and both of them actuate just fine. I did not troubleshoot beyond that yet. The code 51 troubles me because the car doesn't have a manual transmission. What's also odd is that I didn't have this code before I tore the engine apart???

 

I think I have some vacuum leaks and I noticed that the hose going to the pcv valve had a crack at the end. I'm going to see if I can order new hoses for the intake system at the dealer Monday. I also took a bunch of the vacuum hoses to advance auto tonight and the didn't have what I needed so I'm going to try NAPA tomorrow and see what they got. What have you guys been doing with the large hoses and vacuum hoses?

 

My plan of action is to fix the vacuum leaks and see where that gets me and then tackle the engine codes one at a time. Sorry for the lengthy post. Any input on where to go next would be appreciated.

Edited October 27, 2013 by stratman977

[jj421]

Sounds like the idle problem I have. I've posted numerous threads on this and only received minimal assistance, so let's hope you get better results. Only difference is mine is a manual, and it stalls whenever I push in the clutch or put it in neutral. I have to heel-toe and rev it to keep it alive, which is hard to do when you're approaching a traffic light at the bottom of a hill and the car in front is braking hard.

 

I've got code 34 (EGR solenoid) and 35 (purge solenoid) all the time. I get code 24 (air control valve) too when the engine is cold--when it doesn't want to idle. Let me know your findings with the vacuum leaks. I suspect I might have a vacuum leak, but it's not obvious. I'll have to spray some fluid in the engine to find it.

 

Tomorrow I might be trying a new ECU. I've tested the IACV and the wiring, and it all checks out. I'm thinking my ECU might be damaged or something. I haven't tested it yet, but we'll see.

 

Are you getting voltage to the IACV? Unplug the connector, put the key in the on position, and grab your multimeter. Negative lead on negative battery post and positive lead on one of the two terminals in the connector (I forget which one is positive). You should get at least 10 volts. Also, make sure the IACV has 7.3-13 Ohms of resistance, but if you've seen it actuate, it should be okay.

 

Here's another simple test for your IACV. With the engine running, disconnect the connector or pull the vacuum line on the IACV. If the engine is warm, the idle should drop 100 RPM, maybe a little more. If the engine is cold, the RPMs should drop significantly, possibly causing the engine to stall.

Edited October 27, 2013 by jj421

[stratman977]

I tried spraying the vacuum connections with carb cleaner and haven't noticed anything at all. I notice that it stumbles a little when I turn the heat on which is why I'm thinking vacuum leak. Plus everything rubber on mine that is hard as a rock.

 

My work is right near the interstate and it's an older part of I-70 that doesn't have much of a speed up ramp to get on, usually you have to stop and wait for an opening. I had an incident last week where there was traffic and no one would move over. There was gaps big enough for a sports car to pull out in but not a Subaru. The guy behind me kept honking which had me really irritated and I stomped on the gas and it stalled. I was able to get out of the way but I don't want to have that happen again, so I know how you feel.

[hooziewhatsit]

When it doesn't want to idle, thump the IAC with the butt end of a screwdriver.  See if that changes anything.

 

Just because the IAC works fine when you apply 12v to it, doesn't mean it won't stick when it's hit with the fast PWM to control the idle speed.

 

BTDT.  Took a while to find one that actually worked.

[mr sarcastic]

Try bypassing the valve with a hose, connect the hose from the upper intake to the lower intake without the valve in between. Use a set of vice grips on the hose to act like the valve. Open when cold, closed when warm.

[mr sarcastic]

http://www.ultimatesubaru.org/forum/topic/141806-aaviacv-questions/

[ruparts]

hi,

  could you explain a bit more on the idle screw adj you mentioned,   if its a carb ,ok , but if it's SPFI then are you talking throttle stop or?

 i didn't see where you say if your car has a carb or FI , on fi motors this sort of trouble  many times it is the connection to the coolent temp sensor is real corroded and not making proper signal to the ecm,, also the sensor itself might be bad ,, that is the first thing you should check into.   if its carburator then the choke function is whats problematic but it needs someone pretty knowlegable to fix it properly.  also the normal tune up stuff, cap , rotor, wires, plugs,  and be sure  the timing is set right,   you need to have the diagnostic connectors connected to set it ,  then disconnect them for daily driving.  vacuum leaks will cause issues so make sure all the plumbing is sealed up .

Edited October 27, 2013 by ruparts

[stratman977]

I tried thumping the iacv with a screwdriver handle this morning and nothing happened so I tested the signal and there's no voltage being sent to the valve. It's sfi and the idle screw i'm mentioning is right in the throttle body behind the iacv valve. I just changed the temperature sensor with a new one.

 

I followed the logic in the Subaru repair manual and got to the repair harness diagnosis. Sure enough my wiring at the ecu is a major cob job. It looks as if there was a remote starter or an alarm of some sorts installed at one point. There's definitely an open circuit between the ecu and the iacv. I'm going to hold off for another day on this repair. I have other cars to drive but I've learned you never start a new project on a sunday night.  I'm actually a little disgusted at this point.

[Cougar]

The intake manifold gaskets are a pretty common failure point.

[stratman977]

I pulled a new wire from the computer to the iacv and now its working. I went through the body to engine connectors and pulled the wire through the harness inside of the fender instead of rigging it up. It's a pretty big job to repair a circuit properly.

 

Bad part is that I found a little rust to deal with behind the fender.

Edited November 2, 2013 by stratman977