Vacuum line/idling trouble help!

[smallwwb]

My car is a 1988 DL S/R 5mt wagon, SPFI.

So after reading many posts on here, I felt ready to remove my EGR system. It had many cracked/broken lines and the computer continuously throws a trouble code as not functioning. Not worth replacing/fixing.

Here is what I did: removed vacuum canister, removed two lines going into throttle body and capped them. Removed EGR and EVAP solenoids- just unplugged from harness. Removed vacuum line from EGR.

There is a vacuum line that as far as I can tell runs through a solenoid to the transmission for the 4x4 vacuum hubs. I plugged that line directly into the vacuum 'nipple' (whatever it's called) that comes off the intake manifold directly forward of the EGR valve.

So now I have two plugged lines into the throttle body, vacuum pulling directly from the intake manifold to 4x4 solenoid, and all that's left is the gas tank vent which is just open for now.

Now, after initial warmup or driving for a few minutes, the car idles really high, I would guess 3000 rpms or so (no tach yet).

It only does this for about 5 minutes, then all is normal once the car reaches operating temperature.

My Idle Air Control valve had malfunctioned in the past and doesn't work all that great, but this problem cropped up after removing the emissions stuff.

Did I miss something or disconnect too many wires?

Would appreciate any insight.

[ferox]

I don't know about the vac can for and '88 SPFI, but earlier models have a purge line that goes directly to the intake manifold and has an inline check valve. How many barbs are on your canister?

[smallwwb]

Canister came with 4 barbs, but only three were in use in my motor- the 4th was capped off from the factory.

Where would the purge line be coming from?

I'm planning to plug each solenoid back in one at a time and see if it makes any differerence, for lack of anything else to do.

[ferox]

Where would the purge line be coming from?

 

On earlier models it connects to the back of the intake manifold near the center.

 

Reading through your original post I did not see where you plugged the vacuum source for the EGR. Based on your description it sounds like it is still connected to a a thermo-valve that opens after warm-up.

[smallwwb]

The vacuum source for the EGR came from the nipple where I plugged in the 4x4 vacuum line. There used to be a T there for both lines- I just pulled off the EGR stuff and plugged the 4x4 line into the intake manifold.

Also, this problem is occurring on warmup only. Once the engine reaches temperature, everything's fine.

[smallwwb]

Bump

[smallwwb]

So think I solved the problem.

There is a thermosensor (?) that plugs in right in front of the EGR valve that I guessed was opening the EGR and causing a vacuum leak, then causing the high idle. I unplugged it and the problem went away.

I also plan to bypass the Idle Air Control valve instead of taking my chances with a junkyard item. An old subaru mechanic showed me how. I'll post a description once I'm finished.