P0507 and P1507 codes after 2.2 to 2.5 swap

[ryanw]

I had thread http://www.ultimatesubaru.org/forum/showthread.php?p=734010 for the 2.2 to 2.5 engine swap I did on my car. The engine was a '95 2.2 that had been used to replace a 2.5 in a '97 OBW. However, the owner got hit in the side and sold me the engine, which I put in my '98 OBW AT.

 

The swap is done, and it runs great in gear, the symptom is:

 

When I start the engine, its idle jumps to around 2,000 rpm and stays there. If I quickly put it in gear, then everything is fine and I can drive with no problems. If I let it set in park for a 10-30 seconds, then the engine will cut back from 2000 RPMS (sound like its going to die) and either:

 

1. Die

2. Run very rough, like its missing

3. Idle just fine at 600-800

 

OBD codes:

P0507 - Idle control system RPM high

P1507 - Manf. Cntrl. Veh.Spd Idle Speed Control Auxiliary Inputs

 

No vacuum diagram on the hood, and none in the Haynes manual that I can find either. Can someone post one? How many vacuum lines are external to the intake? I didn't remove the intake manifold, so all those were never knowingly touched by me.

[ryanw]

After triple checking the vacuum connections (still couldn't find a diagram)... I decided to troubleshoot other idling trouble causes. After searching on this forum, I found that the PCV valve, IAC, and T/B were the 3 things concerning idling. I decided to check the PCV valve first, as it seemed easiest. The inside plate was clear at the top and was heavily gunked up. I pushed it down with a small allen wrench. I cleared codes and started the car and it idled normally... no codes! I drove it a bit, starting is several times and each time it started normally. Previously, it would shoot up to 2,000+ RPM's on every start. So I went and got a new valve and swapped them out. Seems to be running fine now! I guess I'll just have to wait and see, but I think my swap is complete! Thanks for everyone's help!

[EVOthis]

thats great...it looks like you solved your problem......if the PCV was that neglected im sure it wouldnt be a bad idea to clean out the IAC a little bit...

[screwbaru2]

PCVs are often overlooked and cause problems when they are. I bought a 97 Leg wgn 2.2. Seller repeatly said all manitance was done the motor did have a minor oil leak. The test drive revealed nothing serious and I bought the car. After driving it 100 miles there was a small amount of smoke coming from under the hood and the idle was rough. First thing I did was check the pcv and sure enough NG. Replaced it and the hoses. Oil leaks, smoke no more. Hasn't used any oil in 4k miles now. I put at least 600 miles a week on the car so my oil changes are higher mileage or I'd be changing oil once a month or so. I change my pcvs every 2 years as part of a tune up just befroe emissions testing. Ours always pass.

[ryanw]

EVOthis, I think you were right about the IAC as well. When I started cold the next morning, it shot up to 2,200 RPM for a minute or so then died and threw the CEL again. Discouraged, I drove to work. It "kind of" did the same thing at lunch, except it didn't die after the high initial idle, it just went to normal idle and stayed there. Then the rest of the day, it was normal idle at startup. So now my problem had changed from occurring at every startup to just occurring at cold startup. I decided to clean the IAC.... I poured some seafoam down intake tube for the IAC. She ran real rough while doing this and died once... and they were right, it will smoke A LOT for 10-15 minutes... glad I read that part first, lol. Now the first couple cold starts after the cleaning, I have not had any more problems... Guess I'll see what happens over the next few days.