Yeah my mechanic cleaned my throttle body to fix hesitation and low idle. Hesitation is fixed but low idle was not. CEL came on while driving home from him cleaning TB. Since then it has come on 4 times. Code was p1507 idle control malfunction (fail safe). I fixed the low idle by finding the adjustment on the IACV. CEL still comes on goes off comes on goes off comes on pisses me off. I have tried 4867395 things to fix it. Including cleaning the EGR, mass air flow sensor, and IACV. I an now thinking it has to be related the cleaning of the throttle body. Anyone have any past problems or advice? Thanks

What screw did you adjust? Typically those type of things/screws should not be adjusted as they are set from the factory.

 

I'd suspect the idle air control valve.

Yeah my mechanic cleaned my throttle body to fix hesitation and low idle. Hesitation is fixed but low idle was not. CEL came on while driving home from him cleaning TB. Since then it has come on 4 times. Code was p1507 idle control malfunction (fail safe). I fixed the low idle by finding the adjustment on the IACV. CEL still comes on goes off comes on goes off comes on pisses me off. I have tried 4867395 things to fix it. Including cleaning the EGR, mass air flow sensor, and IACV. I an now thinking it has to be related the cleaning of the throttle body. Anyone have any past problems or advice? Thanks

 

What year and model??

 

SEA#3

year 97 legacy 2.2L

Still in despirate need of help!

year 97 legacy 2.2L

Still in despirate need of help!

Did you troubleshoot the IACV?

Maybe you need a new one?

Well I just got a new IACV today - I will update the results here after installing it tonight. I imagine the high idle will go away but I can only hope it goes back to a normal idle rather than a low idle. Thanks

So i've seen this cool problem where you are working around in that are and you bump the cruise control line... it pulls a little clip out of the selonoid that mounts on the fire wall (near the brake booster), cuasing funny idle issues, and that code. I managed to do that on a car i did a transmission on, took having some one else at the shop look at it with me to figure it out. I'm not sure that your car has the same cruise control as the one that i goofed up, but its worth a look... if that is indeed it, press the clip back in and clear the ecm memory...

Replaced IACV. High idle is gone, low idle is better but I have a feeling the CEL will be back. If the CEL stays out I consider this fixed but it could come back which I have a feeling it will.

So, what's the bottom line?

Not to clean the TB?

Damnitt the CEL just came back on and then it stalled at a red light. Cleaning the throttle body helped the hesitation but not the low idle. I NEED HELP!!!!!

What is the CEL saying this time?

 

It might not solve the problem, but it is a good start.

 

How are your fuel, air filter, PCV valve etc.? What do your plugs look like?

 

Does the idle bobble around and then die?

 

How is the rest of your car's performance ie. mileage, hesitation etc.?

Other than the wacky idle it performs great and gets good gas mileage. The PVC valve is new OEM, plugs are new OEM, and the filter is Fram AirHog 6 months old. Still wacky idle. I hate to go to the dealer and pay them to look at it and not fix it but my mechanic has no more ideas and its pissing me off. Any ideas?

Did the mechanic check out the codes again? What were they?

 

How is the fuel filter?

 

What screw was adjusted before? If it was the idle screw it could the TPS out of whack possibly.

 

I imagine the check engine light will probably tell you where to go looking.

 

Good luck!

 

 

 

Beezer

The code is p1507 idle control valve (already replaced this). This is the same and only code I have been getting through this whole miserable experience. The fuel filter was changed over the summer to whatever autozone has. I have been considering a new OEM subaru fuel filter but there are 10 other parts I could try replacing to correct this and am not sure if I should spend the money on the parts or take it to the dealer. I have a dealer appt tomorrow so I'm sure I'll be paying them for nothing. Any help would be greatly appriciated. Happy Holidays.

There very well could be a bad connection at the IAC. Took me a long time to figure this out on my car.

 

 

Good luck

 

 

Beezer

Guys, he said that it started acting up immediately after his mechanic cleaned the throttle body. There is a 99.9% chance that the guy who serviced the throttle body f'ed something up or adjusted something that he shouldn't have.

 

Only one thing really changes the throttle body from it's factory perfect condition; a small ridge of gunk/carbon buildup in the area where the throttle plate comes to rest close to the inside bore of the body itself. This clearance without a buildup of carbon is critical for proper "minimum air rate" past the closed throttle plate at idle. A few thousanths of an inch of carbon will begin to affect idle performance.

 

Take this for what it's worth, but never spray any cleaner into the throttle body. Never adjust any screws on the throttle body. If you can open the throttle plate and feel a tiny ridge of carbon where the throttle plate comes to rest, simply rub it away with a clean, dry cloth wrapped around your forefinger.

That's all you need to do.

 

The adjustments to the throttle body are sensitive down to a few 1/1000ths

of and inch. The throttle position sensor can be damaged by cleaners. The IAC motor is also sensitive to cleaners. Your "mechanic" may have also left a vacuum hose off somewhere.

Good advice. Heres exactly what happened. The car stalled. This was the first time I noticed the low idle. This is why I took it to the mechanic in the first place. So after it stalled on me he cleaned the throttle body. It wasnt till the way home from his shop that the CEL came on for the first time. So although it stalled before he cleaned, the CEL didnthappen till after the cleaning. Just an update, I replaced the coolant temp sonsor and fuel filter with OEM this week. Not much change. I went aorund looking for a same year Legacy at a car lot to test drive to see what the idle was. Go figure the only one in town didnt have a tach. i drove it anyway. It did the same thing much much worse. When at a stop the idle seemed to drop and this car shook much much much much worse than mine. In fact, this car drove so ************ty it made me feel better about mine. This same dealer has a 99 legacy gt that just rolled over 300k!!

 

 

Still lookin for a solutions for the low idle. Thanks for the feedback.

I would suspect the screws on the throttle body have been adjusted. The butterfly stop screw should be marked with paint, if that's been moved then you need to try and readjust it to where the butterfly is just not quite closing on to the bore of the throttle and then look for the paint being matched up again. Next the throttle position sensor may need adjusting so that the idle contacts are just closed at idle. Last, the manual idle air screw needs to be adjusted till the idle air valve is in the middle of its travel at the idle revs, this you have to try and arrange by trial and error. Be aware that the CEL will come on because the idle valve is struggling to maintain the idle speed without getting out of its operating range, it doesn't nessecarily mean that the idle valve is defective.

trxeslr66, to effectively diagnose & repair a modern F/I system you need to have a copy of the factory manual, a decent multimeter, and a code reader.

 

If you query the CPU for clues then learn how to measure for requisite operating parameters (voltage, current, resistance, etc.), you'll save money and keep your car on the road.

 

If you twist on adjustments and replace parts blindly, your gonna throw money down the drain and horse-up the system beyond what a normal mechanic can put straight, especially if you can't describe to him exactly what you've done to it.

 

Mechanics hate working on stuff that the customer "worked-on" first, because it tends to mess-up the natural order of how things fail. I understand that the person you took it to initiated the CEL, but his cleaning may have merely unmasked a latent problem that was already there. What you're doing is making it worse ...much worse.

did you read this....

http://www.ultimatesubaru.org/forum/showthread.php?t=48477&highlight=cleaning+throttle+body

 

Cleaning=bad

did you read this....

http://www.ultimatesubaru.org/forum/showthread.php?t=48477&highlight=cleaning+throttle+body

 

Cleaning=bad

If you read that thread closely, you'll see that there are conflicting views on that subject and that a majority of people have cleaned their throttle body without ill effects.