Sticking Throttle
#1
02-25-2007, 10:12 PM
My 2002 Saturn SL Silver Blue Special (The $9995 including air special)
has 130k miles on it. At around 80k, I started having a sticking
throttle. I cleaned it and it was good to 90k where it started
sticking again. Cleaned it again, but between 90 and 102k, the
engine started running rough, gas mileage went down (from 38 to 35) and
the throttle started sticking again. At 102k, I got a check
engine light and code P0507 (high idle). Found the factory had
mispositioned the intake manifold gasket (common problem
apparantly). I cleaned the throttle body and intake manifold and
put on a new intake manifold gasket and new PCV valve. Since then
I've had to remove and clean the throttle body about every 5k miles,
and it gets worse each time.
Today, I cleaned it again and put in another new PCV valve. The
backside of the throttle plate is caked in carbon and the intake
mainfold passages are getting restricted with an oily carbon. The
engine runs fine, idles smoothly, oil consumption is low (qt/3000
miles), fuel economy is 38 or better, a little better due to two
speeding tickets last summer. Any ideas?
has 130k miles on it. At around 80k, I started having a sticking
throttle. I cleaned it and it was good to 90k where it started
sticking again. Cleaned it again, but between 90 and 102k, the
engine started running rough, gas mileage went down (from 38 to 35) and
the throttle started sticking again. At 102k, I got a check
engine light and code P0507 (high idle). Found the factory had
mispositioned the intake manifold gasket (common problem
apparantly). I cleaned the throttle body and intake manifold and
put on a new intake manifold gasket and new PCV valve. Since then
I've had to remove and clean the throttle body about every 5k miles,
and it gets worse each time.
Today, I cleaned it again and put in another new PCV valve. The
backside of the throttle plate is caked in carbon and the intake
mainfold passages are getting restricted with an oily carbon. The
engine runs fine, idles smoothly, oil consumption is low (qt/3000
miles), fuel economy is 38 or better, a little better due to two
speeding tickets last summer. Any ideas?
#4
03-06-2007, 12:20 AM
An update, I pulled the valve cover to see if there was any sludge
under there, it was clean as a whistle. After puttin g the valve
cover back on, I pulled the hose between the valve cover and the air
filter runner. I get both vacuum and pressure from the
tube. I'm suspecting a small amount of blowby from one cylinder
causing the puffing, but I still get a good vacuum from the PVC
valve. I guess throttle body cleanings are going to be a regular
maintenance item from now on. I checked teh EGR valve and it was
clean and functioning.
trysten, many people have gotten the P0507 code from their computer
when the check engine light came on. Many found out that the root
problem was a leak around the #1 cylinder, but most had their mechanic
or dealer replace the gasket. I do my own work as much as
possible. When I pulled the intake manifold, I found that the
hole in the gasket at the bottom outside corner of the #1 cylinder had
missed the stud it was supposed to surround. It got bunched up
there and eventually got sucked in far enough to cause a vacuum leak,
it took 4 years and 102k miles to show up. I'm guessing that that
was the cause of the other peoples problem since these engines are
built by robots.
The sticking throttle and build up on the backside of the throttle
plate is apparently due to oil burning, not the intake manifold
gasket. The intake manifold gasket problem could have led to my
condition by causing one cylinder to run rich as another ran
lean. The fuel injection controls are based on the average of O2
in the exhaust, not cylinder by cylinder. The leak would have
made #1 run lean, so the others would have run rich to compensate.
Saturns have a reputation for oil burning, but I don't see other posts
about sticking throttles. It seems that if mine causes the
throttle to stick so quickly when my oil consumption is still pretty
low, then other Saturns should have been almost undrivable.
under there, it was clean as a whistle. After puttin g the valve
cover back on, I pulled the hose between the valve cover and the air
filter runner. I get both vacuum and pressure from the
tube. I'm suspecting a small amount of blowby from one cylinder
causing the puffing, but I still get a good vacuum from the PVC
valve. I guess throttle body cleanings are going to be a regular
maintenance item from now on. I checked teh EGR valve and it was
clean and functioning.
trysten, many people have gotten the P0507 code from their computer
when the check engine light came on. Many found out that the root
problem was a leak around the #1 cylinder, but most had their mechanic
or dealer replace the gasket. I do my own work as much as
possible. When I pulled the intake manifold, I found that the
hole in the gasket at the bottom outside corner of the #1 cylinder had
missed the stud it was supposed to surround. It got bunched up
there and eventually got sucked in far enough to cause a vacuum leak,
it took 4 years and 102k miles to show up. I'm guessing that that
was the cause of the other peoples problem since these engines are
built by robots.
The sticking throttle and build up on the backside of the throttle
plate is apparently due to oil burning, not the intake manifold
gasket. The intake manifold gasket problem could have led to my
condition by causing one cylinder to run rich as another ran
lean. The fuel injection controls are based on the average of O2
in the exhaust, not cylinder by cylinder. The leak would have
made #1 run lean, so the others would have run rich to compensate.
Saturns have a reputation for oil burning, but I don't see other posts
about sticking throttles. It seems that if mine causes the
throttle to stick so quickly when my oil consumption is still pretty
low, then other Saturns should have been almost undrivable.
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