FocusCanada Forums

Hey guys, been tryig ot figure this out for a bit...

My BOV is stuck, I get compressor surge between shifts...I dont think this has anything to do with my idle, but both problems started at the same time, so I thought I'd throw it out there...

When the car is hot and I'm cooling down (idling) for 1.5-2 minutes after a good run, the car will idle fine for about a minute, then the RPM's will drop down almost 0, Vacuum shoots up close to 0, then the car re adjusts its idle and its fine...

Here whats I done...
I replaced the fuel filter last year (less than 5000Km's on it)
Replaced the Spark plug wires at the beginning of this year
New plugs (one step colder)
New PCV valve (SVO Mustang)
New Oil
K&N freshly cleaned and oiled
Cleaned out ProM MAF
Checked my vacuum lines..

Any other ideas? I'm going to run a compression check tonight if My freind brings back my tool...I'll also check the seal around the intake manifold to see if anything can be heard there.

I'm running the O2 sensor that came with the car 7 years ago, and it is very close to my turbo....could that cause a loopy idle?

Your BOV is stuck? Is it atmospheric? I'v been reading up on blow off valves and yeah you get compressor surge if you lose to much boost from the blow off valve. In turn the air that has already passed the MAF and has already been measured so losing that measured air from the BOV actually makes the fuel mixture rich. Over time it can fowl up your spark plugs. Check you blow off valve. Maybe needs adjusting?

sorry should say bypass valve instead of BOV.

I dont think that has anything to with my idle though...Im picking up a new 'BOV' this week so I will know if that is the cause shortly...

where is the IAC?

It's right on the TB, is it not? I'm going off "forum memory" for the Duratecs, so the Zetec might be different.

Aaron had the same issue when the car got hot.

It was the PCV valve. It was defective and was leaking when it got hot and the seal was not 100%. Try putting the old one back (if you still gots)

meford4u,Sep 4 2007, 08:00 PM Wrote:Aaron had the same issue when the car got hot.

It was the PCV valve.  It was defective and was leaking when it got hot and the seal was not 100%.  Try putting the old one back (if you still gots)
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Thats what I thought it would have been, but I replaced the old one (had about 20k on it) and the problem was still there. <_<

I'll try Kevin's suggestion and replace the IAC, I have my old from the blown engine, so we'll see this week-end when Ive got time, hopefully the new Bov gets here so I can do it all at once.

Did you check the hose that goes from the back of the engine to the PCV valve. I know they get soft alot times and get sucked closed.
I had a problem with that till I replaced it.

Mason,Sep 5 2007, 08:05 AM Wrote:Did you check the hose that goes from the back of the engine to the PCV valve. I know they get soft alot times and get sucked closed.
I had a problem with that till I replaced it.
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I read something about that, but I checked it out and it isnt caving in like some of the pcis Ive seen....that tube is in really good condition actually...I'll keep an eye on it when I get under there this week-end

block the IM and vent the PCV to atmos man. that will take the PCV out of question. if you had an xcal2 you could watch the O2 cycle to ensure it was functioning properly as well.

bigman,Sep 5 2007, 07:15 PM Wrote:block the IM and vent the PCV to atmos man.  that will take the PCV out of question.  if you had an xcal2 you could watch the O2 cycle to ensure it was functioning properly as well.
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then Im illegal, my setup is perfecly legal right now other than the missing egr which is tunred off and removed anyways.

Anyways, I dont think its the pvc, I changed it, checked the tubes, etc, problem is still there, I'll update this thread once I change the IAC.

Glad I had a spare one...$200 from ford...and I was selling my intake manifold with it at my garage sale for $40!! :lol: Glad it didnt sell!