2.5 SVT Won't Idle IAC?

[pjw73nh]

Greetings,

I have a 95 SVT that just started to not idle. Runs great no misses, or skips. It starts fine, races up a bit then 2 seconds later will die unless gas pedal is pressed to keep it from stalling.

I highly ssuspect the IAC. I looked at the connector to it and I noticed that one of the wires going in to the connector has some burnt insulation for about 1/4 inch right where it enters the connector. I can see the copper wire through the burnt 1/4 inch. From what I have read I can't accurately test the signal because it is a pulse/duty cycle signal.

If I KNOW that the IAC is bad, I don't mind spending the $90 on it, but I hate to buy one and not have it fix the problem.

Also, If I DO need to replace it, does anyone have any tips on getting access to the bottom nut/bolt? It appears to be well hidden. I attempted to get a look at it, and in the process broke the vacume tube that goes to the brake power assist diaphram. Ford couldn't find a number for it, but I think I can fix it without replacing it.

Thanks for any insight you may be able to provide.

P.

[beyondloadedSE]

SVT's Contours were only made from 98-00. The highest model you could get from 95-97 was an SE.

Could be an IAC. If you have some box end wrenches it comes off easily. I'd try cleaning it first once you get it off and see what that does. The spring inside gunks up over time and sticks. You could always picked up a used one from a junkyard or from the Contour classifieds from people parting out their cars. Guarantee someone has one and would probably let it go for extremely cheap since this isn't a high demand part.

If that doesn't work, you've probably got a large intake leak somewhere.

[pjw73nh]

Thanks for the reply.

Do you know what the correct operation of the IAC is when it is off the vehicle? I took it off. It is carboned up but not much. I tried cleaning some out. I can freely move the sping and plunger with very slight pressure.

When I connect it to the harness, I have someone turn on the ignition to on (not start). I can feel the motor "click" while holding it, and it looks like the plunger "tries" to move a bit but doesn't.

Should I see the plunger move?

Thanks.

P.

[beyondloadedSE]

I believe the IAC works by the vacuum created by the motor. The vacuum pressure created by the motor causes the IAC to open and the spring causes it to retract when the throttle body is open.

[pjw73nh]

Well, The IAC didn't solve it. I put the original one back on. The current status is that the engine will idle for about 10 seconds after a start, and then feel like it is going to stall then will jump up to 2500 or so RPMs and then repeat.

On a road test, it behaves similarly, but also, when shifting (it's a 5 speed), between shifts it will rev 1000-2000 rpms higher from where I shifted. After about 10 mins of driving it will begin to stall at idle again. I checked for vac leaks with a spray can. No difference. WHen on the road at driving speeds it is fine. No misses, skips etc.

I am starting to think there is a fuel control issue or engine management issue.

In the process of changing the IAC, when I went to move aside the power brake booster hose, the little white piece cracked off. The white piece appears to be some kind of check valve, but there is also a black check valve closer to the booster, so I am not positive s to what the white piece is. I have temporarily repaired it, but went to the dealer for a replacement, and they can't find a replacement number for the piece of the entire hose assy. I was hoping someone had a part number for it. It is a direct run from the manifold to the booster. Also, does anyone know how to get it out of the manifold. I can't seem to get it to come out, and I am afraid of breaking it. it doesn't have to be removed from inside the manifold, does it?.

I have a picture of it but am unsure as to how to upload it for viewing.

As always, Any suggestions welcomed..
Thanks

P.

[aztassin]

It could be your fuel pressure regulator

[beyondloadedSE]

Originally Posted by aztassin

It could be your fuel pressure regulator

While thats certainly possible, if it was a bad FPR it would probably run bad thorughout the entire RPM band.

FWIW, in the 10 years Ive owned a contour, I don't recall anyone anyone ever having a bad FPR on the contour.org forums.

[pjw73nh]

Hi folks,

Thought I would follow up with the solution. First of all, at the risk of sounding like a wuss, I didn't have time to work on this vehicle and I had to get it back on the road ASAP. I brought it to my local guy that I trust implicitly. It ended up being the upper intake manifold gasket, and while he was in there I had him replace the lower one as well. The car is back on the road and running great.

Thanks for al the help and advice.

P.