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1995 Contour 2.5 V6 Duratec - not idling

V

vtraudt

CEG'er
Joined
Nov 17, 2009
Messages
214
The engine does not hold idle (and seems to be running rough).

This old Duratec has VACUUM activated secondaries in the LIM (unlike the electrically operated system I am more familiar with). The spring in the actuator seems to hold the secondaries OPEN (and I haven't seen it moving, but not sure if in neutral the RPM get high enough before the rev limiter kicks in).

Also, there is a strange sound (resonance?) coming from the intake. I can stop the noise by opening up the air filter box.

Where should I start with troubleshooting the idle?

Thanks.
 
I had a 95 duratec before changing the engine. The vacum is controlled by a solenoid valve. The IMRC is naturally open by default and is supposed to close when running at idle. It then opens at approx 3500 rpm just like the electric motor control. Mine had the solenoid go bad and the car ran rough at idle. Possibly from poor air velocity across the injetor spray with both tubes open

check the solenoid valve first.
 
I would like to read up on 'moosing', but the link you posted won't work for me. Can you repost?
 
mrutkaus said:
Well there's the idle air valve too to consider.
Click to expand...
Yesterday, I pulled the 'idle air valve' electrical connector: starts dying immidiately. Plugged back in, idles REALLY low (sometimes dies).
So, the electrical parts seems to have basic functionality. Question is: what makes it idle so LOW that it almost dies without manual intervention?
 
The IAC is designed to control the engine idle speed by opening and closing the air supply from the bypass passage. It is possible to clean it with carb cleaner, though not recomended by some sources, I think it's worth trying even though replacement is the best option. You can remove the IAC, with it plugged in, check for movement when key is turned on. If no movement is observed you may want to clean or replace.
 
turboman57 said:
The IAC is designed to control the engine idle speed by opening and closing the air supply from the bypass passage. It is possible to clean it with carb cleaner, though not recomended by some sources, I think it's worth trying even though replacement is the best option. You can remove the IAC, with it plugged in, check for movement when key is turned on. If no movement is observed you may want to clean or replace.
Click to expand...

Thanks turboman!
I will check for movement first (what is supposed to move and how can I detect the movement?), then take it off and check it out (cleaning).
Note: unplugging with engine running creates observable change in engine running (will die quickly). Is that a sign that 'things' move?
 
From your other post it sounds like you may have more going on than just IAC not functioning properly. As I mentioned previously I had some problems like this last year with my 95 most related to the catalitic converter, but also bad wiring, IAC, and O2 sensors. The Intake manifolds throtle body were also a mess and needed cleaning. You may want to get some codes read. It's not as easy on 95's OBDI as it is on OBD II but I found the DTC info to be helpful in pointing to which sensors are indicating problems. The code reader is not to expensive to buy or maybe you can borrow one.
 
You got that right (more going on than just IAC). The seconaries are now working right (the vac line was off!).
the are was idling better today (maybe the IAC was sticking, and is now slowly 'breaking free'? No idea what's inside, but car was sitting for a long time (6 months?), and plugging in/out with engine running my shake the 'rust' off

I have suspected the cat, since we had a similar issue on our 99 Cougar (shop pointed right at a plugged cat when we described the problems back then; removing the cat fixed it). This car has been driven short distance for 90,000 miles; the LIM and UIM were gummed up. We have the pre cats out already. Is there a way of telling if the main cat is plugged? The tailpipe seems to 'puff' ok.

Downstream 02 sensor were cut off by previous owner.

Error codes 327 (EGR or valve position or exhaust pressure transducer circuit below minimum voltage
172 Lack of heated 0xy sensor switch indicates lean bank 1 (O2 cut off!)
 
Our '97 V6 had the same symptoms a while back: often died at idle, and the notorious 'moosing'. I cleaned the IAC valve and it took care of the problem briefly, but both conditions reappeared. Replaced the IAC and the problem was solved.
 
Sounds like you are making progress, I pulled my cat off and punched it out until I could replace it. I don't know how much you want to put in this car, but if your interested in new O2 sensors Rockauto has a great deal on them right now, $28.79 each, for a quality OEM type. The 327 code is most likely the DPFE sensor, in my opinion the most useless part on the motor, these fail, turn on the check engine light when the EGR system they monitor is just fine. I wish you luck in getting the car sorted out.
 
With moosing, low idle (even so now it holds a low idle) and OBD1 error 327 (EGR valve position or exhaust pressure transducer circuit below minimum voltage), I want to start with the IAC cleanup and EGR.

a) How to clean the IAC and check for proper functionality (when I pull the connector off, car does not idle at all)
b) How to remove, check and clean the EGR?
 
vtraudt said:
You got that right (more going on than just IAC). The seconaries are now working right (the vac line was off!).
the are was idling better today (maybe the IAC was sticking, and is now slowly 'breaking free'? No idea what's inside, but car was sitting for a long time (6 months?), and plugging in/out with engine running my shake the 'rust' off

I have suspected the cat, since we had a similar issue on our 99 Cougar (shop pointed right at a plugged cat when we described the problems back then; removing the cat fixed it). This car has been driven short distance for 90,000 miles; the LIM and UIM were gummed up. We have the pre cats out already. Is there a way of telling if the main cat is plugged? The tailpipe seems to 'puff' ok.

Downstream 02 sensor were cut off by previous owner.

Error codes 327 (EGR or valve position or exhaust pressure transducer circuit below minimum voltage
172 Lack of heated 0xy sensor switch indicates lean bank 1 (O2 cut off!)
Click to expand...

Oh ya, and 'moosing'.

Will get the 'pipe plug' fix done, but also want to clean the IAT.

How?
 
The EGR passage behind the throttle body gets clogged up with carbon. I removed the IAC, TB, EGR from the UIM and took the UIM off the motor to give it a good cleaning. A pain, but worth it.
 
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