2000 GT - Motor randomly dies with Heater set on Defrost.

[wmburns]

Get an oil filter cutter!

Forget the idea about the AC diode. The Mustang does not use one. It would be a good idea to check on other cars that do use them.

It is normal for the idle to drop some when large loads turn on/off. There is always a delay from the event until the IAC has a chance to respond. However, if the idle is dropping so much that the motor is on the verge of stalling, then either the idle is too low, or the IAC is too slow to respond to changing conditions. If this is the case, it also explains the AC problem.

As for the noise, timing chains is my vote. The frequency is very fast with a repeative sound at a lower frequency that may be run-out of a rotating part.

Get a mechanic stethoscope and probe around the timing cover. Get an oil filter cutter and examine the oil filter media. Look for bits of metal and plastic.

I have a boat anchor on the engine stand right now that came out of my 2000 GT. It failed when the timing chain tensonioners wore through the plastic down through the metal. The chain went slack and broke the guides on the opposite side. The chunks of plastic clogged the oil pick-up starving the engine of oil. Both heads are ruined due to cam galling.

Had the prior owner realized what was happening, replacing a timing set would have been much easier than an entire motor. But on the other hand, his misforturne turned in to a nice project for me.

In my case, there was a kind of plastic sluge (goo) in the filter and on the pick-up. Since on my motor the tensonioners were also down to the metal, the metal shards were plainly visible on the oil filter media.

At the very least, checking the oil filter can give some piece of mind for not many $$'s.

 

[jayrw]

A buddy of mine talked to a performance shop near his work which deals with a lot of mustangs and they want me drive it by tomorrow so they can take a look at it (for free).

Hopefully they can at least tell me what I'm looking at in repairs. (engine noises is my main priority at this point).

Thanks for all the replies!

Ill let you know what they say tomorrow...

 

[jayrw]

Ack went by there today and shop was closed and later found out owner had to goto the doctor due to a kidney stone lol.. Ill try again next day off (Thursday).

 

[bigc2330]

2000 GT idle issues

I have recently been having idle issues with my 2000 GT too.
If the A/C is on or the heater, it surges then jumps to normal, then surges again. It will do this with or without lights/radio/etc on.
The belt looks good. I have a OBD scanner, but i couldnt find a way to read the IAC voltage. When I unplugged the IAC connector it died immediatly.
Is there anything else i should check?

 

[jayrw]

I spent some time at the shop today and they determined there is nothing wrong with my engine ..the engine noises im hearing was mostly fuel injectors and my camera exaggerated this sound big time (It didn't sound nearly as bad today when we listened to it in person).

2 different people listened to it run and they said it sounds healthy to them even after repeatedly revving the motor.

As for the defrost / idle issues they told me to try cleaning the IAC valve to see if it changes or improves any of these issues, and also need to replace one of the rubber hoses near the IAC as it has a lot of visible cracks in it.

Im going to clean the IAC tonight and see what happens.

 

[wmburns]

Don't clean the IAC with the black vent. It will damage the internal springs/diaphragms preventing it from working correctly. This will trade one problem for another. Replace it. Autozone makes a cheaper replacement.

If the bypass/vacuum line to the IAC leaks, this will cause the idle to be too low.

First thing suggested was to look for vacuum leaks.

 

[jayrw]

Don't clean the IAC with the black vent. It will damage the internal springs/diaphragms preventing it from working correctly. This will trade one problem for another. Replace it. Autozone makes a cheaper replacement.

If the bypass/vacuum line to the IAC has cracks, this will cause the idle to be too low.

First thing suggested was to look for vacuum leaks.

Is there an easy way to test for vacuum leaks?

I had already cleaned the IAC before reading your post and mine DOES have the black vent.

So far since cleaning IAC the engine hasn't died during defrost but I still wish I could figure out the rough idle issues..

 

[wmburns]

Exactly how low is the idle? Note, a vacuum leak on the IAC intake line can cause a slow idle.

A new IAC is a $53 part from Autozone. It is more from Ford. Doesn't seam like too much if this problem is really bothering you.

As for vacuum leak checking, there is the usually visual method. The problem is that most guys don't really take it serious enough. IE, that all lines, connections, tees, O-rings and such have to be in good repair. Sometimes it is hard to believe how even a tiny vacuum leak can affect drivability.

Further, visually checking intake gaskets is not really possible.

Then there is a smoke test. This is best method but only a professional shop can afford a smoke tester.

For the home mechanic, there is a propane based leak tester. It will not harm gaskets (note, I think it is a bad idea to spray carb/choke cleaner all over an engine looking for a leak. The cleaner may harm the gaskets thus making the problem worse).

Amazon.com: Vacuum Leak Detector: Automotive

 

[wmburns]

I was reconsidering the original problem (idle surge with AC on). The problem may be as simple as low Freon. Please see the following post for an explaination.

Note: your problem is idle too low but the same concept still applies.

http://www.stangnet.com/mustang-forums/807996-idle-surge-c-defrost.html