Engine Surging idle issues

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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First, with the x cam it will have a rowdy idle. The LSA on that cam makes it hard for the computer to react to imputs.
Second, that cam will need to have a higher idle than a stock cam again because of the LSA.
Third, if there is a leak at the EGR valve why continue to mess around with trying to fix the idle issues? When the new valve comes in change it out then see what happens.
Forth, all this is covered in the checklist.
While the members here want to help you and will help you with advice/suggestions based on their experience and knowledge, to continue to mess with things, like your idle settings, without fixing an issue that you've found, like the leaking EGR valve, you're beating your head against a fender.
I understand the want to fix this and I'm not criticizing your zest to make it run right but these computer controlled vehicles depend on input from sensors and predetermined settings and reset procedures that when 'fiddled' with can make fixing a issue almost impossible to get a handle on. For example, the IAC (idle air control) valve works in a small rpm range, above that range it does not function. The computer controls it. Outside the range and it's useless.
I hope my rambling helps give you a better understanding of what's going on with your stang.
Let me add that changing the egr valve may make the 94/44 codes go away after resetting the computer of course, if not look at the tab/tad for vacuum or wiring issues. Although I think they should have no effect on the idle unless there is a vacuum leak there.
 
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AnthonyA1234

Active Member
Aug 17, 2020
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It’s possible that your throttle stop screw is turned in to the point the throttle is open enough to give the engine commanded idle without the need additional air from the IAC. If that’s the case then unplugging it would do nothing.

Get the car up to temp, unplug the IAC, and turn the throttle stop screw out slowly about 1/4 turn at the time. Give the idle time to adjust after each turn until to see ~550 RPMs. Then plug the IAC back in and see what it does.

I have my doubts that you will ever get it to run perfectly with that X cam without a tune.

I had the same issue with a much milder cam and was never able to fix it with base idle resets and playing with timing. I tried for years before giving up and getting it tuned.
Any chance you know what’s a good timing setting for the x cam? I have it at 14 right now
 

AnthonyA1234

Active Member
Aug 17, 2020
230
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28
Florida
So I just installed the new iac, egr, and I cleaned my salt and pepper shakers. Did another smoke test right now and the new egr is leaking just like the old one. Is it supposed to do this or did I get a bad one? Don’t know how well you can see it in the pics but it was a pretty good leak coming out of the holes.
 

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AnthonyA1234

Active Member
Aug 17, 2020
230
24
28
Florida
First, with the x cam it will have a rowdy idle. The LSA on that cam makes it hard for the computer to react to imputs.
Second, that cam will need to have a higher idle than a stock cam again because of the LSA.
Third, if there is a leak at the EGR valve why continue to mess around with trying to fix the idle issues? When the new valve comes in change it out then see what happens.
Forth, all this is covered in the checklist.
While the members here want to help you and will help you with advice/suggestions based on their experience and knowledge, to continue to mess with things, like your idle settings, without fixing an issue that you've found, like the leaking EGR valve, you're beating your head against a fender.
I understand the want to fix this and I'm not criticizing your zest to make it run right but these computer controlled vehicles depend on input from sensors and predetermined settings and reset procedures that when 'fiddled' with can make fixing a issue almost impossible to get a handle on. For example, the IAC (idle air control) valve works in a small rpm range, above that range it does not function. The computer controls it. Outside the range and it's useless.
I hope my rambling helps give you a better understanding of what's going on with your stang.
Let me add that changing the egr valve may make the 94/44 codes go away after resetting the computer of course, if not look at the tab/tad for vacuum or wiring issues. Although I think they should have no effect on the idle unless there is a vacuum leak there.
So I just did another smoke test and found a lot of smoke coming out right above the starter. Upon closer inspection it looks like it’s coming out of the oil pan gasket. I also had a lot of oil coming out around there too. Can that be causing idle issues?
 

AnthonyA1234

Active Member
Aug 17, 2020
230
24
28
Florida
Oh if you were talking about the egr smoke possibly being the intake gasket no it was definitely coming out of the egr metal holes. I did another smoke test without the egr and I taped the holes and that was when it all started coming out of the oil pan gasket
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,443
8,643
203
polk county florida
Now this is just my thinking, if the intake gasket is leaking at the bottom where it seals at the lifter valley then the crank case thus finding the oil pan leak, another possibility may be the pcv is letting the smoke through to the lifter valley :shrug:
 

AnthonyA1234

Active Member
Aug 17, 2020
230
24
28
Florida
Now this is just my thinking, if the intake gasket is leaking at the bottom where it seals at the lifter valley then the crank case thus finding the oil pan leak, another possibility may be the pcv is letting the smoke through to the lifter valley :shrug:
I’m a little confused so are you saying that the smoke shouldn’t be able to reach the oil pan unless something is leaking somewhere and letting it in?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,443
8,643
203
polk county florida
That's my thought process, yes.
Now I could be wrong, I'm not Melvin (were did that come from!) you took the hose from the throttle body to the oil fill tube off and plugged the throttle body? The only other way, I could be wrong, is a bad intake gasket, pcv or really bad rings (in that case you would have been smoke testing your neighbors).
I'm not a mechanic by trade but my grandbrats think I am.
Don't tell them.
 

AnthonyA1234

Active Member
Aug 17, 2020
230
24
28
Florida
That's my thought process, yes.
Now I could be wrong, I'm not Melvin (were did that come from!) you took the hose from the throttle body to the oil fill tube off and plugged the throttle body? The only other way, I could be wrong, is a bad intake gasket, pcv or really bad rings (in that case you would have been smoke testing your neighbors).
I'm not a mechanic by trade but my grandbrats think I am.
Don't tell them.
Haha. Oops no I didn’t know you were supposed to take off that tube that goes to the oil fill tube. I did put a glove over the TB. Do you think that’s why?