Driving me F#@*&! nuts

[Hawgman]

No torching the stang - bad form....

Seems to me the possibilities are limited - time for some S. Holmes:

1. vacuum f'd up?
2. O2 sensors F'd up?
3. IAT sensor F'd up?
4. TCS F'd up?
5. injectors F'd up?
6. wiring between #2 through #5 and the PCM F'd up?
7. Tune F'd up?
8. PCM shit the bed... (btw - if you don't have kids or an elderly ward that phrase doesn't quite have the impact it does if you actually seen someone "shit the bed")

1. No. 20+ inches of vaccuum at the manifold at idle. No detectable vaccuum leaks in any hoses
2. Thought that as a possibility also. But O2 sensors are working according to the data log info. Am going to replace them anyway.
3. May be possible. Part of what is going to be checked this week
4. Would have to be BADLY F'd up to do what it is doing with the car sitting still.
5. Again, could be possible. Have not swapped them out. But not getting codes indicating an injector sticking closed, and not getting fuel pressure bleed down indicating one sticking open.
6. Anything is possible, but hard to imagine it just happened to go bad after the bypass valve replacement.
7. Tune rewritten on Saturday and loaded as I indicated above in post 12 of the thread.
8. Ok, this might be possible, but would expect much more of a failure than what is happening.

So, unless I missed something - Quit yer bitch'n, run 'em down and start replacing stuff Ford Service Department style until it gets better...

I would respond to the quit yer bitch'n comment, but the only thing that comes to mind is FOFF... so I will just let it go. As for taking the I have all the parts I need available to me shot gun approach...uh..not unless absolutely necessary.

Have you monitored IAT and Load to see if they go nuts?

Yes, have monitored IAT and MAF counts. Both seem to be operating properly.

TCS stuff is new to me, but given that it does pull fuel, I'd be looking for issues there to (i.e. F'd up ABS sensor?)

Again, it will go nutz with the car parked. So they would have to be drastically jacked

Seems odd that you would have a bypass valve failure AND some other mysterious failure at the same time... Mr Occam is scratching his chin suspiciously, but can't think of why that would cause this positive fuel pulling feedback loop?

Didn't happen at the same time. Pretty sure I indicated in my initial post that this scenario happened post bypass valve replacement. Car was running fine ( except for only making about 5psi of boost ) before the bypass valve replacement

p.s. forgot about fuel pump F'd up - can't remember what your BAP/pump setup is? I presume you are watching fuel pressure and have ruled that out?

As stated in the initial post, running a GT Supercar pump and KB BAP, and that I had swapped out the fuel pump to eliminate that from the scenario.
If it were a fuel supply issue, I would "think" that I would have a lean condition and the data logging would indicate that it was trying to add more fuel to correct it, not a lean condition being caused by it removing fuel. I could be wrong though.

 

[don_w]

Man... I have no clue what could be causing this, but I'll sure be interested to find out once the riddle is solved.

 

[Hawgman]

I'm starting to think it is a lack of beer...

 

[MikeVistaBlue06]

Doc,

Didja run it with the boost bypass valve unplugged from the vac as you were thinking about late Sat.?

Mike

 

[Hawgman]

Yea, I popped the cap off the "T" and it didn't make any difference in the symptoms. DAMNIT.

I rearranged some work stuff and am going to head back up there Thursday to see if we can get it chased down. Provided the fucking thing doesn't vent itself first.

 

[Ratman]

It wants to be traded for a Shelby

 

[Ratman]

On second thought it may be that piece of crap S/C that conman sold you.

 

[don_w]

I'm starting to think it is a lack of beer...

Well, I do know how to fix that.

 

[Hawgman]

It wants to be traded for a Shelby

Well if I can find some nice guy sponsor that owns a metal company over in North Dallas to make up the $30k difference I will hop right on that.

On second thought it may be that piece of crap S/C that conman sold you.

Ya know... I actually have been wondering if it was a buttefly issue in the SC for the boost control/bypass. If the SC is somehow fukkered up, oh well. I certainly got my money's worth over the last 14 months with it. But I will guarandamntee you this, it will be replaced with a turbo and not another SC ( of any brand ).

 

[94tbird]

boo to the hairdryer lol. look at mark he had the S/C went to a hair dryer and now is back haha

 

[Hawgman]

That's a piss poor example. Mark would bitch if he was being hung with a new rope.

 

[cekim]

8. Ok, this might be possible, but would expect much more of a failure than what is happening.

Well, anything is possible once that happens - but see below - I missed a key part of this debug process...

I would respond to the quit yer bitch'n comment, but the only thing that comes to mind is FOFF... so I will just let it go.

Kidding of course - these types of debug are really frustrating. The data logging just teases you with more data - if the problem isn't a sensor or the tune the PCM is just getting in your way (assuming it isn't the problem)

Didn't happen at the same time. Pretty sure I indicated in my initial post that this scenario happened post bypass valve replacement. Car was running fine ( except for only making about 5psi of boost ) before the bypass valve replacement

ahhhhhh.... I missed that... That narrows the possibilities significantly...

Silly question - if you put the "bad" valve back on - does it return to its low boost goodness?

 

[Hawgman]

Kidding of course

I know, as I was as well.. it's all good man.

Silly question - if you put the "bad" valve back on - does it return to its low boost goodness?

d00d... not a silly question at all. MikeVistaBlue06 and I had the same thought driving it back from the shop the other night. That was why I disconnected the cap off of the T in the vaccuum line between the manifold and the valve. To basically put it back in the same scenario it was in with the bad valve ( without having to change the valve back out ).

On a lighter note... whatever the hell the problem is, it is getting worse.

 

[cekim]

I know, as I was as well.. it's all good man.


d00d... not a silly question at all. MikeVistaBlue06 and I had the same thought driving it back from the shop the other night. That was why I disconnected the cap off of the T in the vaccuum line between the manifold and the valve. To basically put it back in the same scenario it was in with the bad valve ( without having to change the valve back out ).

Alright I am confused (what's new?) as to your "before" symptom as well as what's going on now....

Ok, unless I have missed something (again what's new?) - the way this valve works is that vacuum holds it open against its internal spring...

While the TB is closed and/or anywhere south of WOT - there is vacuum in the upper plenum which pulls on the diaphragm on bypass valve which in turn rotates the bypass butterfly...

There are 3 options for failure of the bypass valve that I can imagine with the each having its own symptoms of failure:
1. broken/soft spring
- low boost - even small vacuum is able to pull the S/C into bypass
2. sticky shaft
- erratic behavior - sometimes low boost - sometimes surging at idle
3. leaky diaphragm/housing
- normal boost + surging - S/C always in "go" mode - blowing boost even at idle having trouble sucking against closed throttle-body... but as soon as it the TB is open you get as much as it can give you right away (surging)...

Capping off the bypass vacuum, unless you also tie-wrap the shaft/arm up into "idle" position, will put it in "full" boost at all times (surging at idle)...

Hopefully I haven't missed this in your earlier posts, but have you watched the vacuum on the bypass valve as you drive? rig up a gauge if you need to at the source - rather than relying on vacuum readings else where...

I guess next after that - its time to pull the upper plenum off and take a peek at the bypass butterfly (assuming you have checked that it isn't binding form the outside?)

 

[Hawgman]

Alright I am confused (what's new?) as to your "before" symptom as well as what's going on now....

Ok, unless I have missed something (again what's new?) - the way this valve works is that vacuum holds it open against its internal spring...

While the TB is closed and/or anywhere south of WOT - there is vacuum in the upper plenum which pulls on the diaphragm on bypass valve which in turn rotates the bypass butterfly...

That is the way I understand it to operate also.

There are 3 options for failure of the bypass valve that I can imagine with the each having its own symptoms of failure:
1. broken/soft spring
- low boost - even small vacuum is able to pull the S/C into bypass
2. sticky shaft
- erratic behavior - sometimes low boost - sometimes surging at idle
3. leaky diaphragm/housing
- normal boost + surging - S/C always in "go" mode - blowing boost even at idle having trouble sucking against closed throttle-body... but as soon as it the TB is open you get as much as it can give you right away (surging)...

failure on mine was # 3. The diaphram had separated all the way around inside the bypass valve housing.

Capping off the bypass vacuum, unless you also tie-wrap the shaft/arm up into "idle" position, will put it in "full" boost at all times (surging at idle)...

Agreed. Here's the deal. With the car off, the actuator arm on the bypass valve is at rest against the stop bolt. Start the car, vaccuum pulls the arm up. Now, when the bypass valve had the ripped diaphram, the arm was against the stop all the time. So by me removing the vaccum line "T" cap to the bypass, it was reacting the exact same way it did with the bad valve, meaning the arm stayed against the rest at all times.

Hopefully I haven't missed this in your earlier posts, but have you watched the vacuum on the bypass valve as you drive? rig up a gauge if you need to at the source - rather than relying on vacuum readings else where...

Only observations made of the valve operation was with the car sitting still. Start the car, the actuator arm instantly draw up. Give it hard acceleration, the arm goes down. It appears to be operating freely, not sticking or irratic movement.

I guess next after that - its time to pull the upper plenum off and take a peek at the bypass butterfly (assuming you have checked that it isn't binding form the outside?)

Yea, i'm thinking that might be happening next also. It is not binding from the outside, but wouldn't hurt to check.

Considering that I have basically duplicated the bad bypass scenario by removing vaccuum from it and the car is still doing the same thing of DRASTICALLY leaning out on takeoff, or at a constant speed for 4 or 5 seconds then snapping back to normal. I am really thinking it has to be some electrical malfunction with a sensor or part. It almost has to be just a coinsidence that it showed up after the bypass valve replacement.

Your shotgun replacement approach is starting to sound better and better. Not cheap...but damn, choices are becoming limited.

 

[Cali HP Addict]

I have a theory brewing. Maybe, when you had the bad boost actuator, a piece of the torn rubber diaphram got sucked into the hose. That partial clog slows down the vacuum reaction time to the fuel pressure regulator. This could be causing the delay in fuel pressure regulation which would do 2 things. 1- cause a rich condition when first started up since it would not read the vacuum instantly. 2- cause a lean condition upon takeoff or any transition from vacuum to 0 or boost.