Sigh...same TC lockup issue...

duhtroll

duhtroll

If it weren't for my horse...
I am still having the TC lockup/unlock (formerly bucking at around 2000 RPMs) issue.

I have the issue expressed in a previous thread, but here is a summary. Acceleration is fine and then when I reach highway speeds, 60 MPH and up and 2100-2300 RPMs (thought initially it was a lower range and through data logging found my tach reads low), the RPMs will surge/bounce up and down about 2-300 RPMs repeatedly every few seconds.

Datalog shows "torque converter duty cycle" corresponds with this bucking.

The car has to be warmed up first.

When we load a tune that eliminates TC lockup, the problem is gone. However I want the problem fixed, not just circumvented.

I have swapped from the Stallion TC to the stock, so I doubt both TCs are bad. So I also will have a PI 3200 stall for sale most likely as I no longer need it.

I have had the solenoid in the TC replaced twice. Electrical diagnostic shows high resistance at TCC solenoid, still.

We have tried 4 different tunes - happens in all of them.

It happens in 4th and when OD is locked out.

Replaced both front O2s.

Cleaned MAF twice and disconnected battery to reset also.

I need this problem fixed or I am at the point where I will be selling and moving on. I lost most of the summer to this stupid problem and I am not just going to take up garage space with this anymore.

Any takers on what the next step should be?
 
Last edited:
I am going to tell you this from a lot of experience with this problem on several different Ford platforms. What you do with it is up to you.

I am definitely NOT saying that this is your problem, but almost 90% of the time the problem behind this exact complaint ends up being a low grade misfire caused by one or more failing COPs. Yours is almost the textbook classic example actually. And, it almost never fails that people always argue the same arguments in this instance. 'How can it be the coils when it does it only for this rpm range?' 'How can that be coils when it doesn't do it if the torque converter is unlocked?' 'How can that be coils when the data shows this other thing happening while the problem happens?

The answer to all of these is that it does happen and it can be that because of computer control. Think about the load and the change in load in all of those scenarios. A few of the key things that the computer looks at when determining what it's doing with spark control are rpm and load. Also know that it is entirely likely that there will be nothing noticed at WOT. It happens all the time. These things fail a lot and they don't do it in a way that seemingly makes sense to most people. The complaint is always exactly what yours is.

So, my advice is that if you haven't considered the COP's for whatever reasons then now would be a good time to do so. I tell people to get a couple of good COP's and start swapping them out to see if the problem changes or goes away. Usually they can even borrow them from another vehicle. It isn't that hard and you don't have to change anything else which might give you a false sense of having fixed it when the problem goes away while it's re-learning.

That's just my advice. What you do is up to you.

Darrin
 
Thanks - would this also explain the findings of the electrical diagnostic?

Darrin said:
I am going to tell you this from a lot of experience with this problem on several different Ford platforms. What you do with it is up to you.

I am definitely NOT saying that this is your problem, but almost 90% of the time the problem behind this exact complaint ends up being a low grade misfire caused by one or more failing COPs. Yours is almost the textbook classic example actually. And, it almost never fails that people always argue the same arguments in this instance. 'How can it be the coils when it does it only for this rpm range?' 'How can that be coils when it doesn't do it if the torque converter is unlocked?' 'How can that be coils when the data shows this other thing happening while the problem happens?

The answer to all of these is that it does happen and it can be that because of computer control. Think about the load and the change in load in all of those scenarios. A few of the key things that the computer looks at when determining what it's doing with spark control are rpm and load. Also know that it is entirely likely that there will be nothing noticed at WOT. It happens all the time. These things fail a lot and they don't do it in a way that seemingly makes sense to most people. The complaint is always exactly what yours is.

So, my advice is that if you haven't considered the COP's for whatever reasons then now would be a good time to do so. I tell people to get a couple of good COP's and start swapping them out to see if the problem changes or goes away. Usually they can even borrow them from another vehicle. It isn't that hard and you don't have to change anything else which might give you a false sense of having fixed it when the problem goes away while it's re-learning.

That's just my advice. What you do is up to you.

Darrin
Click to expand...
 
It wouldn't explain that of course. But are you getting any codes from the computer on that? If you think that is the issue then you need to start working your way through the wiring harness all the way from the transmission to the computer to see where the high resistance connection or wire is.

Might not be a bad place to start. It's only time and no cost for parts.

Darrin
 
No, no codes.

Darrin said:
It wouldn't explain that of course. But are you getting any codes from the computer on that? If you think that is the issue then you need to start working your way through the wiring harness all the way from the transmission to the computer to see where the high resistance connection or wire is.

Might not be a bad place to start. It's only time and no cost for parts.

Darrin
Click to expand...
 
That's all I got then for now.

So if you think it's realted to a problem in the TCC circuit somewhere then I would start by ohming out that circuit at the computer and then checking the resistance of the solenoid by unhooking everything and putting the meter directly on the solenoid itself. If there is a discrepancy through the circuit then start from the solenoid end and work your way toward the computer checking every connection until you find the problem.

Again, that is easy enough and won't cost you anything but time.

Let me know if I can help at all.

Darrin
 
$50 shipped if you want them. If that's not the prob, you can sell them cheap to someone else easily enough.
 
Perhaps the TC duty cycle is related to a misfire/stumble of the engine.

Try replacing your EGR/DPFE - it's one assembly. I think is was $100 or so. I had a light bucking at float and I replaced the EGR/DPFE and the stumble at low rpm vanished. May or may not be your problem. You said "end of rope" so try it...
 
I haven't checked list prices lately, but the TC has only a few thousand miles on it and about a dozen passes at the track, so I am guessing something like 60-70% of whatever one would be new.

MrBluGruv said:
Given that the TC is in good working order (sounds like that isn't the problem) and you do sell it, how much are you thinking you'll be wanting for it?
Click to expand...
 
babbage said:
Perhaps the TC duty cycle is related to a misfire/stumble of the engine.

Try replacing your EGR/DPFE - it's one assembly. I think is was $100 or so. I had a light bucking at float and I replaced the EGR/DPFE and the stumble at low rpm vanished. May or may not be your problem. You said "end of rope" so try it...
Click to expand...

He isolated it down to the TC by shutting the lockup off in the tune. If it was the EGR it would be a constant issue no matter what the convertor is doing.

When I had my car tuned we locked the convertor on the dyno. Why? Because it puts more load on the engine and it gives a more accurate idea of how to adjust the AF mixture. When the TC locks up it such a added load on the engine that you can see it on the graph and hear the engine bog down. Which is why I would have to agree with Darrin that its a COP issue thats breaking up under a load. Contact Musclemerc for a great deal on 8 new coils. His price was $110 shipped.
 
I have PMed him, but a couple questions.

Wouldn't the coil issue show up either with a code or through the diagnostic?

Also, you must mean $110 per, right? I'd rather do two and swap them around to see if I can make the problem go away than buy all 8.

Blackened300a said:
He isolated it down to the TC by shutting the lockup off in the tune. If it was the EGR it would be a constant issue no matter what the convertor is doing.

When I had my car tuned we locked the convertor on the dyno. Why? Because it puts more load on the engine and it gives a more accurate idea of how to adjust the AF mixture. When the TC locks up it such a added load on the engine that you can see it on the graph and hear the engine bog down. Which is why I would have to agree with Darrin that its a COP issue thats breaking up under a load. Contact Musclemerc for a great deal on 8 new coils. His price was $110 shipped.
Click to expand...
 
duhtroll said:
Wouldn't the coil issue show up either with a code or through the diagnostic?
Click to expand...


Almost 100% of the time it does not show up any way other than by driving it because the problem is isolated to very specific conditions.

This is another one of those questions that get asked almost every single time that I forgot to mention above.

I think that price was for 8. Snatch those up.

Darrin
 
duhtroll said:
I have PMed him, but a couple questions.

Wouldn't the coil issue show up either with a code or through the diagnostic?

Also, you must mean $110 per, right? I'd rather do two and swap them around to see if I can make the problem go away than buy all 8.
Click to expand...

No, $110 for all 8 shipped. The deal of the century.

I had a coil meltdown when my plug backed out and the boot wore out and it arced against the cam cover. I drove another 20 miles on 7 cyl til I was able to pull over and fix the problem. No CEL the entire time. I also had a sparatic miss due to a coil being not plugged in all the way. No CEL either. Its not a very reliable warning system when it comes to ignition issues.
 
Last edited:
You must log in or register to reply here.
Back
Top