Trilogy Owners who datalog?

[duhtroll]

I am still having the problem summarized in THIS (http://www.mercurymarauder.net/forums/showthread.php?t=67475) thread, which also had a link to another thread describing the problem also.

Since then I have narrowed it down to not being the torque converter, unless both of them are bad in the exact same way -- doubtful. It is also not just in the specific RPM range but everything on the highway (3rd or 4th gear) above ~2100 RPMs.

Tonight TMF and I took her out for a datalog session - I can't run the laptop and drive at the same time. Of course the ENTIRE 40 minute drive she didn't misbehave once. Went back to TMF's place and talked for about 20 minutes, got back in the car and as soon as I hit the highway for home, the bouncing begins around 2200-2300 RPMs.

So, the car has to be pretty much heat soaked for this to happen. The other times were in the sun with ambient temps above 80.

Tonight was no different except the sun was going down and it was about 82 when we started and 78 when we quit, perhaps not hot enough to make this happen until it had time to sit and soak up some heat.

John noticed one thing that didn't seem right - the IAT sensor reading (this is original Trilogy setup, not relocated IAT, so sitting right on top of the MAF) was between 112 and 120 the entire time. As I said ambient air was around 80.

Should it be this high? Anyone ever check this?

Also, I noticed when I got home letting it idle in the garage (I painted my garage floor and wanted to make sure I was on my cardboard squares so I got out to check), the RPMs surged several times from "normal" (have it set at 700 IIRC in my tune) to about 1500. On and off, along with what I believe was the cooling fan, but in the dark I couldn't tell -- sure as heck sounded like it.

Bad IAT sensor? Would that throw a code if it were? Could it be the culprit for the surging in the previous threads?

After tonight, there is no doubt in my mind that this is heat related. The problem simply doesn't occur until the car is really warm.

[duhtroll]

A summary of steps I have taken until now:


I have swapped from the Stallion TC to the stock, so I doubt both TCs are bad.

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.

Replaced all COPs.

[sailsmen]

If your car is running hot, in the coolant ~240* range, the PCM will make commands to reduce the temp such as short shifting to keep rpms down and the car will feel as though it is bucking. At 120* IAT the PCM should not make any such commands.

Suggest you data log the coolant temp.

If your pop off is malfunctioning it can cause "surge" at off throttle.

[duhtroll]

I believe we logged coolant temps and they were normal, but I forget what that normal range was.


If your car is running hot, in the coolant ~240* range, the PCM will make commands to reduce the temp such as short shifting to keep rpms down and the car will feel as though it is bucking. At 120* IAT the PCM should not make any such commands.

Suggest you data log the coolant temp.

If your pop off is malfunctioning it can cause "surge" at off throttle.

[Blown3.8]

Whats your vacuum at in nuetral and in gear? Have you cleaned the IAC valve?

[Michael]

You say you have the trilogy supercharger, have you checked to see if your boost bypass valve is stuck, sticking when hot, the vaccum hose to it is cracked or pinched or any vaccum hoses are leaking.

The reason I say this is the old fashion roots blowers that don't have bypasses and are overdriven will surge because the engine can't injest all the air it is being fed. Maybe your bypass valve is going bad or any of the vaccum hoses that are teed into it could be bad.

If you have a boost gauge, maybe see if the vaccum changes dramatically when it does the surge. At cuise and idle you should have about 20 to 14 inches and load will quickly drop the vaccum. When at light load, if you see it drop and your throttle blades are closed, you should not see much drop in vaccum.

This probably is not the problem, but it is easy to check these items.:burnout:

[duhtroll]

I know the boost gauge does not move at all when this happens - I initially thought the surge could be coming from the blower, so I watched the gauge and saw it stay flat during the "episodes."


You say you have the trilogy supercharger, have you checked to see if your boost bypass valve is stuck, sticking when hot, the vaccum hose to it is cracked or pinched or any vaccum hoses are leaking.

The reason I say this is the old fashion roots blowers that don't have bypasses and are overdriven will surge because the engine can't injest all the air it is being fed. Maybe your bypass valve is going bad or any of the vaccum hoses that are teed into it could be bad.

If you have a boost gauge, maybe see if the vaccum changes dramatically when it does the surge. At cuise and idle you should have about 20 to 14 inches and load will quickly drop the vaccum. When at light load, if you see it drop and your throttle blades are closed, you should not see much drop in vaccum.

This probably is not the problem, but it is easy to check these items.:burnout:

[TooManyFords]

If your car is running hot, in the coolant ~240* range, the PCM will make commands to reduce the temp such as short shifting to keep rpms down and the car will feel as though it is bucking. At 120* IAT the PCM should not make any such commands.

Suggest you data log the coolant temp.

If your pop off is malfunctioning it can cause "surge" at off throttle.


I believe we logged coolant temps and they were normal, but I forget what that normal range was.

Coolant ran 195* -198*. Normal.

[mcgyver59]

Is this.happening when your ac is on?

[TooManyFords]

When riding with Duhtroll to diagnose, it wasn't so much a surge as the converter unlocking and locking back up for a split second. You could see the tach needle flick up and back down, but the car never surged forward.

This is why Andrew and I first thought it was a torque converter problem with slipping. Now that he has swapped them and had the tranny looked at, I suspect a sensor that is getting heat soaked and commanding the PCM to flip out and think it needs to release the converter.

It is not unlike how the converter lock releases when the PCM senses you have lifted your foot off the throttle. And thinking more about this, I believe it is now either the TPS or chaffed wiring leading to the TPS.

Andrew, if I'm correct, we should see a flaky signal from the TPS when we datalog it again. We can also try wiggling (that's a technical term) the wires while it sits at idle to see if that induces the wild RPM issues in park.

[Marauderjack]

How hard would it be to disable the blower and drive it a little??:confused:

[duhtroll]

Not hard... stay under 3000 RPMs. :beer:


How hard would it be to disable the blower and drive it a little??:confused: