RPM fluctuating at all times BUT idle speed

SHOdded · February 20, 2017, 09:59:15 AM

I would thoroughly check/clean the throttle body, the TB motor, and the TP sensor. Grease before reconnecting sensor. The TB is known to be an issue when RPMs fluctuate at idle, so perhaps this is a variant of that problem.

As far as logging, please add TB parameters, including ETC_DSD and ETC_ACT, and ETC_TRIM (should be named pretty similarly). Also look for wastegate duty cycle (WGDC, perhaps?) parameters, and Torque Source/Torque Management parameters and add those. Then re-log & post. I am not seeiing much in your logs to point at right now. The knock readings look spot-on, there MIGHT be a SLIGHT variance in Equivalence, but again, nothing pinned down.

jimmyducati · February 20, 2017, 10:10:42 AM

I just ordered new Motorcraft 02 sensors, so if they are part of the problem it will be eliminated. Ill check the TB components and clean everything really well, gap the new plugs and record the parameters you suggested... Gotta get this back to tip top!

jimmyducati · February 22, 2017, 10:25:41 AM

SHOdded · February 22, 2017, 10:31:00 AM

Very common occurrence, will not affect functionality, BUT best to have a cap on there to prevent dirt & grime from accumulating. If you can find the cap or buy the cap, put it on with a dab of silicone sealant or something similar after cleaning out the area.

jimmyducati · February 22, 2017, 01:00:22 PM

Damn, I thought I was onto something with that! Anyway.. I changed the spark plugs this morning (first time the boots haven't stuck to the plug, so it was a way easy job) then went on a short drive after warming it up and confirming the trans fluid was filled properly (it was).

At idle it is smooth, but the RPM's still surge while cruising and/or accelerating at anything but breakneck speed. The exaggerated studder is also still there when accelerating like a normal person, first the weird surging, then a bad studder. All the PS-534 plugs were gapped to .030" and the old ones didn't show any bad patterns, all grayish tan tips with a trace of dark soot at the base of the threads.

Again, if I drive like an angry person, it sings beautifully.. Shifts nice and firm like usual. Drive like a normal person, crap. I data logged about 30 seconds of it, I think I got all of the symptoms captured:

pmezo33 · February 22, 2017, 01:11:39 PM

Quote from: jimmyducati on February 22, 2017, 01:00:22 PM
Damn, I thought I was onto something with that! Anyway.. I changed the spark plugs this morning (first time the boots haven't stuck to the plug, so it was a way easy job) then went on a short drive after warming it up and confirming the trans fluid was filled properly (it was).

At idle it is smooth, but the RPM's still surge while cruising and/or accelerating at anything but breakneck speed. The exaggerated studder is also still there when accelerating like a normal person, first the weird surging, then a bad studder. All the PS-534 plugs were gapped to .030" and the old ones didn't show any bad patterns, all grayish tan tips with a trace of dark soot at the base of the threads.

Again, if I drive like an angry person, it sings beautifully.. Shifts nice and firm like usual. Drive like a normal person, crap. I data logged about 30 seconds of it, I think I got all of the symptoms captured:

Again... sounds exactly like my torque converter when it went. Same exact symptoms. Low RPM's, the car shuddering through the gears. High RPM's, runs smooth.

jimmyducati · February 22, 2017, 03:14:33 PM

I think its more that I don't want to believe its the trans, but the shudder isn't consistent and went completely away for more than an insignificant number of miles after replacing the vent solenoid...

Keeping my fingers crossed that someone can look at the last data log and identify something else!!

SHOdded · February 22, 2017, 06:35:02 PM

Here's one way to test for TC shudder:
http://www.agcoauto.com/content/news/p2_articleid/203

It is also possible that increasing the pressure of the EPC solenoid may resolve a TC shudder, according to another article. You could talk to LME and see what they think about the idea. If they agree to do it, then you can test with "normal" driving to see 4 yourself.

In your latest log, I do see TC slippage> than desired as accelerator pedal input increases. Throttle body behavior seems normal, as does WG duty cycle.

AJP turbo · February 22, 2017, 06:46:24 PM

The conveter is rarely locked below 5th gear and at low loads so you should see slippage....ill try and look at the log tonight but i dont expect to see much....it seems there are quite a few sho's ,mks' that are doing this bucking thing at low loads

jimmyducati · February 22, 2017, 08:23:45 PM

If AJP's evaluation of my latest doesn't suggest anything BUT converter issues, Ill get it checked out this week.. Are dealers the way to go or would I be better off going to a transmission specialty shop?
Also.

pmezo33 · February 22, 2017, 09:03:03 PM

Quote from: jimmyducati on February 22, 2017, 08:23:45 PM
If AJP's evaluation of my latest doesn't suggest anything BUT converter issues, Ill get it checked out this week.. Are dealers the way to go or would I be better off going to a transmission specialty shop?
Also.

Bring it to a trans shop and have them evaluate. They should be able to diagnose it fairly quickly. Mine never threw any codes, but a five minute drive was enough for them to tell me my TC was shot.

jimmyducati · February 23, 2017, 12:45:35 PM

Transmission was almost a quart down when I checked it with the engine running.. Added a quart to it, seems to run slightly smoother and I get slightly less RPM fluctuation at steady low speed, but the "cattle guard crossing" i still there under acceleration.

I guess a new transmission/converter is in my future

I thought the trans was nearly bullet proof on these?

SHOdded · February 23, 2017, 01:02:14 PM

It is, but it has to be serviced frequently if it is tuned. Plus you have 150K on the car, that's pretty much I'd say Ford expectations for a transmission (i.e., "lifetime"). Did you buy the SHO new, if not, you bought it with how many miles on it?

pmezo33 · February 23, 2017, 01:12:20 PM

My trans was regularly serviced when my TC went at just under 100k. Mine was/is 100% stock too.

When was the last time yours was flushed? I don't know if being down a QT will cause a trans to overheat, but it probably didn't help.

At least you know what your problem most likely is. It's an expense, but at least you have an idea how to fix it and get it running normal again.

derfdog15 · February 23, 2017, 01:39:40 PM

Quote from: AJP turbo on February 22, 2017, 06:46:24 PM
The conveter is rarely locked below 5th gear and at low loads so you should see slippage....ill try and look at the log tonight but i dont expect to see much....it seems there are quite a few sho's ,mks' that are doing this bucking thing at low loads

Mine does a shudder/buck/rpm flutter on decel every once in a while. Done it since day 1. It rarely happens but it does happen.