Slipping? Please Help! - TCCoA Forums
 
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post #1 of 6 (permalink) Old 12-08-2010, 09:43 PM Thread Starter
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Unhappy Slipping? Please Help!

Ok, when I first did my j-mod to my 95 Thunderbird, it shifted INCREDIBLE and I highly recommend this mod to ANYBODY. It shifted crisp and firm up and down at any speed.

Fast forward to when I replaced the ECM. The stock ECM that was in my 95 Bird was F5SF-CA A5W0. It started giving me a bunch of problems, and a friend gave me a 94 Bird ECM F4WF-AC E4A3. The car runs awesome again after I put this 94 EEC in my 95, however.....

Since I swapped the ECM, I noticed it shifts differently. Actually, let me re-phrase that. It upshifts normal, but the LOCK-UP is wayyy different and kind of sloppy now. It used to lock up firmly and disengage quickly. Now it's kind of wishy-washy when it locks and unlocks. The best time you notice it is say when cruising at 65-70 mph and you punch it to pass. It used to downshift quickly and firmly with the old ECM. Now, it acts like it "thinks" about the downshift a few seconds then kind of slides in (feels like you were slipping the clutch on a standard), then finally starts accelerating.

I feel it's ruining something in the tranny/torque converter every time it acts like that, so I kind of baby it now. Is the lock up schedule THAT different in these two ECM's? Oh, I did a Mark VIII torque converter upgrade after all this, but it didn't seem to change these particular behaviors much if at all.....

~Rick

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post #2 of 6 (permalink) Old 12-09-2010, 12:09 AM
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I don't have access to those ECU catch codes, but Ford's solution for any TC shudder was altering how it modulated slip across the converter during a shift. For comfort reasons, Ford actually commands the TCC solenoid to modulate lockup at less than 100% after a shift so as to make it mushy and without any harshness. This slippage eats away at the pathetic clutch lining and this coupled with broken down tranny fluid makes the horrible shudder. One of the most important things to address when getting the car tuned is completely disabling this "feature" to preserve the TC clutch. With a stock converter, the shifts aren't even close to harsh with this totally turned off.

One thing to consider about the different lockup behavior is that you changed TCs but don't have it tuned. There is a scalar in the PCM that essentially (and this is a bit of hand-waiving) tells the PCM the stall speed of the TC. This directly affects lockup scheduling. In addition, there is likely a difference in the commanded slip tables between the two PCMs you used. The earliest ones are going to have the programming that caused the worst slippage. If you've ever seen a sticker on the core support that notifies the vehicle has been repogrammed by Ford, it was because of the TC. This is pure speculation, but I'm guessing you have the original programming coupled with the higher stall which is making it feel the way it does.

When I installed a new TC in my car when I still had the 3.8L, the stall speed was about 600 RPM higher than stock. It also had a larger clutch which meant that it would apply faster. I didn't have the car tuned, so when it shifted into third and applied lockup (with the intended slippage), it applied faster than expected, so the RPMs would go up as it lowered the TCC duty cycle to achieve more slip. But it would let off too much and then start increasing the duty cycle, which would make it apply too much and on and on. It would oscillate about 5 times before staying fully locked. But it did this because it simply didn't know (programatically) that anything was different.

--Chris

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post #3 of 6 (permalink) Old 12-09-2010, 05:29 AM
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Battling torque converter shudder on a high mileage transmission is a terrible thing, not only do you have to worry about the transmission but the engine as well. A slight miss will amplify any shudder. The lien pressure of a high mileage transmission will be low due to a worn pressure regulator valve and presure control solenoid. Not to mention the small orifice in the early seperator plates feeding the inferior early design thin lockup piston with a lockup schedule that wasn't up to par anyway. It makes a never ending battle. Adding more stall with a converter clutch that isn't up to the additional load just makes it worse. What year converter did you use? Was it new or used? If used how many miles on it?
I have seen these issues strictly in the pcm, usually on 97's for some reason.
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post #4 of 6 (permalink) Old 12-09-2010, 07:13 AM Thread Starter
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Ok, it acted like this with the original torque converter. Like I said, when I changed the torque converter, it changed the driving habits of the car, of course. But it DID NOT change the lockup behaviors. It acted like this before I changed the converter, so that is NOT the problem. However, FWIW, I bought the converter from a member here - it has about 5000 miles since being rebuilt by Ford and according to the numbers on it, came from a 1995 Mark VIII originally.

This problem only started when I put that older ECM in the car. Even Daniela noticed that it acts different now (and she didn't even notice the emergency brake was on this morning, and called me that something was wrong with the car). I kind of figured it was a sh**ty lock up schedule on Ford's part with the earlier computer, but what can I do?

Seriously, what should I do? I was going to upgrade to a newer (96-97) Bird ECM, but should I just get a 95 right now? I don't want to cause any damage and really don't think it is, but.....

Master486, yes, it oscillates like crazy whenever the lock-up pressure is changed (which is A LOT), but it did that with the original TC too with that different ECM. I just can't believe how different it behaves. These behaviors existed with the old converter. The only change that the new converter did is the stall. That is noticeable when you launch, or just driving around town lightly AND IT'S A GOOD THING. The only problem I have is with that stupid lock-up modulation - it's not a shudder, but (I don't know how to describe it), it just sucks. What are my options, here? You mentioned a tune. Should I just do the conversion to the 96-97 ECM first like I've been planning?

Dirtyd0g, it's not shuddering. I've been in cars with TC shudder before that literally shakes the whole car whenever lock-up is commanded. This car doesn't do that. It runs and shifts fine, it just took away some of the "sport car" feel that was there with the 95 ECM and jmod. It's "soft" - not as much as before I did the j-mod (the shifts are still crisp), but that lock-up modulation is flat out terrible now. I guarantee that if I had put that 94 ECM in without having a jmod done, the car would feel like the transmission was dying and I'd be scared to drive it - it's that bad. It would feel like pushing a tank around town with a slush box drivetrain. It's funny you mentioned the pressure solenoid & regulator. I was thinking about putting in the XL3P EPC and the Sonnax pressure regulator valve (do I have to use the 76948-01?) Would these be good upgrades? What about a Sure-Cure kit?

~Rick

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Last edited by NetKeym; 12-09-2010 at 07:28 AM.
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post #5 of 6 (permalink) Old 12-09-2010, 09:54 AM
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I don't use the sure cure kit, for the 95 just the valve. It could be the PCM entirely but I don't think a 96/97 PCM will work. There are some distinct changes for example removal of the EDIS module. All my 95's have the a5w0 ( i think) and I have never had a problem like that. I would think a tune or chip would be the only real answer.
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post #6 of 6 (permalink) Old 12-09-2010, 11:51 AM Thread Starter
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Quote:
Originally Posted by dirtyd0g View Post
I don't use the sure cure kit, for the 95 just the valve. It could be the PCM entirely but I don't think a 96/97 PCM will work. There are some distinct changes for example removal of the EDIS module. All my 95's have the a5w0 ( i think) and I have never had a problem like that. I would think a tune or chip would be the only real answer.
Alan
Oh, I'm aware of the changes in the 94-95 to 96-97 ECM. But for right now, I like your advice of the A5W0 (I've had two of those ECM's in my car without any problem as well) with a tune for the immediate and the addition of the valve in the tranny, then the 96-97 ECM for a future mod.

Here is a RD version list of what I have to do for the 96-97 ECM swap (a totally different thread, I don't want to get off my tranny subject):

Cooling Fan Control:
Cut ECM Pin #4 (226-R/O Circuit) Wire (Fan Control Monitor)
Move ECM Pin #68 wire to Hole #45 (LFC - Low Fan Control)
Move ECM Pin #17 wire to Hole #46 (HFC - High Fan Control)

TCC Solenoid:
Move ECM Pin #82 wire to Hole #54 (TCC - Torque Converter Clutch)

Crank Position Sensor:
Move ECM Pin #50 wire to Hole #21 & splice ICM Pins #3 & #4 wires
Move ECM Pin #49 wire to Hole #22 & splice ICM Pins #1 & #5 wires
Ground ICM Pin #10

Purge Flow Sensor:
Add to Evap Canister Vacuum
Wire + to ICM Pin #6 wire
Wire - to ICM Pin #7 & move ECM Pin #23 wire to Hole #11

Coil Packs:
ECM Pin #26 wire to ICM Pin #8 Coil Driver #1
ECM Pin #52 wire to ICM Pin #9 Coil Driver #2
ECM Pin #78 wire to ICM Pin #11 Coil Driver #3
ECM Pin #104 wire to ICM Pin #12 Coil Driver #4

ICM (ignition control module) wires for reference:
Pin #1 (395-GY/O Circuit) goes to Pin #49 ECM (PIP)
Pin #2 (659 Circuit) goes to Pin #48 ECM (Tach)
Pin #3 (929-PK Circuit) goes to Pin #50 ECM (Spout)
Pin #4 (350 Circuit) goes to CKP +
Pin #5 (349 Circuit) goes to CKP -
Pin #6 (361 Circuit) goes to Pin #71 & #97 (+)
Pin #7 (259 Circuit) goes to Pin #23 ECM (Ground)
Pin #8 (95-T/W Circuit) goes to Coil #1
Pin #9 (96-T/O Circuit) goes to Coil #2
Pin #10 (651 Circuit) goes to Ground
Pin #11 (97-T/LG Circuit) goes to Coil #3
Pin #12 (98-T/LB Circuit) goes to Coil #4

~Rick

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