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Someone asked me how I did this awhile back on here and I kept forgetting to post it. Hope you guys can use this in some way. When I still had my 1989 Cadillac Deville, I found a way to put a switch on the circuit that locks up the TC. Unfortunately I don't know how to do it on newer cars just ones with the aldl port.

This link: http://www.robertpowersmotorsports.com/images/ALDL_plug.jpg shows that terminal F in the port is the wire going to the TC, I wired up a switch to F and A so that whenever I wanted to eliminate slipping losses in the transmission I would just flip it. But, I never used too much throttle because I don't think the stock torque converters can handle all the torque the V8 had at the low RPM. After installing this I achieved my first 30mpgish tank! (29.4 MPG) We also ran the AC one way so I was impressed with the FE achieved! Which was almost a 400 mile tank but got gas because we found gas really cheap on the way back.

The only thing that I really had to worry about was to flip the switch off if I was coming to a stop so that the transmission could properly downshift. I will likely be looking for a way to do this in my 1998 Ford Escort, but because of more computer usage for this stuff it might be tricky... Hope this benefits someone. :D

No one has played with this? I am going to try to do this on my 1998 Ford Escort, but I don't think it will be this easy because of it being newer, more complicated, and to be honest kinda cramped space to work with! :P

Most newer transmissions are computer controlled, and make use of pulse width modulation to lock the various clutches. Gone are the days when a switch or relay could be used to provide 5v or 12v to force an action within the gearbox.

Your DeVille has the 440T4/4T60 transaxle, with a simple solenoid (that has been known to stick in the 'on' position) and a viscous converter clutch. Normal actuation relies on either 3rd or 4th gear pressure switches being closed (tells the computer the transmission is in direct or overdrive), throttle position, and road speed. The newer 4T60E uses a variable pulse width converter lockup, and feeding 12 volts into the circuit will set several trouble codes and can also damage the computer. This means your '89 DeVille can be tweaked, but don't try the same modification on a '96 car.

Before exploring the converter lockup circuit on the '98 Escort, confirm that the lockup is controlled by a simple 12v feed to a simple 12v solenoid. It is probably a good idea to download a pdf and parts list for the transaxle to confirm this. If the parts lists shows a solenoid as "pwm" or "pulsed", do not feed battery voltage into the circuit. Any attempt to override converter lockup on an electronic transmission on an OBDii car will set a trouble code - typically a P174x code.

I have read some fun stories about people feeding 12 volts into one of the circuits of the solenoid pack on a Chrysler transaxle. It fries the pack in under 1/2 a second. The solenoids are fed 12v, but pulsed up to 100 times a second. That's the bzzz-zzzz-tic you hear from the drivers side wheel area of Chrysler products during each downshift as they come to a stop. The life and livelihood of each of the five solenoids in these Mopar transaxles depend entirely on current fed in very short bursts rather than a continuous flow.

Thanks for replying! I did the mod on the Cadillac and drove it probably 4000+ miles before removing due to storing the car, never had any problems with it getting stuck (even with long highway trips :) ). I was afraid I will probably have to worry about my car using the pulse instead of the simple 12v, but I will have to try and get some wiring diagrams to confirm that. If the line going to the solenoid is pulsed, is there an easy way to work around it? Or trick the ECU into doing it on its own?

There is another way to accomplish this. Its indirect and does have a cost associated. Why I can't explain how it does, it does do it. It computer controller called a Fuel Saver (FS1) that connects to the ODBII port of a 1996 and on car from a company called Volo.

From the moment I hooked it up and let it do its 1 minute calibration, the tac eagerly falls like a rock when shifting around 2200rpm, especially from 2nd to 3rd, and 3rd to 4th and then lock up. This is in my 2002 Pontiac Montana with a 3.4L v6 and 4spd auto.

There are times when keeping it locked up is very very good . For my urban driving, the volo prevents the trans from unlocking right around 40 to 45 at the lightest throttle touch. I drive through rolling hills on my way to work. Without the volo, even thinking peddle pressure pops the trans out of lockup and the tack jumps over 2000 rpm, when it would be better for it to stay. With it, its stays down and I find a peddle position the keeps the instant mpg fairly stable. (Driving with Load)

Keep in mind that lockup on its own is not a silver bullet. If you have to push the engine to speed up the car and force the throttle open, you will have longer periods with wider throttle in some cases with it locked up and the speed is too low. On my car the instant mpg goes down when this happens. In some cases its more efficient to let it pop up and get up to speed using the gearing.

I had the trans rebuilt just prior to getting the volo and drove it for a month prior to installing it, I'm sure the transmission is fine. I unhooked the volo several times to make sure I wasn't dreaming this up. I also took it back to the trans shop and had them drive it with their trans odb diagnostic tool to make sure there were no codes coming back from the trans based on whatever the volo is doing. The codes were fine.

Volo will take it back if you don't like it as well.

I have a scangaugeII on the way, and I am evaluating gauges to watch while driving, with and without volo.

The volo doesn't give you manual control does it? I want to be able to manually control it so i can manage it myself in similar conditions you described above, and I want to use it for light throttle acceleration. Which will make acceleration more efficent, no more inefficiency from the auto trans.

The volo doesn't give you manual control does it? I want to be able to manually control it so i can manage it myself in similar conditions you described above, and I want to use it for light throttle acceleration. Which will make acceleration more efficent, no more inefficiency from the auto trans.

Nope. It does whatever it does automatically. There are lights that show when its working, but thats it

Paul, I looked up volo and all i see are chips that tune your ecu.

Paul, I looked up volo and all i see are chips that tune your ecu. Right MIke I understand that. Like I said above, I'm fairly sure it can't touch the transmission directly or if it does I can't explain it. (I have the FS2, not the performance chip)

What I reported on above is what I observe when connecting / calibrating the unit vs disconnecting it. The unit connects via ODBII and uses mode 8 to replace values that the ecu uses for engine control. It makes its changes under certain conditions and flashes when it does. I can anticipate that. Usually when starting off or when load changes going up or down hills. Whatever its doing encourages the van to upshift. It goes to lock up 7 mph sooner, 38 instead of ~ 45. This makes a difference for me as I am driving on roads with 40 - 45 mph speed limits.

After shifting to third the tac starts falling within 2 to 3 seconds.

It is also more active when the temperature is below 20 and the engine is cold. Once the engine warms up its back to normal. I ordered an ScanGuage from Wayne and I am planning a couple of experiments with it. I want to see what happens on scangauge when the volo lights show activity on several guages.

Color me skeptic. The Volo ads are for HHO generators. There's no logical way something can hook into a diagnostic port and feed input back to every mfr's different ECU reliably, IMO. OBDII was designed to read output, not accept input. Unless there's some reasonable explanation of how it works, the FS2 simply uses OBDII output to make some lights flash.

That sentiment is general and rampant across boards for reasons unknown to me. The only conclusion I can come to is that the ODBII is typically not fully understood.

Here are the things to consider:
ODBII has 9 operating Modes. Mode 8 is bi-directional data transfer to control the operation of an onboard system, test or component.
Until 2004, car dealers were the only ones who had access to the tools and software needed to reflash PCMs. Starting in 2004, flash reprogramming procedures must also conform to SAE J2534 standards which allow the use of aftermarket scan tools or similar pass-through devices that anyone can purchase and use.
Here is the 2004 SAE J2534 (http://standards.sae.org/j2534/1_200412/) specification now universal today:This SAE Recommended Practice provides the framework to allow reprogramming software applications from all vehicle manufacturers the flexibility to work with multiple vehicle data link interface tools from multiple tool suppliers. This system enables each vehicle manufacturer to control the programming sequence for electronic control units (ECU's) in their vehicles, but allows a single set of programming hardware and vehicle interface to be used to program modules for all vehicle manufacturers.

Here is a performance tuning product that uses ODBII as its method:http://www.codeobd.com/j2534-ecu-programmer.php

and another one:http://www.autotap.com/techlibrary/about_flash_reprogramming_pcms.asp
Comment from the page: Today, almost all PCMs have reprogramming capabilities so changes and upgrades can be made if needed. That's over 100 million vehicles that have been built since 1996.

Here is the manual for a chip to build products that can program ECU functions through ODBII. The reference to Mode 8 is on page 4 "OBD-II Mode 8: Control the operation of an on-board system, test or component."http://www.obdscan.net/APEX.pdf

I don't evangelize volo, it works for me and its the same to me if you believe it or not. But to clarify, this is the product I bought (http://yhst-19807630266082.stores.yahoo.net/fs3fuelsaver.html). If you read their description after understanding the above, it makes sense. to me anyway

It's not impossible to do. What I'm skeptical about is that a no-name company with no independent reviews of its products, can produce a product that actually does anything useful for every model of Acura, Buick, Ford, Nissan, Toyota, Scion, etc.

There are just too many combinations of engines, transmissions, manufacturers, and models to justify the programming time involved. Couple that reality with the notable lack of specifications, operating rationale, and the reputation of do-nothing "performance chips," and there's good reason for the general skepticism regarding these products.