'97 TC sluggish when starting out

Posted by: SVTarHeel

'97 TC sluggish when starting out - 08/11/20 03:02 PM

Our daily driver is a '97 Town Car with 205K. Recently, it has has episodes when it's super sluggish when starting out. I'll back out of the driveway or pull away from the office and, with the pedal pressed down as usual, the car only accelerates to 10 or 15 mph. It will go anywhere from a few feet to 1/8 of a mile and then it seems to 'catch up' and will zoom off. For the last 2 or 3 days, it's been doing this almost every time we take off after it's been sitting for a few minutes.

I'm betting this is a common problem but I must not have searched for the right key words to find a place to start checking.
Posted by: professorP7B

Re: '97 TC sluggish when starting out - 08/16/20 06:09 PM

Could be a number of things. Is the car running normally otherwise? Once it does get going, how does it drive once you're up to speed? Say, 55-70MPH range when cruising?

Ignoring engine performance issues (which it's possible you have) what you're describing sounds like a textbook torque converter stator one-way clutch failure. The one-way clutch inside the torque converter stator is designed to lock the stator when the difference between impeller and turbine speeds is high. This prevents the fluid from splashing back against the impeller and slowing down (or working against) the engine. Once you're cruising the stator should free-wheel, allowing the impeller and turbine to match speeds. Additionally, the torque converter lock-up clutch should engage at higher speeds which eliminates basically all of the components I described above.

If you can confirm that no engine performance issues exist, the only way of inspecting the torque converter stator is to perform a stall test (left foot hard down on the brake, right foot hard down on the gas, like you're trying to do a burnout.) The RPM should only reach a certain point (IDK what stall speed is on a civilian car but it's gotta be less than the 2700 max posted for the CVPI,) if the RPM is higher than spec, a transmission component is slipping (or you're actually doing a burnout, not the point of the test) if the RPM is low it's either an engine performance issue or a torque converter (most likely the stator) issue.

The only way to confirm a converter issue is to remove the transmission and inspect the stator support shaft. If it's in good shape, a new converter has to be installed...there's no way of opening the converter to inspect the one-way clutch.

I have seen mechanical clutches cause intermittent failure although it is rare. Sometimes they'll catch in just the right way and hold for awhile, other times they'll just slip.
Posted by: Preston03LSE

Re: '97 TC sluggish when starting out - 08/19/20 05:52 PM

My 97 Town Car used to do this. It would chug and chug then suddenly take off! Cleaning MAF and replacing fuel filter fixed this issue for me.
Posted by: dRock96Marquis

Re: '97 TC sluggish when starting out - 08/20/20 11:18 PM

Are you saying the engine feels bogged down? I’d start simple and observe the fuel pressure after start up and first driving. There is a capped Schrader valve on the fuel rail you can hook up an external gauge to. Most Gauges have enough slack to go over the wiper cowl and against the windshield so you can see it while driving.
Posted by: 2008interceptor

Re: '97 TC sluggish when starting out - 08/21/20 07:43 AM

I used to clean my intake on my 94 and 98 every year. Otherwise I'd get a somewhat rougher idle and it would be less responsive.
You may need a fuel pump along with the filter or shortly after changing it. Have you pulled any of the spark plugs to see what they look like?
Posted by: SVTarHeel

Re: '97 TC sluggish when starting out - 08/24/20 05:51 PM

Sorry for the delay... I never got notification of replies from the forum. I’ll pass them along to my dad and get back to you all. Thanks!
Posted by: SVTarHeel

Re: '97 TC sluggish when starting out - 08/30/20 02:34 PM

The solution ended up being very surprising, at least to me... we swapped out the mass air flow housing unit from a donor vehicle and the sluggish, bogged down start was gone the next time we started the car. I wanted to post the result so that it could be found by future searchers with a similar issue. Thanks for the pointers!