Solved Converter lock-up engagement/disengagement.

[don-ohio]

Hi! I have a 1993 Aerostar,4.0 , extended 2 wheel drive Eddie Bauer.
It has 235K on it. When I'm going down the road at 55 or better, my lock-up that is engaged will disengage(the tach goes up a few hundred rpm) and then engage after maybe 10-15 seconds and then 30 seconds or so later it will disengage again,and on and on this happens.KILLS my gas mileage,which is really bad anyway, and I know it's not good for the tranny.
ANYWAY.......this is happening on level land,accelerator not varying.
Anyone have an idea? I suspect an emission control,myself,either the MAF sensor or IATC if it has one.
Please help! don-ohio

 

[JohnAerostarXLT]

Hey Don, welcome to the site! Post some pictures of your van when you get a chance.

I have only this comment on your issue, cleaning the MAF sensor is a simple place to start and will probably help with MPG anyway. I strongly suggest using CRC Mass Air Flow Sensor cleaner, which is avalable at AutoZone. Follow the directions on the can.

Usually, I notice runability problems with a dirty/bad MAF but like I said, it is a place to start.

 

[jlh3rd]

I don't know what all sensors the computer uses to send signals to the tcc..but I know there is a signal sent from the brake switch.....if you tap the brake pedal while driving, does the clutch disengage then engage?....if so, there is one very small chance that maybe the brake switch adjustment is too close to the brake pedal and the jarring or bouncing from driving is intermittently causing the disengagement and re-engagement.....or a bad or loose switch....adjust the switch to increase the activation distance, go drive and see if the problem still exist.....or see what happens if you unplug the switch....long shot, I know

 

[jlh3rd]

Remember, if you do this, your brake lights will be delayed coming on, or not at all

 

[BrooklynBay]

Welcome to this forum! How do you know that it's the TCC solenoid cycling each time, and not the 3-4 shift solenoid (overdrive)? Do you have the original transmission? When was the last time you replaced the fluid & filter?

 

[don-ohio]

Thank you all for answering,Brooklyn,Jlh3rd.and John Aero!I will take it all into consideration.
Brooklyn,I am positive it is the TCC locking and unlocking,because the rpm change is way too little to be a change down to third from OD.
As to fluid,it is excellent as is the filter,but it IS the original transmission.
I should've mentioned this earlier about having good fluid and filter.
I'll try the MAF first like you said,John,and then look for a faulty brake switch,too,JLH! Thanks to all! don-ohio

Welcome to this forum! How do you know that it's the TCC solenoid cycling each time, and not the 3-4 shift solenoid (overdrive)? Do you have the original transmission? When was the last time you replaced the fluid & filter?

 

[don-ohio]

Update! Okay,I cleaned the MAF sensor with the correct product like John said.......àn so far,so good! The annoying problem hasn't returned,in about 70 miles of driving.
I found that it was running a little low on coolant,so I've kept it full,àn after these next three day shifts,I'll get 7 days off àn I can do better investigation of it.
Thank you,John, àn you others too! I appreciate the help,àn if I see someone having a problem I've suffered,I'll be sure to speak up about it. don-ohio ^)

 

[BrooklynBay]

Thanks for the update! I'm going to mark this thread solved.