Idles perfect, put in gear it dies, tcc is disconnected (Page 1/2)
thejimbud MAR 30, 03:35 PM
Hey everyone,

I have searched this forum inside out........85 SE V6 starts right up, idles perfect at 900, the tcc has been disconnected for 2 years, almost every time I put it in gear my rpms drop to about 400-500, sputters out dead. No vacuum leaks, new IAC, newer TPS, trans fluid is full, new fuel pump last year, great fuel pressure, and no SES light. Happened two days ago and for the life of me I am at a loss of ideas. I tested the MAP with a multimeter and did the hand pump test as well, all numbers came back acceptable. No EGR, it is blocked off. New 02 sensor last year too. Smells like running a little rich but not terrible. I am replacing the MAP Monday just in case. Any ideas where to proceed ?
Thanks in advance your time and knowledge everybody!

thejimbud
Shho13 MAR 30, 10:01 PM
Maybe your brake booster is leaking internally, that would cause a massive vacuum leak only as soon as you press on the brake pedal. You would need to press the brake pedal to put into drive..........


To test, use a pair of needle nosed vice grips, tips wrapped in a few rags to not damage rubber hose. Squeeze and completely block the hose that supplies vacuum to booster. KEEP IN MIND BRAKE PEDAL WILL FEEL "HARD", AND BRAKE FORCE WILL BE REDUCED, PRESS BRAKE PEDAL HARRRRRRD WHEN PUTTING IT IN DRIVE TO PREVENT CAR FROM MOVING.


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Easy8 MAR 30, 11:49 PM
Does it keep running if you go past drive to neutral? Will it keep running if you give it gas ( point the car in a safe direction.. like not at ANYTHING) Does the car lurch when this happens or does it just bog down and die?
theogre MAR 31, 10:03 AM
Yes, Booster and it's line can cause major vac leak.

May need ECM scanner too. Tran's NS Switch or wires to it may be iffy and ECM is not seeing the trans in gear.

Or Can be iffy engine/trans mounts pulling wires and causing ignition fuel etc problems.


quote
Originally posted by Easy8:
Does it keep running if you go past drive to neutral? Will it keep running if you give it gas ( point the car in a safe direction.. like not at ANYTHING) Does the car lurch when this happens or does it just bog down and die?

Can't "go past drive to neutral"... Can go pass Reverse not drive.
Yes... TCC locked will try to make car move in reverse or drive. Unplug TCC may not help here depending on exact problem.

IOW Solenoid really stuck open the TCC stays locked or enough to stall engine and try to move the car.

Only helps to unplug when valve is slow to close because dirt etc makes some more resistance for core spring closing the valve.
Even if core returns to close position, valve "Rubber" can be bad and leak and keep TCC locked.

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thejimbud APR 01, 06:43 PM
New MAP sensor did not solve this issue. I can shift into drive but it stalls just like when I put it in reverse, if I shift back to neutral sometimes it recovers without touching the gas pedal. Ogre, if you could elaborate a bit more on auto trans sensors I’m all ears sir. I am not familiar with an IOW which you noted on your reply. I’m also replacing cap and rotor cuz they looked a bit corroded and it’s a cheap $20 AC Delco job which I should’ve done already anyways.
fieroguru APR 01, 07:49 PM
Did this gradually get worse, or start all of the sudden?

If gradually, I would clean the bore around and edges of the throttle body plate as well as the IAC passage. On high mile engines carbon can build up in these areas and start restricting airflow. You start to see if first with transitions from park to drive.
thejimbud APR 02, 03:47 PM
This all of the sudden happened.
theogre APR 02, 05:32 PM
NSS is on the trans @ shifter.
Bad or iffy NSS, Iffy Shifter and/or Cable, and other things can make NSS not "Sending" ECM "signal" car in/out of park/neutral. ECM scan tool quickly tell you this as you shift thru different points.
See my Cave, Neutral Safety Switch for what it look like.

You already Unplug TCC in front of Trans right?
Unplug usually stops TCC problems but not always or a lest right away.
Sometimes have to wait until valve closes after solenoid got hot, binding from dirt or both. That can take minutes to hours or even more.
But you have unplug for years so isn't same problem.
Look at how fluidmaster works for toilets... (quick link @ ~ 2:30 min mark) TCC solenoid valve work similar to it. If "rubber" is torn etc and leaking AT Fluid internally then TCC can stay locked or part locked same a foot on clutch pedal pushing part way down. Most times enough load the car and will try move at idle and stall the engine unlike try to move a little at idle but TC works and won't stall.
fieroguru APR 02, 07:30 PM
Check the range switch on the transmission. There are different idle parameters for Park vs. Drive. It might be loose and not in the right position or one of the connectors could have gone bad.
Phil APR 03, 02:13 PM
Same sort of thing happened to my son's car once. Turned out to be a stuck/dirty idle air control valve. To check give it a little gas while shifting into gear.