This just hasn't been my year with this thing...More problems.

[Duke George V]

Can you still unhook the TCC wiring harness from the transmission on the 4T60E? That was the band-aid on the 440T4 and TH125 when lockup was acting up.

[85_Ciera_Rebuild]

1995 Olds Silhouette L27 3.8

Could a salvage yard ECM be tried?

Again, dis-engage lockup TCC, and try it.

[85_Ciera_Rebuild]

bad hesitation...."pounds" at cruising speed. Like the TCC is stuck, It goes away if I tap the brake pedal or accelerate, but gets worse at deceleration.

I can trouble shoot better when I learn about all parts within a system...OBD II ECMs, I know nothing specific.

That said, after thinking more on this topic...I suspect there is a vacuum sensor (MAP, etc) that triggers shifting into lockup mode....see if there is a vaccum sensor that triggers lockup TCC...check the specs and test it.

Hence, what is complete circuit that controls TCC...brake switch, vacuum sensor, TPS....understand that circuit.

[85_Ciera_Rebuild]

Update...??? MAP ???

[Ray_McAvoy]

This is from the 1995 U-body GM factory service manual and might be helpful for troubleshooting:

TCC Operation
For the torque converter clutch to apply two conditions must be met:
- Internal transaxle fluid temperature must be correct.
- The PCM grounds switches internally to turn "ON" solenoids in the transaxle. This moves check balls, which will allow the torque converter clutch to apply, if the hydraulic pressure is correct as described above. The TCC "APPLY" solenoid controls the flow of transmission fluid to the TCC. The TCC Pulse Width Modulated (PWM) solenoid varies the hydraulic pressure at the converter clutch regulator valve to make locking and unlocking of the TCC smoother.

The PCM controls the TCC apply and PWM solenoids after looking at several parameters:
- Vehicle Speed Sensor (VSS). Speed must be above certain value before the clutch can apply.
- Engine Coolant Temperature (ECT) Sensor. Engine must be warmed up before clutch can apply.
- Throttle Position (TP) Sensor. After the converter clutch applies, the PCM uses the information from the TP sensor to release the clutch when the vehicle is accelerating or decelerating at a certain rate.
- A TCC brake switch which opens a 12 volt signal to the PCM when the brake pedal is depressed.

As 85_Ciera_Rebuild suggested earlier, I'd recommend taking a look at that TCC brake switch. And if that checks out okay, it might be worth checking the wiring for any loose or intermittent connections to the TP sensor, that TCC brake switch, and to the transaxle.

Can you still unhook the TCC wiring harness from the transmission on the 4T60E? That was the band-aid on the 440T4 and TH125 when lockup was acting up.

I don't think that will work with the 4T60E because that plug/harness contains more than just the TCC wiring. It also contains wiring for the shift solenoids.

[SexySilhouette]

Sorry for not updating sooner. New wires and it's been fine ever since. Driven it all over and no problems. Even the A/C seems to be holding a charge - had to use it today.

[Prospeeder]

on the A/C line orings you oiled them right? When you say replaced everything, whats that mean. Evaporators, condensors, rubber lines can all leak. Add dye to the system and the leak will be found eventually. if you see the dye on the drain for the Evaporator housing then you know its the evaporator.

[SexySilhouette]

on the A/C line orings you oiled them right? When you say replaced everything, whats that mean. Evaporators, condensors, rubber lines can all leak. Add dye to the system and the leak will be found eventually. if you see the dye on the drain for the Evaporator housing then you know its the evaporator.

Yes I did. And I did add Dye, never a trace. Even checked the Evap and nothing. I couldn't find the leak.

[Jr's3800]

What kind of plugs and wires did you use the last time they were done? Hope its still running good..

[babyivan]

Sorry for not updating sooner. New wires and it's been fine ever since. Driven it all over and no problems.

I had the same problem on my former 3800 Regal.
For me, it was because I bought the cheap wires from Autozone (Duracrap). After putting on a set of Acdelco wires, I had no more issues.

Also, be sure that you re-use the spark plug boot heat shields, I know of a lot of people that simply threw them away thinking they were not needed or just part of the oem wires.

Even though there's less heat up front, having them on the front plugs is a good idea too!
My current 3.8 has them up front, but my Regal didn't, so I had to order 3 of them.

[85_Ciera_Rebuild]

I bought the cheap wires from Autozone (Duracrap).

Always check OEM's mm and match it. That said...

Bosch Opti-layer Mag Technology - Bosch provides premium quality, pre-assembled spark plug wire sets for virtually all American, Asian, and European cars, vans, and light truck applications. And all Bosch Premium Wire Sets are backed by a "no hassle" lifetime guarantee.

Spark Plugs and Spark Plug Wires Cross Reference Guide

[85_Ciera_Rebuild]

cheap wires from Autozone (Duracrap).

I was reading in foreign car forum tonight that there has been a change in spark plugs and wiring used.

As noted there, "the correct combination would be low resistance wires and resistor plugs ,the standard norm now .

vintage was standard ignition wires and resistance end caps to keep ignition chatter down.

Resistance wires and resistance plugs would pull down performance and starting issues may arise."

Also,]


There has been a lot of discussion on this subject in the past! Many opinions. But in end, it seems to me:
- if you have OE style wires with built in resistors, then use non resistor plugs.
- if you have new style Bosch wires without resistors, then use resistor plugs.