GM TH125C/3T40 Torque Converter, 3.3L High Idle,

[1 SX]

Happy February! I was on my local craigslist when i stumbled up on a pretty decent looking, older lady owned 1990 Oldsmobile Cutless Ciera S. It has the same engine, and transmission as in my buick, the 3300, and 3 speed Th125C or 3t40. It only has 90K miles on it, but it was not running. I picked it up for a song and a decent conversation, and had to tow it back home. The fuel pump was bad, so replaced that along with the strainer and fuel filter. car started right up. It sounds pretty good, but has slight sludge

and valve ticks. It sounds like a modern Honda 3.2/3.5L on 0W20.. It drives really well, has a little more power then my 220K buick, and has no rust... Alright now the issues i am having is the torque converter does not seem to engage all the time when it should above 35MPH. I also have a Code 26 sometimes... I changed out the fluid and filter with maxlife and it made a decent difference in the way it shifted/downshifted. When the TC does lock it is silky smooth, and some times will lock and unlock and work 100% normal for miles, so i dont think its a mechanical issue. The transmission shifts pretty good, slightly firm under real hard throttle, but nothing over the top.

Next issue is the idle seems to really be high. I can almost putt along at 30 MPH and not touch the gas. If i put the car in neutral while moving under 5MPH it will rev up to 2K rpms, then slowly come down. the buick does not do this under the same conditions. Even to start it up it seems to rev higher then the buick. When slowing down to a stop with the car in drive i would say the RPMS are 200 higher then normal, or in comparison to the buick this car kinda pushes you more with out giving any gas.

I would also like to clean out the engine alittle. I want to say it has about 22Oz of sludge in the engine total as it takes that much LESS to fill over the buick.. I put in a 1/2 QT of mmo and ran it for 350 miles and changed the oil to MAxlife 5W30.. But this engine might need a little more then maxlife. I think its ticking due to lack of oil on the upper valves or something. Because after i give it a real good spirited drive, ticks go away.. Im thinking of going with a 10W40 maxlife or a diesel 15W40 and then putting 32OZ of mmo in with 3 1/2 Qts of 15W40..

What would you guys suggest i should look in to, so i can fix these issues? Thanks much!! Cheers!.

 

[Radman]

Sounds like a stuck idle air bypass valve is making the engine rev high.

 

[eljefino]

These cars have sticky torque converter clutch solenoids. This is probably most of your problems. Code 26 is a quad driver error, the transistor in your computer that drives various solenoids including the IAC and TCC. But the puter is too dumb to know which one is messing stuff up. HOWEVER if there's a dead short in one spot it can drag down the rest of the computers outputs and make things funky.

In theory even the fuel injectors run on quad drivers, though IDK if they're isolated from the rest of them.

There's a wire connected to the side pan of the transmission; disconnect it for now. You can theoretically change those solenoids without digging too too deep in the transmission.

There is also a distinct possiblity that because the car was stalling when the TCC stuck "on", some idiot mechanic jacked up the base idle screw.

Since you have a virtually identical car you can do stuff like switch MAF sensors between cars in case one is flaky.

PS they're great cars with the 3300, here's the 92 I fixed up for my BIL:

http://img.photobucket.com/albums/v107/eljefino/DSCN7251.jpg

 

[beast3300]

Code 26 is a bad ECM. Like previously said the quad driver is in the ECM. The TCC has a high failure in the 125C. It can be replaced through the side cover. I would pull the MAF and IAC and clean both of them real good. Fuzz on the MAF is another common issue.

 

[QuadDriver]

Originally Posted By: eljefino
These cars have sticky torque converter clutch solenoids. This is probably most of your problems. Code 26 is a quad driver error, the transistor in your computer that drives various solenoids including the IAC and TCC. But the puter is too dumb to know which one is messing stuff up. HOWEVER if there's a dead short in one spot it can drag down the rest of the computers outputs and make things funky.

In theory even the fuel injectors run on quad drivers, though IDK if they're isolated from the rest of them.

There's a wire connected to the side pan of the transmission; disconnect it for now. You can theoretically change those solenoids without digging too too deep in the transmission.

There is also a distinct possiblity that because the car was stalling when the TCC stuck "on", some idiot mechanic jacked up the base idle screw.

Since you have a virtually identical car you can do stuff like switch MAF sensors between cars in case one is flaky.

PS they're great cars with the 3300, here's the 92 I fixed up for my BIL:

http://img.photobucket.com/albums/v107/eljefino/DSCN7251.jpg


On this system the quad driver error is for the injectors. hook up to a streaming scan tool and check the IAC position and the TCC demand and gauge against actuality. The solenoid easy to change, just not so easy to access on the 125C - you can run without it unlike the 440T4

If the IAC is at the lowest position and the idle is high - suspect an air leak (and indeed test for low vacuum)

 

[1 SX]

Hi to follow up, I did clean the MAF already, but will look in to the IAC. When the TC is engaged, if you tap the brake it turns off as it should, give it 60% throttle turns off, let up on the throttle and it will engage again... then out of the blue after a few miles it will just disengage, and it will not engage for miles, maybe 10 or more, then randomly start working again. Another possibility i read online was a 3rd gear switch? Im going to try lubegard red, just for added protection.. Aright, now code 26, BOTH cars have this code... Both cars also have it light when you first get going(first start of the day) it will flash for 5 times or so with in the first 2 miles, then go off and never to be seen again till the next heat cycle. The buick has had this cycle for the last 35K miles.. and i cant feel anything wrong.. It feels better then some rentals. But the Olds, i dont know what to look in to. I wanna say the code 26 is the TC, or something along the lines of the transmission... Also how firm is too firm when it comes to shifts at 75% throttle? The shifts are not so bad where it chirps the tires, but it will give a little kick, almost like a aggressive driver, shifting a manual. If it was a sports car, it would almost be cool & sporty. haha. again both transmissions feel this way so i dont know if they are just designed to be more on the firm side to save the packs & internal components. THanks.

 

[eljefino]

Hmm, my 3t40 was pretty mushy back in the day (the new ciera had the 4t60 with an adjustable modulator) but it had old fluid because I then followed the "don't rock the boat" mentality.

Have you adjusted the TV cable per "pull the sheath out and floor the pedal till you hear it click" method? It should stretch to "mushy" but you never know...

It could be your TCC is a symptom not a central issue of quad driver issues. Is there anything else being commanded in and out like the rad fan or ac compressor since you're using defrost? You could always unplug the IAC, it will complain, but it should stabilize the idle, and just might be what's shorting out and dragging the rest of your stuff down.

 

[QuadDriver]

adjust the cable as suggested, this transmission is not electronically shifted, so shift quality will be independant of ecm. but you could feel a surge if the idle is shooting high while the clutches are open.

 

[1 SX]

"Some iditot jacked up the base idle screw".So as I was looking at the IAC valve I noticed the idle adjustment screw has been extended twice of that on the Buick. So I think this is the high idle. I disconnected the IAC valve and started the car. It revved slightly higher. Plugged it back in and it idled down to slightly above normal.

 

[beast3300]

Originally Posted By: SL2
"Some iditot jacked up the base idle screw".So as I was looking at the IAC valve I noticed the idle adjustment screw has been extended twice of that on the Buick. So I think this is the high idle. I disconnected the IAC valve and started the car. It revved slightly higher. Plugged it back in and it idled down to slightly above normal.


Good deal, any pics of this monster (car).

 

[eljefino]

2000 RPM in New York.

(opens envelope.)

Some idiot jacked the idle screw.

 

[1 SX]

To update. Drove around 1500 miles and it seems the ttorque converter works much better on 60f+ days. The cooler it's out the more it does not like to lock. Seems like a temp sensor or something sending the wrong info so in return the computer thinks it's cold. What should I be looking at if the lock up changes with out side tempature? Thanks!

 

[PF52]

Originally Posted By: SL2
Seems like a temp sensor or something sending the wrong info so in return the computer thinks it's cold. What should I be looking at if the lock up changes with out side tempature? Thanks!


Could be as simple as the thermostat stuck wide open.

 

[1 SX]

Sounds like you are right. It's running very cold, as after a good drive, and a few min idle, the muffler is just warm to the touch. It does have heat but only under 1/2 fan. Give it more fan speed and it gets cold in a hurry. The engine/valve covers are not even warm after a decent run. I dont have a temp gauge but my guess would be under a 1/4. The upper rad hose gets hard, but not really hot. It's a real pain to change out this tstat. Gotta remove the tb? Well maybe I will do some more cleaning.

 

[1 SX]

CSS; Correction. You are right. Tstat was shot. Funny story I bought a new tstat, 192, gasket and tb body gasket for the Buick a few months ago but never installed because it does not need it. The problem was the wrong % of water. I had around 80 to 20 and the water froze.
So installed this tstat. Was not bad at all just for the rubber hose. It's nice to have real heat. I thought because the stop leaked was used(ughhhh) it clogged up the system and that's why the heat was weak above 1/2 fan. Also t/c issue went away. It now locks with in 2 miles of a cold start. Gas mileage seems to have improved greatly, I will give you the real mpg in a couple. But I drove around 50 miles on an less then a 1/8 of a tank. Seems pretty legit. Not really funny but I had to change the transmission fluid 3 times.. first time I wanted to. 2nd time I also wanted to, buttttt on the test drive it would not stay in first slip, jerk. Had to drain the fluid again just to find the filter fell off in the pan. Realllly now and then refill with new fluid. So the fluid on this one is fine for 20k.
Thanks for the suggestions!!.

 

[PF52]

That's good to hear! I love it whan the solution is the easiest/cheapest. Much better than having to get a new transmission.

I put up with the same issue over a winter a few years ago; driving around in town I'd have decent heat and the trans would lockup like normal, but a cruise on the highway would find me freezing inside the car and the engine would be a couple-three hundred RPMs higher than it should have been because it wasn't going into lockup. The giveaway was the temp gauge; it would barely budge from the "cold" position whan I was on the highway. Changing the thermostat fixed both problems.

 

[1 SX]

Re: to the temp gauge, what temp gauge? This is a oldsmobile. Only gauge I have is for gas, speed, and shift position. Same with the Buick lol. Kinda miss All the other gauges such as rpms, volts, and temp. They both had a option for the full dash, but nope. I don't think this car was running any way near warm as the exhaust was just warm to the touch after 20 miles. Now after 5 you can just touch it quickly or it might burn.

 

[eljefino]

They must have added temp gauges in 92. My BILs 91 century just had an overheat light, horrible for spotting trends of "almost overheating."

Sunpro may have the aftermarket gauge you need for less than $10...