Tweak tip for auto Sc shifting!
10-04-15, 08:45 AM
#61
Still pushing the reading-impaired personal agenda, I see. I said, "Unless someone comes along with a solid explanation of how the TPS affects the smoothness of the shifts themselves, I call B.S." That's not the same as calling B.S. I was awaiting an explanation to convince me otherwise.
You're talking about shift schedule, but the thread was about shift smoothness. The latter fits:
Also, bigwhite's question was about the thump when shifting from P to D. If that has anything to do with modulation of air, it would presumably be a IAC issue, not a TPS one, being at idle.
You're talking about shift schedule, but the thread was about shift smoothness. The latter fits:
The throttle position cable on these transmissions control the line pressure only, it does not affect shift points.
10-04-15, 09:15 AM
#62
lmaol, you don't even know what you wrote .. lmaol. Again you prove that you cannot accept mistake when people negate what you say in some threads of this forum. Dude nobody is perfect , we all can be wrong . Being stubborn that one is not wrong when it is so obvious is even worst than being wrong.
OLT was talking about the effect of adjusting the TPS , you said the tip doesn't make sense and it is BS ! Your posts do not lie ! If you don't know, well apparently you don't .... shift schedule affect shift smoothness. It is the timing or precise instance when gears should change based on the input of the TPS and thus spells whether you have a neck braking (thump) shift or a smooth shift...lmaol,
stay on making hood vents and repairing door panels , lmaol. you are spreading a lot of misinformation like there is only one sensor on the throttle body of an SC300. We are still waiting for your proof that you can build a high powered SC400 cheaply and reliably after having refuted all those who have been there, done that , spent countless hours of research and money trying to do it. But when asked for proof , all you said was , I was not boosting my SC.... what an excuse.
I would have not even come into this thread but to read that the TPS has no effect on how the transmission shift because it is done mechanically by the transmission throttle cable is what I call BS and can lead to misinforming people. People , before you even joined this forum , have posted years ago that it works and have proven it.... and here you are jumping into this thread calling the tip BS
.
^ Sensor #1 would be TRAC.
I can't say this tip makes any sense to me, although I didn't read pages 2 and 3. Adjusting the TPS doesn't seem like it should have any affect on the transmission's smoothness of shifting -- that's what the transmission throttle cable is for -- but would have other adverse drivability effects. Maybe one is covering for the other, but it seems like the wrong way of going about it.
I can't say this tip makes any sense to me, although I didn't read pages 2 and 3. Adjusting the TPS doesn't seem like it should have any affect on the transmission's smoothness of shifting -- that's what the transmission throttle cable is for -- but would have other adverse drivability effects. Maybe one is covering for the other, but it seems like the wrong way of going about it.
OLT was talking about the effect of adjusting the TPS , you said the tip doesn't make sense and it is BS ! Your posts do not lie ! If you don't know, well apparently you don't .... shift schedule affect shift smoothness. It is the timing or precise instance when gears should change based on the input of the TPS and thus spells whether you have a neck braking (thump) shift or a smooth shift...lmaol,
stay on making hood vents and repairing door panels , lmaol. you are spreading a lot of misinformation like there is only one sensor on the throttle body of an SC300. We are still waiting for your proof that you can build a high powered SC400 cheaply and reliably after having refuted all those who have been there, done that , spent countless hours of research and money trying to do it. But when asked for proof , all you said was , I was not boosting my SC.... what an excuse.
I would have not even come into this thread but to read that the TPS has no effect on how the transmission shift because it is done mechanically by the transmission throttle cable is what I call BS and can lead to misinforming people. People , before you even joined this forum , have posted years ago that it works and have proven it.... and here you are jumping into this thread calling the tip BS
.
Last edited by gerrb; 10-04-15 at 02:11 PM.
10-04-15, 06:54 PM
#63
Again, just spent $1900. on getting the engine resealed by a great shop, and they did a geat job. My car does not leak a drop now. I tried the turning of my TPS and it still jerked into drive just as hard. The car never did this before the engine work. I have checked what I believe to be the solenoid plugs to be plugged in on the trans. My mechanics checked the trans. line pressure with a gauge and said it was at the low end of the low-high specs. I figured with the help of everyone on the forumn, that I would have a better chance of finding the glitch myself and would learn a thing or 2. Im not above believing my old TPS could be bad, but am having no hesitation or CEL.
10-04-15, 07:01 PM
#64
Thanks geerb, didnt catch your post on the prev. page. I have recently had my ECU remaned. Thinking Ill check all ground cables tommorow since they had the engine out. Proper grounging would be nessesary for ECU.
10-05-15, 12:03 PM
#65
For me it is a setting adjustment of a combination of components .. TPS , Ignition Timing and Line Pressure on the assumption that everything else is good . Like when you put the car from Park to Drive , the ECU receives info from the TPS which is the percentage of Throttle opening. Based on that , it pulls an X amount of timing on the assumption that the line pressure is properly set too.
See how your start up ignition timing looks like which your ECU uses as your base timing. They might be slightly off but still allows the car to start up. Also the cable for the line pressure is set correctly (right tension) . Then your TPS which you already know .
This is a common problem we have on our Built A340 transmissions we use in high power applications , that neck breaking thump caused by an aftermarket ECU not being able to control line pressure properly. We have to set our tune / maps meticuluously just to have a smooth shifting transmission. Though our A340 are slightly different from that of the SC400 A340 . Our line pressure is electronically controlled also... not through that cable which a SC400 A340 has. So make sure that cable has the proper tension.
Last edited by gerrb; 10-05-15 at 01:13 PM.
10-05-15, 06:45 PM
#66
Got the detent cable as loose as I can get it. Also checked block ground cable from battery today as well as the intake manifold to firewall ground strap. Both tight and clean. Added a 10 ga. wire from the ground post cable end over to the drivers fender. Didnt help but didnt hurt.
10-05-15, 10:48 PM
#68
All this and I am wanting my transmission to shift quicker and harder, boy this thing slips like crazy going into gears. I am kind of amazed these transmissions last as long as they with as lazy as they shift gears (build up of heat from slipping). I guess I should be tightening my trans cable to raise line pressure, or is there something else to do (98 SC300)...sorry to create a tangent on this thread
10-06-15, 02:48 PM
#69
Im loving the firmer shifts, the down side is that when you put it into drive it jars the whole car. Also occasionally as the trans. is downshifting you will get a thumping clunk into 2nd or first. I reported that I had a couple of tuns left in my detent cable last night and there is even freeplay in the cable now. It didnt change the hard jerk into drive and the shifts are the same as before. Im going to go back and try TPS adj. in smaller increments this time, instead of big twist that I did last time.
10-07-15, 03:00 PM
#71
So I found my good super phillips screwdriver to break those little screws loose, and turned my TPS CCW, a little. The shift into drive seems 50% better but my shift pattern is a little off. Last time I cranked it all the way to see quickly if it would fix the problem and it was too much. Im going to take the slack out of my detent cable, because I have it all the way backed off, and see how that goes. Id say when the guys pulled my engine, they might have got the chain over by the throttle body and bent something. Stuff happens.
10-07-15, 03:05 PM
#72
The lower TPS screw is pretty tough to get a direct shot at, and as a result previous owners had badly stripped mine to the point where I could barely get it turning. Once I finally had it out, I replaced it with a much more robust allen head that doesn't need a direct line of access.
10-08-15, 06:16 PM
#74
I apologize to the thread opener for jumping on this thread with my own agenda in mind. That said, when I back my TPS CCW a little, the jolt into drive does seem less, but when im going from 55mph to 50mph, its either deceling or unlocking the torque converter. Seems like to much engine breaking for that cruising speed. Am going back to in the middle and wondering about the integetrity of my engine mounts.