Question about 4.44 tranny and Valve Body - Page 4

sd2649 · #46 10-11-2007, 07:34 AM

to try and help with your question, there is no apparent braking , what if feels like is that I pull the throttle half way down. I surely couldn't tell you what does it, but I feel the "gas" pull back, the tranny shifts, and it just stays there for about 2-3 seconds then, instantly it feels like I pushed the throttle right back again. I recently replaced my TPS because my car had a "dead spot" in the throttle as well as it would stay in first gear a little too long for comfort under light throttle on early mornings. After replacing the TPS, the dead spot is gone, but it will still stay in 1st till about 2900 under light acceleration. ALSO, the 1st-2nd shift NEVER has the "smoothing effect" by dropping gas or whatever under light to moderate acceleration, it just does the weird thing at WOT. HOWEVER under moderate acceleration, I feel the smoothing through shifts at every other gear, unless of course I apply WOT, then it acts stupid there too. I attributed some of these symptoms to the TPS before, but now it seems like they are all something different. Does anyone know what a messed up speed sensor on the tranny is supposed to do....symptoms??? I think I want that TCU for $25.

sd2649 · #47 10-11-2007, 03:12 PM

How do you set the idle on these cars? Mine idles at 1200 and it is extremely annoying. What i have done that should have caused this is, i took the throttle body off and cleaned it out, replaced the TPS with a new one. I set the TPS properly and the car idles at around 2000, then i find this backer bolt and am able to pull the throttle down until it idles at 1200, however i cannot get it any lower. i thought it could be my volt meter was out, so i loosened the TPS and pulled it as far as it would go down and am able to get the idle down to around 950, but then my shifts are silly. Does anyone know what the sensor that is on the bottom of the throttle body? i remember reading that it controlled idle somewhere (i think?) but why would cleaning it make the idle so much higher? is there an adjustment to made there? any ideas would be great!

i love this forum, seeing as i seem to break something new on my car everyday!

Trevor · #48 10-11-2007, 04:23 PM

Please ---- This thread is becoming exceedingly confused. The above two posts involve queries which should rightly have been placed within the technical section.

N.B.There is no provision for idling adjustment as such. Idling issues are covered in recent threads and these should be checked out.

sd2649 · #49 10-11-2007, 09:05 PM

Hmmm..... after reading the name of the thread, I do see your point. They become all jumbled up in my head. I know that finding out that the SVX pulls the idle out of thin air has nothing to do with a tranny valve body in many peoples mind. However, the fact that the TPS plays a major part in deciding shift points is why I began my discussion here. This thread is the only place I found any helpful information on the TCU relating to the shifting problems I am having. Seeing as I started the journey to fix the shifting at the TPS, I thought that feedback as to how that was going along would be just fine on this thread. If I am wrong, please someone else tell me that I am stupid.

Back to the car.....
I fixed the idle after looking around (so I am stupid) it was the IAC. So I went spliced a wire as in the diagram and it completely solved the dropping power between shifts. Of course, it shifts hard every time. The car is incredibly quick therough the shifts and they hit real hard. I broke the tires loose on the 1st to 2nd shift (remember I have a FWD) and it was quite nice having the car not "brake" on me. I appreciate all the help, when I get some $, I'm gonna replace the TCU and hopefully get the shifts back to stock. I will switch the wire though, because it is alot of fun to have the extra kick when I want it!

UPnorth362 · #50 10-11-2007, 09:09 PM

Quote:

Originally Posted by sd2649

the website you referenced Myxalplyx doesn't have a tcu right now. I was thinking about the functions that are involved with the transmission during shifts. I don't understand why the TCU would be grounding the signal for extended periods between shifts. What sensor is telling the TCU that the shift is complete. wouldn't this be the first place to look instead of the TCU? I still think that it's the TCU, but I would like to be more certain. If I could check a sensor or sensor lead for voltage, this would be helpful! Any Ideas????

You should also try putting the TCU in power mode full time. It changes the shift parameters, and is a blast to drive.

Myxalplyx · #51 10-11-2007, 09:15 PM

Quote:

Originally Posted by sd2649

Back to the car.....
I fixed the idle after looking around (so I am stupid) it was the IAC. So I went spliced a wire as in the diagram and it completely solved the dropping power between shifts. Of course, it shifts hard every time. The car is incredibly quick therough the shifts and they hit real hard. I broke the tires loose on the 1st to 2nd shift (remember I have a FWD) and it was quite nice having the car not "brake" on me. I appreciate all the help, when I get some $, I'm gonna replace the TCU and hopefully get the shifts back to stock. I will switch the wire though, because it is alot of fun to have the extra kick when I want it!

This is EXACTLY what I want. Nice firm/hard shifts everytime, whether I am cruising or WOT. I never have cared for the luxury shifts (exept on the family car). Thanks for the feedback.

Trevor · #52 10-11-2007, 10:31 PM

Quote:

Originally Posted by Trevor

Within this thread it has been suggested that torque control could be achieved by either fuel shut off, or via blocking ignition.

I have always understood that some, but not all cylinders, are deprived of ignition for the short periods involved. This would be plausible as control would be practically instantaneous, as opposed to a probable slight inherent delay.

Please, can someone confirm the exact mode of operation. Please, no opinions, only exact evidence, e.g. pointers towards verifiable published statements, from an absolutely reliable source exhibiting authority.

Dragged out of the mire. Please, any replies.

sd2649 · #53 10-11-2007, 11:00 PM

Quote:

Originally Posted by Myxalplyx

This is EXACTLY what I want. Nice firm/hard shifts everytime, whether I am cruising or WOT. I never have cared for the luxury shifts (exept on the family car). Thanks for the feedback.

No problem, I will let you know if changing the TCU to a "properly functioning" one does. I was really amazed by how much frustration was bypassed by simply grounding a wire. I really want this car to be 100%, I just know how awesome it would be. Hopefully I'll be able to set it up with two small car shift kits as said possible earlier on another thread. I will try this out in the next month and let all know what happens I hope my crappy TCU isn't getting me different results than the replacement one will, it all seems to work so well.

As to what is happening between WOT shifts to drop the engine power:
Trevor,
What would be the best way to measure fuel pressure in the SVX? If there is an electrical signal I could read at the injectors or somewhere else in the system, I could monitor it and let you know what I find. As far as ignition goes, the car still seems to have some spark, it will hold speed for the three seconds, but you are right about it being instantaneous. I can literally push my throttle back and forth between WOT and just before it, and the car will go back and forth instantly from near WOT to half throttle and back and forth until the 3 second mark has gone. I really wish someone with properly running SVX knowledge lived somewhere near here, I get the feeling noone has any idea what I'm talking about. Seeing as my SVX does WHATEVER between shifts for 3 seconds at a time, I would definitely have plenty of time to see something happen!

I really felt it is cutting fuel, but am not so sure anymore. I know you are looking for hard evidence, sooooo.......... any suggestions on any electrical monitoring solution??????

Trevor · #54 10-12-2007, 04:54 AM

Steven,

Using the shift kit as you suggest is not an option. Refer my advice in the other post.

Fuel pressure can not be measured via any available electrical signal. A pressure gauge must be used.

Cheers, Trevor.

Myxalplyx · #55 10-12-2007, 05:09 AM

Quote:

Originally Posted by sd2649

As to what is happening between WOT shifts to drop the engine power:
Trevor,
What would be the best way to measure fuel pressure in the SVX? If there is an electrical signal I could read at the injectors or somewhere else in the system, I could monitor it and let you know what I find. As far as ignition goes, the car still seems to have some spark, it will hold speed for the three seconds, but you are right about it being instantaneous. I can literally push my throttle back and forth between WOT and just before it, and the car will go back and forth instantly from near WOT to half throttle and back and forth until the 3 second mark has gone. I really wish someone with properly running SVX knowledge lived somewhere near here, I get the feeling noone has any idea what I'm talking about. Seeing as my SVX does WHATEVER between shifts for 3 seconds at a time, I would definitely have plenty of time to see something happen!

I really felt it is cutting fuel, but am not so sure anymore. I know you are looking for hard evidence, sooooo.......... any suggestions on any electrical monitoring solution??????

It IS cutting fuel, at least my SVX does. I posted dyno information on this a while back. Between 1st and 2nd gear is really bad. See chart below-->

sd2649 · #56 10-12-2007, 07:40 AM

(1) TCU wire mod???

trevor, I am going to get a voltage meter on that wire sometime next week (3 day road trip starts...... NOW). grounding that wire is fixing MY problem, I want to know what it is doing before I change the TCU out and have it do nothing for me. Obviously I have some other technical issue with my TCU and my results NOW could differ with the results on a properly functioning TCU. I will get the results out here as soon as I get to it.

(2) Gas pressure drops

I'm guessing that the chart below is pretty hard evidence for a drop in gas pressure, so... maybe it does BOTH to a lesser degree?? just a thought!