Custom 4T40E Trans Controller - Page 6 - Tuning Forum

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Re: Custom 4T40E Trans Controller
Wednesday, June 22, 2011 9:59 AM
color me lost... even though you figure it out and had nothing to do with the stock rev limiter... how are you controlling ur trans?

if you say stock computer i dont quite understand how HPT could have not fixed that issue (had it have actually BEEN the issue i mean...)




Re: Custom 4T40E Trans Controller
Wednesday, June 22, 2011 11:15 AM
You're probably confused because I'm actually "NOT" controlling the transmission right now. I'm simply debugging. What I'm doing is first making sure the correct signals are going to my board (TPS, CLT, TFT, CPS, VSS and Trans Switches). The reason I was getting a "rev-limiter" was due to the strength of the CPS signal or unwanted electrical noise. My board is likely acting like a low-pass filter, loading down the line as the frequency (i.e. RPMs) increases. HPTuners wouldn't have done anything for two reasons.

1) It was a hardware issue and not a software issue
2) The Jbody PCM is only in my car to control the trans (temporarily) and the gauge cluster. It has no control over the engine itself. So there's no way that HPT could change my revlimiter.

If I had experienced a problem that was transmission related and software related, then yes, HPTuners would have likely been able to solve it.




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Re: Custom 4T40E Trans Controller
Friday, June 24, 2011 8:14 PM
I hate to be a video whore, but sometimes they show more than pictures and text can alone...and I think it might be a good reference for the future DIYers interfacing with VR signals. Just a forewarning though, sorry for all the background noise (what you hear is the combination of my oscilloscope fan and power inverter fan).




So, as I predicted, my circuit is acting as a LPF. What I wasn't expecting, though, is the asymmetric nature between the voltage peaks as the RPMs increase.......an interesting problem indeed




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Re: Custom 4T40E Trans Controller
Wednesday, July 06, 2011 6:11 AM
Updates?





Re: Custom 4T40E Trans Controller
Wednesday, July 06, 2011 9:08 PM
NEIN




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Re: Custom 4T40E Trans Controller
Thursday, August 04, 2011 4:01 PM
Finally got around to testing this again. I removed the input filtering cap and the engine revs fine now with the trans controller plugged in. Next step is to check the output of the optoisolator to ensure the PIC is seeing the correct signal.




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Re: Custom 4T40E Trans Controller
Sunday, August 07, 2011 4:08 PM
Update...



I messed with the circuit a little more today and now have a proper pulsed 5V signal going to the PIC. It's raining right now, but the next step is to test the TPS signal. Then I can plug in the 20-pin connector.....and pray.






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Re: Custom 4T40E Trans Controller
Sunday, August 07, 2011 5:59 PM






Re: Custom 4T40E Trans Controller
Monday, September 19, 2011 9:38 AM
Well again for the 1000th time. lol



Re: Custom 4T40E Trans Controller
Tuesday, September 20, 2011 10:59 AM
Sorry Mike. I've been busy with my welding/turbo project and haven't really gotten back to this.

FWIW, when I did test it, the circuit worked fine for about 5 minutes, then @!#$ goes to hell. I don't know if it just loads the CPS line down so much that MS just can't read it anymore, but the car misfires horribly, and it won't let me go faster than like 30mph.




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Re: Custom 4T40E Trans Controller
Sunday, October 09, 2011 8:34 PM
Idk is it a tps issue? Sounds like you could be reaching the rampout limit. But im no engineer just a theory.




Re: Custom 4T40E Trans Controller
Monday, October 10, 2011 11:59 AM
brodycog wrote:

Idk is it a tps issue? Sounds like you could be reaching the rampout limit. But im no engineer just a theory.

That's an interesting remark. I had an issue with the TPS not too long afterwards, and as a quick fix, I simply disabled it in MS-II. Since I'm only using MAP and MAP delta for tuning right now, this would be an easy check to see if TPS was the issue. I'm not too terribly confident this is what caused the problem, but it wouldn't hurt to check. Thanks Jay




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Re: Custom 4T40E Trans Controller
Monday, October 10, 2011 1:29 PM
Or maybe the tcs is on and you have some major torque reduction going on.



Re: Custom 4T40E Trans Controller
Monday, October 10, 2011 2:18 PM
If the TCC were locked, then it would rev slower and eventually bounce off the rev-limiter. There's no way for anything the JBody PCM controls to cause misfiring. However, the Jbody PCM, MS-II and my circuit all share the signals from some sensors...the tps being one of them. Before, I was blending TPS and MAP for transient fueling. So, if the TPS signal is acting up, then I can possibly see this causing problems. I'll look into it.

However, I'm pretty sure it's a signal loading issue like I had with the Trans switches before. I'm simply driving the output of the cps with an optoisolator. So on the positive wave, it's loading down considerably (as you can see in the photo I posted on August 7th). What I don't understand, though, is why it works perfectly to any rpm I rev to for ~5min, and then just goes to hell after that. I've tried it no less than 3 times and the outcome is always the same.




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Re: Custom 4T40E Trans Controller
Monday, October 10, 2011 2:40 PM
That does sound pretty odd..

If I understood what I read correctly, your sending the CPS signal to the controller, then with a opto whatever (never heard of one) sending the signal to the MSII? If so, you can't configure the MSII to output the CPS to the controller instead? I'm probably completely misunderstanding what I have read here though.


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs
Re: Custom 4T40E Trans Controller
Monday, October 10, 2011 3:22 PM
No. The cps is another one of the sensors that all 3 systems ties into. As such, they all have their own circuitry for manipulating the VR signal. Mine is based off the way Megasquirt handles it. Considering timing isn't critical to transmission control though, I will try including a transistor in the same fashion as I did the trans switches. This will increase the input impedance and eliminate loading the signal. If this does fix the problem, though, I'm at a loss to why the engine even runs well at all. I would think it would run like crap the whole time.

In any case, the tps is a good place to start.




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Re: Custom 4T40E Trans Controller
Monday, October 10, 2011 4:16 PM
Well....it's not the TPS




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Re: Custom 4T40E Trans Controller
Tuesday, January 03, 2012 4:00 AM
and then................





Re: Custom 4T40E Trans Controller
Tuesday, January 03, 2012 7:09 PM
....been lazy

I just wired up the input buffer for the cps. I'll test it again tomorrow.




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Re: Custom 4T40E Trans Controller
Wednesday, January 04, 2012 3:15 AM






Re: Custom 4T40E Trans Controller
Wednesday, January 04, 2012 5:45 PM
Update.

I think I had the positive and negative cps signals swapped before. I tried with the buffer, and that just made things worse. I replaced the wiring and the circuit just worked fine. I drove around for 20minutes with no problems, and the LEDs were lighting up at the 1000, 2000, 3000 and 4000 RPM marks as I programmed them to....strange.




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Re: Custom 4T40E Trans Controller
Wednesday, January 04, 2012 6:18 PM
Well...so does it work, per design.

I.E. you can select any gear?





Re: Custom 4T40E Trans Controller
Thursday, January 05, 2012 5:59 AM
Given the way things have turned out so far, if I were a betting man, I would say no. In the order of things to do, I will test the shift solenoids, then the pcs, and then the tcc. When I verify that I can manipulate these at will, then I will do further verification tests with the actual transmission control code.




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Re: Custom 4T40E Trans Controller
Thursday, January 05, 2012 6:43 AM
Well come on. I have a running cavalier now. lol





Re: Custom 4T40E Trans Controller
Thursday, January 05, 2012 11:12 AM
You should be used to disappointment from me by now, Mike.




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