4L80E Build Instructions

[Silverado]

Have built the Megashift for my 4L80E and installed in my truck. Had idled for a while while working on another unrelated issue then went for a drive. Everything seemed to work just fine. Next morning tried to go for a drive and would not seem to shift out of 1st gear and the "Current Gear" gauge showed 0 when in drive. Monitoring Input 1 - 3 (switch A-C), input 3 would start out just under 5v and slowly drop. Once it dropped below .98v the input indicators would appear correct in 3rd and 4th.

Now about the build instructions, step H is to build the circuits for SwC (EGT3) and SwA (EGT4). The photo and instructions show to build in EGT1 rather than EGT3. Is this correct? Since there is no circuit in EGT3, SwC would not read properly causing my problem, correct?

If the instruction is wrong, could I move from amp 25 to 24 and install jumper from EGT1 to AD3 to correct?

Silverado

[dch]

Silverado,

Sorry for the mistake, it is suppose to be built in EGT3 and I mistakenly built it in EGT1. You should be able to jumper EGT1 to AD3 to correct it . I will have a corrected photo up loaded in a couple of days and corrections to the instruction.

Dave

[Bernard Fife]

Dave,

Thanks for the correction, I will update the manual shortly (I see the confusion is caused by the EGT circuits being arranged 2341 rather than 1234 as most would expect). And many, many thanks for doing the 4L80E docs in the first place, the 4L80E build manual wouldn't have happened at all without you!

Lance.

[Bernard Fife]

Many thanks to Dave (dch) for providing the corrections and picture for the 4L80E EGT3 circuit.

The corrected document is here: http://www.msgpio.com/manuals/mshift/4L80.html You may have to refresh your browser (often Ctrl-F5) if you have visited this page recently.

Lance.

[gui67]

I built the circuits on EGT4 and EGT1 instead of EGT3 and EGT4. (I followed the pictures instead of the text.

So, should I unsolder the 4 components from EGT1 to build the EGT3 circuit, or can I connect switch A to pin 24 on ampseal connector and jumper AD3 to EGT1 with a wire on the 25x2 header?

For the moment, I did not tested the transmission, I will finish it at the end of the week, but I hope to finish everything and test it in 10 days.
Regards
Guillaume

[Bernard Fife]

Guillaume,

You can just jumper the EGT1 circuit to the appropriate processor pin (AD3) on the 25x2 header (and use the Ampseal pin #24 for Input 3 == switch C), if you wish.

Then the code will work fine.

Lance.

[gui67]

Thank you Lance,

In fact, I just saw I had enough components in the kit to build a 3rd EGT circuit, so I soldered all the components on EGT3 and let the ones I soldered on EGT1.
Then I can use the right inputs on the main connector and not make any mistake.

[Silverado]

Dave/Lance,

Believe that I found another error in the 4L80E build instructions. For the input speed sensor section "I" for VR3 circuit calls for a resistor in R62 that is part of VR4 circuit. This should be in R61.

Silverado

[Bernard Fife]

Silverado,

I will have a look (you sound right to me!) and fix up the docs, thanks!

It sure helps having people look these over as they build units, it's the only way to get all the bugs out (the MegaSquirt assembly docs took years to get all the errors out).

It's also one of the reasons why supporting new transmissions isn't trivial, there's lot's of information to be gathered, sorted, written down, and verified! Compared to that, making code and hardware changes is pretty straightforward.

Lance.