88toyblackjack

Here's another question to pose to those that have done this before.
Can the A340H auto in my 88 with the 3VZE retained in a 3.4 swap? What kind of electrical/linkage issues are there if so. I have searched, but most of the info out here is for a 5 speed. 1 member has done this I know, but no other information was given. The TOYODIY site has some good pics and part numbers, and lots of that stuff is listed as the same between the A340H(88,3.0) and the A340F(96 3.4).
Lemme tell ya, this build consideration from afar(across the Atlantic) is driving me nuts. I want a clear plan drawn before I get home, and I keep finding issues/ideas that keep changing my direction

waskillywabbit

iTrader: (-1)

No.

:wabbit2:

88toyblackjack

Where's that dang Thanks button?!. Thats what I figured.

thefatkid

No is the easy answer.

Will the A340h from a 3.0l bolt to a 3.4l..... yes
Will a 4runner or Tacoma ECU correctly control an A340h without shifting issues or Check light on..... No
Will a T100 ECU control an A340h..... yes
Is this an easy swap like a manual transmission swap.... no

Read this thread here....https://www.yotatech.com/forums/f160...-a340h-128200/

I no longer have an A340h due to it could not handle the power from a 3.4l supercharged. I currently have an A340f from a T100

88toyblackjack

Thanks for the detailed info. I thought I had seen a post by somebody that had done the swap with the A340H, but my internet connection is so bad on the weekends, the program would "time out" before the search was completed!

UKrunner

Lots of people have done the swap. I used a 98 4runner ecu instead of a T100 ecu. Sometimes the shifting is odd at very high revs and the speed signal is different, leaving a cel on but other than that it works perfectly. It wont kill you or the 340 to not use a T100 ecu.

88toyblackjack

Thanks! I have put up with the CEL for 4 years now, so that does not bother me. I pull codes from time to time to make sure nothing has changed. I may have to give this a go, as I am pretty sure I can find a junker taco with the 3.4, just cant remember what year it is though.

thefatkid

If by perfect you mean, no lockup and delayed shifting due to vehicle being in limp mode due to your speed sensor code, yes perfect.

Next time you take your truck for a spin, hold the throttle wide open and don't let off until it shifts. Please count how many times it bounces off the rev limiter before it completes the shift.

UKrunner

It locks up, it is not in limp mode, and it only bounces off the rev limiter every once in a while.

If yours has all those problems I suggest you take another look at your wiring.

thefatkid

Funny, I've completed more 3.4l swaps and wired more 3.4l conversion harness then most shops. My 4runner has no problems, shifted perfect when it had the 340h and shifts perfect now with the 340f. Mine never bounces off the rev limiter as it functions as stock. Because yours does it proves that your truck is not functioning "perfect" as it never should.

The issues comes when you talk about using an ECU from a 4runner or Tacoma. The output shaft speed sensor uses a different voltage signal for the Tacoma/4runner then the T100. I'm not going to explain again the signal differences as I already have in this https://www.yotatech.com/forums/f160...-a340h-128200/ thread.

In that same thread you claimed to have made a converter box or pic. If you did and it could function as described you should not have a CEL. Check your wiring and skills.

So what voltages did you end up finding when you made your PIC? Why is your CEL on now?

R.DesJardin

iTrader: (1)

Or just make a manual shift controller and forget the TCU like I did. It's not a DD and it's not that bad to drive around if it was using full manul control.

thefatkid

I know a couple of guys who did this with a paddle shift setup and manual ECU. It is kinda cool as they control everything, including lockup in 2nd gear.

88toyblackjack

More good info.Confusing, but good. Will definitley be researching this more, unless I stuble on a tranny/transfer case combo that will work with the 3.4 engine/1st gen IFS.

UKrunner

My skills are fine, but you need to check your reading comprehension. And as you're trawling my posts you should have your answer as to what happened with the converter and why it hangs at red line sometimes. It has nothing to do with the ecu.

thefatkid

Straight from the manual for the description of what the #2 vehicle speed sensor does. If it is not functioning correctly shift points and lock-up will be effected.

I don't know what I'm missing, you never said what you built (other then a magic box), other then you build it. If your vehicle and PIC were running correctly you would not have a CEL. Give some circut and board descritions of what you built to prove you know what you say you know. I never saw where you said how your converter turn out as I was only following the A340h works fine thread. Please quote some of your description threads.

I have only stated fact, can back up what I say with Toyota documents. Your spouting mis-information, and will cause headachs for people who want a correct functioning "perfect swap". A completed swap with a tripped CEL is still incomplete and really a failure of the true nature of what most want to acheive. A 100% stock functioning vehicle with all correct vehicle functions in place.

UKrunner

Ok look. I never said "perfect." I said "Sometimes the shifting is odd at very high revs and the speed signal is different, leaving a cel on but other than that it works perfectly"

That is full disclosure. If anyone interprets that as just "perfect" they get what they deserve.

The pic module worked for a while but died due to vibration. I lost all the code and schematics to a hard drive crash. The concept is basic. Capture, time, multiply, convert and output.

I've read the manual too. I also had LED's on each solenoid so I could see what each one is doing, I also had scope readings of the waveforms, and it behaves fine minus the odd rev limiter behavior once in a while. I had also mentioned in a previous post somewhere that I adjusted the cable and most of that behavior disappeared.

And finally, to add, I also posted I wanted to try a T100 ecu to take a look at the differences in operation. When I get around to doing that, I was also going to provide a full diagram of how to swap a '97 T100 into 4Runner harness.

thefatkid

Perfectly, I guess my selective reading missed your first part of it. Somtimes a word causes fixation.

Your PIC would still set a light due to the missed time in the inital siginal. I did a little experiment also. The siginal box couldn't keep up with the vss and so the siginal was stepped and uneven as the duration of the 1 pulse per revolution was always changing. On the labscope the pattern would do 4 voltage waveforms but would have a pause at the output speed decreased and set a code. I couldn't keep the pattern looking "clean" due to changes in the input siginal. At a constant speed it worked great.

I have a T100 ECU, have had for 2 or 3 years now. It solves all the transmission shifting issues. I'd say try it, for me the wiring plugged in and only need 3 or 4 wires re-pinned.

Edit: I'm currently running a T100 ecu and transmission, I did swap the T100 ecu prior to the tranny swap. I only swapped to the newer transmission due to the 340h failure. The 340h did shift just like (untill it started to slip from high HP) the current 340f with the same ecu.

I'm not sure why a TV cable would have any change on shifting point. The TV cable only changes line pressure based on throttle angle. Upshifting is controlled only by the shift solenoids.

UKrunner

I cant remember what the spec is but as long as there is a pulse within that time the cel will not light. You have to convert both the positive and negative going analog pulses into positive square waves. This gives you a signal twice as fast as you need, thus you can divide by 2 and slightly vary when the pulses get output based on setting a timer to detect if the car is slowing down, speeding up or cruising. The pic will output its result one revolution behind the incoming analog signal.

Dan.3

Has anyone verified if this resolves the electronic VSS issue with using a 340h? http://www.marlincrawler.com/transfe...eed-sensor-mci