yoda87

I have a 91 4runner that had a 3.0 manual transmission, and got a donor 96 tacoma with a nice 3.4 with an auto tranny. I have both engines out and am starting to put the 4runner back together.I read on posts that when using an auto ecu u need to trick it into thinking its in neutral in order to bypass tranny codes. Can anyone walk me through this? I absolutely dislike wiring and computers because I dont know exactly what I am doing. Any info would be very welcome. thanks

dntsdad

I honestly think that the tricking the ECM thing is a legend. I still have not read of anyone doing it successfully. Maybe I just haven't seen it though.

Just get a manual ECM and repin your harness to match.

That method is tried and true, and been used by many people....including me.

vasinvictor

iTrader: (3)

delete- i misread the question

dntsdad

I realize that this will make it start and run but he asked about bypassing codes from the tranny. I assume that he wants his setup to function without the check engine light on. I don't think that the above method will achieve that will it?

I can't see how.

anthony1

iTrader: (1)

I second dntsdad. Get a manual ecu. Makes your wiring easier. It may take a few ecu to get it right. Check your TPS to see if you have 3 wires or 4 wires then get the matching ECU.

vasinvictor

iTrader: (3)

I'm with you fellers... I misread the question and edited my post accordingly

yoda87

thank you all for replying to me on this thread, I have been busy with school and the such so I have not been on this site as much. I did however manage to trick the ECU into thinking its in neutral it just took some hours looking at wire diagrams, talking with a few more people and getting the right resistance on the loops i made in order to get it right but I have no tranny codes so far and my engine does not seem to have a rpm limit in the neutral setting. so i am happy about that. If any one is interested in knowing the specifics just let me know.

Any how now I have a bigger problem that i need to deal with. my engine keeps on wanting to over heat. I rebuilt the engine, and have all new everything you can think of, except I am using my old 3.slow radiator (which I read is appropriate to use in this swap). When i go to bleed the system the water, coolant, boils out of the top of the radiator. Its like the water is backing up and coming back out of the top instead of circulating through. Another thing I noticed is that both hoses top and bottom get really hard like they have a ton of water pressure.

This leads me to believe that my thermostat is working, my water pump is circulating creating pressure in the lower hose, and that my radiator is no longer letting water flow as fast as it should.
I am a 22re guy and have never really played with any engine bigger so I know there are a few things different I want to make sure I dont miss something simple.
I would be great full for any advice or tips
Thanks.

4x4runr

I had the same issue with the overheating. Make sure (when the motor is cool) that you put coolant on the top radiator hose that goes into the motor. Fill it up until it is about to come out then reconnect hose back to radiator (best way to do this is to raise the front several inches higher than the rear). Now you have coolant in the motor so it should stay cool. When you start the motor and the Tstat kicks in, the water pump will push in new cool coolant into the motor and the hot coolant will be pushed out and flow through the radiator to cool off. It is very important that you do this otherwise it will always over heat and could warp/damage your your heads/head gasket. Keep an eye on the level of coolant in the radiator, it may drop down a little bit because of the pocket of air you had. Make sure you properly purge the radiator of air. The 3.0 radiator works perfectly fine. I live in a hot very humid climate and a bunch of us guys just remove the Tstat altogether so that there is constant flow. I use my rig for offroading and less than 30% D-driving so keeping it at a steady 172 at idle is important for my driving style. Hope this helps! Post some pics!!!

4x4runr

Any updates???

yoda87

Sorry I have been busy with school. Have not really worked on the truck, last time I did it kept over heating with the thermostat in, without the thermostat the engine run great so I just need more time to tinker with it. Ill post some picks of the truck here as soon as I get a second. But I want to make it as close to a factory job as possible. If anyone has any more tips on how to bleed the coolant system on a 3.4 I am all hears

4x4runr

If it ran great without the t-stat then you just need to follow what I mentioned earlier. Put coolant in the radiator and fill, then put coolant through the upper radiator hose and fill. You have an air pocket. Do that and everything should work perfectly.

yoda87

well thank u all for trying to help me but the problem ended up being that the machine shop I had machine the heads and block did a bad job and the engine had a head gasket leak. so after much heart ache and pain I dropped in another engine I found for cheap and the thing runs like a charm.

david braun

The auto to manual swap with the auto ecu and harness is much easier do then swap out an entire harness for a manual or try to re pin the harness. That scares me.

My swap was a 95 4runner with a 98 taco 3.4, auto ecu, auto trans. I later swapped in a 5 speed, 4.10's, 88 IFS axle and Manuel hubs and 285's while using the same ecu and harness with only 1 code no problems and 19.5 mpg last fill up.

I pulled the 3 shift solenoids from the crap auto trans and the temp sensor and plugged those back into the existing harness and ran them into an oil bath because they heat up.

I later found out the right resistors i needed to take their place and took the solenoids out still have the temp sensor
and have only 1 code P01700 speed sensor which i tried tricking (lots of info on yotatech about that) which i'm not worried about.(Oregon)

I was worried that i would have a ton of problems with the auto to 5 spd swap but because there where several others out there that did it and documented it. Lots of research and reading but WELL worth it!

Seatbelts

I Did that Neutral trick on the Auto ECU for my 84' 5mge Supra, i swapped in a 6mge and a w58 5spd. (It thinks it's in park).
But i agree getting the right ecu would probably be easier