jweav12

Question here I am doing a engine swap in my 1995 3.4 manual 4wd the engine i have already installed is a 2001 4runner 3.4 auto 2wd limited. apparently in 1995 they used one ecm and then change the ecm in 1996. So right now my truck is not running and I have never really done anything like this and I am pretty much out of time and money...if I was to get a wiring harness and ecm for the 2001 engine and change it out with existing wiring harness and ecm would this work is there an easier fix? the truck turns over and has started for brief moments then turns off. any help much appreciated

waskillywabbit

iTrader: (-1)

You are replacing a 3.4 with a 3.4 is that right?

:wabbit2:

vasinvictor

iTrader: (3)

If I am reading this correctly, and you are doing a 3.4 to 3.4 swap; there are differences in wiring thru the years of 3.4s. You'll need the matching harness and ECU. Unless you are good with EWDs, then you might just be able to get by with just a 2001 ECM.

jweav12

I was told even with the the matching harness and ecu it wouldn't work because the shift points of the manual compared to automatic. I am not very good with EWD's have not done much wiring.

vasinvictor

iTrader: (3)

Well then I don't understand what you are trying to do? Try to state your problem again.

jweav12

Ok my tacoma which is a 3.4l manual 4wd...I put an engine from a 2001 4runner 3.4l 2wd automatic. engine is installed and wont start it has started briefly but then shuts off... i also changed the sensors from the old engine to the new engine hoping that would work...it did not...it seemed to help but still didn't run. Through research I found that the P codes for my 95 are only used in the 95 tacoma and t100 and they change in 96 which leads me to believe they must have had problems with the computer and changed it from 95 to 96 so I am trying to find out if getting the right computer and wiring harness for the 2001 auto 2wd 4runner will solve my problem... I was told it wouldn't but would like other advice thanks

SacRunner

So first off, your Tacoma sounds like it's a '95.5 and with that it is an OBD-I (not OBD-II) system; Toyota went to an OBD-II diagnostic and monitoring system in '96 because of federal regulations. The '01 4Runner ECU is an OBD-II unit. That shouldn't have anything to do with the issues you're seeing, but it is something to be aware of.

If you still have the "old" 95.5 3.4L use as much of that motor as you can on the "new" '01 3.4L. Use the '95.5 wiring harness, throttle body, MAF, rubber intake tubes, O2 sensors, and ECU at a minimum. Yes, this means you'll need to take the top end of both motors apart (really only need to do do whatever is necessary to remove the 2 intake plenums) to get the wiring harness off/out. I don't know if fuel injectors are different from the 2 years or not, but that could be something to keep in mind while you're in there.

If I understand things correctly, the problem you are seeing sounds like a MAF/ECU compatibility issue that others have run into (Toyota changed styles somewhere around '98 if I remember correctly).

I guess, the question really needs to be asked: why are you swapping in a newer motor? Did you have a problem with the other one, or did you do it just because you could?

jweav12

he only thing i used from the 2001 4runner is the 3.4l engine everything else is from the 95 tacoma i didnt change anything else out except sensors.....so your telling me to keep the wiring harness and ecu for the 95 to operate the 2001 which is backwards from what everyone else says....and i did the swap because my old engine seized up i would have had to re-build it

jweav12

And my truck is obd-II according to the connector obd-I is a rectangle obd-II is the other which i have

jd20phill

iTrader: (7)

1. It's not a swap, you are replacing what's in it with....well...what's in it.

2. Put the electronics and sensors from the 95.5 on the 2001 engine. Keep the harness and ecu from the 95.5. The motor is fundamentally the same, its the sensors and whatnot that changed over the years.

3. Start it up and go.

jweav12

Its not that easy i have done that the computer is diff from 95 to 2001 they actually changed it from 95 to 96

anthony1

iTrader: (1)

Is the ECU throwing any code? Check engine light on? Do you have a code reader?
Maybe your problem is somewhere else...maybe check the MAF make sure it's connected.

vital22re

iTrader: (2)

the easiest thing to do and what any mechanic or shop would do is to just use the 2001 motor as a long block. Meaning you would use all of your tacomas wiring, injectors, sensors, etc. They only thing from the 2001 should be the heads, block exhaust. If its not starting after you swapped the motor than you have a prexisting condition and or you left something unhooked, unplugged. Check the basics, compression, fuel, spark.