Troubleshooting 3.4 Swaps

Runnerfan · 08-31-2009, 09:10 PM

I thought that this would be a good idea after searching for hours for users who had similar problems. I would like this thread to go like this:

Post your symptoms first.
Then the cause of your problems.
(optional if necessary) How you fixed it.

Similar to a Haynes manual if you have seen their troubleshooting section.

NO QUESTIONS!!
STAY ON TOPIC!!

I will post the first one to show what I am looking for.

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Runnerfan · 08-31-2009, 09:15 PM

Symptoms:
Hard to start, bogging at first of quick throttle action while at a stop, bogging if more than a feathering of throttle was applied while under load, Backfire.

Solution:
I forgot to hook up the power wire going to my sensors.

RobD · 08-31-2009, 10:07 PM

Great idea.

Symptom: battery not charging.

Solution: my 3.4 wiring harness did not charge the battery. Had to graft the 3.4 alternator plug onto the 3.0 harness that I didn't remove (thankfully).

Runnerfan · 10-31-2009, 04:41 PM

Symptom: Couldn't get codes from ECU, Code reader just said error.

Solution: I had my STA wire jumped with a constant 12v which made the ECU think I was trying to start it when I would turn on the key.

vital22re · 10-31-2009, 04:44 PM

i have had no problems... so far... 3.4 since feb.

Runnerfan · 10-31-2009, 04:47 PM

Symptom:
While driving there was no power at all, Slight bogging at idle rev.

Solution:
I unplugged my spliced plug going to the ECU and it ran great, which told me it was wiring. I had my STA wire to the ECU supplied with a constant 12v, instead of 12v just while the key was in the start position.

Runnerfan · 10-31-2009, 04:51 PM

Symptom:
Pulling a "Temp circuit error" code.

Solution:
I had spliced into the temp wire for the ECU instead of the temp wire in the body harness plug.

BIG RON · 11-08-2009, 01:00 AM

after my last swap, I kept getting a po125 code. when I did the swap, I put a new cat and o2 sensors. ended up that the brown ground wire was broken at the pin inside the connector for the o2 sensor and had pulled away just (unuff) how ever it's spelled

to not make the connection. once fixed, no more code.

08-31-2009, 10:07 PM	#3 (permalink)
RobD Registered User Join Date: Jun 2006 Location: Calgary, AB Posts: 1,726	Great idea. Symptom: battery not charging. Solution: my 3.4 wiring harness did not charge the battery. Had to graft the 3.4 alternator plug onto the 3.0 harness that I didn't remove (thankfully). __________________ 1991 4Runner, 3.4 5VZFE swap, OME shocks/springs, 33" BFG All Terrain T/A KOs, Pioneer head unit, Infinity speakers, XM Satellite radio

10-31-2009, 04:41 PM	#4 (permalink)
Runnerfan Registered User Join Date: Jun 2009 Posts: 36	Symptom: Couldn't get codes from ECU, Code reader just said error. Solution: I had my STA wire jumped with a constant 12v which made the ECU think I was trying to start it when I would turn on the key. __________________ 92 4Runner 3.4 Swaped

10-31-2009, 04:44 PM	#5 (permalink)
vital22re Registered User Join Date: Feb 2006 Location: kirkland washington Posts: 679	i have had no problems... so far... 3.4 since feb. __________________ 92 toyota truck 3.4 5spd 4.56 gears magna flow cat and muffler2 1/4 piping isr mod to intake 1.5 bjsfront add a leafs and 2inch lift shackles rear rancho shocks all around sitting on 265/75/r16 nitto terra grapplers

10-31-2009, 04:47 PM	#6 (permalink)
Runnerfan Registered User Join Date: Jun 2009 Posts: 36	Symptom: While driving there was no power at all, Slight bogging at idle rev. Solution: I unplugged my spliced plug going to the ECU and it ran great, which told me it was wiring. I had my STA wire to the ECU supplied with a constant 12v, instead of 12v just while the key was in the start position. __________________ 92 4Runner 3.4 Swaped

10-31-2009, 04:51 PM	#7 (permalink)
Runnerfan Registered User Join Date: Jun 2009 Posts: 36	Symptom: Pulling a "Temp circuit error" code. Solution: I had spliced into the temp wire for the ECU instead of the temp wire in the body harness plug. __________________ 92 4Runner 3.4 Swaped

08-31-2009, 09:15 PM	#2 (permalink)
Runnerfan Registered User Join Date: Jun 2009 Posts: 36	Symptoms: Hard to start, bogging at first of quick throttle action while at a stop, bogging if more than a feathering of throttle was applied while under load, Backfire. Solution: I forgot to hook up the power wire going to my sensors.

11-08-2009, 01:00 AM	#8 (permalink)
BIG RON Registered User Join Date: Nov 2005 Location: Rancho Cucamonga Posts: 175	after my last swap, I kept getting a po125 code. when I did the swap, I put a new cat and o2 sensors. ended up that the brown ground wire was broken at the pin inside the connector for the o2 sensor and had pulled away just (unuff) how ever it's spelled to not make the connection. once fixed, no more code. __________________ Concrete is the cancer of our land,just give me dirt...

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