I have read in a few places that at some point the 3.4 changed it's method of measuring air/fuel. Something about an extra O2 sensor, and being better for the supercharger. Can someone fill me in on what the change was, and what year and newer engine do I need to look for in a donor for my swap?

Thanks

 

I believe you are talking about the front o2 sensor vs, the newer wideband Air/Fuel sensor. I want to say I read that in 99 the CA ones had the A/F sensor and other states it was an o2 sensor, then from that year on they were all A/F. That may have been in 98 though. If I can find the article I was looking at I will post it.

But all these motors need a 2nd o2 sensor, so the computer can see how well the cat is working. That is all the 2nd one is for. If this is going to be an "off-road" vehicle and not run a cat, then you can make a simple circuit that can fool the computer. There are many rights on how to accomplish this.

 

It will be a street legal vehicle with the cat installed. I do have plans to supercharge it, so I want to get the better engine option. Thanks for the help. I'll be interested to hear if you find that article with the exact date of change.

 

sorry for bringing up an old thread but i have Question,and yes i have searched, i was told by a wrecker that the 5vz was changed and only the newer ones can accept the super charger. is this true? if so what was the cut off year?

 

i know 99s have diff maf sensors and from what ive seen accept a s/c better

 

the guy working in the junkyard is there for a reason. NO OFFENSE as I know this doesn't apply to everybody lol. But no, there is not reason why any 3.4 couldn't run a s/c. What he is most likely talking about is the fact that the earlier models had issues unless mods were done. The S/C's would lean out the vehicle at high rpms. The newer models have better fuel injection, therefore helping the lean condition. Also the changed the the better wideband a/f sensor, so the computer can better control the fuel mixture. This is to the best of my knowledge and research on here and other places, so take it with a grain of salt.

 

The TRD SC will physically fit all 3.4 engines, however the kit is designed for:

'97-'04 Tacomas
'96-'02 4Runners
"97-'98 T100s
'01-'04 Tundras

The engine management electronics of the ECU in pre '97 Tacomas and T100s do not respond well to the sc.

http://www.trdparts4u.com/ProdPDF/TR...020_3400CC.pdf

 

i agree.

If it was me, no matter what year you choose, i would check the air fuels, after the install, be it on the dyno, or an in car, with wideband display.