Topic: changing EVAP stuff beteen early and late model 5vz's

[mrdoug]

Sorry if this is in the wrong place, feel free to flame or move if necessary .

I'm working on putting a 2003 5vz into an 85, (frame up build, learning everything along the way). I read in some vague posts that earlier motors were better (199.5-2000). I didn't see any of the reasoning then, but now I have. The plan was to use a ford gas tank (pretty successful from what I've read on pirate), but I've run into a snag... the 2003 fuel pump has the vapor pressure sensor embedded, and I don't see alot of possibilities for moving it over to the ford. I understand (now) that the earlier motors had the same sensor up in the engine compartment along with the canister and rest of the evap stuff (vsv's, etc).

I'm considering my options now. What I'm researching is if anybody has tried to retro fit 95.5-2000 evap system to the newer style motors (I think it started in 02 but could be wrong).


The other options I have is to ditch the ford tank, and simply custom mount the 2003 tank (I have a mock up in the garage now that will work).

I'm not sure how many other problems I'm going to have working with the 2003 motor (I'm reliably told that the wiring is about 10x harder  (I get to learn wiring next), so I'm also contemplating (worst case scenario) of simply getting an early motor and selling this one.

[Quick Draw]

Sorry to see that you're not getting responses here, Doug...  Bump for you.

You know I don't know the correct answer...  But maybe you should have somebody open the hood on their early 3.4 truck, so that you can compare the differences side by side.  Is your Tacoma the early or the late version?  Anyway, I thought maybe you could see a more simple solution where you just switch some components around if you see the two next to each other.  I'm curious what makes the wiring so different too.

[mrdoug [OP]]

I haven't gotten any replies on any of the boards that I posted this question. I guess I'm not surprised, it's kind of an odd thing to do.

My taco is the same as this donor engine (which i thought would help me with the swap)... Ike has an older one, but I haven't been able to get him over here to do a comparison. My fear is that while the older model 3.4 has the sensors up in the engine bay, I'm wondering if they feed the same info to the ECU (different ohm's, etc) which would be damn near impossible to track down and fix.

I did get a line on an older 5vz with an offer to do a straight across trade for my setup (with some cash). I am trying to sit down with Brian to go over more of the problems I might run into and see if it's worth it. When people say the wiring is more complicated, I wonder if they think it's complicated to try to plug into the factory harnesses, or if running standalone custom built harness would eliminate that difficulty.

I'm not opposed to running all the wires myself (vs. trying to reuse and/or hack other harnesses to fit).

[Russell_G]

My 3rz has the same evap box as the older 3.4's if you want to check it out. I think they are about the same and all this hype about them needing to be exact is BS my evap box has had an unplugged hose and still no codes.