3.4 swap problems
 

my tcuck will start up and rev up to about 3 grand and wont go down to a normal idle and i just got a new maf anybody know what it could be thanks for the help

grab an ohm-meter and check the resistance of the tps make sure that its within spec

vacuum leak?
throttle stuck?
a sensor disconnected? connected to the wrong sensor?
spec check your TPS and AFM like BC4 said.

and its AFM, not MAF

what happens if you move the butterfly to the idle position by hand? If it idles at 3000 with the butterfly closed I would start by checking linkage adjustments to be sure the butterfly is actually able to close to idle and not being held partially open by an adjustment screw or throttle cable tension, or even tension from shiftdown or cruise control cable.
You said this is a 3.4 swap. Is your tach working or are you guessing that the rpm is 3000. The engine will idle fast (1500) until it is warmed up.

Yeah I'd check the throttle cable, it may be binding where it turns out of the firewall. Lots of heat there from the crossover, maybe melted the rubber covering.

throttle linkage is fine and i got it to stop reving but now ive got a fluxuating idle and while im driveing down the road it will fluxuate like im on the gas than let off than back on but the pedle doesnt move.

what did you find was the cause of the high idle?

1999 Tacoma 3.4 manual indicates the fuel pump control circuit as the probable cause of surging. This might also be able to include fuel supply and delivery issues. Clogged injectors, fuel filter, pressure regulator, etc.

i put more intake tube on it and i belive my fuel stuff is fine it will still acclerate real good

ok its running at a really high idle again and i put a brand new cold air intake and new maf. is there any way to adjust the idle on the 3.4 thanks for the help

What throttle cable did you use? If I remember right, I had to use the cable from a Tacoma or a 3rd gen. 4Runner because mine was too short.

i got the old one to work i bent the bracket down for it to work but even if i disconnect the throttle cabel it still does it theres nothing wrong with the throttle body it goes back to normal position when its released

On my swap I use the original 3.0 throttle cable without issue. You should be okay since you said it is smooth and adjusted correctly. I would give this a good look and maybe clean or replace. If you want more detailed electrical troubleshooting data let me know. Data below is for my 1999 Tacoma 3.4 engine.

How do you like the swap so far?

CIRCUIT DESCRIPTION
The rotary solenoid type IAC valve is located in front of the intake air chamber and intake air bypassing the throttle valve is directed to the IAC valve through a passage.
In this way the intake air volume bypassing the throttle valve is regulated, controlling the engine speed.
The ECM operates only the IAC valve to perform idle-up and provide feedback for the target idling speed.

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ok the high idle went away and now its got a fluxuating idle again give me any ideas on what it could be

What did you do to get rid of the high idle?

This thing is throwing something different at you everyday.

Did you build your own wire harness? Just curious.

For hunting idle manual suggests ECM power source circuit or fuel pump control circuit.

You have already said you know you fuel supply system is good.

I had a problem where I would hit a bump the engine would quit for a split second. Turned out I found the EFI relay was loose in its plug. Pressed it in tight and the problem never came back.

Start at the ECM as noted in the diagram and work your way through the EFI circuit checking for power, and grounds as appropriate and for shorts, or opens.

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Have you got the OBDII hooked up? If, so are you throwing any codes?

bought the ors swap kit and yes i am throwing a code for the evap solenoids just cause there not there and i have no clue y the high ide went away i was drivein around and it just went away to the surging idle and i cleaned the iac today and nothin and checked the maf and tps all good

Just one code, that's it?

So what did you do with all the vac lines for the evap solenoids, that may be your problem. You know you can use the 3.0 evap can with Mikes instructions.

Did you replace your o2 sensor with one that matches your 3.4?

i never got the solenoids with the engine and i reused the 02 sensor from the 3.0 and got the one behind the cat from the 3.4

I'm kind of shocked you used a 3.0 O2 sensor. :think: What year is your ECU?