Air Flow Meter Modification

[Walky88 Member Find all posts View Profile Close Walky88]

Gday all just bought myself a 97 Prado with a 3.4L V6 (5VZ-FE).

What i was wondering is, I have the old style Air flow meter and was wondering about what mods are required to change it over to the later model style.

I'm a mechanic by trade and have just bought a manual with wiring diagrams so waiting for that to be delivered but thought i may just ask the question in case someone has already done this. I know you will have to change the airbox lid and air intake tube to throttle body but just unsure about the electrical side of things. I am thinking may require a new wiring harness and maybe ecu but unsure. I know a good toyota wrecker who can supply a harness and computer but he didn't mention the price. :-o

Sorry if this question has already been asked but i'm hopeless with these forums. Basically i only know how to post and reply

Thanks in advance

Grant

[baders Junior Member Find all posts View Profile Close baders]

My question would be, why bother ? The mechanical MAF sensor is probably more reliable than the later hot wire one.

[scottkz Senior Member Find all posts View Profile Close scottkz]

youl need a late ecu, engine harness,atleast one key from the new ECU (early cars have a separate immobilizer late have it internal to the ECU)
2 plugs on the body side that plugs into the ECU need to be changed to late....
5-6 wires need to be run from the the old immob to the new ECU
or you could change the engine/bulkhead/front wiring harness
but the rear harnesses are not plug and play only one plug on each side is the same
rear harness colour codes are the same early/late cars
but engine colours codes have a few differences
if your good with wiring then its doable but if not steer clear
i have just rewired my 96 V6 to 02 wiring then put a 120 1KZ ECU in it
rewired as i upgraded to ABS/TRC/Airbags/climate control

[Walky88 Member Find all posts View Profile Close Walky88]

I was told by a good auto electrician i know that the later model hot wire should give me better fuel economy. Don't know if he was jerking my chain or not.

I know i can get a lid, intake tube and sensor for next to nothing so that is no problem. Tomorrow i'm pulling out the multimeter and testing my current air flow as i believe that is the fault with not only fuel economy but its very sluggish down low. I have done the normal things like replace spark plugs air and fuel filters and the current air flow looks very clean. Have just had the manifold up and cleaned the throttle body in the process. (Yes problem existed before removing manifold). Next thing is air flow meter before pulling manifold back up to get injectors cleaned. (I know should have done it while manifold was up)

[baders Junior Member Find all posts View Profile Close baders]

I was told by a good auto electrician i know that the later model hot wire should give me better fuel economy. Don't know if he was jerking my chain or not.

For the amount of stuffing around involved in grafting in a new hot wire sensor, just grab a new mechanical sensor or at least one from a wrecker. Some other questions for you.

Is the ECU throwing any fault codes ?
Have you tested the MAF sensor resistance ?
Have you checked base timing ? (timing belt jumped a tooth ?)