1UZ Hilux hesitating, loosing power, dragging ass up to 300 rpm?!

[trinisouljah]

My 1UZ has been seriously loosing power up until it hits 3000 rpm, then it takes off like a rocket. I have been trying various combinations to try to get it to run right, as I have read many different things on different forums.

The only solution I have found to work is disconnecting the MAF and then the problem goes away, but it then runs extremely rich and smokes a lot. Based on one recommendation I put in 2 new coils, but this did not help.

I am tempted to send the computer to be worked on, as I have seen this service being offered and the problem I am experiencing is one of the problems they say it will fix. Does anyone have any experience or recommendations for this PLEASE??

 

[XR8tt]

Have you tried another MAF ??
Sounds lean down low or AFR all wrong ??
Could also be TPS or O2 sensors..

In closed loop fueling, the computer takes readings from the oxygen sensors which read +/- of 14.64 AFR (Stoich) and makes corrections for it. If your car is idling @ 13.5 AFR, the 02s can see this, and will know to pull out enough fuel to get back to stoich.

In open loop, the fueling is purely based off the MAF transfer function and the open loop fuel table. This table has to be calibrated any time you make MAF changes, and changes that affect the airflow of the MAF.

When a car is started, the computer is in open loop until certain criteria is met. The o2 sensors need to be heated to work properly, so this is the main reason there is a delay.

After the sensors are heated up, the car goes into closed loop and the O2 sensors make their corrections.

The computer will go back into open loop under a variety of conditions. Throttle Position (TP) is one way.

There are parameters in the computer that determine what the TP is for Open Loop, and other things.

When that TP is reached, and the car goes open loop, and richens up.
HTH...

 

[gloverman]

I think you should buy one of my link setups and an airline ticket for me (and my wife) and ill come over and fit it up to your ute and fine tune it for you. Cheers

 

[XR8tt]

Yep!!!
Kiwi's will have a go at anything free.. Lol...

 

[George_R]

trinisouljah maybe you would describe your setup in details? Which production year is your 1UZ? Any error codes present? Are you 100% confident you use the right MAF type and 100% stock air duct? This one can be tricky.

If the engine was previously run in hot and humid climate then replacing caps in the computer *may occasionally* fix the problem.