Altezza, No Power Until 6000Rpm

[jono395]

Hi all

I've just bought an altezza, it has no power until 6000rpm, and is very flat until this point, but does get even flatter at 5k until 6.

It has no air filter, it has the maf, on the end of the throttle body, and then a sock stretched over the end of the maf. How would these engines react like this?

I've also noticed, if you could imagine this... The vacuum hose that comes off the throttle body at the top, and goes into a solenoid type device with another hose coming off of it, what does this do? As its blanked but still plugged in, I'll get a pic when I can.

I have no engine lights on, they go out when engine is running, when stamping on the throttle from low revs it sort of bogs abit,

Hope this helps

[ColinBarber]

where is the MAF, cannot clearly see it in the picture.

Given that you have very little filtration I would first look at the MAF wires to see if they are dirty. I would suspect the MAF positioning isn't helping matters

http://www.lexusownersclub.co.uk/forum/tutorials/article/104-gs430-43-3uz-fe-engine-cleaning-maf-sensor/

[jono395]

The maf is under the sock type thing in the pic. Also, it runs slightly better when it's cold weather.

Would it matter how close the maf is to the TB? Is it designed to be a certain distance away? And what does that vacuum solenoid do please? Thanks

[ColinBarber]

I don't think distance is too much of an issue but it could be. The air passing over it ideally needs to be non-turbulent and more importantly the sensor needs to be at 90 degrees to the airflow so the correct amount of air is forced down to the wires. Obviously it needs to be mounted the correct way around.

The vacuum solenoid sounds like a VSV (vacuum switching valve). These are used for a few things, EVAP emissions and the ACIS operation are the common two.

[jono395]

Okay I'll have a mess later on and see how I get on. The solenoid wouldn't be an issue then and is fine the way it is? Could The problem be anything else or is the maf a fussy sensor on these engines, and can easily cause this? Cheers

[ColinBarber]

I believe that VSV is there to operate a flap in the stock intake at a certain engine speed. As you don't have the intake it is fine for the VSV to be capped. Provided air isn't getting in this won't be the cause of your problem.

There could be a number of problems that are causing your poor running but considering that the intake has been messed about it is a good place to start. Make sure you don't have any other air leaks around the throttle body with vacuum pipes being disconnected. Do you have the stock intake you can put back on? There have been a number of people in the passed who have tried a DIY intake and experienced similar problems.

[jono395]

Thanks for your reply. No I haven't got the standard airbox or anything. However I've fitted an air filter and moved the maf out of direct air flow. It's better, however it's still stuttery. It's better if you cone on the power slowly. The maf has been cut at the intake end for some reason. Could it possible be a faulty tps?

[jono395]

I think the maf has bbeen cut off on the intake end, as it usually is moulded to the air box? So is this ok?

I picked up a new denso maf sensor which made it alot better! But it still seems quite flat until high rpm, any other ideas?

[E910]

Find your self a stock air box & all your problems will be solved. The 3SGE doesn't like pod filters although they seem to run ok if you get an Apexi or HKS which are specifically designed for them, anything else will make it run like a pig. It's all to do with the position of the MAF & they way the air has to flow over it. If you're really stuck put a bit of fine metal mesh before the MAF to try smooth the air flow out a bit.

[jono395]

ive fixed it, the new AFM sorted it out after around 10 miles of driving it. :)

Edited July 29, 2013 by ColinBarber

[jaba0x]

ive fixed it, the new AFM sorted it out after around 10 miles of driving it. :)

what does AFM means? have the similar problem...

[E910]

AFM = Air Flow Meter. It's the black plastic thing with wires coming out of it after the pod filter in the photos above. Usually cleaning them will fix the problems but worst case scenario they do fail & need to be replaced