Lexus AFM
 

quick question...my turbo mk3 was running fine, completely stock. i put a lexus afm on it and now it breaks up while driving normal, and seems to have a hard time idling.

You upgraded the injectors or added 25% more fuel some other way I hope... Can't run more air until you've got more fuel or you're going to run lean and destroy stuff VERY quickly.

are you talking housing or black box? if you replaced your stock metal honeycomb then yes, your going to ruin you engine unless you have a way of tuning. The black box used as a replacement for your kvafm (i.e my old one busted.) is acceptable and should not affect your daily driving. granted you wired it in correctly..

from what i have heard if you put the lexus afm you can also take its injectors which already flow 550cc which both will plug and play( i would get them flow tested first, dont want a bad injector)if you dont have the injectors you'll start damaging things really quick

If the lex are low impedance. I don't think they are if I recall correctly
That's something I'd check into.

The stock 1UZ injectors flow around 250cc/min.... NOWHERE near what even the 7M-GE's injectors flow. The 1UZ also uses high impedance/'saturated' injectors where the 7M-GTE uses low impedance/'peak and hold'. Actually, the 7M-GE's '89+ injectors are an upgrade for the 1UZ; '89+ GE injectors (with the green top) are high impedance.

The ELECTRONICS within the 7M-GTE and 1UZ-FE KVAFM are the SAME and may be interchanged.

The HOUSING of the two KVAFMs are different. The 1UZ's flows about 25% more unmetered air. As this air is unmetered and the ECU has no way of knowing that it needs to provide additional fuel to match the airflow.... Hence the REQUIREMENT for larger injectors; It's not an option.

I thought they were high impedance. I was at work tho posting from my iphone.

can you make that a sticky please. or move to the faq.

You thought correctly... they are. You can use high impedance injectors on an engine which came with low by removing the resistor pack but you cannot run high impedance injectors with an ECU that's built for low (at least not without a good amount of work... often including a different ECU ;) ).

I'll move it to the FAQ for now. I may put together a more concise thread without all the additional chatter in its place later on. I didn't realize that this upgrade wasn't even covered in the FAQ.

Ok. I've moved it to the FAQ. Everyone keep in mind that if you reply to this thread now it is moderated so your post won't show up until a staff member approves your post.

We haven't heard back from 2genfun.... Are we to assume he's busy swearing while pondering the easiest way to replace a piston with 'speed holes'?

that explanation you gave, covered that question most thoroughly. It deserved a spot in the faq. Rather then repeatedly spouting it. Cheers!