newbie build trouble...

[wckedintentions]

I have a MAF code in the ecu for a redtop sr, how can i voltage test it, and what would be considered good voltage?

Just want to make sure before i spend the $180 on the new one.... or should i buy used? much cheaper but not sure how reliable that would be, and i don't want to ge another bad one.

[wckedintentions]

can i vent the bov to atmosphere if i keep the maf in the intake "pre-turbo" or do i need to relocate maf to behind the turbo?

currently bov = atmosphere and maf is pre turbo, i am tripping a MAF code, but that prob because i have a gaping hole in my intake where that hose would normally be right???? currently i can't rev over 3000rpm and im thinking this could be the issue, any help appreciated!

[badbob2121]

wow wow, maf behind the turbo? lol

and before you buy anything plug the "gaping hole"...

and i would trust buying a used maf, just ensure that the buyer states its in good working condition, and pay with paypal (not as gift) and you should be fine..

and a bad maf/ maf reading/ bad voltage will cause the car to only rev to 2-3k rpm like you stated

[Morph]

Sounds like a bad MAF. Plug that hole and start the car, then remove the MAF plug and see if the engine runs better or still sounds like s***. If it still sounds like s*** get a new MAF. The SOHC KA24 MAF works, so you could get a reman from AZ if you feel like spending 100+.

[wckedintentions]

wow wow, maf behind the turbo? lol

and before you buy anything plug the "gaping hole"...

and i would trust buying a used maf, just ensure that the buyer states its in good working condition, and pay with paypal (not as gift) and you should be fine..

and a bad maf/ maf reading/ bad voltage will cause the car to only rev to 2-3k rpm like you stated

"behind" meaning in the charge pipe as opposed to the intake??... (this is my first turbo car and im still learning, sorry...) sounds like good advice all in all, thanks for the reply, the gaping hole did bother me... im glad to hear that it might be a simple fix...

Sounds like a bad MAF. Plug that hole and start the car, then remove the MAF plug and see if the engine runs better or still sounds like s***. If it still sounds like s*** get a new MAF. The SOHC KA24 MAF works, so you could get a reman from AZ if you feel like spending 100+.

awesome, my brother has a ka24 in his pignose, maybe he would let me borrow it for a quick diag. Thanks for the advice...

[FlipCoupe]

If you end up needing a MAF I have a few SOHC MAFs from my old hatch, in working order. I would do like $20 shipped if you're interested.

[wckedintentions]

If you end up needing a MAF I have a few SOHC MAFs from my old hatch, in working order. I would do like $20 shipped if you're interested.

awesome, thanks... i will be working on it later this afternoon, so as soon as i know for sure that i need a maf i will let you know. thanks for the offer.

[wckedintentions]

ok so i took a few pics after i pulled the intake out, just want to make sure i am understanding this correctly...

the wastegate can vent to atmosphere...?


the intake hole can be plugged and does NOT need to connect to the bov


plug this vacuum line hole or does it need to connect to something?


what if anything does this bov vacuum line connect to?

[wckedintentions]

plugged the air intake hole and the small vacuum line hole and revved it, still won't go over 3k, ive tried the sr20 maf and the ka maf that i know is good and the problem was the same with both...

[badbob2121]

no your wastegate cannot "vta"...lmao...that needs a vaccum source ..

[Morph]

ok so i took a few pics after i pulled the intake out, just want to make sure i am understanding this correctly...

the wastegate can vent to atmosphere...?

Nope, you want to hook that to a vac source. What i have is a hose running across the front of my valve cover that T's off to connect to my wastegate and to my BOV.

the intake hole can be plugged and does NOT need to connect to the bov

Doesnt need to no, you can go to your local auto parts store and get some rubber caps and plug that thing off.

plug this vacuum line hole or does it need to connect to something?

I didnt think that was a hole untill recently lol, i just put a screw in it with some epoxy to seal it completely.

what if anything does this bov vacuum line connect to?

After looking at it again im not sure, i thought it was the vac source but there is already a line connected. Not sure with that bov im running an HKS.

[Chris28]

There is some confusing wording, but most of the information is correct.


This tells when the internal wastegate to open. Technically it should connect to a boost source, not a vacuum source, however they are normally one in the same. As long as it's connected to a source that sees boost it's fine, so connect it anywhere after your turbo but before your brake booster check valve. If you care about how it works positive pressure pushes against the diaphragm inside the actuator. The diaphragm works by a spring, so when you have 7 psi of boost it moves and pushes the wastegate arm and opens the internal wastegate.



You can use this to recirculate your BOV if you don't want it to vent to atmosphere. In order for your MAFS to get a proper reading it needs to be capped off or connected to your BOV. Since your using an eBay BOV it's possible that the BOV itself is leaking and creating the same scenario as leaving that hole unplugged, so as a preventative measure you might want to go ahead and recirculate your BOV to that fitting.



Plug it.



It might just be there to relieve pressure inside the BOV with the piston inside actuates, but I've never taken apart an eBay BOV before so I can't tell. Once you solve your other issues put your finger against it and if it is sucking in air it needs to be capped.


Your 3,000 RPM limit is the ECU running in limp mode because your MAFS signal is bad. If the KA and SR MAFS didn't work break out your multimeter and check your wiring. Download your ECU pinout here - http://www.midweststreets.com/240SX/ecupin.html and get to checking for continuity.

[wckedintentions]

awesome! beautiful explanation chris28, thank you!!!! I think the bad maf is still possible, i didn't realize at the time that i had to use a sohc maf from a ka and not the dohc. I am still thinking that the maf could be the issue. My brother is coming over with the sohc maf tomorrow so i can check for sure, as far as the other issues, greeat advice. I will make a list and check it twice. Morph, thanks for all the help, and chris28 thanks for putting it in lamens terms for the newbs like me.

[wckedintentions]

on a side note, would it be wise to ditch the crappy ebay bov and fork over the cash for the real toys? this one came with the fmic kit and i don't know if i trust it...

[badbob2121]

^^ yes i would ditch the ebay bov... you already have a greddy flange, might as well just pick up an authentic greddy bov

[wckedintentions]

sounds good, i'll do some shopping this weekend... thanks..

[wckedintentions]

put my brothers maf on and she ran like a champ. i fell in love with this car all in a single rev. felt so good to hear it all the way through the power band. Thanks for all the help! i still need to get the frame strightened out and finish up all the body work, i'll post some pics when she is all sexy again... Thanks again!