Help! Weird MAF issues

[Fairlady280Z]

Hey guys really need your help here! Car is a '95 KA-T with a Enthalpy tune tuned Z32 MAF and 550cc DW injectors. (No SAFC or FPR, BTW) Ive been running this setup for at least 3 months now and my AFRs are never the same. I have fixed all my boost and vacuum leaks and now my AFRs are high 14s to low 15s (never steady though) while cruising but in boost sometimes ill get mid to high 11s on a pull and the car runs awesome, but then say later in the day my AFRs go rich to flat 10 and the car hardly pulls. Since i fixed all my boost/vacuum leaks but still had this problem i figured it had to do with the MAF. I redid the wiring on my Z32 MAF and even ran the chassis ground to the chassis (before was spliced to the other ground and ran to the engine harness ground wire) Didnt improve anything instead now when i ground to chassis while idling my AFRs go lean into the high 16s and even 17s! Car runs better with the ground off. Also sometimes while idling with the hood open my idle AFRs are normal low 15s, but then i close the hood and it leans out like the chassis ground does...wtf

Today I replaced my MAF with another Z32 one to see if maybe the MAF itself was bad since i redid the wiring right, it ran even worse and pulled a code 34 from the ECU saying knock detonation sensor..but i dont think the knock sensor can cause all this. Im running the MAF without a filter too BTW, just have a bit of stretched pantyhose over it. Any ideas guys? Any help is appreciated!!!

[Fairlady280Z]

c'mon...no one?

[DevilMB3017]

A MAF without a filter will not work properly - they are VERY intolerant to air passing over it too quickly.

How far is your MAF from your turbo? This is assuming it goes into your turbo intake.

Also it sounds like your knock sensor just might not be any good or is getting triggered.

[Fairlady280Z]

Yea

A MAF without a filter will not work properly - they are VERY intolerant to air passing over it too quickly.

How far is your MAF from your turbo? This is assuming it goes into your turbo intake.

Also it sounds like your knock sensor just might not be any good or is getting triggered.

Yea thats what im told, but when i put a filter on my MAF it makes the car run **** rich, like low 13s cruising and flat 10 in boost, i can smell the unburnt gas as i drive

The MAF is drawthrough (i wish i was blowthru) about a good 9 inches from the turbo, i have a JGS mani so i dont have alot of room to run intake piping.

Im hoping my knock sensor isnt good but my motor only has 81xxx miles on it and its only been boosting for about 2k miles. Becasue if not then that would mean i have premature detonation no? (im only on 7psi and on 93 oct) How can I check to see if the knock sensor or the harness itself is faulty? Thanks btw!

[DevilMB3017]

You have to remove your knock sensor (how to is in the FSM) and you can test it for resistance. I believe the proper procedure is in the FSM for the whole thing.

Do you have any vacuum problems or something? Sounds like something else is going on and making you run rich.

[Fairlady280Z]

You have to remove your knock sensor (how to is in the FSM) and you can test it for resistance. I believe the proper procedure is in the FSM for the whole thing.

Do you have any vacuum problems or something? Sounds like something else is going on and making you run rich.

Nah, before this i thought it was a boost/vac leak problem so i tested for that and fixed all boost leaks

A friend suggested that a injector may be shooting more fuel that its supposed to, even though i bought the DW 550s brand new. but im gonna check them out anyway. He says that may be why the knock sensor is going off too, because the flooding of the cylinder by the bad injector causes metal to metal contact and the sensor picks it up. I think he may be right as i always have noticed the cylinder 1 spark plug to be a bit darker than the other 3...

[Fairlady280Z]

Nah, before this i thought it was a boost/vac leak problem so i tested for that and fixed all boost leaks

A friend suggested that a injector may be shooting more fuel that its supposed to, even though i bought the DW 550s brand new. but im gonna check them out anyway. He says that may be why the knock sensor is going off too, because the flooding of the cylinder by the bad injector causes metal to metal contact and the sensor picks it up. I think he may be right as i always have noticed the cylinder 1 spark plug to be a bit darker than the other 3...

ok so it wasn't the injectors they all had the little caps. And to make sure it was my MAF i put a filter on it and it made my AFRs go way too jumpy the car would drive like crap, it drive the best with just a pantyhose stretched over it. I guess ill have to start with checking out the knock sensor.