Fueling Problem!

[Daboss]

Hey guys need some expert opinion again. Ok here is the deal at wot full boost my afr's are in the mid 13/14's. They use to be in the high 11's/12's, but the other day as I punched it it started to miss horrible after I went into cruise. When applying load it was fine but at cruise horrible miss, got her home to find the number 2 and 4 spark plugs were damaged. Insulators were cracked and on the number 2 the tip of the plug was gone was able to glance at the wideband and afr's were in the mid 13's/14 during that pull. Replaced the plugs miss went away but left the leaning out problem. I am using a chipped ecu on 10 psi stock turbo. Now that setup should not be able to flow enough air to make me lean out that bad. So I tried to compensate by adding fuel with the piggyback no luck as soon as full boost comes in afr's lean out. So I figured my problem has to be fueling, I clamped the return line and the fuel pressure sky rocketed depending on how tight I clamped it and stayed at that level showing me that the fuel pump is up to scratch. I let it go and the car automatically leaned out at idle, afr's in the 17/19's and didn't level out until I increased fuel pressure through the regulator. 1)What I want to know is if it supposed to do that when I release the clamp or is this a sign that the regulator is shot? I also noticed that on the fuel pressure guage attached to the regulator that when car is off the needle sits at about 8psi and with the regulator increase and the piggy back adding 15% fuel when full boost kicks in the car still has afr's in the 13's. Under cruise and light load everything is fine, but as soon as full boost is in the car leans out not as bad as before but still bad. I have walbro 255lph fuel pump with direct power rewire mod and have already established that the pump gets full voltage from the battery the pump is probably 18-24 months old. I am not running the car just allowing full boost to kick in at 3000 rpm and checking the afr at that point. 2) What do you guys think it is and also is there a way to just test the regulator without running the car at full boost?

[700HP-GTR33]

AFM, Wrong heat range on spark plugs, Bad fuel.

But I am guessing your spark plugs were bad from the start.

[Daboss]

AFM, Wrong heat range on spark plugs, Bad fuel.

But I am guessing your spark plugs were bad from the start.

Hmm that could be. I had or at least still have denso, coppers gapped at 0.8 heat range 6. I will be sticking with the same except moving the heat range to 7 as it is always hot here. Had the spark plugs in there for maybe a month. The two that were bad I just replaced with two old plugs I had taken out to put in the denso's the other four are still from the same stock. Will change the lot this weekend. How would I check the afm? Just swap it with a known working one and that's the only way. I have a z32 installed. Quick question bad spark plugs or the wrong heat range can cause a car to lean out? What about the fuel pressure regulator, from what I described it seems to be ok then?

[blind_elk]

Which side of the FPR - engine or return - is the fuel pressure gauge sitting? Because if it's on the engine side, it should basically show around 2 bar when the engine switches off (unless you don't have the non-return valve in the pump).

What pressure does it show with the engine idling?

[The Dan]

Fuel pressure does not = fuel flow

[Guilt-Toy]

do this test and get back to me, take your air flow meter off, CLEAN IT with contact cleaner or brake cleaner. get it as clean as possible. re-fit it and check the AFR's and let me know what happens.

was the car tuned with the z32 afm? or was it tuned with a stock one and you changed it later?

cheers