Thread: Quick question?

Has anyone ever had this problem? I just upgraded my fuel/air management system with a 255 walbro, 370cc inj, and a Z32 MAF. Running a JWT ECU programmed for 9.5:1 ratio, 95-99 SE-R, Z32, Turbo, and Pop Charger. When I WOT in neutral, it feels like the fuel cuts off on the low end or doesn't want to rev freely until it hits bout 3k rpm, then shoots all the way to redline like normal. I just need some inputs on what could be the cause before going out to by a Nismo FPR. On Vadim's roller rocker build he also mentioned that when he did the 255 walbro pump upgrade it didn't change his fuel pressure all that much and the stock FPR did fine. Open for suggestions. Thanks in advance.

MAF. When there is a problem with the MAF reading the ECU cuts the fuel to 3000RPM, or cuts it completely at 3000RPM. If you can't get to 3000RPM but then can soar past it, that sounds like it has something to do with it. Rarely is a problem that occurs at a specific RPM everytime a mechanical issue, its almost always something electrical.

1) Check your MAF wiring. My guess is either a wire came loose or a wire is connected wrong.

2) If the wiring checks out, call JWT asap because you may have something on the ECU that you don't have on the car.

I would say TPS sensor maybe mis adjusted or possibly a o2 sensor going haywire, then when you go WOT it goes into open loop and doesnt have a set paramater it has to follow and just dumps fuel and then you get the throttle response.

If a maf were bad i would think it would only rev to about 2500 and go no higher, or not give you any throttle response at all.

Did you reground the MAF as suggested in the how to thread I inconveneintly cant seem to find at the moment?

Wait.... so the ecu is tuned for a turbo but it's being used on an N/A car and you're not expecting problems....

Many have ran their cars N/A with upgraded ECU, fuel pump, inj, and Maf before bolting on their turbo kit. Only right way to prevent problems when piecing a turbo together. Easier to troubleshoot issues vs slapping everything on and then find out there is a problem. There is even a sticky on how to go about installing a turbo kit step by step. Correct me if I'm wrong.

No I haven't yet. I've started trouble shooting the obvious first. Checking spark, and spark plugs(re-gaping), made sure plug wires aren't damaged which could cause mis-firing, check engine light is on but only due to the intake temp sensor not being plugged in because of after market intake system and pop charger. I'll try regrounding soon and see if that works.

Hopefully that works