JWT problems?

[Ramathorn-hammercock]

Hey guys,

I'm looking for some help here.

My Buddy and I just finished restoring a '83 280zx Turbo. 

The engine is completely rebuilt. everything is new. We installed the JWT z31 450hp package and triple checked everything. 

 

-Dropping resistors installed

-fuel pump mod done

-Checked the base timing (0*) and set the operational timing to 20*BTDC. 

-Fuel pressure is 50psi on the rail. the 450cc injectors are all tested and firing. 

-MSD box and all new ignition components are providing a nice spark to all 6 cylinders.

-Compression is 100-105psi on all cylinders.

-Cobra MAF is wired correctly.

-All emission crap has been removed

-pressure tested intake (no vacuum leaks)

-Encoder disk installed (flipped it over to check in case installed upside down)

 

 Car starts up if I turn psi at rail down to like nothing, if I try turning it up slowly to the 58psi (nismo regulator) that jwt recommends it floods out. 

    I took the rail (pallnet) off with all injectors in tow and stuffed a rag under them, I crank and fuel poors out of all plugs at same time it seems. 

The timing was checked by two mechanics and they say it is correct. ( they two can't figure out the problem) 

We did everything the jwt 450hp up grade said to do. (4 bar)

I'm sending the ecu back to ben at jwt to recheck it just to rule that out.

 

I've replaced the coolant temp sensor by spark plug 5, checked the install of the kit 6 times. 

Car was running great when I decided to restore it.

pulled  motor and did the valves,head, mild cam, clutch ect ect. 

I keep thinking we are missing something, maybe not grounding something?  we did eliminate a lot of stuff from the car,eg air conditioning, cruise, air smog crap ect ect. 

Maf was brand new (cobra) as well as injectors and resistors. I unhooked the msd box just to eliminate it from the equation. Were running the walbro 255 pump as well. 

 

 

Any suggestions would be a great help

 

Thanks guys,

                     Johan

[Brad-ManQ45]

I'm pretty sure that the fuel pressure should be set around 38 psi. This is the stock Nissan setting as compared to industry standard of 43 psi.

 

Sure there wasn't a typo in the instructions?

 

The only reason to up fuel pressure is to provide more fuel - the bigger injectors already do that.

 

At idle on ztock FI Z's the fuel pressure is ~30.

[Brad-ManQ45]

I just read JWT's instructions for the 280 Z31 450HP swap upgrade and there is no mention of changine FPR's or needing to.

 

Why did you remove your stock one.

 

Put it on and see what happens, or reset the NISMO one to 38.

[Ramathorn-hammercock]

Thanks brad-man, I'm running the 4 bar system so bigger injectors. They said it has to be at 58psi. I even tried putting the stock fpr back in at 36psi and same issue.

Thanks again for the reply

Johan

[Ramathorn-hammercock]

So, just got a call from ben at jwt, and hey said that the MAF circuit was fried/burnt. He said he didn't know if it was sent out like that or if I did it. He was good about it and is fixing it and paying for shipping. I sure hope this is what's been giving mr all these headaches.

[mario_82_ZXT]

Definitely recheck your wiring at the MAF before plugging everything back in just to rule out that it's not in your harness.