Common rb problem?

[Texasrb240]

Hey guys I'm new here, just got my rb20 s14 cranked up, got a few questions. So my rb seems to be running fine, got the crank and cams on the timing marks but I don't have my lower timing belt cover so I can't put it in time . I read up a bit and have my cam angle sincer right in the middle so I'm sure it's just a little off by a couple of degrees or so.. Anyone have a lower timing belt cover there willing to sale?

Also can I use a ka power steering pump in the rb PS bracket? Anyone ever done this before ? The rb PS pump has two ports that aren't common. I plugged the rear and I don't wanan blow the pump up. Any solution ?

Ok and now for my real problem. I can only get half throttle. Anything over half seems to just kill it. It seems like the fuel totally cuts off.. I have the walbro 255lph pump. It's new so I know it's not the pump. I had a buddy tell me he had the same problem when he jz swapped his Cressida. His problem was the fuel pump ran on 9 Volts until over half throttle then past half throttle the pump needs 12 volts. I think this might be my problem. But I've read a bunch of other forums with people saying they have the same problem but no one is saying this is the solution. Everyones saying change your plugs or fuels pump. I figured I'd come here and get some help..

[240z4u]

240sx's supply 12v to the pump at all times, it's not variable. Not sure what the problem is but almost every time it's an unmetered vac leak that is causing it. Do you have a BOV that is vented to atmosphere or breather on the valve cover?

[Texasrb240]

Stock BOV and no breather on Valve cover. It's all stock. Just dropped in and cranked up

[ItzGenX]

A lot of this can be ruled out with a simple multimeter. You can check your voltage at the fuel pump, MAF, TPS, CAS, etc. If you want to truely rule out the fuel pump, just use a fuel pressure tester and see how much pressure you have. If everything checks out fine, then your timing is probably just way off.

[placham]

You have a HICAS P/S pump, remove the back cover and pull out all the vanes there, that will disable it and it will run as standard pump. Than u can plug the ports. You can replace it with Rb25 regular pump, but think bracket and mounting bolts are different so you need all them, otherwise its a bolt on. You can use ka24de pump, think you need bracket as well, and think theres some grinding cutting involved, pulleys are different, but it has been done before and it works, seen it on Rb26. But I dont know for sure if Ka pump and Rb bracket go together they might.

Try unplugging MAf and see what happens, get a inline fuel gauge see how pressure is, do you have S2 Rb20, with dual pressure regulators-try switching the fuel lines and see what happens, did u change fuel filter to Z32 or replaced with stock new one. Thats all I can think of at the moment, if car runs on all 6 than, I would try to pull the codes out the ecu. But then again if ur not sure about it being timed .

Get ahold of Ricky at Raw Brokerage (coolwhip on nico) they might have some in stock used ones. and I think Rb20/25/26 lower covers are same, I know uppers and valve covers are interchangeable. Or search egay for replacement.

[Vkoslak]

If you are in the Austin area, I may be able to help. I have a bunch of spares from my old rb20 swap (running a rb26 now, if I can figure out high hc issue). I even have a spare rb25 power steering pump and bracket. My rb20 used to do exactly what you are describing. It turned out to be corroded wiring harness for the mafs. I discovered it by flexing the mafs harness while the car was running and it caused it to change into the 2500rpm limit mode. Worth a shot anyhow.

[Ty P]

kind of off subject but what diagram or info did you use for converting the wire harness? any info would be helpful
Thanks
Tyler

[Adam Kresse]

Sorry to bump an old thread.

What fpr are you using with your 255 walboro? If its the stock one that is probably your problem.