OK, Here's what going on. I have a Datsun 510 with an SR20DE. But, ever since I swapped it in my car I have been having a strange problem. The motor runs really nice and has plenty of power, but everything cuts out and bogs when I am at 6,000 RPMs in third gear, 5,000 RPMs in fourth and 110mph in fifth. When it cuts I cannot accelerate for about 5 seconds and then the motor runs again. The strange thing is that when I am going downhill I can go 125+ MPH and when I go up hill I can't even get it above 100 mph. I am guessing it has something to do with load but I am completely stumped. If somebody could help me I would really appreciate it. Thanks

note: I know that it is not a speed limiter because I have no wires running from my transmission to tell the computer what gear I am in, nor how fast I am going.

-Keith

http://www.sr20forum.com/showthread.php?t=95129&highlight=hesitation+car+WOT

tuneup? sounds like its bogging from lack of fuel. Might be fuel filter?

Are you using the stock 510 fuel pump it could be that.

No, I have a walbro 255 inline fuel pump. I also have huge custom fuel lines and bigger inlet/outlet from the tank

I just checked the fuel filter. Nothing changed. It is a really strong cut off and the engine does not come back until you let off the gas for a few seconds. Any ideas? Thanks for your replys.

Ok tell us more about the motor is it stock ? Does it have a turbo kit? What modifications have you done? When did this start happening ?

Intially my thinking is plug gap ,igntion timing and cam timing. But i know nothing of what done tyo your car or if it was just dropped in stock.

I have a greddy manifold, unorthodox pulley set, sard fuel pressure regulator running 36psi. Non-turbo. This has been happening ever since I got my car running with this imported engine. I have the timing set to 15 degrees...and my tps is adjusted properly. Thanks

What have you checked so far to eliminate possibles causes?

I have raised/ lowered my fuel pressure...disconnected my tach, replaced my fuel filter, went from 10 degrees of timing to 15 to 20...nothing..so I went back to 15. I just did a tuneup on the motor with a cap, rotor, wires, denso platnum plugs.

It kills the engine completely for about 5 seconds if I let off the gas pedal. If I stay on the gas the car wil continue to bog until i have come to a complete stop.

anybody?

do you have stock tank with inline fuel pump if you run 1/4 tank it starves fuel for some reason so you have to make sure your tank is always above 1/4 due to some thing with the baffles in the tank

what ecu are you running/ maf combo are you running?

im going to be running bone stock for now just act stage 3 clutch and 2.5 exhaust with a intake ****** i spoke to told me the same thing unless you put baffles on the lower part of your gas tank to correct this problem but i think its cheaper to just put a surge tank in your engine bay to correct this problem