I am currently running on a stock KA fuel pump for the SR20DET which i am planning on upgrading in a lil bit. Anyway, with moderate acceleration there is congestion and air would come back out of the mafs. I can never take the car pass 3500 RPM without this annoying bog as if you are misshifting. I advanced the timing just a few notches and noticed the crank angle cap is cracked; however, the car can be accelerated to redline from 1st to 2nd gear but 3rd gear still has that bog but not so heavy as before. How can I solve this problem or what can be the problem? I can really use some help right about now for the amount of money I spent on the engine.

 

sounds like you are running lean...get that fuel pump upgraded to a 300zx unit or better, and reset that timing, you should be fine...

 

check your oxygen sensor i bet it went are you running rich check your plugs

 

I am not sure but the air that is being taken into keeps coming back out of the MAFS intake box, so i am assuming i am running lean. What do you think?

 

if he were running rich, there would be no air coming out, you are IMO running lean, now, im not 100% sure, but i think thats it, do like i said, and you should be fine, but it couldnt hurt to check/replace the O2 sensor...

 

i have a stock ka fuel pump on my car at stock boost, actually runs alittle rich, my thang back fires like crazy, and ive never experienced any bog'n even while racing...doesnt sound like a fuel pump issue to me unless youve bumped the boost, but then agian i dont even know how to spell!!!

 

Yeah i am also running a stock KA fuel pump; however, it is off of a 90 240sx. Would there be a huge different between the two??

 

nope..to my knowledge its all the same, how much boost r u running
?

 

I found my problem. There was a leak coming from the intercooler. Getting a new intercooler installed next week. Thanks for your input guys. I appreciate your help.

 

well now that makes sense, sorry we didn't nab the solution, glad you did!

Dr.

 

awesome good luck keep us posted

 

Just after the intercooler swap i took the car out for a drive and mahn let me tell you. The car was the best ever of describing of how ****ty a car can run. Anyway that tells me that the intercooler wasn't the problem. So i searched for leaks and i decided to reroute the blow off valve because i left it open so it can make a louder sound. Little that i knew it solved the acceleration problem. I believe whenever the boost would kick in at about 3,000 RPM the blow off valve would leak. But the car is great now and FAST! ! Thanks guys for trying to help. I hope you all learn an important lesson when getting an SR20 swap done.

 

yeah dude go with the 300zx fuel pump or go with one you can only get in Japan, if you have the money, TOMEI makes a fuel pump for s13 and s14 and can be good to 500hp and is a true direct replacement. The 300zx TT fuel pump is not a direct replacement and you will have to make it work... if you know what i mean.

 

Walbro is a great fuel pump and pretty cheap, can be found under 100 on ebay