Dented Gas tank causing problems?

[lilskyline240]

well i still have not solved my problem of no power over 4000rpm zerothread?id=339559

i have since sent my harness out to get redone by Mark (S14-Neo) in hopes that is the problem. but last night while trying to fall asleep i remembered my gas tank is badly dented on the underside. The guy who had the car before me drifted the car regularly and drifted over something which dented the tank upwards about 1.5 inches in 2 diff spots. Now what im wondering is could this be causing my problem of no power over 4000rpm? I have perfect fuel pressure and A/F ratio when at WOT so i doubted that was the problem. but the longer this problem continues the more i think it might be.

any imput?

[mello88]

Could be causing the pump to not suck fuel up... But if you have good AFR and fuel pres that is probably not the problem...

Does your AFR change after 4000? What is it at that point & beyond? What do you have for tuning? Sorry you probably answered these in the other thread, but I forgot...

[lilskyline240]

Fuel pressure and A/F ratio dont change above 4000 rpm i dont believe. Im just running out of things that could be the problem

[rb25drag]

I think its your plugs, I had the same problem when running on a NGK plug, Changed to an AcDelco and problem went away. Have you tried new plugs?

[lilskyline240]

really? weird. i got NGK's gapped at .028. I never had a problem with NGK's but i could try something diff i guess. Wouldnt i be gettin spark blowout or a missfire or something? cuz its smooth all the way to redline. Just has no power like it should

[rb25drag]

Ya, I had both problems, Sometimes it would pull ok but not like it should and others I would get the spitting, spuddering and bucking, Well changed plugs and it was like Night and day, Also added some timing and it ran even stronger. So those are the 2 things I would look into.

Were is the dents in the tank? Close to the pickup?

[s13point5]

what ECU are you running auto or manual? i had to advance my timing 5 degrees because of my auto. the car felt completely different in higher RPMs. i talked to my buddy who had a manual rb25 ecu. somehow blew that so he bought an auto ECU off ebay and had to advance his timing 5 degrees. 15 degrees for manual, 20 degrees for auto in my experience. atleast thast what my nissan mechanic friend said. with mine set at 15 degrees, everytime i get in boost, the car would just feel like it wasnt going anywhere. it would just feel like it was accelerating normally. i advance the timing and the car started pulling hard when it saw boost

[lilskyline240]

yeah one big one right under the pickup i think and one like a foot to the left if looking at the rear of the tank

[rb25drag]

My guess is to take out the pump, Measure from the mounting bracket to the bottom of the pickup, Then do the same to the bottom of your tank. If you have 1/4- 1/2 inch clearance I would say its ok.

[lilskyline240]

heres a sketch of the bottom of my gas tank. The blackened areas are the area that is dented in quite a bit

[mello88]

what ECU are you running auto or manual? i had to advance my timing 5 degrees because of my auto. the car felt completely different in higher RPMs. i talked to my buddy who had a manual rb25 ecu. somehow blew that so he bought an auto ECU off ebay and had to advance his timing 5 degrees. 15 degrees for manual, 20 degrees for auto in my experience. atleast thast what my nissan mechanic friend said. with mine set at 15 degrees, everytime i get in boost, the car would just feel like it wasnt going anywhere. it would just feel like it was accelerating normally. i advance the timing and the car started pulling hard when it saw boost

Yes according to FSM m/t is 15 deg and a/t is 20 deg. Would be nice for OP if the problem is only from this hehe

[s13point5]

so lilskyline240, im curious to know what ECU you have. like i said, i advanced my timing 5 degrees and the car drove completely different

[lilskyline240]

ive set my timing anywhere from 10* to 25* with no real change. Rb25 s2 ecu