Ghetto Blaster Problems (RB25DET).

[omgsky]

For referance I have a RB25DET swapped S13. Power is great till I start boosting really hard (Guessing rpm, gotta swap in a GTR tach). 1st gear pull is good till roughly 5k and then it starts acting like it's starving for fuel. Has a R33 fuel pump wired in. I hooked up a fuel pressure gauge, shows 35psi on idle, little above idle drops to 32, and when reving the piss out of it, it goes to 40. Thinking about swapping a walbaro in just to see if it makes any difference. Any thoughts are great. Car starts and idles great.

-Sky

[Darius]

what fuel pump are you running? sounds like it isnt keeping up under load.

[Shocker]

what fuel pump are you running? sounds like it isnt keeping up under load.

he said r33 fuel pump, your base should be 43 psi with vac. try adjusting it.

[omgsky]

Is there anyway to ajust a stock one? Do I need a regulator?

[Shocker]

Is there anyway to ajust a stock one? Do I need a regulator?

yeah, your pump could be taking a **** on you too.

[uber95]

Make sure you are getting full voltage available from your electrical system to the pump. Very common to have voltage drop due to insufficient/old wiring..

[R33GTS-T]

once you get the fuel pressure resolved, if that doesn't fix it check the vtc solenoid. when mine started taking a crap on me the car would fall flat on its face around 5,000rpms

[leesredgt]

he said r33 fuel pump, your base should be 43 psi with vac. try adjusting it.

so it needs to be set at 43 not 36? b/c mines doing the same garbage.

[Darius]

Sorry for the stupid question about the fuel pump. I was trying to read this thread on my phone at a bar while playing pool, so I missed it. Yes it should be at 43 psi at idle with the vacuum line off of the regulator. If you aren't seeing that, there are three things that can be wrong.

1) Clogged fuel filter/line2) Faulty fuel pressure regulator (rare)3) Fuel pump is wearing out

[omgsky]

I just put in a brand new 300zx TT fuel filter. I swapped in another fuel pump. I have the SAME problem. Bogs down hard at around 5k. Gunna clean the MAF tomorrow.. RB makes me sad .

[omgsky]

The worst part of it is.. I get up to 5k and I feel that it really wants to go.. then...BLAH

[Carl H]

check your base timing and make sure there arnt any intake leaks...

[silviasgp06]

guessing rpm? go buy an auto meter tach or something. ide be scared doing that for any kind of trouble shooting. plus you cant really set base timing with out setting a basline idle and you cant set idle without knowing a exact rpm speed.

Its in the FSM but here you go if you dont have it downloaded, Happy Easter.+/-50rpms of 650rpm. timing at 15 deg(4th mark from left) unplug TPS before setting timing. (i think thats all correct someone correct me if im wrong)

have an update yet?

[omgsky]

Cleaned the MAF and filter. Same problem. If you baby it on the gas it'll go up to like 6800rpm then start breaking up. On a up note I got my tach working..

[omgsky]

bump, gunna check the fuel pressure under load tonight.

[Cjmartz2k]

If the pump is dying, your not going to see pressure drop until you are romping it and it'll be a little hard to check it than with out an in car gauge. Slap a Walbro in that thing and go ($100). Maybe it'll fix it, maybe not, but you'll have a 500hp capable pump anyways.

[omgsky]

Put a good pump in it and it still has the same problem. Checking the pressure under load in a few minutes as well as the voltage going to the pump.

[omgsky]

Fuel pressure is good. Go's to 50psi under heavy load. What next? I can maybe borrow a MAF tomorrow to swap in..

[matafied]

man mine started the same crap! revs fine and builds boost but as soon as you throtle down blahhhh. ahhh just like it isent getting the fuel, i swapped in a new walburo that i had and it's doing the same crap! so first thing tommorow is voltage checks at the pump! might not be getting the voltage i need to the pump. i hope thats what it is

[omgsky]

Just looked up the TPS inspection specs. I'll let you know the results.

[silviasgp06]

man now that im finally done with the swap and driving now i realize i am having the same issue. at 5k the power seems to drop off. pulls nice til then though. i thought it was just cause i havnt bought new plugs and gapped them yet, but its exactly what everyone is seeing.

My car:s2 rb25detWB 255 fuel pumpproject nissan FPR @ 44psiTiming @15*FMICboost @.5 bar no controller SAFC2 for RPM, MAF is tapped in but not adjusted SR downpipe, no cat, N1Dual copy 3" to two 2.5"

[omgsky]

Unplugged the TPS and it does the same **** .

[S14-NEO]

if the MAF isnt supplying the proper signal to the ECU under a heavy load conditions then the ECU will not compensate by adding more fuel..i would try swapping out for a known good MAF..i know you said youve cleaned it but sometimes you cant resurrect the dead yanno..

[matafied]

well i checked voltage at my fuel pump and im getting 10.7 volts when i turn the key on, could this be my problem??

[Shocker]

well i checked voltage at my fuel pump and im getting 10.7 volts when i turn the key on, could this be my problem??

Yes, your going to want over 12 volts. I'll check mine tonight I've got it hardwired straight to my bat through a relay, I should be seeing 13.5-14 volts.

[silviasgp06]

guess ill be doing the same tonight then, cause now that i think of it when i tested for voltage it was less than 12v. But Shocker your getting 13.5-14 at idle? how, what relay did you tap into?

[Shocker]

guess ill be doing the same tonight then, cause now that i think of it when i tested for voltage it was less than 12v. But Shocker your getting 13.5-14 at idle? how, what relay did you tap into?

well I'm running a Mircotech Unit so it might be slightly different than the stock ECU, but same idea. So I pin 87 I believe it is, I can check the manual for it in a bit, its at my garage. 87 to ign I think, 86 goes to something fuel related I'm gonna have to look. 30 goes to the battery with a fuse, and 85 goes to the pump. The relay is a bosch.

I'll check the voltage too while I'm there. I'll get back later this afternoon.

[silviasgp06]

ok ill be waiting on a reply then, but ill double check my voltage today to see where it stands.

.omgsky: yes you need a regulator unless your using a r33gts-t pump, buts its good to have anyways. but check yours pump voltage
Modified by silviasgp06 at 6:56 AM 3/24/2008

[matafied]

well back to zero for me, i ran power wires and still no dice! idk i started a thread thats a little more specific with my issues

[craz4240]

I think you guys all may have an air leak.....what to afr's look like?My car did the same thing.