rb25det s14 runs like a terd

[gsn0526]

so when i just step on the gas quickly it runs like shit and builds boost slower ....when i kind of 1/2 to 3/4 throttle itll build boost alot better. when i get higher in the rpms itll start popping and just kinda fall on its face.
my thoughts 1. fuel...but it idles fine and in neutral itll rev just fine.
2. timing...but again it revs freely
3. boost/maf....my guage only reads six pounds and my thought is when i get high in the revs the maf is not reading correct amount of air..i also extended maf wires and did not replace the shielding film on one of the wires.

going to change the spark plugs. and change ic piping (i got a shitty setup.)

if anyone has any ideas please post.

the car gets waxed by a n/a 300zx...really makes me angry. pls help

[240sxwanted]

check for boost leaks, and explain what you mean with "it starts popping"

[gsn0526]

like a misfire...stutter....hard to explain...but its not a backfire.

[240sxwanted]

when you let off the gas on a hard pull, does it backfire? maybe injectors, or boost leak

[skazat]

it could definitely be any of those 3 things you mentioned but with out knowing more its hard to determine. is this a new issue or has it always run like this? how is it tuned? any a/f info?

[240sxwanted]

also make sure you ignition timing is at 15 degrees

[gsn0526]

yes it has always ran like this. its doesnt backfire at all after hard driving. just has a walbro....and front mount has 3" piping im gonna put 2.5" on as soon as i get a chance. i have the new piping

[skazat]

ok so if its always ran like this it could be a wiring issue, but if your IC piping is pretty shitty like you said maybe your getting boost leak. is it a stock rb25 and are you just using its stock ecu? Im just wondering if the tune might be off

[240sx123$]

Drive the car up the road, and get on it pretty good. When you get back, shut the car off and pull a spark plug. If the electrode is white, its running lean. The electrode should be tan, like coffee with creamer in it.

Sounds like its got a boost leak or something. Does it rev up normally, just breaks up? A video speaks 1000 words..

[gsn0526]

its all stock except for the walbro and fmic...stock ecu....how would it be possible for it to run lean?

[Pirate_Freder]

check your fuel pressure regulator, I had noticed a similar issue with WOT not being a very happy place and I just tested my FPR and it's bad. pretty easy to do also

[gsn0526]

did read more about the effects of of a bad fpr or that the stock fpr doesnt do well with the walbro and it describes my problem. so im gonna try to get a adjustable fpr and a guage. where can i find the best price for something that is quality?

[gsn0526]

what is the correct pressure setting for the fpr? i bought the nismo but ive read multiple things just confused.

[Sileighty_85]

check coil packs for cracks as well

[s13Kurt]

I had the same exact problem with my rb20. It turned out to be that my exhaust cam was off by one tooth causing the car not to make any power. It got walked by a stock KA. It would free rev fine but under load it would do anything especially in the higher rpms. Hope this helps

[gsn0526]

just drove it for the first time with the new fpr....feels alot better for normal driving goes into boost alot better but now backfires during high rpms. i set the fuel pressure to 36...with vacuum line on...at idle is that correct. sounds to me like timing just want other opinions.

[240sx123$]

At this point youre basically just guessing. Messing with the fuel pressure to adjust a/f ratio will only get you so far. If the FPR made a difference, Id be inclined to say the problem is related to that, not timing. You need to find out what your a/f ratios look like, and adjust from there. Although a FPR is not an ideal way to tune, its doing you absolutely NO good without knowing where your a/f's are. At least if you know what those look like, you can get the car "close" with the fpr.

[TheGrim]

electronic boost controller or manual?

[gsn0526]

no controllers...so it cant be the timing?

[gsn0526]

anyone agree that it can be the coilpacks?

[redline racer510]

The only way to test if it is a CP is to have a known working CP and switch out until your car runs better. If it doesnt cause any change then its not your cp's.

[gsn0526]

so when i was thinking about the coilpacks i remembered when i changed the spark plugs when i first got the engine the plugs came with a lil extension/screw on piece on the end of them where a wire would plug on or the contact of the coil would be made....should i have left them on the end of the plug or taken them off.