RB Problems!!! Please Help!!!

[MATTs14]

ok so ive had my rb in my car for over a month and this is my second swap. The problems i am having are a low load miss like at idle and im getting a bad fuel cut in 3rd 4th and 5th. Ive tried everything and i cant seem to find. I really really need some opinions on what it could be.

[d356bud]

I would recomend getting a consult program and cable to see what codes are being thrown and see if any sensors are messed up.

[MATTs14]

Any other suggestions?

[MATTs14]

I just converted to wasted spark and my fuel pressure is correct. I havent been able to check timing yet

[RBinside]

I was gettin alot of break up in my RB25 around the low end of 3rd 4th and 5th so i played with heat ranges in the spak plugs which seemed to help..

[Cjmartz2k]

How sure are you this is fuel cut in 3rd, 4th, an 5th. Stock turbo, injectors, EMS?

[MATTs14]

im running stock turbo, injectors, and ecu. Its all stock, open downpipe, wasted spark, fmic,nismo fpr with correct pressure, ngk bcpr6es. I think my plugs might be fouled but im not sure. I just cant figure it out. It runs great and doesnt miss up top but it does fuel cut and i assume thats what it is because at about 90 in third it will just lurch forward and you have to wait a second to press the gas again.

[RBinside]

What do ur plugs look like when u take them out??

[MATTs14]

Well i believe its running rich. The plugs are kinda dark but i had some ngk iridiums in there before and they were white when i took them out. I can smell gas and i get loud backfires in betweens shifts sometimes. Its definitely running rich though

[RBinside]

yea i was gettin the same thing real bab spittin out some nice size fire balls. I switched my to a seven same ngks.

[mentordrift]

i assume thats what it is because at about 90 in third it will just lurch forward and you have to wait a second to press the gas again.

When I first installed my RB25, I had something very similar to this happen. As it turns out, it was my alternator. It was too wasn't charging enough or was just old and worn out -something. We replaced it with a Quest alternator and the lurching hasn't came back since. I would check your ignition and all that assuming you have a good alternator, because I'm assuming it feels like is your car is on, but when you step on the gas, it sort of pulses at certain RPMs?

[MATTs14]

Well my alternator isnt the best. It was in the car when i wrecked and the housing is cracked. When its cold and drive it it will feel like it doesnt wanna go and then it will lurch and finally move ok. What spark plugs do you suggest using? Im running the ngk bcpr6es now. I have a quest alternator laying around and i had one put on but some metal shavings got down into it and caused it to short our so i had to use the old rb20 one.

[MATTs14]

Any more suggestions guys?

[240z4u]

I have never had any sort of fuel cut on my RB. My car used to go really rich then misfire but that was it.

You need to look at the basics like sensors and boost leaks.

[BoostFab]

Any other suggestions?

have you check your grounding ?

[MATTs14]

Grounding to what? What sensors could be bad that would cause this. I checked all my couplers and they all seem fine. I really think its my alternator like someone suggested because its terrible. The idle goes way down when the fans come on, when i turn my lights on, and even when i hit the brakes so i think its my alternator. Does that sound about right to you guys?

[the_garynator]

+1 for alternator... Mine was on it's way out when I bought my car and I put it off for like 20k miles...had all these random issues that I could never figure out. I replaced it and bam, most of them went away.

BTW, cheap replacement, get an alternator for a ka24e at advance or autozone. they're like 90 bux or something. Requires almost no modification. Just notch out the top bolt hole in the upper swing arm (where it bolts to the water pump) so that you can swing it down about a 1/8th to a 1/4 inch. Bolts right up, even uses the same mounting hardware.

Upgrading to a quest alternator or something is probably a better route to go. But if you don't want to mess with all the bracket modification or don't have the access to a welder and stuff, a ka24e alternator is the way to go, whether it's a temporary solution or permanent. Let me know if you want some pictures or some more information on how to do this.

[mentordrift]

If you're having weird electrical problems like you said with the idle dipping way down when other systems come on/turn on - then it sounds like a charging system issue.If you wait too long, though, you'll end up like me - the battery AND brake light will come on, and you'll be stuck on the side of the road at 2 am.

If you're really good at fabricating things, the Quest alternator will not do you wrong.

Like I said, I have one in my RB, but I didn't have to mess with the bracket for some reason, the tension is dead on, and it lined up...weird.

[MATTs14]

Ok guys thanks a lot for all your help. I'll swap it out and see how it does. I have two quest alternators laying around so i'll just slap one of those on and hopefully it will fix my problem. Thanks again

[jonh317]

I had a similar problems, and I replaced the alternator, which does give it better spark, but it ended up being a clogged fuel filter, the afr were not dropping, but it was cutting out, so i figured it was ignition, so i replaced the alt. and that didn't fix it, so I replaced the fuel filter and it took care of the problem.