So its been a while since i drove my car, its a 4th gen 3.5 swap s/c. Recently, when the temperature got lower, the car now hesitates under 3k rpms. at wide open, it still pulls strong, just bucks and hesitates BAD just cruising sub-3k rpms.

Now, I've changed the plugs thinking maybe its just that since i didnt change them last oil change( i change oil every 1k miles). TPS looks fine, coil packs are all functioning right, and well as injectors.

NOW, i noticed that my Fuel Pressure is jumpy, going from 40-50psi just bouncing at idle, when i pull the vacuum off, it still does the same jumpy problem. btw, the Fuel Pressure regulator is an Aromotive A1000. the fuel filter is a little over a year old and is a ZX one. same with the MAF (Z32) and Walbro 255 pump.

I'm thinking, could a shortage in voltage be the issue why fuel pressure is that way? bc if it is, that could explain the hesitation coming from lack of fuel.

Any Ideas guys?

 

Maybe the Aeromotive FPR needs a rebuild kit? I got one a while back from either Jegs or Summitt - I think it was Summitt.

At low RPMS, and in closed-loop, I would think that the engine isn't pulling much fuel... Have you tried pulling off the fuel feed line and dumping it into a bucket while turning on the key? Or some way to check for erratic fuel delivery?

Just guessing, of course.

 

I haven't checked to see if fuel delivery was erratic from the pump yet. I'm going to try that later in this afternoon. I just got done driving for about 20 minutes and with light throttle on the highway it seems fine. It's also raining out now too. It seems to run smoother now with more humidity in the air. Maf possibly bad?

 

Well if your fuel pressure is all over the place that's a problem so I'm wondering why you are wondering about MAF and other things? If it was anything other than a fuel problem (in ur case regulator, pump, and yes voltage to the pump, as well as other things, one might say even an injector issue could cause it to be erratic. Check for kinked return line also) I would look towards a ghetto'd tps bracket flexing before anything else causing a driveability issue, unless you have pathy

I know your car is hardcore tuned out, but just wondering what your FP is set at to start?

Side note, I'm the guy who started pointing out **** and you got pissed and closed the hood @ the NWP meet, it was kinda funny because everybody thought I was some retard worried about breaking the hood or something when I asked for permission to open it.

 

lol yeah i knew who you are before you asked to look at the setup. i didnt like you touching everything under my hood like i said on another board. its cool that you look, NOT cool to touch. when you spend the kind of money i did, you would do the same thing. go to any car show, if you touch anything you most likely wouldnt be leaving with your fingers attached. i'm an easy going guy but ask any board member, I AM 100% SURE NO ONE would put up with it.

My "Ghettoed" TPS? i did the swap more than a year ago and went by Tavarish's write-up. the TPS never gave me a problem to change out to a Pathy. 304L stainless steel 16 gauge so its not "flexy" unless you're purposely bending it like you obvioiusly did. i mention MAF bc i know if you have a dirty MAF, it could cause hesitation issues and since i do have blow by, being that its a boosted motor, i could put that as a variable. Your Post seems completely Erroneous as to help me but to badger me on my setup.

anyway, i found my issue. the alternator is not charging the battery causing the pump to fluctuate, thus making the pressure erratic. how did i find out you ask? the car died on me when i had the blower motor on for the defogger, wipers on, lights on, and music on blast. after i jumped it, i put a multimeter on the battery and saw it wasnt charging.

Simple fix, i'm glad.

 

nice now come out to the track sunday, it's tnt with no jr dragsters

 

this sunday? i'll try to come out if i get a chance to put in a new alternator and test this i30 trans i have

 

yo coming out sunday night?

 

nice i30t or i30

this should help alot with traction , I just got a new tranny too

trade ya

 

96 i30t. found it at a junkyard in southwest philly. it was pure luck that i found that thing lol. i should be able to make it out sunday im dying to make some passes, its been sooo freakin long since i drove it lol

 

damn and I was just down there

btw I called atco and if it rain tomorrow they are going to cancel sundays tnt and run saturdays event

I'm never going to get this car to the track, I am thinking about doing some dyno pulls are you guys open yet