3k sputering!!

[mofugger]

[ca20det]

[asher4857]

ummm... maybe i can help him out.. from the post of the title alone, it appears i have the same problem..

i noticed it after i installed my 3" exhaust. I went for a drive on the highway and when I gave it a good ammount of gas, after the 3K mark it started to hesistate really bad and jerk around.. any ideas?

[float_6969]

Do you have a boost gauge installed? Sometimes opening up the exhaust will increase the boost enough to hit fuel cut.

[mofugger]

sorry i guess my comp. F@*$ed up....but yeah my car ran fine for like 2 weeks then it just started to sputer at like 3k to 3.5k......i have a boost gauge installed...im running 7psi and creeps to like 10psi.....and my car smells rich so i pulled the plugs and they were white and pretty dry......????so any ideas cuz i want my baby runnin good again....lol......oh and one more thing, it is now idleing at 1500rpm's....

[ceniack]

check your timing

[mofugger]

ok ill do that tommrow....ill let you guys know if it makes a difference!

[Chris859]

Im starting to think this is a widespread problem - I have the same problem. Car idles fine, starts easy, and runs fine when under boost(7-10psi), but at that 2500-3500 spot just before it gets full boost it runs like crap. I would like to say its loading up with fuel, however IO dont have a wideband to verify the afr. I have checked timing, changed spark plugs, cleaned maf, changed temp sensor, etc. Only things I haven't tried are going to a better fpr (have the 255 fuel pump installed), and I haven't tried changing the cas yet. not sure what else to look at...

[asher4857]

i dont have my boost gauge installed just yet to check about spiking to hit fuel cut.. ill do that as soon as possible though..

[adam-gtX]

fixed?

[fitch9014]

i don't know if this thread is dead or not, but I was having the same problem; at about 2700-3500 i was getting like a super rich charge at full boost and the car just bogged down...i'm running a hks pfc fcon and a hks gcc3 for management, so i leaned out the mix a little in between the 2400 and 4100 marks and the car runs great now , not saying you should start messing with fuel mixes without gauges, but it is colder outside in most of the country and cold air means dense air, so i'm just saying...i'll let you know if a i melt a couple of pistons

if it helps, the car's got a s13 sr turbo @ 7psi, saab fmic, a cone filter, stock injectors, 255 fuel pump, and a full 3" exhaust...

[Chris859]

Thanks for your input, Seeing as how I haven't found really anything else wrong yet... This further enforces my idea on the car loading up (aka too rich). Ill see if the problem goes away when I get around to putting in larger injectors, z32 maf, and an emanage... Nice to know im not alone on this issue though

[float_6969]

I think chris859 is on the right track. I though of it last night and I'm just now getting on here to post about it.

It is well established that the walbro ovverruns the stock FPR and makes the car run rich. I would think the rich problem would cause the most trouble when the manifold is reaching atmospheric pressure (no boost, no vacuum). IIRC my car was running 48psi static fuel pressure and it's stupposed to be at 36. That's basically forcing the injectors to put 33% more fuel into the car than it's supposed to. That's a BIG change. I would bet the a new FPR would solve this problem.

[fitch9014]

I think chris859 is on the right track. I though of it last night and I'm just now getting on here to post about it.

It is well established that the walbro ovverruns the stock FPR and makes the car run rich. I would think the rich problem would cause the most trouble when the manifold is reaching atmospheric pressure (no boost, no vacuum). IIRC my car was running 48psi static fuel pressure and it's stupposed to be at 36. That's basically forcing the injectors to put 33% more fuel into the car than it's supposed to. That's a BIG change. I would bet the a new FPR would solve this problem.

I know for a fact that to much pressure on a 16 year old factory fuel hose will blast high test all over the back of the intake manifold. I just got done replacing those two short hoses for the fpr and rail. My question is, is there an fpr out there that doesn't require any adjustment that could handle increase in pressure from the pump? Basically, just an uprated stocker, or do you have to go full nelly and get a high flow adjustable joint?Sorry to go off subject, but it's sorta pertinant...

[float_6969]

Most of us run the NISMO unit that bolts to the fuel rail. The outlet is angled wrong, but a longer hose that simply loops around is fine. The adjustment is easy as well. You'll need a Brass threaded "T", two threaded-to-barbed fittings that will thread into the "T" and into the fuel line, and a cheap $15 gauge from a pool store. Shouldn't cost you more than $25 for the gauge. The FPR can be had from most of our sponsor, Heavy throttle is my personal favorite as they have a little love for the CA. You can leave the gauge on after you reset the fuel pressure if you want, or leave it on. I've had the one I built just as you described for almost a year and so far, so good.

[driftin8ez]

I just recently, seemingly arriving with the cold air, have a sputter around those rpms. I have a walbro 255lph as well. Sometimes if it sputters bad enough i will get a small flutter from the intake.(no BOV installed) Anyone ever get a small flutter. Also i have a stock NA catback so maybe if i had a full 3inch i wouldn't be able to hear it... So you guys might not be able to hear your engine as good as i can. But ya i also get a small cloud of black smoke behind the car only under wot and high rpm. I'm going to get a nismo fpr and see where im at after that.