studdering/jerking on acceration (sr20det) - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

DMN · 07-12-2009, 05:08 PM

So Ive had this car for about 2 months its always studdered a bit around 2500 and i let off the gas and it smooths out, today i turned up the boost 1psi and drove it to work in the rain, it bucked at 2.5k,3k,4k ran like crap, so i turned down the boost(dont think that caused it) still the same deal, also it does not rev freely it will studder/misfire at 2.5k 3k 4k and so on, it seems to be happier in open loop than closed loop but both are not great,

I have all vaccum lines ziptied, fpr is nismo and i have a walbaro 255 fuel pump,new spark plugs a week ago gapped at .028

oh yeah it also idles fine
and it also seems to hold boost fine

Please help i dunno what it could be

ford_o · 07-12-2009, 07:12 PM

check your fuel system... i had sludge built up in my tank and caused complete power loss till i cleaned it out. fuel filter mayb also!!

wings_s13 · 07-12-2009, 08:52 PM

I had a prob just like this and it was be my maf was loose, not off just loose. it ideled fine and all that but would not let me get above 3k rpms, so check that. if its not that then something to do with your fule system. good luck

nismolism · 07-12-2009, 08:52 PM

try your tps sensor i had same issue when i got my swap done...im also runnin a stock fuelpump...

DMN · 07-13-2009, 10:46 AM

Hey thanks guys im checking the TPS today, Just cleaned the maf so that wasent it, could it possibly be coil packs? it started doing it bad when it was raining i dunno if that helps or not?

hottscennessey · 07-13-2009, 11:03 AM

What turbo, how much boost?

clark · 07-13-2009, 11:11 AM

sounds like a boost leak to me....

DMN · 07-13-2009, 11:12 AM

I just unplugged the tps and it runs about the same...

DMN · 07-13-2009, 11:13 AM

t28 9psi, but the thing is it seems to hold boost fine

hottscennessey · 07-13-2009, 11:15 AM

Sounds like you may be running out of fuel.

I'd do 550's/Z32 MAF and PM me if you want it tuned. It's very reasonable.

DMN · 07-13-2009, 11:22 AM

it studders yet smells rich,om thinking coils possibly anyone else think it could be them?, and yes im doing 555/z32 at some point but atm i want to work this out

hottscennessey · 07-13-2009, 11:27 AM

Quote:

Originally Posted by DMN

it studders yet smells rich,om thinking coils possibly anyone else think it could be them?, and yes im doing 555/z32 at some point but atm i want to work this out

I've had people tell me their car smells rich, when we get the wideband hooked up, it's leaning out. You'll be supprised how well a car will run when it's extremely rich.

I definately know what you mean about getting the problem at hand straight, but with a larger then stock turbo you could easily be maxing out the stock fuel system, and could be talking potential damage to your motor.

On the other hand it could be your coils, but I have no experiences with bad coils, so I'll wait for someone else to chime in on that.

DMN · 07-13-2009, 12:20 PM

welll i pulled the plugs to take a look and see if that was it and when i put them back in it runs good so i think maybe a coil became loose or something along those lines if anything else comes back ill post here again

rastaman · 07-13-2009, 01:02 PM

low vtec psi

guitaraholic · 07-14-2009, 07:47 PM

The coils HATE to get wet,, just a little water, and you car will run the SHIT!!! Trust me I know

jackal264 · 07-14-2009, 08:27 PM

i'm having this EXACT issue. i thought i had fouled my plugs so i replaced them but still the problem persists. i'm heading to the dyno tomorrow morning to get a re-tune b/c for me i just slapped on a new intercooler and manifold so i could be leaning out in the mid range.

for me i studder and bog between 2.5 and 4k rpm but above that i run fine.

other things that i recently change are no more bov and a breather filter on the iacv pipe instead of running to the coldpipe.

all of this b/c of an accident. i'm praying the motor comes back to life with a good retune b/c then i'm out of ideas.

07-12-2009, 05:08 PM	#1
DMN Join Date: Apr 2009 Location: VA Age: 35 Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	studdering/jerking on acceleration (sr20det) So Ive had this car for about 2 months its always studdered a bit around 2500 and i let off the gas and it smooths out, today i turned up the boost 1psi and drove it to work in the rain, it bucked at 2.5k,3k,4k ran like crap, so i turned down the boost(dont think that caused it) still the same deal, also it does not rev freely it will studder/misfire at 2.5k 3k 4k and so on, it seems to be happier in open loop than closed loop but both are not great, I have all vaccum lines ziptied, fpr is nismo and i have a walbaro 255 fuel pump,new spark plugs a week ago gapped at .028 oh yeah it also idles fine and it also seems to hold boost fine Please help i dunno what it could be

07-12-2009, 07:12 PM	#2
ford_o Banned from the Marketplace Join Date: Sep 2008 Location: woodbury Age: 35 Posts: 101 Trader Rating: (0) Feedback Score: 0 reviews	check your fuel system... i had sludge built up in my tank and caused complete power loss till i cleaned it out. fuel filter mayb also!!

07-12-2009, 08:52 PM	#3
wings_s13 Zilvia Junkie Join Date: Dec 2007 Location: California Posts: 440 Trader Rating: (0) Feedback Score: 0 reviews	I had a prob just like this and it was be my maf was loose, not off just loose. it ideled fine and all that but would not let me get above 3k rpms, so check that. if its not that then something to do with your fule system. good luck

07-12-2009, 08:52 PM	#4
nismolism Zilvia Member Join Date: Dec 2008 Location: "562" Posts: 275 Trader Rating: (4) Feedback Score: 4 reviews	try your tps sensor i had same issue when i got my swap done...im also runnin a stock fuelpump...

07-13-2009, 10:46 AM	#5
DMN Join Date: Apr 2009 Location: VA Age: 35 Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	Hey thanks guys im checking the TPS today, Just cleaned the maf so that wasent it, could it possibly be coil packs? it started doing it bad when it was raining i dunno if that helps or not?

07-13-2009, 11:03 AM	#6
hottscennessey Leaky Injector Join Date: Nov 2008 Location: Richmond, VA Age: 38 Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	What turbo, how much boost?

07-13-2009, 11:11 AM	#7
clark Zilvia FREAK! Join Date: Mar 2008 Location: new york Posts: 1,035 Trader Rating: (1) Feedback Score: 1 reviews	sounds like a boost leak to me....

07-13-2009, 11:12 AM	#8
DMN Join Date: Apr 2009 Location: VA Age: 35 Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	I just unplugged the tps and it runs about the same...

07-13-2009, 11:13 AM	#9
DMN Join Date: Apr 2009 Location: VA Age: 35 Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	t28 9psi, but the thing is it seems to hold boost fine

07-13-2009, 11:15 AM	#10
hottscennessey Leaky Injector Join Date: Nov 2008 Location: Richmond, VA Age: 38 Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	Sounds like you may be running out of fuel. I'd do 550's/Z32 MAF and PM me if you want it tuned. It's very reasonable.

07-13-2009, 11:22 AM	#11
DMN Join Date: Apr 2009 Location: VA Age: 35 Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	it studders yet smells rich,om thinking coils possibly anyone else think it could be them?, and yes im doing 555/z32 at some point but atm i want to work this out

07-13-2009, 12:20 PM	#13
DMN Join Date: Apr 2009 Location: VA Age: 35 Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	welll i pulled the plugs to take a look and see if that was it and when i put them back in it runs good so i think maybe a coil became loose or something along those lines if anything else comes back ill post here again

07-13-2009, 01:02 PM	#14
rastaman Zilvia Addict Join Date: Apr 2009 Location: Fl. Posts: 708 Trader Rating: (1) Feedback Score: 1 reviews	low vtec psi

07-14-2009, 07:47 PM	#15
guitaraholic Zilvia Junkie Join Date: Jun 2006 Location: Spanish Fort, AL Posts: 430 Trader Rating: (0) Feedback Score: 0 reviews	The coils HATE to get wet,, just a little water, and you car will run the SHIT!!! Trust me I know

07-14-2009, 08:27 PM	#16
jackal264 Zilvia Junkie Join Date: Feb 2007 Location: vancouver, canada Age: 39 Posts: 360 Trader Rating: (1) Feedback Score: 1 reviews	i'm having this EXACT issue. i thought i had fouled my plugs so i replaced them but still the problem persists. i'm heading to the dyno tomorrow morning to get a re-tune b/c for me i just slapped on a new intercooler and manifold so i could be leaning out in the mid range. for me i studder and bog between 2.5 and 4k rpm but above that i run fine. other things that i recently change are no more bov and a breather filter on the iacv pipe instead of running to the coldpipe. all of this b/c of an accident. i'm praying the motor comes back to life with a good retune b/c then i'm out of ideas.