2g GSX sputtering - just got this car

[xaaronx]

okay, so my bro just purchased a GSX from a kid. we've had this car for like 4 days.. seriously. according to my brother he was just driving down the right at about quarter throttle maybe and it just started to sputter a ton. it idles okay, a little higher than normal, but okay. he's also not driven this thing hard at all yet.

here's the mods
-FP Ported BIGT28
-Apexi 3" down pipe
-Precision Turbo 680 Injectors
-255 Wal. hf fuel pump
-Custom cat back
-NGK wires and plugs
-Apexi S-AFC II
-Bomz intake
-Voodoo Boost Controller
-SARD AFPR
-Apexi intercooler piping
-Greddy Type-S BOV
-and gauges and whatever else

any idea? it's still getting a reading on the boost gauge.

 

[dsmboy51]

check for boost leaks

my $0.02

 

[95CarbonEclipse]

+1 for Boost Leak test.

 

[Street_Killer]

Check around for vacuum lines that may have came loose.

 

[viperlp01]

You guys have a boost gauge. YOu will notice slow boost when you give it some gas if you have a boost leak. If not check the spark plugs. Did you guys throw a check engine?? Most likely boost leak though.

 

[xaaronx]

what's all involved in a boost leak? we're not engine illiterate but we're not mechanics. i was also told that the maf may be going bad? we've got another one sitting around from our last 2g so we're going to try that.

also, the check engine is on and will stay on because of the apexi s-afc.

 

[xaaronx]

You guys have a boost gauge. YOu will notice slow boost when you give it some gas if you have a boost leak. If not check the spark plugs. Did you guys throw a check engine?? Most likely boost leak though.

my bro said that when he would give it gas the gauge would start to go up, then go back down, but would eventually go back up a little bit once he started to give it gas

any ideas? boost leak test still?

 

[laserspeeddemon]

Yes, boost leak. It really sounds like an intercooler coupler popped off.

 

[viperlp01]

hey buddy. There is a link in the tech forum to make your self a boost leak tester. go from there.

 

[voodoogsx]

Check all of the vac lines that are on the intake mani. I've had those pop off, causing all sorts of issues.
most of the hoses can be seen in this pic. They are red....note the spark plug wires are red as well...just check to make sure they are nice and secure.
virtual tour of a dsm engine - quadrant q2

 

[95CarbonEclipse]

Yes, boost leak. It really sounds like an intercooler coupler popped off.

I'm thinking the exact same thing.

To the OP... definitely make yourself a boost leak tester and do a boost leak, but you can also do a visual inspection of A) Your vacuum hoses, and B) your upper and lower intercooler pipes. Especially if they're stock pipes (hoses), they're notorious for popping off right where they connect to your stock side mount.

If that's the case, a good trick to keeping them puppies on is to get some high tack gasket sealer and coat the inside of your hoses and the outside of your IC inlets/outlets with it. The sealer will help give your hose something to grip with (along with tighting the hell out of your hose clamps).

Also, I don't own an AFC yet, but I'm pretty sure that even when using an AFC you shouldn't have a CEL on. You might wanna get a datalogger and check to see what code(s) are coming up.

 

[DsmDave95]

boost leak, you should also do a compression test to make sure everything is copasetic.

 

[erald01]

The easiest way to see if you have a boost leak is by looking at your boost gauge while the car is just idleing and sitting still. If you see a huge movement on your boost gauge without pressing the gas pedal, then you have a boost leak, other wise you should be fine.

 

[MountainDew]

If the car has a 1G Cam Angle Sensor, you could be throwing a code with barometric pressure..

You have to wire a volume control knob to pin 85 on the ECU.

 

[PitBullDsm]

I had the same problem when I first bought my dsm. I was able to solve it by replacing the spark plugs, which were old NGK7s. Don't forget to gap them correctly. If the spuddering still persists try performing a boost leak test.

 

[xaaronx]

The easiest way to see if you have a boost leak is by looking at your boost gauge while the car is just idleing and sitting still. If you see a huge movement on your boost gauge without pressing the gas pedal, then you have a boost leak, other wise you should be fine.

according to my brother he didn't notice any significant movement. and we're not hearing any leaks at all (yeah, i know. it's hard to hear them but still) everything sounds good until we give it gas

I had the same problem when I first bought my dsm. I was able to solve it by replacing the spark plugs, which were old NGK7s. Don't forget to gap them correctly. If the spuddering still persists try performing a boost leak test.

well this one is using ngks, too. i'll have him maybe buy some new ones and see how it does. what should the gap be set at?

 

[Clay]

Gap the plugs .028

 

[Toxicangel]

"the check engine is on and will stay on because of the apexi afc"

I had the apexi afc, the check engine light is not suppose to come on.

 

[xaaronx]

"the check engine is on and will stay on because of the apexi afc"

I had the apexi afc, the check engine light is not suppose to come on.

really? i was told it will. i'll look into it then. but would that really matter since the apexi is pretty much it's own computer that can adjust and whatever else?

 

[1999silverGSX]

I see you have a 255 pump most people tend to get a afpr when they get this full pump. just an idear

 

[Toxicangel]

really? i was told it will. i'll look into it then. but would that really matter since the apexi is pretty much it's own computer that can adjust and whatever else?

It does matter, check what code it has. Any kraggen or autozone will check for engine codes for free. Also the afc only reduces the air the computer sees to compensate for bigger injectors.

 

[snowborder714]

according to my brother he didn't notice any significant movement. and we're not hearing any leaks at all (yeah, i know. it's hard to hear them but still) everything sounds good until we give it gas

Do another one and this time spray soapy water all over the area you're testing. This will help you 'see' the leaks (so, anytime you see bubbles, there's a leak). Test from both the turbo inlet and also the tb. I'd be willing to guess a coupler for the intercooler as well.

Do you happen to be venting your bov to the atmosphere? If so, recirculate it.

Also, I'd suggest getting an AFPR since you're running a 255lph fuel pump.

And also go get your CEL code and post it back up so that we know for sure what's causing it. Most auto stores will check them for free.

 

[kenamond]

S-AFC shouldn't throw a code. Get that code read; the ECU is trying to tell you something, and it might be telling you exactly what's wrong with the car. It's a lot better than guessing. That should be your first step.

Like everyone said, make yourself a boost leak tester and get that intake air-tight. Boost leaks will leak metered air and the ECU will not know this and add too much fuel.

With all of those mods, you really should get a logger of some sort. Who knows what kind of tune the previous owner came up with. A logger will also tell you in English what codes the ECU is griping about.

The plugs you need will depend on what boost you're running. Higher boost needs a colder plug. You want either NGK BPR6ES or BPR7ES depending on the boost.

 

[kenamond]

Do another one and this time spray soapy water all over the area you're testing. This will help you 'see' the leaks (so, anytime you see bubbles, there's a leak). Test from both the turbo inlet and also the tb. I'd be willing to guess a coupler for the intercooler as well.

Do you happen to be venting your bov to the atmosphere? If so, recirculate it.

Also, I'd suggest getting an AFPR since you're running a 255lph fuel pump.

And also go get your CEL code and post it back up so that we know for sure what's causing it. Most auto stores will check them for free.

He listed AFPR in his mod list in the first post.

 

[xaaronx]

I see you have a 255 pump most people tend to get a afpr when they get this full pump. just an idear

we actually do have one. i think i listed it?

It does matter, check what code it has. Any kraggen or autozone will check for engine codes for free. Also the afc only reduces the air the computer sees to compensate for bigger injectors.

k. i'll try to convince him to drive it to an autozone. we live decently close to one, hopefully it makes it there alright