sputtering in high rpms

[1gTurboTuner]

Well like it says my car starts sputtering once i get to about 5k rpm. I rebuilt the engine last summer and it never sputtered before the rebuild and i had all the same mods then except for an FPR i installed.
mods:
3"exhaust
evoIII 16g
8mm plug wires
bosch plugs (put new ones in after rebuild had ngk before these)
new o2 sensor
FPR
the boost is set at 10psi since the rebuild
The car sputtered before the FPR install but not as much so i raised the pressure to about 42psi it was at like 38 or so. And it seemed to make it sputter even more. I bought a palm logger just last week and took a log it said (all these were done with a 3rd gear pull WOT) INJ duty cycle was at 82% and it had 32 counts of knock (this scared me thats really high isnt it?). What else should i log for i was thinkin of doin a fuel pressure log, maybe my FPR gauge is off or something. My fpr gauge is also mounted on the fuel filter, ive seen them bolted directly on the FPR should i connect mine to the regulator or is it fine where its at?

I was also wondering how to log with my palm, should i just drive like normal with it, should i do a dead stop from 1st gear at WOT, should i do 3rd gear pulls? what rpm should i go to?

Whats wrong with my car?!

ahhh i have so many questions....
thanks for any and all help!!

 

[andymoraitis]

First things first, the Bosch plugs need to go, especially if they're platinums. If you can't find a set of suitable NGK's, switch to a set of Autolite 63's and gap them to .028.

The knock counts would concern me as well. Until you can post a log so we can look at the O2 readings, you may want to reach around the back of the block and inspect the knock sensor. If there's black ooze coming from it, it's shot and needs to be replaced. As far as the FPR guage, the most common location is on the FPR itself. I can't asnwer as to whether this is contributing to your issues, but I would mount it on the FPR for peace of mind.

Start with the plugs, check the knock sensor, post a log of a third gear pull and let us know what you find in the interim.

Andy

 

[TurboChrged93]

NGK COPPER!!!!!!!!!! BPR6ES for 9-14 PSI. BPR7ES for 15+ NEVER USE PLATINUM!! Check your base idle timing. 5 Degrees. Adjust your fuel pressure regulator back to the stock base pressure. Assuming you have a FPR that raises with boost, makesure the vacuum line is not leaking and is secure. Take a log again with more characters. Ignition timing, FO2 Reading, RPM, TPS, Knock. What are your LMH fuel trims sitting at?

 

[4g63t]

Does your fpr raise your base pressure at a 1:1 ratio what brand is it? Hopefuly not a camandflow.

 

[ddavisaf]

NGK COPPER!!!!!!!!!! BPR6ES for 9-14 PSI. BPR7ES for 15+ NEVER USE PLATINUM!! Check your base idle timing. 5 Degrees. Adjust your fuel pressure regulator back to the stock base pressure. Assuming you have a FPR that raises with boost, makesure the vacuum line is not leaking and is secure. Take a log again with more characters. Ignition timing, FO2 Reading, RPM, TPS, Knock. What are your LMH fuel trims sitting at?

NGK BPR 6ES are usually good up to 17 psi...ish...

 

[ddavisaf]

First things first, the Bosch plugs need to go, especially if they're platinums. If you can't find a set of suitable NGK's, switch to a set of Autolite 63's and gap them to .028.

Andy

That post was for me wasn't it?
NGK's and Autolite will both work. To be perfectly honest, any copper plug will work. But NGK's have been running in our cars for 15 years now. I'd try and stick with them if possible.

 

[1gTurboTuner]

Well i have an XS performance fpr. I went out and logged today but i cant get the dumb thing to hotsync to the computer... i'm workin on it. I will go tomorrow and buy some NGK plugs if i can find them. What are LHM fuel trims?

thanks guys i'll get the logs on here ASAP

 

[1gTurboTuner]

ok i got the NGK 6es's today and went out and the sputtering went down ALOT. It still sputters but only past about 6200 rpm and it only does it once or twice. Before it would do it constantly and i thought my motor was gonna blow up.... I still cannot post any logs because it will not hotsync with the software ( i tried to download the software but it says its corrupted and wont work). I will check the base timing, maybe this weekend its pretty cold in SD still.

thanks for all the help guys,
allan

 

[Evil1gDsm]

ok i got the NGK 6es's today and went out and the sputtering went down ALOT. It still sputters but only past about 6200 rpm and it only does it once or twice. Before it would do it constantly and i thought my motor was gonna blow up.... I still cannot post any logs because it will not hotsync with the software ( i tried to download the software but it says its corrupted and wont work). I will check the base timing, maybe this weekend its pretty cold in SD still.

thanks for all the help guys,
allan

I would check your fuel trims and for boost leaks! Sounds like your running a little rich?!

 

[1gTurboTuner]

Yes i do need to do a boost test. I will try and do one this weekend but it started snowing again and is getting pretty cold again. I will lower the fuel pressure what do you recommend 38? Its at about 42 right now.

thanks,
allan

 

[Evil1gDsm]

Yes i do need to do a boost test. I will try and do one this weekend but it started snowing again and is getting pretty cold again. I will lower the fuel pressure what do you recommend 38? Its at about 42 right now.

thanks,
allan

what size injectors do you have? Yes lower your Fuel pressure down to about 38psi!! That will help you out greatly!!

 

[1gTurboTuner]

I'll lower the fuel pressure... i have the stock injectors.

 

[4g63t]

Log your maf I had a related problem ware it was bucking around from 6 to 7 grand. I went out and got a GM Maft set up and it has never ran better. I also thaught it was a fuel problem. Studering WAs Gone right away. Just an idea.

 

[gsxboost20g]

has anyone brought up the need to remove or retain the stock fuel pressure controll solenoid that is in line of the vacuum/boost line going to the FPR?? I dont have an answer for ya, but if you have a 1:1 FPR shouldnt the stock solenoid be removed from the system due to the regulators controll of the pressure due to vacuum/boost....