#8798, "Motor hesitation and exhaust popping sound...please help"
Ever since I put on the 3" downpipe w/ no cat, I have been having issues with the car at WOT. I did notice the downpipe let the boost go higher than my dsmlink is set for. It is peaking out at ~20psi when I just reset my fuel curve for ~18psi, but I tend to set my fuel curve really leaned out anyway. But then when I was over at Taloniized house last night I noticed my fuel pressure gauge is reading almost 60 at idle. Isn't that supposed to be at 42psi???? And is that 42 w/ the vacuum line connected or disconnected???
I also lowered my boost last night from ~20 to ~15 and it felt like it was fixed last night, but then it started doing it again on the freeway today on my drive to work. I need help with this before my long drive to CA or before all the AZ2gnt guys get together for a dyno day.
Any other advice on what could be wrong with my car is greatly appreciated. Thx guys.
#8799, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 0 Apr-08-05 04:45 AM by HybriDSM
FP at idle should be 43 with no vacuum line and ~38 with it on.
Remind me what turbo you are running again. Did you port the turbine housing and wastegate hole if it's a 16g or smaller? Boost creep could be an issue with a 3" turbo back.
#8801, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 1 Apr-08-05 08:13 AM by FlyinEsi
Originally posted by HybriDSM FP at idle should be 43 with no vacuum line and ~38 with it on. Remind me what turbo you are running again. Did you port the turbine housing and wastegate hole if it's a 16g or smaller? Boost creep could be an issue with a 3" turbo back. What do you DSMLink logs look like? New plugs and wires?
Turbo is a Big1G from RRE ported & clipped (I think) and ported 02 housing.
DSMlink logs look pretty clean. My timing usually gets down to the 7* range, but not horrible, and I have absolutely no knock across the whole range, but if I lean out just a couple more % points then I start getting knock. O2 reading stays normal, and my A/F ratio stays normal.
I was also thinking about new plugs or wires. Both were replaced about a year ago. Probably time for new plugs for sure, will have to check the wires.
#8802, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 3
You are probably creeping....16g's are notorious for creeping. Do a third gear pull and watch your boost gauge. If it goes higher then what you set it at then you have creep. 3" Downpipe will make a 16g creep if it isn't ported to hell.
_____________________________________________ Jerrome B. 1995 GSX - Race 1997 GST - Drive 1995 GST - Who the hell knows
#8803, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 4
Originally posted by BigBald You are probably creeping....16g's are notorious for creeping. Do a third gear pull and watch your boost gauge. If it goes higher then what you set it at then you have creep. 3" Downpipe will make a 16g creep if it isn't ported to hell.
It is not creeping...it is higher than I set it, but it does that from 4000-7500, once it gets to 20 it stops. And doesn't creep, just goes straight there.
Now I have my boost set at approx 15psi and it does not go beyond 15, but my motor still hesitates and every time it does that it sends a backfire or some kind of popping sound out the exhaust.
#8807, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 8
It was set to 18 and now it goes to 20 but stays there...it was always my impression that boost creep meant that it kept going up...my boost gauge never hits 18 it goes right past it to 20, like it was set there and then stays there until redline.
#8808, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 9
Originally posted by FlyinEsi It was set to 18 and now it goes to 20 but stays there...it was always my impression that boost creep meant that it kept going up...my boost gauge never hits 18 it goes right past it to 20, like it was set there and then stays there until redline.
no...Creep doesn't mean it keeps going. Some poeple only creep one or two psi somtimes. USUALLY, it slows down where you want it set to, and then creeps. If you have it real bad it will, it will just keep going and going. If it is stopping at 20psi, it would seem that you set boost to 20psi. What makes you think it should be only 18psi?
_____________________________________________ Jerrome B. 1995 GSX - Race 1997 GST - Drive 1995 GST - Who the hell knows
#8811, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 12
Have you checked the condition of your MBC? It sounds a little bit like creep, but adding the DP could have just changed how the MBC sets the boost. A malfunctioning MBC will sometimes lead to inconsistent regulation of the PSI levels, but it does sound a tiny bit like creep, but if it stays rock solid at 20, I really doubt it's creep.
Once you changed it back down to 15, how did you verify that you went exactly back to where you 18 before? If you have an electronic controlelr, all these questions are useless.
Also, I like the idea of changing you plugs and wires. Might as well do it as maintenance anyway and eliminate a possibility.
#8812, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 13
i bet its the wires... my car did that for a while until i changed the wires, it would studder while taking it up to redline sounds like iginition or some sort
Boca Raton, Florida 95 Eclipse GS- sold 99 Eclipse GSX- 386awhp 98 Eclipse GS- sold 92 Prelude
#8813, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 14 Apr-09-05 02:12 AM by BigBald
nah,,,its sounds like Hybrid's first comment that the DP Altered Exhaust Flow whiched changed how boost was set. Very possible. Adjust the MBC till you get 18psi on the gauge and see what happens. Make sure everything is Zero'd out on DSMLink also to verify its not your tune causing the hesitation.
_____________________________________________ Jerrome B. 1995 GSX - Race 1997 GST - Drive 1995 GST - Who the hell knows
#8814, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 15
Boost creep. Reset the MBC and watch the boost like everyone already said. If it goes to 20 again it is creep.
When I had my stock 14B with the 3" turbo-back it would creep to 20 and stay there too. I ported the bejesus out of the wastegate hole and turbine housing and it went away.
#8815, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 16
Originally posted by Jeff_99gs Boost creep. Reset the MBC and watch the boost like everyone already said. If it goes to 20 again it is creep. When I had my stock 14B with the 3" turbo-back it would creep to 20 and stay there too. I ported the bejesus out of the wastegate hole and turbine housing and it went away.
mine did the same. im on a factory controller and it will sit at about 10psi and creeps to about 17psi and sticks there through 7k. your missing sounds like plugs/wires. Mine did this at high rpm's, I was on factory wires, and plugs were platinums
#8816, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 17
this is in total disagreement wiht everyone else, but i'm gonna take a shot in the dark here: Is it doing it at partial throttle or full, or both? Are you running an AFPR?
i have SERIOUS issues with my evo16g at partial throttle---i'm gonna get an AFPR and see if that helps in the tuning, but basically I can't tune to where I want to be at WOT if I want the car to be drivable, or if I tune to WOT I can't go under partial boost past 4k...
also, is your boost guage memory peak/hold?
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Black 98 GST missing her owner and looking for a new one...Inquiries welcome
#8820, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 21
Dammit, I want a wideband, but I really want to stop spending so much fucking money on this car. *Ugh* I just wish it would run perfectly and leave my wallet alone for like a year.
#8822, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 22
Originally posted by FlyinEsi Dammit, I want a wideband, but I really want to stop spending so much fucking money on this car. *Ugh* I just wish it would run perfectly and leave my wallet alone for like a year.
wideband would help lots or you could do the unthinkable *back to stock* that would stop you from wasting money
#8823, "RE: Motor hesitation and exhaust popping sound...please help" In response to Reply # 24
Originally posted by kelvinb1
Originally posted by FlyinEsi Dammit, I want a wideband, but I really want to stop spending so much fucking money on this car. *Ugh* I just wish it would run perfectly and leave my wallet alone for like a year.
wideband would help lots or you could do the unthinkable *back to stock* that would stop you from wasting money
