sts cough need help!
sts cough need help! While under full boost or 5psi right when it gets to 5 psi my engine starts
coughin is the best way I can explain it.
it wasnt everyday but ounce in a while it would start to hesitate
and pop a little. while at idle or under boost but not mid throttle.
but now its constant.
I thought it was a bad tank of gas when it happened last month.
so switched gas stations and had no problems for a bit and now
its doing it again. i just filled up too....
its also pulls timing like crazy. normally im at 16- 15 deg when under full
boost and when this happens it drops down to 7 or 6 deg on my scan
guage should i start with a fuel filter? or try and put a fuel guage onit
and tape it to the windsheild and see if im losing pressure at boost
maybe this gas station has bad gas too now.....
where would you guys start??
if i half throttle it my car runs as smooth as glass but when i nail it ...it
coughs almost like a misfire but its not backfiring at all just little pops in
succession like its coughin...
my car was tuned on 91 octane . and thats what i have been running
any help would be appreciated..
my mods are listed below 42lb injectors walbro pump...
thanks
matt
coughin is the best way I can explain it.
it wasnt everyday but ounce in a while it would start to hesitate
and pop a little. while at idle or under boost but not mid throttle.
but now its constant.
I thought it was a bad tank of gas when it happened last month.
so switched gas stations and had no problems for a bit and now
its doing it again. i just filled up too....
its also pulls timing like crazy. normally im at 16- 15 deg when under full
boost and when this happens it drops down to 7 or 6 deg on my scan
guage should i start with a fuel filter? or try and put a fuel guage onit
and tape it to the windsheild and see if im losing pressure at boost
maybe this gas station has bad gas too now.....
where would you guys start??
if i half throttle it my car runs as smooth as glass but when i nail it ...it
coughs almost like a misfire but its not backfiring at all just little pops in
succession like its coughin...
my car was tuned on 91 octane . and thats what i have been running
any help would be appreciated..
my mods are listed below 42lb injectors walbro pump...
thanks
matt
Last edited by 98Ztwentyeight; Feb 6, 2006 at 11:10 PM.
Originally Posted by CODE4LS1
sounds to me like you may be running a little lean....may want to upgrade the injectors to at least 30# if running stock fuel pump
everything is about 4 months old now.
sorry i didnt even bother looking.....my bad.....then I would have to say it may be a fuel filter. Sounds to me that your timing issue is the most probable culprit, especially under 5lbs boost.
fuel filter anyone prefer one fuel filter to another??
any one brand to stay away from?
i think im gonna try that and see what happens..
any more suggestions? my fuel filter is about 5 month old too..
any one brand to stay away from?
i think im gonna try that and see what happens..
any more suggestions? my fuel filter is about 5 month old too..
Last edited by 98Ztwentyeight; Feb 6, 2006 at 11:42 PM.
TECH Resident
Joined: Mar 2002
Posts: 782
Likes: 0
From: North Las Vegas, NV
change the fuel filter and put in some dry gas. Sounds like you may have water in the tank? Might just ask Rob or Jason to look at it quick. I know their busy 
but maybe they might have another solution....
but maybe they might have another solution.... Mine use to do the same thing strap it to the dyno lost 150 hp it ran pig rich right off the scale reloaded the tune it ran fine for 4 days full boost 8psi and then it did it again the culprit was my mass air meter and my map sensor funny thing was on the dyno it was fine reading where good my tuner took it for a test ride with me in it and it was good but when it started again i had my scan tool and my map sensor was stuck at 1.0 and my mass air meeter was at 0.00 while cruzing then i boosted on the low setting it sputterd and then took off readings where still the same odd thing is i change them both and the car ran fine not sure what caused it but that was my deal when my car cough.
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Verdad Gallardo thanks thanks for all the suggestions
i guess ill start with a fuel filter and go from there
according to my scan guage my map sensor is definatley reading
but i guess it could be my mas airflow sensor on its way out
or just crappy gas again... we'll see
i guess ill start with a fuel filter and go from there
according to my scan guage my map sensor is definatley reading
but i guess it could be my mas airflow sensor on its way out
or just crappy gas again... we'll see
Check your plugs as well. Your symptoms sound similar to spark issues. I've found gapping to .028 works the best on ngk tr6's. I had a cracked plug and it acted very strange, would run ok until I hit 3 psi then it sounded like the car was falling apart. Would also miss at times at idle. If you have scanning software pull up your missfire counts and see if you can locate the culprit cyl. It should be the one with the most miss counts. Don't be suprised to see two with high counts with one slightly lower, it's probably just a carry over since it's the next one in firing order.
thanks again DAMMIT ITS NOT DOING IT AGAIN!! 
this is driving me crazy
i went out at lunch and its fines now drove it for 20 minutes
not a pop out of it..its like 30 degress warmer now though......
i dont remember what i gapped my plugs at but i did use ngk tr6's
i do have a little pop at idle ... cracked spark plug could be the
culprit i had a hell of time trying to get the plugs in with my big
hands in the way and i may have knocked one and put a harline
crack init. well so far this weekend im doing plugs and the fuel filter.
I dont have a data logging scanner /program and it looks like it
would be beneficial to own that.
im using taylor thundervolt wires.
they are really thick wires almost redicoulous lookin.
I allways used taylor wires on my muscle cars I have owned over
the years so thats why I went with those . i hope they arent the
culprit
this is driving me crazy
i went out at lunch and its fines now drove it for 20 minutes
not a pop out of it..its like 30 degress warmer now though......
i dont remember what i gapped my plugs at but i did use ngk tr6's
i do have a little pop at idle ... cracked spark plug could be the
culprit i had a hell of time trying to get the plugs in with my big
hands in the way and i may have knocked one and put a harline
crack init. well so far this weekend im doing plugs and the fuel filter.
I dont have a data logging scanner /program and it looks like it
would be beneficial to own that.
im using taylor thundervolt wires.
they are really thick wires almost redicoulous lookin.
I allways used taylor wires on my muscle cars I have owned over
the years so thats why I went with those . i hope they arent the
culprit
Last edited by 98Ztwentyeight; Feb 7, 2006 at 03:50 PM.
Dark Blue TA
Originally Posted by DarkblueTA
change the fuel filter and put in some dry gas. Sounds like you may have water in the tank? Might just ask Rob or Jason to look at it quick. I know their busy but maybe they might have another solution....
but maybe they might have another solution....
It turned out to be the ends of the ngk plugs "the screw-on tips"
were backing themselves off even though i tightened them!
i guess i should of cranked on them harder
now its all back to normal. Thanks zombie for the gap sizing
info.. my car is runing better with the .028 gap setting!!!
i have zero hestitation under boost now!
were backing themselves off even though i tightened them!
i guess i should of cranked on them harder
now its all back to normal. Thanks zombie for the gap sizing
info.. my car is runing better with the .028 gap setting!!!
i have zero hestitation under boost now!
Last edited by 98Ztwentyeight; Feb 8, 2006 at 01:34 PM.
Usually it's something simple. 