car runs just a few problems left with volts, studdering, and fuel pressure
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Registered User
Joined: Mar 2005
Posts: 69
From: st. pete florida
car runs just a few problems left with volts, studdering, and fuel pressure
the opti is in and it runs and pulls hard from about 3000 rpms to 6200 rpms. the problems im haveing ar as follows:
first of all, the volt gauge still reads right at the beginning of the yellow line below 13. it just bothers me.. i haev a brand new battery, brand new alternator, put my stock pulleys back on, brand new blaster coil and still low volts!!
second problem is the car studders at low rpms... it isnt so bad in 1st gear but 2nd and 3rd suck.. it only does it bad when the car is cold but even after it warms up it does it.. this might have something to do with the fact that i didnt put my thermostat back in??
last problem is low fuel pressure! the gauge i have reads 30psi at idle and 40psi at full throttle... it used to be higher! i wonder what this is? im thinking this could be related to not having the thermostat as well...
any suggestions would be greatly appreciated!!
first of all, the volt gauge still reads right at the beginning of the yellow line below 13. it just bothers me.. i haev a brand new battery, brand new alternator, put my stock pulleys back on, brand new blaster coil and still low volts!!
second problem is the car studders at low rpms... it isnt so bad in 1st gear but 2nd and 3rd suck.. it only does it bad when the car is cold but even after it warms up it does it.. this might have something to do with the fact that i didnt put my thermostat back in??
last problem is low fuel pressure! the gauge i have reads 30psi at idle and 40psi at full throttle... it used to be higher! i wonder what this is? im thinking this could be related to not having the thermostat as well...
any suggestions would be greatly appreciated!!
Registered User
Joined: Nov 2001
Posts: 3,515
From: Kansas
Re: car runs just a few problems left with volts, studdering, and fuel pressure
Your fuel pump is going out and when that happens they tend to suck a lot of voltage out of the system which is what you are seeing.
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Joined: Nov 1998
Posts: 71,110
From: Hell was full so they sent me to NJ
Re: car runs just a few problems left with volts, studdering, and fuel pressure
Fuel pressure may not be a problem. Check it at idle, with the vacuum compensation line off.... anything from 41-47psi meets spec. You should be within 1-2psi of this number at WOT/max load. There is no way having or not having a thermostat would affect the fuel pressure. But weak system voltage will cause the fuel pump to lose capacity.
Why are you running w/out a t'stat? What temp does the engine reach? High enough to go into closed loop?
As far as the system voltage, have you ever had the PCM scanned, with a full data log for a WOT pass? You can read the system voltage from the PCM, and that might be a more accurate number than what the gauge shows.
Finally, add a "signature" with basic info like the year of your car, model, tranny type and any major mods. Not all LT1' are the same.
Why are you running w/out a t'stat? What temp does the engine reach? High enough to go into closed loop?
As far as the system voltage, have you ever had the PCM scanned, with a full data log for a WOT pass? You can read the system voltage from the PCM, and that might be a more accurate number than what the gauge shows.
Finally, add a "signature" with basic info like the year of your car, model, tranny type and any major mods. Not all LT1' are the same.
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Joined: Oct 2001
Posts: 6,070
From: newton, kansas, USA
Re: car runs just a few problems left with volts, studdering, and fuel pressure
Originally Posted by formula69
the opti is in and it runs and pulls hard from about 3000 rpms to 6200 rpms. the problems im haveing ar as follows:
first of all, the volt gauge still reads right at the beginning of the yellow line below 13. it just bothers me.. i haev a brand new battery, brand new alternator, put my stock pulleys back on, brand new blaster coil and still low volts!!!
first of all, the volt gauge still reads right at the beginning of the yellow line below 13. it just bothers me.. i haev a brand new battery, brand new alternator, put my stock pulleys back on, brand new blaster coil and still low volts!!!
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