Need HELP-stalls at WOT and check gauge flickering?
09-14-2012, 11:11 PM
#1
Need HELP-stalls at WOT and check gauge flickering? just got done swapping in a 01 LQ4 with cam 232/238 .596/.601, 650# dual valvesprings, headers, ls6 intake, ported ls6 oil pump. also using LS7 lifters, TR 7.4 PR, ls2 lifter trays on stock 317 heads.
did some idle and cruising tuning in Open Loop then started doing some part throttle and then WOT tuning on the freeway(empty lanes). wideband showed 12.4 straight up to ~5700RPMs then i noticed the needles(tach and speedo) bouncing/twitching and the "Check Gauge" light comes on and the car falls on its face and shuts off for a 1-2 seconds then comes back to life again. i was using a small portable scanner and right when that happend voltage was 11.8v, then 12.1v when power came back on. crusing the voltage is at 13.0v
so after that happened i just cruised along casually and i also noticed the check gauge would come on only when i apply throttle but turn off when i let off then i noticed my oil pressure steadily go from ~75-80psi dont to 0??? but the car ran fine. pulled over and i vaguely could hear a ticking sound on the driver side valve cover. shut the car off and checked the dipstick and oil cap and they were fine. fired her back up and the oil gauge rose back to normal again. the check gauge and the tach/speedo would flicker whenever the RPMs go beyond 5K.
battery is new, only a day old. any ideas? i think the ticking sound is another issue and im going to pull the valve cover and see if its a loose rocker bolt(hopefully it is
. in regards to the check gauges light and the tach/speedo, any ideas?
did some idle and cruising tuning in Open Loop then started doing some part throttle and then WOT tuning on the freeway(empty lanes). wideband showed 12.4 straight up to ~5700RPMs then i noticed the needles(tach and speedo) bouncing/twitching and the "Check Gauge" light comes on and the car falls on its face and shuts off for a 1-2 seconds then comes back to life again. i was using a small portable scanner and right when that happend voltage was 11.8v, then 12.1v when power came back on. crusing the voltage is at 13.0v
so after that happened i just cruised along casually and i also noticed the check gauge would come on only when i apply throttle but turn off when i let off then i noticed my oil pressure steadily go from ~75-80psi dont to 0??? but the car ran fine. pulled over and i vaguely could hear a ticking sound on the driver side valve cover. shut the car off and checked the dipstick and oil cap and they were fine. fired her back up and the oil gauge rose back to normal again. the check gauge and the tach/speedo would flicker whenever the RPMs go beyond 5K.
battery is new, only a day old. any ideas? i think the ticking sound is another issue and im going to pull the valve cover and see if its a loose rocker bolt(hopefully it is
. in regards to the check gauges light and the tach/speedo, any ideas? 
09-15-2012, 05:12 PM
#3
Doesnt sound like a fuel issue to me. Id guess that you have a loose ground, your battery cable connections are bad or loose, or you're shorting (ie (+) battery moving at touching something).
Which would cause what your talking about as the fuel pump would then have a loss of voltage, thus not supplying pressure. Also causes the gauges to flicker.
Could even be a bad alternator...
Which would cause what your talking about as the fuel pump would then have a loss of voltage, thus not supplying pressure. Also causes the gauges to flicker.
Could even be a bad alternator...
Last edited by xxrillixx; 09-15-2012 at 05:21 PM.
09-15-2012, 07:29 PM
#4
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It's likely an electrical fault. I've had battery cable short
to A/C pulley making trouble on hard right turns mostly.
Battery can roll back and short to fenderwell if the hold-
down is loose. Ground straps can also be loose and get
squirrely behavior from bumps and acceration.
If it's more RPM than acceleration related, this may be
just a bad alternator or exciter wire problem. Some alts
don't like to be overspun.
to A/C pulley making trouble on hard right turns mostly.
Battery can roll back and short to fenderwell if the hold-
down is loose. Ground straps can also be loose and get
squirrely behavior from bumps and acceration.
If it's more RPM than acceleration related, this may be
just a bad alternator or exciter wire problem. Some alts
don't like to be overspun.
09-17-2012, 01:28 PM
#5
its not lack of fuel. its got a walbro 255lph fuel pump and the portable scanner shows 80-80%IDC and 19ms IPWs. i took the alternator to advanced auto parts to get tested and it turned out to be in working order. i'm going to do the Big 3 upgrade and use 4awg wire. battery (-) to chassis, battery (-) to block, and alternator to battery (+). im not running an A/C anymore. the battery hold down is tight and secure, its not moving anywhere.
seems to be RPM related. i applied dielectric grease on the alternator plug and still cuts out above 5K RPMs. also i noticed a red 16awg wire coming from the main wire harness that comes from the injectors that goes down to the alternator with a ring terminal on it. i dont recall if it was connected to the alternator or not when i bought the car, but after i did the motor swap i connected it to the back of the alternator along with the 4awg wire that is from the battery. after doing some reading, there was never a 2nd wire connector to the alternator so it leaves me to believe that that red 16awg wire shouldnt be connected. i gotta go and see where it originally comes from. anyone know the wire im speaking of?
seems to be RPM related. i applied dielectric grease on the alternator plug and still cuts out above 5K RPMs. also i noticed a red 16awg wire coming from the main wire harness that comes from the injectors that goes down to the alternator with a ring terminal on it. i dont recall if it was connected to the alternator or not when i bought the car, but after i did the motor swap i connected it to the back of the alternator along with the 4awg wire that is from the battery. after doing some reading, there was never a 2nd wire connector to the alternator so it leaves me to believe that that red 16awg wire shouldnt be connected. i gotta go and see where it originally comes from. anyone know the wire im speaking of?
