98 LS1- issues when hitting bumps/ lights come on, car bogs and odo trip resets/hesit
03-09-2008, 12:11 AM
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98 LS1- issues when hitting bumps/ lights come on, car bogs and odo trip resets/hesit i have turbo 1998 camaro Z28,
I checked the battery and ground connections and the ecu connections and everythings clear and tight.
the motor just got changed to a forged motor and
at times i get random CEL's pop up such as
a high idle, which may be due to my new motor/cam setup.
low oil ( however there is sufficient oil pressure and oil in the motor)
once at high rpm the tachometer flucuated/shut off and came back on.
the MAIN issue here is -
when i hit a hard bump in the road or take a speedbump a little faster
the ODO trip goes back to zero, the gauges flicker and random lights will turn on.
if i were to have a CEL, that too would reset and turn off.
i figured it was because the ecu may have been loose from the engine transplant, however that was not the case.
are there any specific sensors that may cause malfunction such as this>?
these issues are QUITE annoying. any ideas ?
I checked the battery and ground connections and the ecu connections and everythings clear and tight.
the motor just got changed to a forged motor and
at times i get random CEL's pop up such as
a high idle, which may be due to my new motor/cam setup.
low oil ( however there is sufficient oil pressure and oil in the motor)
once at high rpm the tachometer flucuated/shut off and came back on.
the MAIN issue here is -
when i hit a hard bump in the road or take a speedbump a little faster
the ODO trip goes back to zero, the gauges flicker and random lights will turn on.
if i were to have a CEL, that too would reset and turn off.
i figured it was because the ecu may have been loose from the engine transplant, however that was not the case.
are there any specific sensors that may cause malfunction such as this>?
these issues are QUITE annoying. any ideas ?
03-09-2008, 12:29 AM
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I would think the trip resetting indicates the cluster is loosing power/ground momentarily. That would explain the lights on/off again, as well as the tach dropping and returning. One of the cluster grounds is on the engine block. Check all the grounds on the block and heads, and check the harnesses near them as well.
03-10-2008, 09:19 PM
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upon inspection
the rear ground wire was loose.
however this did not fix our issue with the gauges.
upon tuning today we stumbled upon yet another issue is that the motor would not pass certain RPM's and act as if it hit a revlimiter or speed limiter. violent jerking aroudn anywhere from 5-6000 RPM
the tuner tried diffrent timing maps, fuel maps, raised the boost to get out of the particular parameters in question. tried reloading the original maps.
no CEL's to speak of.
leaving the shop the car had real bad issues with hesitation/ constant gauge flickering and engine shutting off. at the gas station i inspected the wires and checked out the wires on the ecu/ecm and fiddled with them, the key was in the on position and fuel pump primed, the culprit is somewhere in the engine harness/ecu area.
i wrappped 4 suspicious wires in electrical tape and drove 30 minutes home with no hiccups upon every bump I drove over.
the rev revved however, upon high load, the tachometer might freak out a bit and the speedo would fluctuate.
I waited until I arrived at home to get on it so as to make sure if anything were to happen, i'd be near home.
godammit the vehicle still bucked at 6K. what could be the issue here ? ?? any suggestions ?
the rear ground wire was loose.
however this did not fix our issue with the gauges.
upon tuning today we stumbled upon yet another issue is that the motor would not pass certain RPM's and act as if it hit a revlimiter or speed limiter. violent jerking aroudn anywhere from 5-6000 RPM
the tuner tried diffrent timing maps, fuel maps, raised the boost to get out of the particular parameters in question. tried reloading the original maps.
no CEL's to speak of.
leaving the shop the car had real bad issues with hesitation/ constant gauge flickering and engine shutting off. at the gas station i inspected the wires and checked out the wires on the ecu/ecm and fiddled with them, the key was in the on position and fuel pump primed, the culprit is somewhere in the engine harness/ecu area.
i wrappped 4 suspicious wires in electrical tape and drove 30 minutes home with no hiccups upon every bump I drove over.
the rev revved however, upon high load, the tachometer might freak out a bit and the speedo would fluctuate.
I waited until I arrived at home to get on it so as to make sure if anything were to happen, i'd be near home.
godammit the vehicle still bucked at 6K. what could be the issue here ? ?? any suggestions ?
03-11-2008, 07:34 AM
#6
Some ??'s:
1. Did you try lowering the boost?
2. What was the fuel PSI doing when bucking/missing?
3. Valvesprings gone **** up?
4. Corrosion on/in any of the connectors?
5. What do the plugs look like?
6. Any valvetrain problems, such as bent p rods, loose rockers, broken spring, etc??
7. Have you stripped and retaped the harness [s]?
8. Any fuses loose in the panel?
9. TPS reading smooth?
10. Correct MAP sensor for the tune?
11. Battery voltage up to at least 13?
12. Engine grounded directly to the chassis?
Just "shotgunning" possible problem areas..HTH.
1. Did you try lowering the boost?
2. What was the fuel PSI doing when bucking/missing?
3. Valvesprings gone **** up?
4. Corrosion on/in any of the connectors?
5. What do the plugs look like?
6. Any valvetrain problems, such as bent p rods, loose rockers, broken spring, etc??
7. Have you stripped and retaped the harness [s]?
8. Any fuses loose in the panel?
9. TPS reading smooth?
10. Correct MAP sensor for the tune?
11. Battery voltage up to at least 13?
12. Engine grounded directly to the chassis?
Just "shotgunning" possible problem areas..HTH.
03-11-2008, 09:36 AM
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1) tried lowering hte boost yes
2) no fuel pressure gauge =(
3) its got patriot gold springs
4) today im going to go through the harness and solder/shrink the questoinable wire ( it has small cuts in it)
5) havent taken the plugs out, the AFR was perfect 11 AFr all the way up
6) valvetrain looks and sounds good
7) refer to #4 ( hehe)
8) no loose fuses
9) TPS is reading a bit off, tuner said it only reads 99% on full throttle
10) SD 2 bar map
11) good batt voltage
12) engine grounded
2) no fuel pressure gauge =(
3) its got patriot gold springs
4) today im going to go through the harness and solder/shrink the questoinable wire ( it has small cuts in it)
5) havent taken the plugs out, the AFR was perfect 11 AFr all the way up
6) valvetrain looks and sounds good
7) refer to #4 ( hehe)
8) no loose fuses
9) TPS is reading a bit off, tuner said it only reads 99% on full throttle
10) SD 2 bar map
11) good batt voltage
12) engine grounded
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03-12-2008, 12:08 AM
#8
had exactly the same problem twice......... first time it was a fried pcm that did not start after like a week of what you described.. The next time it happened, it was a short in the battery. The battery would short hitting a bump internally causing everything to lose power momemtarily.....
Change battery and go from there is my suggestion.
Change battery and go from there is my suggestion.
03-12-2008, 12:11 AM
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my next move is to get another 98 pcm. they're fairly inexpensive soo its not too bad. and im going to change my battery next also cuz it looks like an old pos.
i had a loose ground on the head previously and felt the same issues everytime i hit a bump. I tightened it up. Im curious if the ground wire bouncing around caused the PCM to fry out due to the surges .
i had a loose ground on the head previously and felt the same issues everytime i hit a bump. I tightened it up. Im curious if the ground wire bouncing around caused the PCM to fry out due to the surges .
03-13-2008, 10:06 AM
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I had the exact same kind of behavior when I discovered that the wire that runs from the battery to the starter had melted onto one of the header tubes. When I hit a bump, it contacted the header and caused the abs and tcs light to come on and then it'd act like it wanted to die.
