Wiring experts come in...injector problems.. shutting down
07-13-2010, 09:19 PM
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Wiring experts come in...injector problems.. shutting down
whats up guys...
on a 2000 model
what can cause an injector driver to shut down
truck works fine under normal driving conditions without a hiccup..but when u mash the throttle and gets to about 4500 hits a wall and will shut down all 8 injectors while fuel pump pressure stays 60 psi
if i rev it in park/neutral...slowly it will rev all the way to WOT without a probplem, but if u mash the throttle it will shut down fuel injectors for a second or so and then pulse again...
i have changed so far
this is on a SD/OL with no maf, and no O2 sensors
motor
crank sensor
cam sensor
ECT sensor
tps sensor
Map sensor
injectors
cpmplete wiring harness
fuse box
BCM
PCM
checked all grounds
checked all Positive to battery terminals and such
fuel pump and main feed line
i can see in a log that injector duty cycle say if i am at 4000 rpms and 20% idc and then smash the pedal it will go to 40% idc and then bam 10% idc .....and if u leave it floored it will come back to normal and rev to redline..
it acts like it shuts off and then comes back to norm...
anyone have had this issue before???
Flaco
on a 2000 model
what can cause an injector driver to shut down
truck works fine under normal driving conditions without a hiccup..but when u mash the throttle and gets to about 4500 hits a wall and will shut down all 8 injectors while fuel pump pressure stays 60 psi
if i rev it in park/neutral...slowly it will rev all the way to WOT without a probplem, but if u mash the throttle it will shut down fuel injectors for a second or so and then pulse again...
i have changed so far
this is on a SD/OL with no maf, and no O2 sensors
motor
crank sensor
cam sensor
ECT sensor
tps sensor
Map sensor
injectors
cpmplete wiring harness
fuse box
BCM
PCM
checked all grounds
checked all Positive to battery terminals and such
fuel pump and main feed line
i can see in a log that injector duty cycle say if i am at 4000 rpms and 20% idc and then smash the pedal it will go to 40% idc and then bam 10% idc .....and if u leave it floored it will come back to normal and rev to redline..
it acts like it shuts off and then comes back to norm...
anyone have had this issue before???
Flaco
07-14-2010, 03:13 PM
#3
wow...that sucks a big pair.....
While I don't have much to add, only thing I can say is (to me) it must be something in the computer (either tune or damaged).
As I'm sure you know, injectors are either ON or OFF. If they turn ON, they are good and are getting power. So, your injectors and wiring sound to be ok.
It sounds like your sensors seem to be working so that sounds ok. Though even if they weren't, it shouldn't rev to "4500" then hit a wall.
Which...back to computer. Is there any way you can dig up a spare PCM somewhere?
Sorry I can't be of more help..... best of luck
Edit: Just a thought. You could you be hitting a fuel cutoff in the PCM. The standard cutoff is (whatever... lets say you set it at 6K). There is an alternative cutoff for bad VSS. I just check my tune and from the factory this is set at 4500RPM. That sounds exactly like a candidate what you are hitting. Perhaps try reflashing your PCM with the "bad VSS" setting set to your desired cutoff (again.... say 6K). You might have a bad VSS (or at least the computer THINKS it's bad).
Note: In the attached picture, ignore the fact that mine says 6000. I had already set that number long ago.
I know my computer has done some crazy things at times. One time I flashed my computer and it inverted the entire fuel sending unit table (empty = full and full = empty). I wasted a whole weekend going through the entire truck till in frustration I finally gave up and said "F*ck it....I'll tune the table backwards to make it work..." thereby finding the issue.
While I don't have much to add, only thing I can say is (to me) it must be something in the computer (either tune or damaged).
As I'm sure you know, injectors are either ON or OFF. If they turn ON, they are good and are getting power. So, your injectors and wiring sound to be ok.
It sounds like your sensors seem to be working so that sounds ok. Though even if they weren't, it shouldn't rev to "4500" then hit a wall.
Which...back to computer. Is there any way you can dig up a spare PCM somewhere?
Sorry I can't be of more help..... best of luck
Edit: Just a thought. You could you be hitting a fuel cutoff in the PCM. The standard cutoff is (whatever... lets say you set it at 6K). There is an alternative cutoff for bad VSS. I just check my tune and from the factory this is set at 4500RPM. That sounds exactly like a candidate what you are hitting. Perhaps try reflashing your PCM with the "bad VSS" setting set to your desired cutoff (again.... say 6K). You might have a bad VSS (or at least the computer THINKS it's bad).
Note: In the attached picture, ignore the fact that mine says 6000. I had already set that number long ago.
I know my computer has done some crazy things at times. One time I flashed my computer and it inverted the entire fuel sending unit table (empty = full and full = empty). I wasted a whole weekend going through the entire truck till in frustration I finally gave up and said "F*ck it....I'll tune the table backwards to make it work..." thereby finding the issue.
Last edited by 2001CamaroGuy; 07-14-2010 at 03:32 PM.
07-14-2010, 06:15 PM
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flaco are you using hptuners? is this for Lil Sis? if you want you can pm me a file to over look for ya
as for your question check the grounds as the pcm sends its command then grounds the injector. its possible a ground on back of head may of came loose as the sudden ramp of the motor from side to side could possibly ripped the wire from the terminal or it may of rubbed and now is a thinner wire from the wear
as for your question check the grounds as the pcm sends its command then grounds the injector. its possible a ground on back of head may of came loose as the sudden ramp of the motor from side to side could possibly ripped the wire from the terminal or it may of rubbed and now is a thinner wire from the wear
07-14-2010, 10:50 PM
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thanks for your suggestions
but i finally got it figured out.....the weirdest motha fkng that i never even checked because i said to my self...it turns on fine every time..
so, a buddy of mine that works for the dealer told me that they have had 2 strange issues with the BATTERY, yes BATTERY...
i was like WTF, it turns on fine and all..
so i went to replace it and this thing revs fine all the way to wot like no tomarrow..
he said the battery could be charged and all but when putting a real load to it, it could be grounding it self in the inside due to bad cells or such...
it was the battery i had for as long as i had the truck...so i put a new one and bamm it works...
definatly this thing had me scraching my head for 3 weeks complete and was a very simple thing causing it...
i actually had changed every possible thing to it exept it...
so next time someone has a weird problem shutting down at WOT its not a bad idea to change the battery...Thanks again
Flaco
but i finally got it figured out.....the weirdest motha fkng that i never even checked because i said to my self...it turns on fine every time..
so, a buddy of mine that works for the dealer told me that they have had 2 strange issues with the BATTERY, yes BATTERY...
i was like WTF, it turns on fine and all..
so i went to replace it and this thing revs fine all the way to wot like no tomarrow..
he said the battery could be charged and all but when putting a real load to it, it could be grounding it self in the inside due to bad cells or such...
it was the battery i had for as long as i had the truck...so i put a new one and bamm it works...
definatly this thing had me scraching my head for 3 weeks complete and was a very simple thing causing it...
i actually had changed every possible thing to it exept it...
so next time someone has a weird problem shutting down at WOT its not a bad idea to change the battery...Thanks again
Flaco
