No spark need some help
#1
No spark need some help
before i start throwwing new parts at it...got a 95 z28 took motor out replaced oil pan intake rear main timing cover gaskets, now got the motor back in the car and have no fire...
got on all data and checked i have igniton at the icm amd ground but i dont have the 1-4 volt signal, it had .1-.3 volts
tried new icm it was easy, checked and ohm the opti harness from side of intake to opti...all is good icm didnt fix it
no spark going into the opti either
so my opti went bad and isnt sending the rpm signal to pcm? or wiring between the pcm and opti?
alldata says check wire from B5(black connector) to the coil terrminal b...those are open in my volt meter but at the pcm its a white wire and at the coil its black and white? is that correct?
i threw a code 41 for icm circuit open? i tried juming wire B5 to coil prong b...no luck
got on all data and checked i have igniton at the icm amd ground but i dont have the 1-4 volt signal, it had .1-.3 volts
tried new icm it was easy, checked and ohm the opti harness from side of intake to opti...all is good icm didnt fix it
no spark going into the opti either
so my opti went bad and isnt sending the rpm signal to pcm? or wiring between the pcm and opti?
alldata says check wire from B5(black connector) to the coil terrminal b...those are open in my volt meter but at the pcm its a white wire and at the coil its black and white? is that correct?
i threw a code 41 for icm circuit open? i tried juming wire B5 to coil prong b...no luck
Last edited by Daniel6718; 02-16-2010 at 08:50 AM.
#2
Seems as though you were on the right track. It also appears that someone has added an end(black w/white) to the white IC wire at the ICM(not the coil). And no that is not correct. the wire should be white from end to end. So the question is when you say you jumped that wire, did you add a second wire all the way from B5 of the PCM to the ICM or did you do some other kind of jumper?
You probed the ICM for the presence of 1-4 volts at the ICM like you should but were you on the AC scale of the meter? When you did not see the correct voltage at the ICM did you then measure it at the B5 terminal of the PCM?
If it's not there you have to go back and look at the distributor signals.
You probed the ICM for the presence of 1-4 volts at the ICM like you should but were you on the AC scale of the meter? When you did not see the correct voltage at the ICM did you then measure it at the B5 terminal of the PCM?
If it's not there you have to go back and look at the distributor signals.
#3
#4
ok code 41 was wrong i had a wire in the short opti harness pushed out...thats fixed code gone and code hasnt come back...
the wire at the pcm is white...and at the icm is white i just double checked..the wire is so dirty even after i cleaned it looks yellow...at the icm white with black stripe was pin d...sorry for confusion
seems as if everything is in order...if im not gettin 1-4 volts my opti bad?
its simply hard to believe that i puled it apart and put it right back together and something went bad...
the meter was on the ac scale...
the wire at the pcm is white...and at the icm is white i just double checked..the wire is so dirty even after i cleaned it looks yellow...at the icm white with black stripe was pin d...sorry for confusion
seems as if everything is in order...if im not gettin 1-4 volts my opti bad?
its simply hard to believe that i puled it apart and put it right back together and something went bad...
the meter was on the ac scale...
#6
Check the white wire again for 1-4 volts. If you don't get it, unplug it and check at the PCM while someone cranks the engine. Be sure your opti is plugged in and you don't have any codes when you try. If you don't see it after cranking, check for codes again.
Remember that for some codes to appear, there must be enough rotations. So if nothing appears right away, you may need to check a couple of times.
Remember that for some codes to appear, there must be enough rotations. So if nothing appears right away, you may need to check a couple of times.
#8
ive got between .25 and .40 volts ac when cranking...11.8 in the battery
opti harness is good...pcm to icm is good...so what possibilities do i have...sounds like opti...
also my scanner says 50rpm all the time...cranking or not
this will be my first opti failure in 6 years ive seen
95 car if i didnt mention before
opti harness is good...pcm to icm is good...so what possibilities do i have...sounds like opti...
also my scanner says 50rpm all the time...cranking or not
this will be my first opti failure in 6 years ive seen
95 car if i didnt mention before
Last edited by Daniel6718; 02-16-2010 at 02:31 PM.
#9
You haven't proved anything. Did you crank it and check the white wire for signal while it was disconnected from the ICM?
If you suspect the opti, did you check any of the feedback signals? The only signal that should matter from the opti is the low res signal and if it was gone, you would have a code 16.
If you suspect the opti, did you check any of the feedback signals? The only signal that should matter from the opti is the low res signal and if it was gone, you would have a code 16.
#10
yes the white wire at the icm has between .2 and .40 volts AC when cranking...my scanner says 50rpm all the time cranking or not...and no i havent checked the low res signal im not sure how to...and i have no codes
#13
As far as the opti is concerned, there are 2 outputs that make essentially a 5 volt square wave. If you look at the signal with a DVM and rotate the engine slowly over by hand, you could see the drop to 0 and back up to 5 volts.
#15
Here is a site that I found helpful to figure out that my unit was damaged.
http://www.gmhightechperformance.com...ing/index.html
Its like reading Chinese at first but it will help dude!