no spark help
no spark help Guys, i need some help. i got a 95 trans am lt1 mt6
no spark. i see no ses light.
i did the test for opti, the instructions seem wrong though.
it says to unplug the opti harness from the ecm. i did so and on the ecm side i have 12v and ground no +5 on either the purple w or the red blk wires.
when i connect it back and check the voltage inline then i get +5 on one of the wires but not on both. depends if i crank over the car or not.
this is of course with KOEO.
im at wits ends, can anyone give me something else to check....
I also changed the ecm with another unit and still no go.
no spark at the plugs or at te coil. no pulse at the injectors with noid light on any of them.
Edit: checked shbox opti diagnostic and still no go.
could it be wiring before the pcm missing power or a ground?
please help...
ps this car has been parked for about 1.5 yrs. just cleaned out the fuel and flushed the tank also.
changed the head gaskets and now this.
no spark. i see no ses light.
i did the test for opti, the instructions seem wrong though.
it says to unplug the opti harness from the ecm. i did so and on the ecm side i have 12v and ground no +5 on either the purple w or the red blk wires.
when i connect it back and check the voltage inline then i get +5 on one of the wires but not on both. depends if i crank over the car or not.
this is of course with KOEO.
im at wits ends, can anyone give me something else to check....
I also changed the ecm with another unit and still no go.
no spark at the plugs or at te coil. no pulse at the injectors with noid light on any of them.
Edit: checked shbox opti diagnostic and still no go.
could it be wiring before the pcm missing power or a ground?
please help...
ps this car has been parked for about 1.5 yrs. just cleaned out the fuel and flushed the tank also.
changed the head gaskets and now this.
Last edited by dually681; Aug 3, 2013 at 02:19 PM. Reason: checked more stuff
update Well I still need help from the LT1 Guru's !
I went out and bought a reman optispark.
put it on and no spark.
so i said screw it and took it off and went back to parts store.
Got a new one and still same no spark.
checked coil and ICM both good at parts store so not a problem there...
Any bright ideas???
I went out and bought a reman optispark.
put it on and no spark.
so i said screw it and took it off and went back to parts store.
Got a new one and still same no spark.
checked coil and ICM both good at parts store so not a problem there...
Any bright ideas???
Teching In
Joined: Feb 2006
Posts: 20
Likes: 8
From: Live Oak TEXAS
Well I still need help from the LT1 Guru's !
I went out and bought a reman optispark.
put it on and no spark.
so i said screw it and took it off and went back to parts store.
Got a new one and still same no spark.
checked coil and ICM both good at parts store so not a problem there...
Any bright ideas???
I went out and bought a reman optispark.
put it on and no spark.
so i said screw it and took it off and went back to parts store.
Got a new one and still same no spark.
checked coil and ICM both good at parts store so not a problem there...
Any bright ideas???
cool. something new i hadnt checked yet.
so i went outside and checked to make sure the harness wasnt backwards and no luck.
it was on right.
so i checked something else thats in the back of my mind.
the data link i cant connect my scanner software tunercat nothing.
so i checked the fuse to the cigar/horn and the radio one and both good. w DVM.
next i gotta check the tan cable D30 serial data cable to the pcm.
if u guys think of anything else please let me know...
thanks.....
so i went outside and checked to make sure the harness wasnt backwards and no luck.
it was on right.
so i checked something else thats in the back of my mind.
the data link i cant connect my scanner software tunercat nothing.
so i checked the fuse to the cigar/horn and the radio one and both good. w DVM.
next i gotta check the tan cable D30 serial data cable to the pcm.
if u guys think of anything else please let me know...
thanks.....
So the starter still works and it just cranks?
I had an issue with a brand new opti harness being wired backwards so I found a diagram from shoebox's site. I changed the diagram on the opti plug so it matches my car's configuration (the diagram was backwards for me but shoebox said no one has ever said anything to him about it, so I don't know).
Have you verified the ICM and coil harnesses are functioning properly?
I had an issue with a brand new opti harness being wired backwards so I found a diagram from shoebox's site. I changed the diagram on the opti plug so it matches my car's configuration (the diagram was backwards for me but shoebox said no one has ever said anything to him about it, so I don't know).
Have you verified the ICM and coil harnesses are functioning properly?
TECH Veteran
Joined: Dec 2008
Posts: 4,147
Likes: 62
From: Little Rock, AR
So the starter still works and it just cranks?
I had an issue with a brand new opti harness being wired backwards so I found a diagram from shoebox's site. I changed the diagram on the opti plug so it matches my car's configuration (the diagram was backwards for me but shoebox said no one has ever said anything to him about it, so I don't know).
Have you verified the ICM and coil harnesses are functioning properly?
I had an issue with a brand new opti harness being wired backwards so I found a diagram from shoebox's site. I changed the diagram on the opti plug so it matches my car's configuration (the diagram was backwards for me but shoebox said no one has ever said anything to him about it, so I don't know).
Have you verified the ICM and coil harnesses are functioning properly?
The connector plug may be labled ABCD, but you flip it over and it is DCBA. Not saying a factory manual can't have an error (because they often do), but you'd think they would correct it during the many years they were produced.
actually my factory service manual has them labeled like on shboxs site..however i do see what you mean by backwards.. hehe
well i think i may have found my problem.
we got very low fuel pressure....like a very soft flow. not even 1 psi.
any suggestions what page to start at in the service manual?
well i think i may have found my problem.
we got very low fuel pressure....like a very soft flow. not even 1 psi.
any suggestions what page to start at in the service manual?
Trending Topics
TECH Veteran
Joined: Dec 2008
Posts: 4,147
Likes: 62
From: Little Rock, AR
actually my factory service manual has them labeled like on shboxs site..however i do see what you mean by backwards.. hehe
well i think i may have found my problem.
we got very low fuel pressure....like a very soft flow. not even 1 psi.
any suggestions what page to start at in the service manual?
well i think i may have found my problem.
we got very low fuel pressure....like a very soft flow. not even 1 psi.
any suggestions what page to start at in the service manual?
http://shbox.com/1/fuel_pump_wiring.jpg
http://shbox.com/1/fuel_pump_connector.jpg
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Verdad Gallardo thnaks shbox made some serious progress here.
took the relay and jumped it, boom pump ran so im sure the wiring to the back is good.
pump made great pressure.
next traced the green wire to pcm no power at the connector from pcm.
starting to think my pcm is bad.
no low res, now high res, no fuel pump.
welll im heading to auto parts to return my new opti and to see if they have reman pcm's.
saw some cardone ecm/pcm units on advance's website....
Thank you guys will keep you posted.
took the relay and jumped it, boom pump ran so im sure the wiring to the back is good.
pump made great pressure.
next traced the green wire to pcm no power at the connector from pcm.
starting to think my pcm is bad.
no low res, now high res, no fuel pump.
welll im heading to auto parts to return my new opti and to see if they have reman pcm's.
saw some cardone ecm/pcm units on advance's website....
Thank you guys will keep you posted.
Last edited by dually681; Aug 4, 2013 at 01:18 PM. Reason: misspelings...
Were you able to get the data link connector figured out? I know you said there's no SES light but knowing what codes are present could be a big help.
So there's no spark, no fuel pressure, data link connector under the dash doesn't work but the PCM is getting the correct juice. Does that summarize accurately?
So there's no spark, no fuel pressure, data link connector under the dash doesn't work but the PCM is getting the correct juice. Does that summarize accurately?
man you got the summary down packed.
the datalink is not getting signal.
i got +12 and ground and checked the tan signal wire to pcm and wire is checking ok, not open.
so this all boils down to a bad pcm!!!///????
the datalink is not getting signal.
i got +12 and ground and checked the tan signal wire to pcm and wire is checking ok, not open.
so this all boils down to a bad pcm!!!///????
help !!! ok got a ocm from a known fbody shop and tried it. nothing. that wasnt it. still have no pcm signal to fuel pump, pump works great wheni jumper the relay in kick panel. traced wire to pcm and no voltage coming from that wire.
no low res +5 , yes high res +5.
can anyone chime in and tell me what could be causing the pcm to not send the proper fuel on signal and no low res voltage to the opti???
no low res +5 , yes high res +5.
can anyone chime in and tell me what could be causing the pcm to not send the proper fuel on signal and no low res voltage to the opti???
TECH Veteran
Joined: Dec 2008
Posts: 4,147
Likes: 62
From: Little Rock, AR
ok folks heres the low down
Problem resolved we have start !!!
it was under hood fuse panel missing 3 fuses.
3,4 hdlp dr hdlp L and R, also the one not labelled 8.
will upload a pic tonite.
i cant believe something so simple caused me such a headache... =)
maybe this will help someone in the future.
Problem resolved we have start !!!
it was under hood fuse panel missing 3 fuses.
3,4 hdlp dr hdlp L and R, also the one not labelled 8.
will upload a pic tonite.
i cant believe something so simple caused me such a headache... =)
maybe this will help someone in the future.
I almost forgot....
THANKS !!!
thanks to all that have given their input and helped me throughout the troubleshooting process.
its all been worth it.
By the way my MSD opti is sparking super hot.... love it !
THANKS !!!
thanks to all that have given their input and helped me throughout the troubleshooting process.
its all been worth it.
By the way my MSD opti is sparking super hot.... love it !
