Looking at this. On my 03 there are no grounds battery to head. Battery to side of block. Ground on side of block has two wires to it. Large gauge from battery circuit and smaller to the harness.Quote:
Originally Posted by 468Blazer
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Looking at this. On my 03 there are no grounds battery to head. Battery to side of block. Ground on side of block has two wires to it. Large gauge from battery circuit and smaller to the harness.Quote:
Originally Posted by 468Blazer
Quote:
Originally Posted by GasGuzzler
no, just the old fashioned way of spark plug to block, crank engine. he has tried a brand new coil pack though.
he couldnt find a noid light, none of the local stores have them.
witih just the key on, he found a ground and constant power at each coil.
he'll have to test the grounds tonight.
thanks
KY silverado
do you think the ground matters aluminum vs cast iron? he connected his MM to the battery, touched the negative, then touched the ground wires that run to the head and got the same voltage, do you think he should still move them? it wouldnt be a big deal if you said yes.
As sensitive as these things are to ground offset I would say yes.Quote:
Originally Posted by LSXmyford
Pictures if it helps. Its easy to sink the bolts and not get all the wiring in them.
altbracket.jpg - Image - Photobucket - Video and Image Hosting
groundsrear.jpg - Image - Photobucket - Video and Image Hosting
lefthandmotor.jpg - Image - Photobucket - Video and Image Hosting
random thought do u have 12 v while its cranking ?
Aluminum will ground just as well as cast iron. All of my grounds are on the back of my heads and I ground my test light on the master cylinder all of the time. LOL You really need to put your scanner in real time or borrow someones HPTuners and check rpm while cranking it and rule this out.
well man if we knew someone with an HPtuner...we would but...what can ya do, this is a daily driver so it wouldnt make sense to buy it.
he put a test light on one injector pigtail, using both the hot and ground side, it pulsed with the engine cranking.
we traced the other wires and Im fairly certain we found the problem, I need to run this by someone, when its confirmed and if she fires, Ill let you all know something.
thanks
removed 7 wire harness which branches out to individual coils.
from the seven wire pigtail, DISCONNECTED, back to the pcm. All wires tested hot with key on, however, black wire didnt respond as expected, this is what happened.
with key ON (run position)
one probe on B+ (12v constant source)
other probe to:
black shown zero volts
one probe on ground
other probe to:
black shown 12.19v
Black is a common ground for all coils, on top of that, it was disconnected from everything else (coil harness), yet it shown voltage with the key on...acting like a switched power source....that cant be right. I guess hes gonna have to see if hes getting current at the harness grounds, if not, then this will totally make no sense, and he will have to follow that black wire into the new harness and see what the hell is happening?
sound right?
This problem needs addressed before looking into the second part of your post.Quote:
Originally Posted by LSXmyford
You should have 12V (one lead on ground at battery and one lead on the orange wire) on ONLY ONE WIRE OUT OF SEVEN key on (run).
You should have 12V (one lead on POSITIVE at battery and one lead on the wire to be tested) on the ground and low reference wires as described in my post above. NONE OTHERS.
Testing the power and the two grounds is better done with a test light in this case because it takes much more amperage to light a test light than the meter uses to measure voltage.
The other four wires should flash a test light HOOKED TO POSITIVE while cranking.
While we're at it...
A disconnected ground wire can should 12V (meter hooked to ground) if there is a low resistance component in series with the ground tested. This is called "open circuit voltage".
there is no orange in the seven wires.Quote:
You should have 12V (one lead on ground at battery and one lead on the orange wire) on ONLY ONE WIRE OUT OF SEVEN key on (run).
it doesQuote:
You should have 12V (one lead on POSITIVE at battery and one lead on the wire to be tested) on the ground and low reference wires as described in my post above. NONE OTHERS.
you mean IC control wires? with key on, test light to 12v and IC wire, they lit up without cranking engine. will retest this later.Quote:
The other four wires should flash a test light HOOKED TO POSITIVE while cranking.
im thinking, if he is getting current through the black wire, then chances are he would get current through the IC as well, they must share the same ground point. this would explain why we got current with only the key on but im guessing.
I meant pink, sorry for using my memory. I should have looked back.Quote:
Originally Posted by LSXmyford
That doesn't sound right at all. That means the PCM (or a bad wire somewhere) is ground ALL the IC wires ALL the time.Quote:
Originally Posted by LSXmyford
They don't share the same ground. The "real" ground is supposed to be on the block. The low reference goes to the PCM to be able to compare the ground at the coils to "real" ground.Quote:
Originally Posted by LSXmyford
Try unplugging the other side main coil harness 8-way plug and retest the ground. You're getting open circuit voltage for some reason.
What year is the harness based on again?