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1990 Cadillac deville
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Discussion Starter #1
I was wondering if someone could give me some info on how to check a short to ground and not damage the computer in the process. I should have included a simple circuit picture so that someone could show that proper placement of my probes of my DVOM as to perform this testing correctly.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
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20,255 Posts
I was wondering if someone could give me some info on how to check a short to ground and not damage the computer in the process. I should have included a simple circuit picture so that someone could show that proper placement of my probes of my DVOM as to perform this testing correctly.
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I assume you have a code - or something isn't working -
we need SPECIFIC information -
 

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Registered
1990 Cadillac deville
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48 Posts
Discussion Starter #3
Yes, as soon as I figure out how to get the picture of the circuit in question from my phone to the forum I will pose the question I have again.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
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20,255 Posts
Yes, as soon as I figure out how to get the picture of the circuit in question from my phone to the forum I will pose the question I have again.
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just a brief description of the problem -
and the code number along with its definition -
would be a good start -
 

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Registered
1990 Cadillac deville
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48 Posts
Discussion Starter #5
Well there is no code. I know i have two injectors out of range. What I,m trying to do is make sure all the grounds are good. Ive located the one on the alternator, the on by the starter and the one by the battery. The circuit i was attempting to check is for the oxygen sensor, and I wanted to make sure it was not shorted to ground and that its ground was good. Also I wanted to make sure the ECM and oxygen sensor were ok as far as them reading eachother correctly. So I am attempting to check all the grounds and check with my DVOM that voltages are correct and to check for shorts to ground but not sure how to place my probes without damaging the ECM. The Basic problem is its still running rich, but I have not changed the injectors yet, been procrastinating on that becasue there is so much I have to take apart to get to the injectors that are ohming out at 2-3 ohms.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
20,255 Posts
Well there is no code. I know i have two injectors out of range. What I,m trying to do is make sure all the grounds are good. Ive located the one on the alternator, the on by the starter and the one by the battery. The circuit i was attempting to check is for the oxygen sensor, and I wanted to make sure it was not shorted to ground and that its ground was good. Also I wanted to make sure the ECM and oxygen sensor were ok as far as them reading eachother correctly. So I am attempting to check all the grounds and check with my DVOM that voltages are correct and to check for shorts to ground but not sure how to place my probes without damaging the ECM. The Basic problem is its still running rich, but I have not changed the injectors yet, been procrastinating on that becasue there is so much I have to take apart to get to the injectors that are ohming out at 2-3 ohms.
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sounds like you are creating a LOT of extra work -

1990 was the first year for multi-port injection -
and the injectors were problematic -

check the FPR - Fuel Pressure Regulator -

and if you have a couple bad injectors -
replace the entire set -
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
Following the diagnostics info in the service manual for the different parts will rule out most problems and tell you how to determine if a sensor is faulty or there is a problem with the wiring.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
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20,255 Posts

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Registered
1990 Cadillac deville
Joined
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48 Posts
Discussion Starter #9
If I replace the whole set, which injectors should I roll with. The originals, or go with the rock auto or the one Ive seen for about $18.00 a piece. Not really looking forward to spending $80.00 per injector, but if thats the best bet then I guess I have no choice.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
20,255 Posts
If I replace the whole set, which injectors should I roll with. The originals, or go with the rock auto or the one Ive seen for about $18.00 a piece. Not really looking forward to spending $80.00 per injector, but if thats the best bet then I guess I have no choice.
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If I replace the whole set,
which injectors should I roll with.


here is what I would use -
http://www.ebay.com/itm/3-YEAR-WARR...990|Model:DeVille&hash=item2ed7c2b251&vxp=mtr
 
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