pwilluttley Posted November 29, 2006 Report Share Posted November 29, 2006 Can anyone tell me where the ground point for the ECM module might be in my 1991 seville 4.9L? Is it behind the battery? Also, I have heard that the main engine ground can be a problem - Is it located by the starter? If so, what's the easiest way to get to it? I'm having flaky problems with error codes and I've read that these are common problems in my year / model of caddy. Link to comment Share on other sites More sharing options...
JimD Posted November 29, 2006 Report Share Posted November 29, 2006 As a quick check, you could use several jumper cables to temporarily supply redundant ground connections between the battery negative terminal and any components you suspect could be acting up. Use the battery negative terminal post as the common point. Run a large guage jumper to any clean metal point on the engine. Fabricate smaller wires with appropriate sized alligator clips and connect suspect component cases to the battery negative terminal. When your flaky symptoms go away, you have found a component that has a poor ground connection. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 29, 2006 Report Share Posted November 29, 2006 See Scotty's post #8 here with the 92 4.9 grounding schematic: http://caddyinfo.ipbhost.com/index.php?sho...5&hl=ground Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
adallak Posted November 29, 2006 Report Share Posted November 29, 2006 Can anyone tell me where the ground point for the ECM module might be in my 1991 seville 4.9L? Is it behind the battery? Also, I have heard that the main engine ground can be a problem - Is it located by the starter? If so, what's the easiest way to get to it? I'm having flaky problems with error codes and I've read that these are common problems in my year / model of caddy. The ground on the engine block by the starter is made with a M8x1.25 stud and a couple of star washers. It is recommended to replace all that stuff along with cleaning cable contacts . You have to get under the car to access it. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
pwilluttley Posted November 29, 2006 Author Report Share Posted November 29, 2006 Can anyone tell me where the ground point for the ECM module might be in my 1991 seville 4.9L? Is it behind the battery? Also, I have heard that the main engine ground can be a problem - Is it located by the starter? If so, what's the easiest way to get to it? I'm having flaky problems with error codes and I've read that these are common problems in my year / model of caddy. The ground on the engine block by the starter is made with a M8x1.25 stud and a couple of star washers. It is recommended to replace all that stuff along with cleaning cable contacts . You have to get under the car to access it. Thanks - I will check the grounds. My problem is with the car starting when it is cold. When I first turn on the key, the engine will crank but will not start. I get a consistent E012 current error when this happens. I have already replaced the distrubutor, but I still have the same problem. I've also checked all of the wiring to the distributor. Whenever this happens, the car's radiator fan will kick on and run for about 10 minutes. Once the radiator fan quits, the engine will start. Usually the engine will die after about 5 minutes..no sputter, quickly shuts off just like you've turned off the key. It sounds electrical. Does this sound like a bad ground somewhere? Any ideas? Link to comment Share on other sites More sharing options...
bobnsue2 Posted November 30, 2006 Report Share Posted November 30, 2006 [is it behind the battery? Also, I have heard that the main engine ground can be a problem - Is it located by the starter? If so, what's the easiest way to get to it? I'm having flaky problems with error codes and I've read that these are common problems in my year / model of caddy. The ground on the engine block by the starter is made with a M8x1.25 stud and a couple of star washers. It is recommended to replace all that stuff along with cleaning cable contacts . You have to get under the car to access it. Thanks - I will check the grounds. My problem is with the car starting when it is cold. When I first turn on the key, the engine will crank but will not start. I get a consistent E012 current error when this happens. I have already replaced the distrubutor, but I still have the same problem. I've also checked all of the wiring to the distributor. Whenever this happens, the car's radiator fan will kick on and run for about 10 minutes. Once the radiator fan quits, the engine will start. Usually the engine will die after about 5 minutes..no sputter, quickly shuts off just like you've turned off the key. It sounds electrical. Does this sound like a bad ground somewhere? Any ideas? -------------------------------------------------------------------------------------------- Hi, I went through weird problems when the 91 STS was cold. It ran terrible. But always cranked good and started. After testing and replacing a number of sensors, I took it to a reputable dealer. They worked on it for several days and even replaced the computer, but couldn't find the cause, So they only charged for the original diagnosis and no parts. $150.00. I finally put my jumper cable on the engine block to the battery minus, This cleared up the bad running. I didn't figure out which ground was bad, so I ran a heavyish wire from the engine to the grounding points near the battery. If you look around the battery side and front you will see several studs with a number of black wires on them. This is the grounding points for most circuits. After I figured this out I removed all the nuts and cleaned all the terminals. I left the extra wire on for good measure. Bob B Link to comment Share on other sites More sharing options...
pwilluttley Posted November 30, 2006 Author Report Share Posted November 30, 2006 [is it behind the battery? Also, I have heard that the main engine ground can be a problem - Is it located by the starter? If so, what's the easiest way to get to it? I'm having flaky problems with error codes and I've read that these are common problems in my year / model of caddy. The ground on the engine block by the starter is made with a M8x1.25 stud and a couple of star washers. It is recommended to replace all that stuff along with cleaning cable contacts . You have to get under the car to access it. Thanks - I will check the grounds. My problem is with the car starting when it is cold. When I first turn on the key, the engine will crank but will not start. I get a consistent E012 current error when this happens. I have already replaced the distrubutor, but I still have the same problem. I've also checked all of the wiring to the distributor. Whenever this happens, the car's radiator fan will kick on and run for about 10 minutes. Once the radiator fan quits, the engine will start. Usually the engine will die after about 5 minutes..no sputter, quickly shuts off just like you've turned off the key. It sounds electrical. Does this sound like a bad ground somewhere? Any ideas? -------------------------------------------------------------------------------------------- Hi, I went through weird problems when the 91 STS was cold. It ran terrible. But always cranked good and started. After testing and replacing a number of sensors, I took it to a reputable dealer. They worked on it for several days and even replaced the computer, but couldn't find the cause, So they only charged for the original diagnosis and no parts. $150.00. I finally put my jumper cable on the engine block to the battery minus, This cleared up the bad running. I didn't figure out which ground was bad, so I ran a heavyish wire from the engine to the grounding points near the battery. If you look around the battery side and front you will see several studs with a number of black wires on them. This is the grounding points for most circuits. After I figured this out I removed all the nuts and cleaned all the terminals. I left the extra wire on for good measure. Bob B Bob - I'm thinking that I have the same problem. I will try your suggestions - thanks! I'll let you know how it comes out. I'm almost sure it's a grounding issue..I hope anyway. Do you happen to know where the ground wire for the ECM is located? Link to comment Share on other sites More sharing options...
bobnsue2 Posted December 1, 2006 Report Share Posted December 1, 2006 Bob - I'm thinking that I have the same problem. I will try your suggestions - thanks! I'll let you know how it comes out. I'm almost sure it's a grounding issue..I hope anyway. Do you happen to know where the ground wire for the ECM is located? ------------------------------------------------------------------------------------------ If I remember correctly,Ths ECM ground goes to one of the studs along side of the battery. Most grounds are there and the book shows there are some in or near the trunk for the stuff back there. BTW, on my car the black wires to the studs were not rusty or corroded, but were a bit dull. So I shined them up as best I could with sandpaper. There are a lot of grounds running there. Bob B Link to comment Share on other sites More sharing options...
povich444 Posted January 16, 2007 Report Share Posted January 16, 2007 [is it behind the battery? Also, I have heard that the main engine ground can be a problem - Is it located by the starter? If so, what's the easiest way to get to it? I'm having flaky problems with error codes and I've read that these are common problems in my year / model of caddy. The ground on the engine block by the starter is made with a M8x1.25 stud and a couple of star washers. It is recommended to replace all that stuff along with cleaning cable contacts . You have to get under the car to access it. Thanks - I will check the grounds. My problem is with the car starting when it is cold. When I first turn on the key, the engine will crank but will not start. I get a consistent E012 current error when this happens. I have already replaced the distrubutor, but I still have the same problem. I've also checked all of the wiring to the distributor. Whenever this happens, the car's radiator fan will kick on and run for about 10 minutes. Once the radiator fan quits, the engine will start. Usually the engine will die after about 5 minutes..no sputter, quickly shuts off just like you've turned off the key. It sounds electrical. Does this sound like a bad ground somewhere? Any ideas? -------------------------------------------------------------------------------------------- Hi, I went through weird problems when the 91 STS was cold. It ran terrible. But always cranked good and started. After testing and replacing a number of sensors, I took it to a reputable dealer. They worked on it for several days and even replaced the computer, but couldn't find the cause, So they only charged for the original diagnosis and no parts. $150.00. I finally put my jumper cable on the engine block to the battery minus, This cleared up the bad running. I didn't figure out which ground was bad, so I ran a heavyish wire from the engine to the grounding points near the battery. If you look around the battery side and front you will see several studs with a number of black wires on them. This is the grounding points for most circuits. After I figured this out I removed all the nuts and cleaned all the terminals. I left the extra wire on for good measure. Bob B Bob - I'm thinking that I have the same problem. I will try your suggestions - thanks! I'll let you know how it comes out. I'm almost sure it's a grounding issue..I hope anyway. Do you happen to know where the ground wire for the ECM is located? Had all these same probs and took yor advice and tried the jumper cable!! Exactly what the problem was! Many thx to all of ya! Link to comment Share on other sites More sharing options...
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