micahdaniel Posted July 19, 2007 Report Share Posted July 19, 2007 My '95 DeVille began a rough idle several weeks ago. The best way to describe it is what used to happen to my '87 ford escort when the timing was off. Every couple of seconds it misses and loses power for that moment. It is as if the distributor was loose and moved further away from correct timing--only this is my caddy and I don't know how similar the timing mechanism is. On my escort, I could just whip out my timing light and wrench to fix it up. What do I need to do with my caddy? Link to comment Share on other sites More sharing options...
Cadillac Jim Posted July 19, 2007 Report Share Posted July 19, 2007 Usually when something is wrong in a GM vehcile the OBD II sets a diagnostic trouble code (DTC). You can pull the codes. Here's how: http://www.caddyinfo.com/readingcodes.html Please pull the codes and post them here. In distributorless cars like the Northstar engine in your 1995 Deville, timing is controlled by two computers and a number of sensors, including a knock sensor and the fuel injection sensors (oxygen sensors, mass airflow sensors, intake air temperature sensor, coolant temperature sensor, manifold air pressure sensor, etc.) so the timing is not adjustable. The stumble you describe sounds more like either a spark problem or a fuel injection problem. If you don't normally use premium gasoline, you might try a tank and take a drive on the highway or freeway for at lest 20 or 30 minutes and see if that helps. A lead foot during this process will help too. The car is about 12 years old. If the plugs and plug wires have never been changed, they are a very good candidate for causing the occasional miss at idle. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
micahdaniel Posted July 19, 2007 Author Report Share Posted July 19, 2007 I should have mentioned that I checked for codes and I have none. I thought that was weird. Also, I've been putting premium in for at least the last 2 fillups and I drive >10min on a 75mph highway to work each day. I've done WOT a couple times with no noticeable benefit. I probably need to change the plugs anyways. Any brand recommendations or tips there? Link to comment Share on other sites More sharing options...
BodybyFisher Posted July 19, 2007 Report Share Posted July 19, 2007 AC DELCO 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...
Cadillac Jim Posted July 19, 2007 Report Share Posted July 19, 2007 I was hoping BodybyFisher would step in. I notice that the 1995 Deville uses the 4.9 liter OHV engine; I was thinking Northstar. Please consider changing the plug wires, and use AC Delco for those, too. Since this engine has a distributor, I would suggest that you consider a new cap and rotor if the plugs and wires don't do it for you. A good source: http://www.rockauto.com/ Rock Auto sells both the AC Delco Rapidfire and Platinum plugs for your car. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
micahdaniel Posted July 19, 2007 Author Report Share Posted July 19, 2007 I notice that the 1995 Deville uses the 4.9 liter OHV engine; I was thinking Northstar. Does that change anything you said about the timing? Link to comment Share on other sites More sharing options...
BodybyFisher Posted July 19, 2007 Report Share Posted July 19, 2007 I notice that the 1995 Deville uses the 4.9 liter OHV engine; I was thinking Northstar. Does that change anything you said about the timing? I would not think this is related to timing. Check the cap, rotor, ignition wires and plugs. Also look for vacuum leaks. The OBD I system will not throw out misfire codes. 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...
micahdaniel Posted July 27, 2007 Author Report Share Posted July 27, 2007 OK. If I had just opened the hood and listened I would have heard the clicks coming from the distributor. I replaced all the spark plugs, the cap and rotor. These needed to be done anyway. Still the clicking sound coming from the distributor. I'm sure this clicking is arcing and is causing the misses that have given me rough idle. What should I go after next? I see there are some electronics inside the distributor below the rotor and the coil that rests on the cap. What is the most likely source of the arcing? Link to comment Share on other sites More sharing options...
BodybyFisher Posted July 27, 2007 Report Share Posted July 27, 2007 take the cap off, grab the rotor and see if it has side to side play, I have seen the bushings go bad. It may not be arcing you are hearing. Feel the cap when its running and see if you feel mechanical contact with the cap.. Since you have replaced the cap and rotor its not that. It could be your coil arching also. Did you replace the little carbon electrode in the cap also? 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...
micahdaniel Posted August 1, 2007 Author Report Share Posted August 1, 2007 Of all things it was the spark plug wires. They appeared to be in fine shape, but there must have been a break in one of them right near the distributor. I guess I didn't see the arcing because it arced to itself across the break in the line. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.