tannertaylormusic Posted June 23, 2010 Report Share Posted June 23, 2010 97 Cadillac Deville 4.6 northstar. I'm continuing my troubleshooting today. I hope to test all of the spark plug wires to make sure none are faulty. I need someone with experience on this car to give me step-by-step instructions on how to correctly test these. I do have an OHM tester - never used it until today :-). Also, anybody know where I can find a spark plug wiring diagram or routing diagram for this model? I want to make sure that the mechanic didn't mix up the plug wires when he switched out the intake manifold. Thanks! Link to comment Share on other sites More sharing options...
JimD Posted June 23, 2010 Report Share Posted June 23, 2010 Your plug wire resistance should be in the range of 220 to 240 Ohms per inch. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
tannertaylormusic Posted June 23, 2010 Author Report Share Posted June 23, 2010 I just tested 4 of them. wires are about 34 inches long. The readings I got were between 3.50-4.00. If my calculations are indeed correct, these are low.. Any thoughts? I'd like to get this knocked out today Link to comment Share on other sites More sharing options...
Cadillac Jim Posted June 23, 2010 Report Share Posted June 23, 2010 Are these measurements 3.5 kOhms to 4 kOhms? That's more like 120 Ohms per inch. I wouldn't think that this would hurt anything in terms of the resistance value, but if the resistance is out-of-spec it may mean that there is some insulation breakdown inside the wires. -- 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...
tannertaylormusic Posted June 23, 2010 Author Report Share Posted June 23, 2010 Are these measurements 3.5 kOhms to 4 kOhms? That's more like 120 Ohms per inch. I wouldn't think that this would hurt anything in terms of the resistance value, but if the resistance is out-of-spec it may mean that there is some insulation breakdown inside the wires. Yes - 3.5 to 4 kOhms. I don't know anything about Ohms, but it seems consistent from one wire to the next so I'm thinking the wires are ok. I didn't notice any cracks or anything of that sort. I hate to take it to my mechanic, but this P1645 (Evaporative Emission (EVAP) Vent Solenoid Control Circuit) must be the culprit - and I am NOT an electrical guy lol. Link to comment Share on other sites More sharing options...
adallak Posted June 23, 2010 Report Share Posted June 23, 2010 I just tested 4 of them. wires are about 34 inches long. The readings I got were between 3.50-4.00. If my calculations are indeed correct, these are low.. Any thoughts? I'd like to get this knocked out today The resistance of wires may vary from one manufacturer or part number to another. Your wires seem to be fine. Just check them out for sparking (spread some water and let the engine idle in the dark). The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Cadillac Jim Posted June 23, 2010 Report Share Posted June 23, 2010 Find the EVAP solenoid and check to see if the connector is loose or disconnected, and check to see if the harness to that connector is OK. -- 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...
tannertaylormusic Posted June 23, 2010 Author Report Share Posted June 23, 2010 Find the EVAP solenoid and check to see if the connector is loose or disconnected, and check to see if the harness to that connector is OK. Any idea off the bat as to where the EVAP solenoid would be on a 97 Deville? I'll do some research on the subject. Seems like there is a ECS fuse that I should check out too - that delivers power to the solenoid I THINK... Link to comment Share on other sites More sharing options...
Ed Hall Posted June 23, 2010 Report Share Posted June 23, 2010 97 Cadillac Deville 4.6 northstar. I'm continuing my troubleshooting today. I hope to test all of the spark plug wires to make sure none are faulty. I need someone with experience on this car to give me step-by-step instructions on how to correctly test these. I do have an OHM tester - never used it until today :-). Also, anybody know where I can find a spark plug wiring diagram or routing diagram for this model? I want to make sure that the mechanic didn't mix up the plug wires when he switched out the intake manifold. Thanks! One way to test spark plug wires is to find a very dark place at night and open the hood and check for any sparking coming from the wires. My 1993 Allante had what looked like brand new AC Delco wires and opening the hood revealed a lightning show. The lightning show was concentrated mainly back by the fire wall arcing with other wires and with the fan motor. I ended up replacing with my own custom made MSD 8.5mm wires. Link to comment Share on other sites More sharing options...
Ranger Posted June 24, 2010 Report Share Posted June 24, 2010 Why are you testing the plug wires? My '97 started to misfire after the wires were jostled around when I had the fuel rail recall done. They Ohmed out OK as I recall, but the misfire continued until I replaced the wires. Link to comment Share on other sites More sharing options...
tannertaylormusic Posted June 24, 2010 Author Report Share Posted June 24, 2010 Why are you testing the plug wires? My '97 started to misfire after the wires were jostled around when I had the fuel rail recall done. They Ohmed out OK as I recall, but the misfire continued until I replaced the wires. Because I'm not a mechanic - just a dude trying to save some money lol.. I am planning on changing out both the wires and the spark plugs.. They look a bit dirty, and since I've only had the 97 for 4 months I feel better about changing them out anyway. Thanks for your help everyone Link to comment Share on other sites More sharing options...
Cadillac Jim Posted June 24, 2010 Report Share Posted June 24, 2010 The EVAP solenoid is on the rear cam cover on the driver's side near the EGR valve. The purge switch is a little behind it and to the right. The connectors for teh EGR valve, teh EVAP solenoid, and the vacuum purge switch all lead to the same branch of the wiring harness. -- 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...
twocoltbob Posted June 25, 2010 Report Share Posted June 25, 2010 97 caddydeville, If the wires are original, I would not even bother to test them. After 13 years they certainly deserve a rest! If you replace them one by one, you will not need a wiring diagram. Don't forget the Anti-seize on the plug threads or the di-electric grease on the ceramic part of the plugs. Regards, TCB Link to comment Share on other sites More sharing options...
KHE Posted June 27, 2010 Report Share Posted June 27, 2010 DO NOT use anti-sieze or any other lubercant on the spark plug threads. The use of lubercants can result in overtorquing the spark plugs. The spark plug threads are plated to prevent corrosion. Also, the use of dielectric grease is not recommended on the plug boots due to the possibility of causing misfires. These points are stated in the service manual. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 27, 2010 Report Share Posted June 27, 2010 Ditto what KHE said, no anti-seize or dielectric grease, it is detailed in the manual. That is one reason to use AC delco plugs and ignition wires. The wires are impegnated with a dielectric grease http://www.acdelco.c...al-platinum.jsp 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...
PAUL T Posted June 28, 2010 Report Share Posted June 28, 2010 The biggest problem I ran into with spark plug wires after a fuel rail change is that the old fuel rail was plastic and the new is steel. When you reroute the wires they come into contact with the steel fuel rail and if they are not in wire looms they might have a greater tendancy to arc especially if you place the beauty cover over them and tighten it down mashing them against the steel fuel rail. Therefore I put wire looms on all the wires coming across the new fuel rail and have not had any trouble since. I even thought about running the wires over the beauty cover. After my fuel pump change and cleaning up and tightening down the intake manifold after a starter solenoid replacement, I am now seeing MPG averages around 24 to 25.2, up from 18 to 19 MPG's for my 97 Deville. 97Deville if you are having engine missing or hesitation problems heed my suggestion and check the fuel pressure. A weak pump will cause all kinds of issues and codes. If you are still having Evap issues check the vacuum hose connection at the throttle body to make sure it is not plugged up. A good cleaning of the throttle body would not hurt while you are there. You might also check to see if your plug wires are in contact with the Evap wiring. If so, separate them. Link to comment Share on other sites More sharing options...
JimD Posted June 28, 2010 Report Share Posted June 28, 2010 ....after a starter solenoid replacement.... Where did you purchase a starter solenoid? Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
PAUL T Posted June 28, 2010 Report Share Posted June 28, 2010 ....after a starter solenoid replacement.... Where did you purchase a starter solenoid? At the local NAPA store. I think it was about $50.00. Link to comment Share on other sites More sharing options...
JimD Posted June 28, 2010 Report Share Posted June 28, 2010 ....after a starter solenoid replacement.... Where did you purchase a starter solenoid? At the local NAPA store. I think it was about $50.00. Thank you. My apologies to the original poster for this little diversion. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
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