Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, Starting problem after changing spark plugs in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; With 114,000 on my '04's clock I started getting a #5 cyl misfire code and decided it was time to ...
With 114,000 on my '04's clock I started getting a #5 cyl misfire code and decided it was time to finally change the plugs. So I got a new set of double platinums and replaced #5, 4, & 6 first, unbolted the intake and lifted it up just enough for the plug coil packs to clear and replaced #1, 3, & 2. I didn't replace the upper intake manifold gasket since they weren't replaced on a couple of videos I watched. I bolted the intake back up and it started right up, no problem. I next changed the oil and again it started right up and ran Ok. After letting it down off the jackstands a couple of hours later I tried to restart it and it went "rrww" twice but wouldn't start. It's never not started before. Then when I turned the key the starter made a different, higher pitched sound like the solenoid wasn't engaging the flexplate. I banged on the solenoid but no change except for an occasional stumble. Suspecting a bad seal on the intake I unbolted it and checked it. Broken gasket on #1 cyl. Not having a gasket I did a repair with ultrablack RTV and the broken piece, let it set up for 15mins, and bolted it back down making sure it was seated all the way around and the gasket stayed put. A little later I tried it again and still no start, same as before but if I kept cranking it would try to start, stumbling occasionally. I kept trying and trying and the stumbling became more pronounced and eventually after many tries it finally stumbled to life and stabilized after a few seconds, running fine after that. It's started up and run just fine ever since. I'm going to let the RTV cure before I try driving it. So, What happened?? It's like the computer forgot how to start the car and had to relearn while I kept cranking it!
I would probably disconnect the battery let it sit for 15 mimutes and try again. I left my keys in the ignition listening to the radio when i did my plugs. At first it didnt start at all reading reduced engine power, when it finally did it ran extremely rough and then died out within 20 seconds. The battery trick fixed it for me tho. Was the gasket like that before you replaced the plugs or did it happen when u put the intake back on? (pinch or tore the gasket) if it was like that before, id relace both upper and lower gaskets. My lower gasket was almost disintegrated
It's been starting fine and running great all day. I drove it to work with no issues. I talked to the dealer service advisor and he was stumped. He advised that I leave well enough alone on the gaskets since it's running good. I may buy a set and keep them just in case. The torn gasket must have torn when I first lifted the intake. One of the little plastic pins on the front corner was stuck in the lower intake and didn't lift up so that's probably why it tore. I think it'll be fine with the RTV patch. I'm thinking more that it may have been a coincidental starter issue and the solenoid stuck like I first thought. When I lifted the intake the second time I smelled gas fumes pretty strong so I may have flooded it if the starter was just spinning by itself. The fuel wouldn't have gone anywhere without the pistons moving. It's not direct injection so all the gas would have collected in the intake runners. I couldn't see if the pulleys were turning or not from inside the car. Maybe I need to buy a starter and hang onto it in case it does it again.