I have what I think is a persistent carbon build-up problem in my combustion chambers. The symptoms are stumbling and surging at low throttle angles at low speeds. I run cleaners all the time, but it keeps coming back. The reason I think it is carbon is the CC’s is that a quick Italian tune-up remedies the problem. As an example, on Saturday, the stumbling seemed a bit worse than usual. I did an Italian tune-up and it went away. But the problem will come back again. Strong fuel system cleaners combined with frequent Italian tune-ups keeps the problem at bay.
On Sunday, I thought maybe I could speed up the process and/or keep it away for a bit longer if I did one of those “cleaners through a vacuum port” treatments. I had a 12oz bottle of Techron on the shelf. The car was good and warm. I started by using a syringe type injector and fed the Techron through the PCV line. This was taking forever. Fill the syringe, remove the PCV line, inject it, and replace the line. I had to replace the line each time because of the huge vacuum leak with it disconnected. The engine didn’t stumble at all during these “injections.”
This was taking so long I found a quicker method. I connected a hose to the PCV port and put a funnel on the other end. I VERY SLOWLY poured the remaining Techron through the hose. The engine was stumbling because of the vacuum leak. When I was done pouring I ran to the key to turn it off. This is when the “fun” began. NOT! The car started dieseling. In hindsight, it was due to the open vacuum line allowing air into the engine. I did this for quite a while. I thought maybe I hadn’t turned the key all the way so I ran back to the key and pulled it all the way out. The car was still dieseling and making HORRIBLE noises. I heard some LOUD metal banging. I was in a state of shock and fear, thinking I had done something horrible to my motor. Finally the dieseling stopped.
After it stopped, I buttoned up the PCV line and restarted the engine. It made a couple more loud bangs, but finally started idling again. I took it for a drive. It stumbled a bit at first but soon cleaned up and drove fine. I even hit some high revs just to be sure.
While I think everything is OK, I guess I’m looking for some reassurance. Man, I was worried for a while! It was hard to sleep last night! I guess I’m a bit OCD about my car (welcome to the club, right?!). At first, I thought the loud banging might have been piston slap, and I started worrying about dents in the sides of my pistons, having them unbalanced, etc, etc, but I’ve changed my theory. I think the loud banging might have been a hydraulic lifter starved for oil at the low RPM’s during the dieseling.
Any thoughts as to what caused the noise? The whole scenario doesn’t sound too different from the stories of Seafoam, water injection, etc. I didn’t get the clouds of white smoke, but then again I poured it in pretty slowly. I did NOT choke off the engine with the Techron. I also did not let it soak in. I was in too much of a hurry to get back to a running engine to do that.
Any reassurances? Any ideas as to the cause and solution to the carbon build-up problem? I don’t know what is worse over the long run: frequent use of strong cleaners or frequent Italian tune-ups.
If you got this far, thanks for reading. I really appreciate it.
On Sunday, I thought maybe I could speed up the process and/or keep it away for a bit longer if I did one of those “cleaners through a vacuum port” treatments. I had a 12oz bottle of Techron on the shelf. The car was good and warm. I started by using a syringe type injector and fed the Techron through the PCV line. This was taking forever. Fill the syringe, remove the PCV line, inject it, and replace the line. I had to replace the line each time because of the huge vacuum leak with it disconnected. The engine didn’t stumble at all during these “injections.”
This was taking so long I found a quicker method. I connected a hose to the PCV port and put a funnel on the other end. I VERY SLOWLY poured the remaining Techron through the hose. The engine was stumbling because of the vacuum leak. When I was done pouring I ran to the key to turn it off. This is when the “fun” began. NOT! The car started dieseling. In hindsight, it was due to the open vacuum line allowing air into the engine. I did this for quite a while. I thought maybe I hadn’t turned the key all the way so I ran back to the key and pulled it all the way out. The car was still dieseling and making HORRIBLE noises. I heard some LOUD metal banging. I was in a state of shock and fear, thinking I had done something horrible to my motor. Finally the dieseling stopped.
After it stopped, I buttoned up the PCV line and restarted the engine. It made a couple more loud bangs, but finally started idling again. I took it for a drive. It stumbled a bit at first but soon cleaned up and drove fine. I even hit some high revs just to be sure.
While I think everything is OK, I guess I’m looking for some reassurance. Man, I was worried for a while! It was hard to sleep last night! I guess I’m a bit OCD about my car (welcome to the club, right?!). At first, I thought the loud banging might have been piston slap, and I started worrying about dents in the sides of my pistons, having them unbalanced, etc, etc, but I’ve changed my theory. I think the loud banging might have been a hydraulic lifter starved for oil at the low RPM’s during the dieseling.
Any thoughts as to what caused the noise? The whole scenario doesn’t sound too different from the stories of Seafoam, water injection, etc. I didn’t get the clouds of white smoke, but then again I poured it in pretty slowly. I did NOT choke off the engine with the Techron. I also did not let it soak in. I was in too much of a hurry to get back to a running engine to do that.
Any reassurances? Any ideas as to the cause and solution to the carbon build-up problem? I don’t know what is worse over the long run: frequent use of strong cleaners or frequent Italian tune-ups.
If you got this far, thanks for reading. I really appreciate it.
