This is about my mother’s 2005 Camry (4 cyl., about 21,000 mi.). She called this evening and told me that the engine kept going for more than a minute after she shut it off. She didn’t notice any problems with the engine while driving, only when she shut it down. I assume that the car has an electronic ignition, so I’m puzzled. The transmission parking rod was just repaired, but I don’t see how that would be related.
Any ideas? I suggested that she fill her half-empty tank with premium gas from a national brand.
This used to be a.common problem back in the carburetor days. The engine would load up with carbon which would retain heat and the gasoline would drip in from the carburetor and ignite. I am almost certain this Camry has fuel injection which makes,me think one or more injectors is leaking. This car has traveled only 21,000 miles in 10 years, so the engine may be loaded with carbon. In the old days, I would pour a can of Casite Motor Tuneup in the gas tank, drive around for a few days and then take the car out on the highway. I would put it in a,lower gear and really run it fast in that fear for half a,mile. I would repeat rhis process several times. Whether Casite is available today or whether this,process is advisable today someone else will have to comment
In the early '70s dieseling was common even without the carbon to retain the heat. In an effort to reduce emissions, manufacturers “leaned out” the carburetors, causing the cylinders to run hotter, and the fuel would self-ignite. In a carbed engine, the vacuum from the cylinders will continue drawing fuel out of the carb until the float bowl runs dry, and if the cylinders are hot enough to ignite the fuel, the engine keeps dieseling. Manufacturers had to add “anti-dieseling solenoids” to totally shut the throttle plates when the engine was turned off, choking the engine. My '72 had one.
I agree with Triedaq about that leaky injector… or perhaps even more than one. I don’t know if at today’s cylinder temps the carbon is even necessary for dieseling, but that’d be pretty easy to check out by pulling a few sparkplugs.
There’s a system called an Exhaust Gas Recirculation (EGR) system designed to prevent the cylinders from getting too hot, but if that were malfunctioning you should get a CEL, so I’d be inclined to dismiss that… unless of course your mom has a CEL illuminated? A check for any stored codes is always a prudent first step.
That is almost impossible…at least in the manner in which we are discussing. TRUE Dieseling is not possible in this vehicle… Is it? No…wait…it isnt…thats my story and I’m sticking to it.
I am in agreement that a gunked-up EGR is at least part of the problem.
A leaking injector, coupled with a malfunctioning EGR, might be able to produce dieseling.
I’m more likely to suspect an electrical failure instead of a mechanical one, although a car that only gets driven 2000 miles a year can start to have problems with either.
If the engine continued to run normally for a full minute I would suspect an ignition switch or relay that stuck momentarily.
If the car gets driven regularly with such low mileage I would recommend a Motorvac or other fuel injection/intake service as well.
I’m w/ @asemaster on this one. When the key is turned to “off”, the fuel pump should shut off. I don’t see how, even with leaking injectors, there’d be enough gas in the fuel rail to idle the engine for a minute, and that would happen only if there were indeed hot spots in the cylinders. On a 2005 Camry, I just don’t see this many coincidences happening all at once.
I’d guess the same thing as “asemaster”, a faulty ignition switch or sticking relay, perhaps the main engine relay.
OP, here’s a question for you. How much stuff is on your mom’s key-ring? A lot of weight swinging around as the car turns & goes over bumps can damage the ignition switch. This is not an uncommon thing reported here.
I have to agree with @andrewRA on this one. If it’s running on smoothly for a full minute it’s not dieseling. If it’s running roughly and pinging it’s dieseling. This needs to be clarified. I suspect it’s running smoothly in which case I’m also with @asemaster.
It would help to know whether the engine was actually dieseling or it just running on normally.
Without knowing what was done by whoever dug into the transmission control (Interlock???) maybe someone got something out of whack in relation to the ignition switch and the engine was running on normally instead of dieseling. Maybe a review of that repair needs to be done.
Does the repair order provide any details or is it one those that (sadly and unfortunately) very generic with little useable info?
I can’t say with certainty, but I think that even if an injector were leaking the fuel pressure would dissipate within a one or two intake cycles, shutting the engine down.
Like others, I think it’ll take a good look-see by a qualified diagnostician to get to the heart of the problem. I don’t think this one can be diagnosed over the internet.