My 95 Corolla 1.6 4A-FE with 100k miles has been pinging when going uphills for quite a while. It used to ping on hot days only. The pinging is getting progressively worse and now it pings also in cooler weather. Oil consumption is 1 quart per 3k miles. Could these be related? I considered replacing the (original) distributor cap due to a slight miss at idle. Is it possible it will solve the pinging problem? Any other ideas what could cause the pinging? Thanks.
Either the ignition timing is off, or the engine compression has increased, or the gasoline you are using is too low octane.
The engine compression can increase when the cylinder volume decreases, due to a build up of carbon junk on piston and head.
If the distributor cap has 100k miles on it, it's probably time to replace it anyway, but I would also check the detonation sensor on the engine too, because it should be causing the computer to retard the spark automatically when the engine pings.
A scanner will allow you to see where the computer has set the spark timing, and once you know that you'll know where to start looking. If it's already as far back as it will get and the engine is still pinging, I'd look in the cylinder with a borescope and see how nasty it is in there.
You can try some of the cleaning products out there that claim to remove carbon buildup. I don't know how any of them work, but pulling the head and scraping it out by hand is not a fun job so I'd try them all first once you have looked with a borescope and seen crap in there.
I think they could be related. As you burn more oil, the deposits on your spark plugs can build up more. This can cause a situation of preignition which may be your pinging source.
If you pull the plugs and take a look, you can see if this might be the case.
Could be as a result of carbon building up in the engine from the burning oil. That can cause hot spots and higher compression in the cylinders. Those can cause pinging.
Go get a can of top cylinder cleaner from GM or a can of Sea Foam cleaner from a parts store and follow the directions regarding top cylinder cleaning. (Basically you find a vacuum line and use it to draw in the cleaner, then you dump in enough to stall the engine. Let it set for 20-30 minutes and then start it back up. Make sure you do this OUTSIDE and not in a place where the smoke will not draw attention. It WILL SMOKE LIKE CRAZY once you start it up again.) This will clean up the carbon and crud in the cylinders. The next step is to change the oil after you warm the engine up. The cleaner will get through the rings and dilute the oil some. This may also improve your oil use if it is due to sticking oil control rings.
Your oil usage sounds okay to me. I'd make sure the EGR passages/ valves are working, if they get plugged or restricted you won't have sufficient EGR, combustion chamber temperatures get too high and you'll start hearing the pinging. Get it fixed before you punch a hole in a piston....
As for the 'slight miss at idle', when was the last time you changed the plugs, cleaned the cap and rotor, and checked the plug wires?
More likely other problems would surface if it was overheating, but temp is a possible cause. Check air intake temp also.
It might, but that is unlikely to do much . Most of the other clean-out-the-carbon additives also have a small chance of working. You would better off to put in some higher octane fuel and do a long trip over hilly highways. If you get it to run right it may clean itself out and then you could go back to regular. An engine that is pinging badly will probably get better mileage from premium fuel so that is a solution that may not cost anything.
My car has been pinging when going uphill for quite a while. It used to ping on hot days only but it's getting worse and now it also pings in cooler weather. ______________________________________________________________________________
The most likely source of increasing pinging is a growing air leak into the intake system causing lean, hot burning. This could come from loose fasteners, a defective EGR/IAC/PCV valve, a failing manifold gasket, a loose carb/throttle body, etc.
If you continue to press hard on the accelerator when it is pinging, it can eventually burn a hole in a piston, cook an exhaust valve, or pound out a rod bearing.
Is this a US market car or a foreign build one? I'm not trying to call anyone a liar but I thought all US models had to have an EGR system, at least cars built since the mid 1970's.
A bad cap to me means one that leaks coolant or fails to hold pressure. You can test yours with a radiator/radiator cap pressure tester, you can usually rent them at a local auto parts place. If the cap is more than a few years old chances are the gasket is worn and it will not hold pressure. New ones are inexpensive, so if you have any doubt about it replace it.
A bad thermostat can fail in one of two ways. If it is stuck closed, you'd know it. The car would overheat, badly. A thermostat that is stuck open will prevent the engine from reaching normal temperature and it will take a long time to get any heat into the cabin area.
If the engine is heating that can cause your pinging.
Define "takes a bit". If it gets to the middle within 5 minutes or so of a dead cold start and stays in the middle all the time after that I would say your cooling system is working normally.
Spraying water into the intake is one way to try and break up excessive carbon. It might help, it might not. If you have a mass airflow sensor trying to do this procedure will almost certainly cause your check engine light to come on because you will have to spray the water into the intake, not the air cleaner. And you need to do that with the engine running. If you take off the air hose that feeds the intake the airflow sensor is no longer going to see any air moving past it and the ECM will trigger a fault code.
Without an EGR valve, a few more things come to mind. Overly advanced ignition timing can cause this problem. Another possibility is a vacuum leak somewhere in the intake system. You can test for a vacuum leak by getting yourself a can of spray carburetor cleaner. Start the engine and let it idle, then spray the carburetor cleaner around the intake manifold where it joins the cylinder head, around the throttle shaft area, and if you have a mass airflow sensor, around the boot connections between the air cleaner and the intake manifold. Also check the vacuum line that goes to the brake booster and any other vacuum lines you see. If the idle speed changes when you hit a certain spot with the carburetor cleaner it means you have an air leak, the solvent is being sucked into the engine and burned and causing the idle to change as a result. Vacuum leaks can be tricky to find, so check carefully. If you have any cracked, broken or hardened vacuum lines under the hood replace them.
The procedure for checking and setting ignition timing depends on the car, and I've never worked on a 95 corolla. Sometimes you have to disconnect a plug, sometimes you have to jumper a few pins on a diagnostic connector, sometimes you have to do nothing. It would help if you had a service manual for your vehicle as it would tell you how to check and adjust the timing. At the very least you will need a timing light, the inductive ones are the best. If you get one of the old ones that uses a spring between a plug wire and the timing light just be warned that they can(and very often do) light up your life...in a bad way. Been there, done that.
Thanks for the inputs. Car is for the non-US market, therefor no EGR for the 95 model. I've been at the dealer and they retarded the ignition a bit (can't tell by how much). When going up the same hill, pinging is much less noticeable now. Maybe that was the problem in the first place. I wonder why would the ignition become too advanced since the distributor has never been tinkered with (could normal engine wear cause this?) I'll also try the vacuum leaks option.
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