I have a 93 Loyalw w/ 150k bone stock. It runs beautifully, full power (oxymoron) and good gas mileage (32mpg/29 city). Problem is I am getting bad pinging, pre-detonation, spark knock, whatever it's called, when I am going uphills, and under heavy load or acceleration, and always with the AC on. I retarted the timing to 16 BTDC, as the hood sticker calls for 20 BTDC, regardless of altitude. I live at almost 8000 ft. and the car had a fairly recent tune up with Bosch platinum plugs. What do I do about this?? Also, it happens with all gas grades.

With that many miles on it, I would probably suspect some fairly haevy carbon deposits inside the cylinders. I'd recommend a good fuel system cleaner. I usually use either a product called Sea Foam (available through NAPA) or a small can of B12 Chemtool. Either one works well, but the Sea Foam is probably the safer choice.

Would this answer apply to a carbed engine?

You may want to refer to this thread

 

 

http://www.ultimatesubaru.org/forum/showthread.php?t=15208&page=2&pp=10

Yes, Josh it would apply to a carbed engine. What happens is the carbon acts as a sponge, soaking up some of the fuel, resulting in a lean condition in the cylinder, which causes it to run hotter, which in turn, heats up teh carbon to where it glows, creating a "hot spot" that causes pre-ignition.. Or something to that effect...

never heard that sponge theory. i think its because the carbon takes up so much space in the combustion chamber that it raises your compression to dangerous levels. or a real hard piece of carbon can glow red, and light your charge before the spark plug gets to

My 90 Loyale did the same (no A/C) on my bare bones rig. The cure was a new oil pump. Other stuff I've done that may have augmented the cure: new distributor cap, rotor, magnecor wires, accel coil, five minute motor flushes at oil change time, Castrol High Milage 10w-30. Clean throttle body interior with carb cleaner, good NGK plugs. If you haven't replaced the oil pump before, and decide to take care of this now, put in a new water pump, cam seals, and timing belts (if they're close to due) at the same time. Get it over with. If this doesn't cure the problem and make you feel like a new man, I apologize.

So this glowing coal could be causing the dieseling of my 83 carter/weber motor?

dump the bosch plugs, german plugs german cars. get a good set of NGK's and suck some seafoam in through a vacuume line, try for somewhere in the middle of the intake or you'll only clean one half of the engine.

The carbon soaks up fuel which, as someone pointed out, can cause a lean condition. With sufficient buildup, this results in harder starting and rough idle. In an injected engine, it can cause flooding. This is because the computer instructs the injectors to dump large(ish) amounts of fuel into the engine at start time. But if that fuel is being absorbed by the carbon buildup, the engine might not start immediately or might start briefly and then stall. If this is happens, then you are likely to hit the starter again. The computer again instructs the injectors to saturate the cylinders and, with repetition, you quickly flood the engine. In a carb'd car, it usually just makes for hard starting and rough idle.

 

Put some seafoam in the gas tank and let 'er rip. If you've never done this to this car before, you might want to fill the car with good quality gas (I use chevron) and add a bottle of seafoam. Run it WITHOUT filling up until you've run the whole tank. Fill up again with good gas, add another bottle of seafoam and back to normal driving you go. That will usually clean up most fuel system deposits, so if that does not solve the problem, you'll want to look into some of the mechanical solutions that have been brought up.

You can backyard steam clean the cylinders by running a stream of water through the throttle body while the engine is held around 2500 RPM's. That will be a decent job of cleaning your cylinders, and it's cheap.

 

GD

GD, perhaps I am unclear as to the procedure you are recommending, but it sound to me like a REAL good way to hydrolock and engine....

Apparently you have never tried it then. It won't hydrolock because it isn't water - it's steam. Remember that the engine is running at 200+ degrees, and even higher inside the combustion chamber. A small stream of water (not enough to kill it) will vaporize instantly. Besides - ever heard of water injection?

 

Beleive me - it works, and I've used this method for years. My auto shop teacher in high school actually showed us that.....

 

GD

Would all volunteers please bring their vehicles to my place. I'll provide the garden hose. Towing services are the responsibility of vehicle owners.

It should probably be stated that the amount of water should be SMALL. Your engine should be at FULL OPERATING temp. If you are worried about just pouring water down the carb try a spray bottle for more control over the amount of water coming in

I've used the steam method and it does work. I had a bmw 2002 with dual 45mm webers on it that made alot of carbon. Spray bottles work good

I guess people think that I have over 3000 posts here because I routinely hydrolock all my engines with a garden hose.

 

Beleive what you want - but why do you suppose that engines with blown HG's still run, and pour loads of smelly steam out the tail-pipe? Because a little water in the cylinder WILL NOT KILL your engine. Water injection is used often to cool the incomming air, and increase compression. It both cools the charge so it's denser, and it also fills part of the cylinder with unburnable water vapor - this increases compression. It also cleans the hell out of anything it touches. That's why people use steam cleaners to clean nasty engine parts.....

 

GD

I have a 93 Loyalw w/ 150k bone stock. It runs beautifully, full power (oxymoron) and good gas mileage (32mpg/29 city). Problem is I am getting bad pinging, pre-detonation, spark knock, whatever it's called, when I am going uphills, and under heavy load or acceleration, and always with the AC on. I retarted the timing to 16 BTDC, as the hood sticker calls for 20 BTDC, regardless of altitude. I live at almost 8000 ft. and the car had a fairly recent tune up with Bosch platinum plugs. What do I do about this?? Also, it happens with all gas grades.

Maybe your EGR passage is all clogged up or the valve isn't opening.

GD, I wasn't trying to imply anything. I'm all about whatever gets the job done. I just needed some clarification because what I read was that I should run a stReam (note the R) down the intake and THAT seems like a good way to hydrolock an engine.

 

Sorry if I came off the wrong way.

Yes - stReam - although a thin one for sure.

 

No problem with you Scooby - it's Bill up thar ^ that thinks it would be really funny to provide a garden hose for me to play with. Apparently me steam cleaning my cylinders is highly amusing. Ha-Ha, very funny.

 

GD

ya water works good. about a half gallon should be all you need. use a vac port near the tb. dont let it die though, keep on the gas, to keep it runing. its kinda cool, as your car sucks up water through a straw.

Relax General. Just enjoying the thought of observing this process. I get a big kick out of reading your contributions, and thank you for them.

Bill

I will also say check your EGR because it is designed to reduce CYL temps. my85 GL was verry prone to pinging. I did the sea foam and the water method. yes the watter method works but be verry carefull because yes there is a chance of hydralocking. any way after all that was done my car still pinged unless I retarded the timing. It was better but not fixed.

 

have you tried higher octane fuel?

 

and I also say Bosh plugs are great.... in a german car. use NGK. the bosh heat ranges are usually incorrect. that may be part of the problem as well.

I'll try the water method, carefully, but where do I introduce the water? Via the pcv valve??? Also, the engine spec is 20BTDC for the timing, regardless of altitude, I have it down to around 16, and slight pinging while driving, but it gets really bad when the ac is on, hmmmm........ what else, oh and I'll check the egr valve