Pinging

[rcmaniac791]

So my 5th runs fine, starts on a dime, idles great, and has decent pick-up for still being an ELB 318. But I'm having an issue with the engine "pinging" at partial throttle. If I go over half throttle it stops pinging, and it idles smooth as glass. I'm running ethanol-free, so fuel quality is not an issue, but I am just not sure whether it's timing or fuel-delivery related. It also stumbles occasionally when it's still cold, but once it warms up, it runs fine besides the pinging. I won't be able to work on it for at least 2 months, because I just came back to school for the last chunk of the spring semester. So there's no rush, I just want to know what to look for. Thanks for the input.

 

[Aspen500]

I would first make sure the EGR system is functioning. If it isn't, you can get pinging at part throttle.
Possible also the ELB processor has a problem and giving incorrect ignition timing. Make sure the vacuum hose is hooked up to it and that it is giving a vacuum signal.
A lean condition can do it too. Dirt in the carb, etc. Just remember that 90% of carburetor problems are the ignition
Question. Has it been doing this for a while or did it suddenly get warm where you live and they still have winter blend fuel in the tanks. That also can cause pinging on a carbureted car. Even summer blend fuel isn't like it used to be. It's made for fuel injection and the high fuel pressures and carbs with 6 psi pressure and fuel in an open bowl don't always get along well with it.

 

[89.Fifth]

I would check your timing, both initial and total. Also check to see that a vacuum advance carb hasn't been put in place of the lean burn carb. Running it that way can cause pinging when both the computer and the distributor are providing advance.

 

[rcmaniac791]

It's been doing it awhile, this isn't the first year. Does it worse in warmer temps than in cooler temps. Last year it was not so much pinging as it was dieseling. I'd be driving and all of a sudden the thing sounded like a 12 valve Cummins. I threw in a different set of plugs and that was fixed. The carb and dist. are all original, apart from the normal tune-up stuff. I wish that it were as easy as making the a/f ratio richer. Do the lean burn carbs have a mixture adjustment?

Also, the EGR has probably never been touched. I can check that when I finally get a chance. Seeing that this thing was owned by by elderly folks, I seriously doubt it ever saw anything above 2000 rpm until I got it.

 

[Cordoba1]

You can try "red neck timing": Just loosen the distributer hold-down bolt just enough so you can rotate the distributor. Retard the timing a tiny bit, and try to replicate the pinging. If you've eliminated it, and the car is driving okay, re-torque the hold-down bolt, and you're done! If the car bogs down on acceleration, you've retarded too much, advance the timing. If the car pings while accelerating, you have the time set with too much advance. As a rule of thumb, you're goal is to get as much advance on the timing without initiating ping. Bog Down = timing too late. Ping = timing too early.

 

[Jack Meoff]

You can try "red neck timing": Just loosen the distributer hold-down bolt just enough so you can rotate the distributor. Retard the timing a tiny bit, and try to replicate the pinging. If you've eliminated it, and the car is driving okay, re-torque the hold-down bolt, and you're done! If the car bogs down on acceleration, you've retarded too much, advance the timing. If the car pings while accelerating, you have the time set with too much advance. As a rule of thumb, you're goal is to get as much advance on the timing without initiating ping. Bog Down = timing too late. Ping = timing too early.

Exactly the way I setup my Fifth.
I advanced as far as I could without pinging. I'd basically do exactly what Cordoba 1 said and then do a sort of brake stand. Hold the brake and put the engine under load. No pinging? All is well.

 

[Darth-Car]

What octane of fuel are you running? You might just need to step up a grade level of fuel. Darth Car seems to like the mid grade 87 octane Shell stuff.

 

[Aspen500]

That's a good point Darth. The 87 octane of today isn't the same as 87 octane of 25 years ago. My dad has to run his '62 Fury on mid grade 89 octane now days.

If it was driven by eldery folks, there's a VERY good chance the EGR system is plugged up with carbon. Actually, they used to plug up no matter how they were driven. Shouldn't say USED to, still run into it on newer cars that still run an EGR system, especially diesels.

 

[Jack Meoff]

The highest octane I can get here that's ethanol free is 91. That's all I run in all three of my Mopars.

 

[rcmaniac791]

--- Post updated ---
--- Post updated ---
Pretty sure it is the EGR valve. I pulled it off tonight, and it's the original; still has the pentastar sticker on it. Surprisingly, there is very little carbon at all, but the vacuum diaphragm is shot. I manually opened the valve, stuck my finger over the vacuum port, and the valve closed. So off to NAPA I go...

Also, I'm planning on recording the repair. I can post it if anyone would like to see.

 

[Justwondering]

I would like to see the egr valve repair.

 

[AJ/FormS]

Well you might not want to hear this, but a fully functioning EGR system, can actually make pinging worse in an older high-mileage engine. Now the ruptured diaphragm may have contributed to a lean A/F. The EGR system is supposed to dump a small amount VERY hot exhaust gasses back into the intake, from where it goes back into the cylinder, to take up space.(Actually it's supposed to reduce NOx, to reduce pollution. Pollution which actually comes from the reduced compression ratio, which was introduced because....yadyadayada.) Anyways the hot gasses can wreak havoc on those hi-mileage engines. Many times this can be traced to excessive carbon deposits in the chambers. So you probably need to try and flush those out. You can purchase products to do this. Some go into the oil, some the gas, and my favorite is the stuff you pour down the carb throats. It is by far the fastest acting. After your chambers are cleaned up, your problem may disappear, and the fully functioning EGR will be a non-issue.
Be advised tho that even with a fully functioning EGR valve, the system may still not be fully functioning.This is because the passages inside the intake may be fully or partially plugged with carbon. There is an easy test for this.With the engine idling,and a functioning valve, just apply vacuum to the diaphragm. If the passages are open, the engine will usually stall. If the idle changes not a bit, then the intake needs to come off, and the passages cleaned out.This involves a lot of chiseling, and then a trip to the engine shop for a caustic bath.You absolutely don't want those carbon pieces getting into the chambers.While most of them might harmlessly pass through, it is possible for some to lodge in places they can do damage.
One of the biggest causes to pinging (after too much timing),is chamber temperature.Chamber temp is principally controlled by correct A/F and timing, but the cooling system also plays an important roll, as does the inlet air temperature.So you need to verify those systems are working as well. If the carb is sucking hot air up through the carb heating system,fulltime, this will not be good. So in addition to checking the cooling system temp, it is very important to verify that the carb is getting fresh cold air.
If your engine is covered in dirt and oil,give it a pressurewash.
Verify the exhaust system is properly functioning. If it is restrictive, it will heat up the chambers real quick.
Make sure the car rolls easy, as in the brakes are not dragging and the tire pressures are up.
That's all I can think of for now....

 

[BudW]

In Oklahoma, we have gremlins here.

They like to poke underneath the hoods of our cars, and mischievously unplug the EGR valve hose and plug it with items (sometimes screws, sometime sticks, I’ve even seen ball bearings used).

I’ve yet to catch one of these gremlins yet, but they are out there.
Actually, if I catch one, I might pass him (or her) a $20, under the table.

I’ve heard rumors these gremlins don’t care too much for other states, like California, for example.
They are, however, are plentiful here.

BudW

 

[MiradaMegacab]

Let's say your car is sitting for a couple of days. Upon start up, do you notice any blue smoke out of the tail pipe?
If your valve seals are bad, oil is getting into the combustion chamber. Oil burns hotter than gas, resulting in pinging AND DIESELING.

 

[rcmaniac791]

Sure enough: the pinging is worse. but on the bright side, my fuel economy is much better.

It doesn't smoke at all, and the engine only has 60,000 miles on it. It does diesel occasionally. There were very little carbon deposits in the EGR chambers, and the old valve was clean underneath, just dark. I'll post the video once I get it edited. But it idles really rough now. and it pings pretty significantly at about 5-10% throttle. Open it up anymore and it runs great.

 

[AJ/FormS]

If by dieseling, you mean it runs on after the ignition is shut off; this proves two things, 1) the throttle is too far open, and 2) there is hot glowing carbon in the chambers, which is lighting the mixture that is still coming through the carb. This very same carbon is likely to blame for the pinging under acceleration, as it is also probably lighting the mixture before the sparkplugs do.

 

[rcmaniac791]

there is quite a bit of carbon in the cylinders on the pistons. I'll probably try seafoam, but have you guys had any luck with anything else?


and by dieseling, I do mean running after I turn it off.

 

[Darth-Car]

I have direct injected Seafoam into cars through the vacuum booster hose, in the past; but you have to give it very small sips at a time. Frankly Seafoam is good stuff at breaking up the carbon, but if you have that much in there you must be careful. If it breaks off in to large of chunks you can do some real engine damage with large chunks of carbon suddenly moving around in a motor. -----Extreme Caution Advised with the Seafoam idea.--------

 

[AJ/FormS]

They make specific additives; some for in the gas,some for in the oil and some to pour down the carb under specific instructions.The latter are the fastest acting.

 

[rcmaniac791]

What about Marvel Mystery Oil? Apparently you can add it to your gas/oil and it will fix stuff.

Also, call me crazy, but this is not the first performance issue that I've had. It's always has a misfire, never quite idled right, and bogs/stalls at part throttle sometimes. I don't have any vacuum leaks, and most of the gaskets on the engine have been replaced. The carb has been cleaned out, fuel pump checked, fuel filter replaced, on and on and on. I've done a full tune-up a few times, and even with all the work, she never quite runs right. I've been wanting to get rid of the Lean-Burn for some time, so I've decided to just go ahead and do it. I have the funds, and I have an MSD distributor and new Carter 2bbl on the way. I'd just feel better about getting rid of that computer. I know that mine is probably fine, but I really don't want to have to worry about the possibility of it crapping out on me. Will a Lean-Burn swap fix my issue? maybe-maybe not. But I really just want to get rid of that variable. I do know that cleaning out the engine (internally) is also important, and I'll be doing that too.