Chevy 5.3l V8 & pinging

[drm7]

I just recently bought a 2001 Suburban w/5.3l V8. It had 45,000 miles and runs great. In just over 1000 miles the oil is still golden honey colored. The 2 cars I bought new can't do this. They turn the oil black pretty fast. Anyway, the manual states to use 87 oct and that light pinging is "normal". To me it seems this thing pings too much. I just ran 425 miles with 1 2/3 cans of SeaFoam in the tank hoping if it had carbon that the SeaFoam would get it. Didn't seem to have any affect. Any other 5.3 owners out there have this? This thing locks the TC on the trans at like 1500 rpm @ 45-50 mph. This seems a bit low because when you start applying more throttle it starts pinging. Can this be lugging it? Should I be worried? I need 200k+ outta her.

BTW, on the 425 mile trip I got 19.4 mpg!!!

This is nearly what my 4.0l V6 Ranger got on this type of trip.

I am 1000 miles into my Auto-RX and will go 2000 or so rinse then syn (M1 5w30 @ 5-6000 OCI).

 

[Ugly3]

Ready - Fire - Aim

You need to try more chemical additives before you diagnose the problem.

 

[tpi]

The low RPM, locked converter, and timing advance to the point of ping are the reason you're getting 19.4 MPG. A 5 liter engine @ 1500 RPM pumps the same volume as a 2.5 liter engine @ 3000 RPM.

Check and see if you have any codes set, and try another carbon treatment. Try another brand of fuel.

If not, you're looking at the nature of the beast. This is very common to squeeze out MPG. The ping should be light in nature, not a heavy rattle. My '04 Camry did this nearly from new, before the engine could have developed carbon.

[ September 26, 2004, 10:02 AM: Message edited by: tpi ]

 

[Mike_dup1]

I drove a 1999 5.7L k2500 subruran at work for over 100,000 miles. I first heard it ping when it was new and was still pinging when it went to auction last fall.

You are going to have to get used to the pinging as there is no cure for it. Fuel econony standards, emissons and fuel quality all affect his. Heck my 2002 Firebird with the 325HP LS1 pings on premiun fuel and I have used every major brand, BP, Mobil, Shell, Marathon and no-name, still pings under certain conditions. Car was checked out and all checked normal, 18,800 miles. 99.9% of the vehicle on the road ping to some extent.

 

[Jim Spahr]

Check the timing. See if it is set correctly. If it is, try another brand of gasoline. If that doesn't help, try a higher octane level. Check EGR system because that will also make it ping if it isn't working properly.

 

[Ugly3]

Mike - 99.9% of the vehicle on the road ping to some extent.

Horsefeathers!

 

[sbc350gearhead]

You could try running FP for a few tanks. Many members say that it has fixed their pinging problems, or has allowed them to use lower octane gas.

 

[Gary Allan]

quote:

---

Mike - 99.9% of the vehicle on the road ping to some extent.

Horsefeathers!

---

It's twew ..it's twew!!!

..or rather...

knocking is considered "normal" in contemporary engines ..and has been considered normal, to some extent, for over a decade. Excessive knocking is not normal.

 

[tpi]

quote:

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Originally posted by Ugly3:
Mike - 99.9% of the vehicle on the road ping to some extent.

Horsefeathers!

---

I won't go so far to say 999 vehicles per 1000 ping. But I bet his statement is more true than false.

We're talking a barely audible ping at low RPM under fairly low loads. This is most noticeable in "torque" engines with big pistons. You have to be listening for and tuned into the sound. If you have a van, try it with engine hatch off.

The tuning that makes this ping is the same reason these vehicles get good HWY MPG.

Additionally many vehicles ping by design. The PCM runs an intentional check of the knock sensor occasionally. It ramps up the timing expecting to hear a ping. If it doesn't hear one, it assumes the knock sensor isn't working and throws a code.

I don't think the 5.3 uses a distributor and the timing isn't adjustable. The EGR system is monitored and if it is out of spec. it should throw a code.

I think these engines just have a tendency for a little light ping. Cleaning carbon may help, different gas may help, but don't expect miracles.

 

[drm7]

Hey Ugly, thanks for the suggestion. I bought techron, fuel power, Slick 50, etc. I'm sure it'll fix it right up. a$$hole.

Everyone else: thanks! My Cherokee used to ping ever so slightly in the same conditions. This thing just pings more than I'm used to. Once you increase throttle enough it seems to go away. I've tried a couple differnt gas stations and even went to 89 oct. I don't want to feed the beast expensive gas if I can help it. The manual states to use 87 and that pinging is normal. Maybe so with these. I've not owned a Chevy in years and my Fords never pinged. Like I said, I just bought it a few weeks ago and I'm in the process of getting all the maintenance items taken care off. SeaFoam for carbon/injection cleaning. I plan to get the trans / brakes / radiator flushed etc. I'll have to get used to pinging I guess.

 

[Terry]

I agree in a perfectly maintained 5.3 FP may be the answer as carbon formation in these engines is formidable.

Properly interpreted Oil analysis would help diagnose the cause.

Plugs,PCV, EGR,coils that are failing slowly undetecded by OBDIII, and finally the most simple problem of all, Air filter that is loaded with fine dust , may look clean at initial inspection but is slowing air flow.

 

[tpi]

quote:

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Originally posted by Terry:


Plugs,PCV, EGR,coils that are failing slowly undetecded by OBDIII, and finally the most simple problem of all, Air filter that is loaded with fine dust , may look clean at initial inspection but is slowing air flow.

---

Plugs: Failing plugs cause misfire, not ping. If the plugs are wrong part # (incorrect heat range) could cause ping.

PCV. Unlikely to cause ping. I guess it could stick open and upset mixture, but you'd notice it in the idle, plus it should throw a code. I've never seen this happen.

EGR. Yes can cause ping with too little EGR flow. Should be weeded out by OBD, but EGR on the edge of spec could push ping above tolerable limit. This one is the most logical.

Air filter: Unlikely to cause ping. The throttle is slowing air flow. Air filter restriction is most problematic at full throttle. This leads to reduced cylinder filling and lower output. If anything a clogged air filter will reduce the tendency to ping.

Failing Coils: Misfire or dead cylinder, not ping.

 

[Terry]

tpi, I think you missed this part of my comments;
that are failing slowly undetecded by OBDIII

I am ID'ing these issues DAILY using UOA's.


Causing exactly what drm7 is describing.

And correcting them without guessing since no code is displayed.

 

[tpi]

quote:

---

Originally posted by Terry:
tpi, I think you missed this part of my comments;
that are failing slowly undetecded by OBDIII

I am ID'ing these issues DAILY using UOA's.


Causing exactly what drm7 is describing.

And correcting them without guessing since no code is displayed.

---

Could you educate me as to the mechanism of how a clogged air filter, slowly failing coil, or failing spark plug of the correct heat range can cause an engine to ping or detonate?

 

[Terry]

tpi, yes and very simple, any of those items allowing a incorrect rich situation, due to incomplete combustion will cause the ECM to artificially lean through timing, MAP/MAF,injector operation and cause pinging. Not always hitting the threshold of code display.

Partly failed defective individual coils are becoming a real issue since they are being employed for improved efficiency. While allowing smooth operation they can be inefficient enough to affect fuel dilution, reduced MPG, increased CC deposits, etc. Many/ most times not being alerted by CEL/SEL from what I am seeing and hearing from my customers.

GM,SAAB,VW,Audi,are notorious for these issues in the last 3 years.

 

[tpi]

quote:

---

Originally posted by Terry:
tpi, yes and very simple, any of those items allowing a incorrect rich situation, due to incomplete combustion will cause the ECM to artificially lean through timing, MAP/MAF,injector operation and cause pinging. Not always hitting the threshold of code display.

---

Why would a misfire show the ECM (via oxygen sensor) a rich condition? Incomplete combustion (poor ignition) by definition would mean some of the *oxygen* wasn't combined either. I don't see how the oxygen sensors would get a rich signal under those circumstances, in fact it would see *more* oxygen.

 

[Terry]

tpi, computer doesn't see it as a misfire ( non fire) it sees less spark intensity. Thus the problem.

The coils don't put out enough hammer to drive the nail !

 

[sbc350gearhead]

Wouldn't some of those conditions cause incomplete combustion, leading to carbon deposits in the CC, which of course......leads to ping?

 

[Patman]

quote:

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Originally posted by Mike:
I drove a 1999 5.7L k2500 subruran at work for over 100,000 miles. I first heard it ping when it was new and was still pinging when it went to auction last fall.

You are going to have to get used to the pinging as there is no cure for it. Fuel econony standards, emissons and fuel quality all affect his. Heck my 2002 Firebird with the 325HP LS1 pings on premiun fuel and I have used every major brand, BP, Mobil, Shell, Marathon and no-name, still pings under certain conditions. Car was checked out and all checked normal, 18,800 miles. 99.9% of the vehicle on the road ping to some extent.

---

Mike, there are a lot of good shops in Michigan which can dyno tune your LS1, and bring your spark advance curve lower so you don't get pinging like that. The LS1 tends to come from the factory with too much timing advance, so a good tuner will set it lower to eliminate this problem. The knock sensor on the LS1 just simply doesn't work fast enough, or agressively enough to eliminate pinging. Tons of LS1 owners hear it. I get some myself, even though the C5 has two knock sensors vs one in the f-body LS1. Also, a lot of LS1 owners have found they get more pinging with Sunoco 94, due to the ethanol in it. I was talking with a friend of mine in Michigan yesterday who did some testing a few years ago with different fuels in a few different LS1s, and they found Sunoco 94 was one of the worst for showing knock retard, while Mobil 93 was one of the better ones.

I was getting no pinging at all this weekend at the dragstrip while running Shell 93 that I got in Michigan. On the way home I topped up with Meijer 93 octane, and then later topped up with a few gallons of Amoco 93 just before I crossed into Canada, and even at full throttle and over 100mph speeds, I heard no pinging (although it was also pretty cool out at the time too, only 50 degrees, so that effects it a lot too, as it's less likely to detonate in cooler weather)

 

[TheTanSedan]

1500-rpm in that vehicle, at that speed, is similar to "lugging"; needs more rpm to avoid situational pinging. Tight OEM tuning, as above.

Are tires same as OEM recommended in height? An increase of even an inch can exacerbate this problem.

We have a 2001 JEEP Cherokee (L6-242) that is in a similar situation. I went to larger height tires a year back. Am pleased in all ways, BUT rpm is lower at any given speed. I simply keep it out of overdrive until I hit 60-mph, or am going to be traveling a good distance. Around town, on/off highways, 3rd is great (until I change gear ratio to numerically-higher one).

I'd certainly check what is recommended above.

I have had excellent luck with FP, LC and A-Rx. (Two UOA's last summer on this vehicle; see Terry and Franks comments).

UOA pays for itself!