Well I posted this up before and I figured I would again since I didn't get that many replies last time. Anyways, my car has been pinging at WOT fairly badly for months now. It seems to get worse with the lower octane I use. I always run 91, which is the highest you can find in CALI unless you go with 100, which is like 4.50 a gallon. I replaced the MAF as sensor a few months back but it still pinged. It stopped throwing the code 34 for a few months and then in the last couple weeks its started doing it again. Now my main concern is this pinging. Whats going on? What would be the major cause of such a thing? I have checked the timing a few times and its set at the factory specs. I do not want to retard it anymore cuz the car doesn't do crap as is. It feels very sluggish and gets off the line decent enough, but I cannot put my foot into because of the damn audible pinging. I don't want to damage anything more than it already may be. ANY idea fellas? Im replacing my gas tank/fuel pump this month, Hoping that could be the problem, a weak pump. Any other suggestions? Thanks fellas

Will

 

Trickster has a MAF trouble shooting chart. Do a search under his name.

Or, if he would be so kind, he might post it (actually, i think its in 2 parts)

But on a side note, dont replace the pump if you dont have to. Replacing parts hoping that they fix things is never the best method to fix a problem.

 

Yeah hes been very helpful today, maybe he can chime in on this topic as well

Will

 

Well, I've had a new walbro sitting in my toolbox for a few months now. And with this pump being 15 years old, im replacing the tank anyway, why not save a headache later on down the road

Will

 

Have you tryed just changing the fuel filter?

 

Yes, it barely has 8k miles on it

Will

 

I have a problem which is close to what you are describing...

When I first bought my car, the timing was at 12* btdc, and whenever I gave it any gas, it would ping like crazy. WOT was terrible, sounded like i was going to blow somehting up.

I turned the timing down to 6* and it got better, but I still get some pinging sometimes. I have changed my PCV and it seemed to help a tad... I read somewhere that if you have leaky valve seals, bad rings, or a bad PCV it can force oil into the combustion chamber, which lowers the octane of your gas, causing ping. I don't know how true this is... but if you have a lot of miles on your engine like I do... it makes sense, if it is indeed true.

My valve seals leak, which is shown when I start my car once it's warm by the big blue cloud. And I believe my engine is the stock engine, with 177k on it, so I'm sure I also have deposits everywhere, and probably worn out rings, so I would get a fair amount of oil in the chambers as it's running.

That's all I have on the pinging... what kind of mileage do you have on your engine? Do you think you're burning oil?

Another thought.. maybe the outter ring on your balancer has slipped... I tried to check mine, but I never found out where the line was supposed to be in relation to the keyway. A good idea is to locate TDC with a TDC Stop, then check it against your timing mark and see if it lines up. I believe mine is right, but i'm not totally sure.

Hope I said something helpful or useful, and if anyone has any information about anything, or any proof/facts about what I said, please let me know.

 

That's at least one of the easiest things to check for. Is there blue smoke coming out of your tailpipes?

Edit: Nevermind. It's late and I can't read.

 

Yeah she smokes a pretty good puff on cold starts. Motor has approx 70K, it is the rebuilt stock block. I dunno why the motor was rebuilt in the first place, but I would prolly guess from the way its running and all the temps probs, it might have blown a head gasket at some point. I dunno if I am really gonna invest alot of money into this motor. Its been pinging like this for a long time and I dont wnana mod the hell out of it only to have it blow a few K down the road. Thanks for all the help guys, keep the ideas coming. I am losing FP @ wot as well so this is a major factor.

Will

 

Well, if you're burning oil...

You can limp along with that engine for a while, but chances are you've got a damaged gasket somewhere. Keep a really close eye on the oil and water as long as you drive that engine; since you're burning oil, you'll have to top it off periodically and change it more frequently than normal. Also watch very closely for metal filings in the oil.

As for the bottom end of the engine, when you rev it up do you hear a lot of rattling? Easy way to check is to leave the transmission in park and just run the engine up to around 3-4000 RPM for a second or two. If there's a lot of rattling noise, beyond the pinging at WOT that you've already described, you've got loose rings on the crankshaft.

So basically, if it's only pinging, you may want to pull the top end of the engine apart, clean things up, replace the gaskets, and maybe give the heads a valve job. If it's rattling as well, it's likely grinding metal off the rings and will need a total rebuild somewhere down the road.

There are a lot of bad rebuild jobs out there, my car had one (at least they didn't screw up the bottom end, but they did quite a number on the heads...)

 

She only makes noise under a load, in gear. I could rev it up to 6 all day in park, and nothing out of the ordinary will be heard. I had planned a heads/cam this summer, but fear the pinging/detonation might have damaged the pistons. If this is so, I don't know what I'll do. If they turn out to be cherry, I will just flip this motor for what its worth, and have some fun with it while I build a replacement.

As far as oil CONSUMPTION, I change it every 3k on the dot, and the car burns almost nothing, the line stays well up to the fill, barely gets 1/4 of a quart below in the 3k mile period, and it stays relatively clean, compared to some I have seen

Thanks fellas, keep em comin!

Will

 

just a stab in the dark, is the knock sensor in good order? If it is bad, i know it can transmit false knock which in turn unnecessarily retard the timing. Perhaps you have pre-ignition going on?

As for the puff, replace the valve seals if its only at startup. If its also at WOT, rings may be taking a turn.


Crayz9000,
If by "loose rings on the crankshaft" you mean bearings. There is a big difference between knock and pinging. and thats a far cry from rattling.

 

You know, I've always thought about replacing the KS, just slipped my mind with all these other sugestions being thrown out there. I also heard some people inadvertently replace it with a 5.0L KS and it can severely hurt performance due to the different harmonics of the 305 and the 350. Worth a shot, im replacing a buttload of stuff this month anyway.

How much of a job are we talking about to replace the valve seals? If I am gonna do a heads/cam swap, will this get taken care of anyway? And the rings.... can you elaborate on that a little more. thanks man

Will

 

If you do a head/cam swap, yes the valve seals are going to get replaced.

Only worry about the piston rings if you blow blue smoke at WOT. If its just on start ups, valve seals should do it.

 

Yep, she only smokes when fired up cold. My fuel pump though is very weak it seems, as I am not hearing it prime the lines at all. Im replacing it as well with the new gas tank this week. But it takes a good 2-3 tried before it cranks over in the morning. I hope I don't toast the starter!

Will

BTW valve seals are in the heads yes??? im still learning!

 

yep valve seals are in the head. They are located under the valve spring. They basically form a seal to keep the oil from dribbling down the stem of the seal. If you have bad seals, is what happens, as the car sits, oil dribbles down the stem and makes its way to the combustion chamber so that on the initial firing of the chamber the oil burns, hence the smoke.

If it takes a good while to start up, yes, it sounds like your either a.) lacking fuel pressure or b.) dying fuel pump. If the filter is that fresh, i would point fingers more at the pump.

 

Good stuff, so I am guessing a set of assembled, oh say vortec heads would already be complimented by a fresh set of seals? Thanks man

Will

 

Just wondering if anyone heard anything about what I posted eariler up there... Oil Causing Pinging?

I burn about 1/2 quart every 1000 miles, and I change it a little before 3000 miles. It leaks a few drops, but I believe most of it is being burnt. I don't plan on putting any money into this engine, since I am planning a 350 soon (just needs a rebuild, cam, and head rebuild... then it'll be in) so I was wondering if any of these "OIL TREATMENTS" will do anything at all for the seals? I figure they wouldn't really hurt my engine, and if they can cut back on some of the valve seal leaks, i'm up for it.

 

I run oil "treatment" every oil change, and she still smokes like a b!tch

 

As good as vortec heads are, keep in mind you will need a special TPI base plate. Vortec heads dont share the same mounting patterns as factory SBC heads like yours. They have raised runners that dont seat properly with a standard SBC intake. They also only use 8 intake bolts whereas yours requires 12.

Also, vortecs need machining to see lifts above about .450". Otherwise they run into guide-retainer clearance issues. Theres a few other small issues, but the intake and lift are the biggies. Take a peek at your cylinder head casting numbers. They are under the valve covers, between the valve springs. Depending on the casting numbers, it might be most beneficial to do some DIY port work.

 

... right, I'm not thinking here... Gah.

I mainly work on computers, so I have all of that jargon down. I don't work on cars quite as often, so I don't have that jargon down perfectly, but I try to at least have an idea of what the car's doing even if I can't adequately describe it...

 

Hey, as long as you know that its a "bad sound" your in good shape. Being able to describe it in a manner that someone else udnerstands so they can help diagnose the problem, thats the other part. Your description was fine. You got a basic noise and the basic area mentioned. I know several people who couldnt do that much. youre on the right track.