Strange pinging sound on acceleration and uphill - Toyota Nation Forum : Toyota Car and Truck Forums

archfubar · 08-28-2009, 12:16 PM

Hello all,

I'm driving a 1999 toyota camry - it's a 5 speed with a 4 cylinder engine.

Lately I've been noticing that when I accelerate hard, particularly when going up hills, there's some kind of pinging sound. I'm calling it a pinging sound, but I'm not sure if it's more of a knocking sound, I don't have the ear to know the difference. Anyway, it's especially noticeable if I'm changing gears while going uphill, particularly from 2nd to 3rd (while the clutch is engaging). I want to say it's also related to the warm weather, but it could just be that I only have the windows down in the warm weather and that's what allows me to hear it.

Anyway, it definitely seems to be related to the car being warm. I don't notice it when the engine is cold. I thought maybe it had something to do with the exhaust, but I checked it pretty thoroughly and didn't see any loose heat shields or anything like that. Then I noticed that a couple of the spark plugs looked kind of crappy and I put in a new set, but that doesn't seem to have changed anything either. Finally, I'm running a complete fuel system cleaner through the gas tank right now in the hope that the problem is carbon buildup in the combustion chamber, but that doesn't seem to have had much effect yet, if it's going to have one.

The only other 2 suspects I can think of at the moment are the EGR valve and the spark plug wireset. I haven't done anything with those yet, but I'm thinking about checking them out.

If anyone has had a similar experience, though, and has any ideas on what it might be, I'd greatly appreciate it, because I'm not sure what to make of it at this point.

Axxis8203 · 08-28-2009, 12:45 PM

try stepping up to the next higher octane rating gas when you next fill up and see if that reduces or eliminates the problem. since you are running a fuel system treatment currently the noise may go away for a bit as these treatments increase your octane rating...

most knocking and pinging is caused by predetonation, so if this is the cause then the higher octane gas confirm it, and we can go from there

Bdub215 · 08-28-2009, 09:30 PM

Cheap gas. use premium be it 91 or 93 and the problem will go away.

JCamry94 · 08-28-2009, 10:07 PM

The 4 cyli is OKAY on 87 octane, so I'm not sure why that would be the problem?

I say seafoam it really nicely, throw some 91 or 93 in the tank and hopefully it will go away.

flyeri · 08-28-2009, 11:06 PM

Have two things checked.
1) Ignition timing. You need a timing light to do this. I am making an assumption there is adjustment on your 1999. It may be completely controlled by the ECU.
2) Knock sensor. Retards timing when ping is detected. I'm pretty sure yours has this and it can go bad.

Running higher octane gas will help but does not fix what is not adjusted properly or broken. Seafoam will not fix it either. The engine is made to run on 87 octane and should not ping.

Mike Gerber · 08-29-2009, 08:37 AM

You were probably right with 1 of your most recent assumptions. Check the EGR valve and it's related piping for being clogged with carbon. Clean and remove the carbon as necessary.

Mike

archfubar · 09-08-2009, 10:25 AM

Hello again all,

I appreciate all the suggestions.

So, I tried removing the EGR valve. It turns out that the two bolts that connect the valve to the pipe that goes to the engine are basically rusted on completely, so there wasn't really any way of taking out the valve by itself. So I unbolted the pipe from the engine and then took off the other two bolts that hold the EGR valve in place and removed the whole thing as a unit in the hope that if I could get a better grip on those rusted bolts I could detach the valve.

To make a long story short, I wasn't very successful, and I really can't say for sure if there was a lot of carbon buildup there. I just tried to clean it off with some carb cleaner as best I could and put it back on.

I haven't really ruled out the EGR valve as the source of the problem, but I'm thinking I should at least try to run some seafoam through the intake before trying to replace any expensive parts. I've never actually done it before, though, and I'm not sure what the best vacuum line is to run it through. If anyone could offer any tips on doing it right in my camry I would greatly appreciate it. I've heard you can run it through the line from the PCV valve, but I don't want to go sending stuff through my engine if I don't know exactly what I'm doing.

Thanks for any and all help.

Jimnist · 09-08-2009, 12:07 PM

Check spark plugs and ignition leads too. Under high loads, weak spark can cause pinging. Happened in my gen 2, had oil on the spark plug for cyl #4 and would ping when going up a hill.

But yes, bumping up the quality of fuel will improve it.

archfubar · 11-20-2009, 08:28 AM

Hello again all,

If anyone's interested in the outcome of this whole thing, I guess I'll keep the story going. I ran some seafoam through the intake in the hope that the pinging was primarily due to carbon buildup in the combustion chamber. Well, after doing that it seems like the car is running a little smoother, but it doesn't seem like the pinging is gone.

This means I'm back to the EGR valve and/or spark plug wires. I'm leaning toward the EGR valve, but, if you'll recall from one of my earlier posts, I couldn't actually disconnect the valve from the pipe it's connected to (the one that goes to the exhaust manifold). For lack of a better term, I'd say the screws on the bottom are melted to it. The rust has not only frozen them in place, but it's also managed to take away any trace of the hexagonal shape they once had, so I really don't know what to do with them. If I want to get a chance to look at the carbon buildup (or to replace the valve) I need to be able to get in there, but I'm not sure what the best approach to removing those screws.

If anyone has any experience with that sort of thing, I'm very open to suggestions.

Kenny_McCormic · 11-20-2009, 02:18 PM

Working properly the knock sensor should pick up on this and retard timing.

hill8570 · 11-20-2009, 03:21 PM

Quote:

Originally Posted by Kenny_McCormic

Working properly the knock sensor should pick up on his and retard timing.

OTOH, this being an OBD-2 rig, it would take a really strange failure mode of the knock sensor to not throw a code. Doesn't mean it can't happen, 'tho.

archfubar -- is the MIL (check engine light) on?

***JohnGD*** · 11-20-2009, 07:47 PM

If you pull vacuum on the EGR valve, does the engine run rough or quit? I think you can borrow the vacuum pump under Autozone's free loaner tool program.

Have you ever replaced the fuel filter on this car? One thing however, is that the flare nut can seize on there, resulting in a twisted fuel pipe if you have rust problems. I wish Toyota stayed with the banjo bolt.

If you need to replace the spark plugs I'd use NGK Iridium-IX. It's listed in the NGK catalog for that model (but not the Laser Iridium for some reason).

archfubar · 11-22-2009, 07:52 PM

Thanks for your input, everyone.

As far as the knock sensor goes, I performed the check my Haynes manual recommended, which basically involved checking for resistance using an ohm meter. It passed that test - again, not to say there coulidn't be anything wrong with it, because I'm sure it's not a simple part.

I have changed the fuel filter, although I guess at this point it's going on 30k miles since I did it. I should probably do it again, but I did run into that problem you mentioned, JohnGD, where it's a pain to get it off without twisting the fuel line, so I'm not overly excited about doing it again.

Finally, there isn't any check engine light. I almost wish there would be so I'd have something more concrete to work with. Having said that, the car hasn't given me any significant problems, I just know it shouldn't be pinging and I don't want to be doing any damage to the engine that I can avoid.

I'll see if I can get my hands on a vacuum pump and check on how the EGR valve fares against that test.

Thanks again for the input, and if this response gives anyone else any ideas, feel free to keep them coming.

dustoff · 11-22-2009, 08:10 PM

What fuel system cleaner did you use?

EDIT: The first one you used, not seafoam.

Use cleaners that have polyether amines. They are very effective. The ones I know that have this are Techron concentrate and Gumout Regane. I personally used Gumout Regane since it was cheaper than techron. It's a yellow, clear bottle. The detonation was completely gone after 2 tanks of gas.

***JohnGD*** · 11-22-2009, 08:12 PM

If you put an advanced OBD-II reader on there. Look at the short-term fuel trim. If it's pegged max add, I'd consider changing out the fuel filter and see how it goes. I know, I wish Toyota stuck with the banjo bolt connection. But I guess the flare is cheaper to manufacture.

Autozone has free loaner tools that includes the MityVac vacuum pump.

Also, maybe tee into the hose at the EGR valve. Raised the RPM and see what the vacuum reading is at the valve. I vaguely recall helping one owner who had a knocking problem. And the signal ports in the throttle body was plugged up from a prior cleaning. So the EGR valve wasn't getting the vacuum signals to open. You might want to check that too.

Quote:

Originally Posted by archfubar

I'll see if I can get my hands on a vacuum pump and check on how the EGR valve fares against that test.