Pinging

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May 9, 2006
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Sandy Eggo
I have searched and read trying to find a definitive answer to the cause of pinging. What causes pinging specifically to the 1FZ-FE? Anyone know? Heat, low fuel pressure, fuel quality, timing, sensor failure, EGR system (dirty), age? Combination of things?

I have been experiencing excessive pinging lately. My timing IS NOT advanced and is right on. I know that pinging can cause damage. My 40 lost the #6 piston due to pinging (detonation?). Adding higher octane fuel and/or additives can help, but not actually correct the problem.

Result of pinging::mad:
192626987_2a791348f5_o.jpg
 
Hhmm,
Tricky questions.
Nice pic by the way. Is this yours or whats the story behind it.
I am not expert but I know that my 80 tends to have a little pinging in the hottest summer months. I have been told that switching to higher octane helps and I did so a couple times. It improves alittle after the computer adjusts. I ended up running a couple bottles of redline fuel system cleaner. Pour in the gas for a tankfull and noticed some improvement after. Its supposed to remove the deposits on the valves. End story is "from what I understand" engine pinging is caused by excessive carbon build up which causes premature detonation of the combustible gases on the compression stroke prior to spark plug ignition. So the routes people tend to go consist of:
1. Snake oil (seafoam, redline, marvel mystery oil etc)
2. New Spark plugs, distributor rotor, correct timing, clean out the TB, clean out EGR system, new air filter.
If you have pingin going on now in the cooler months then you have something very odd in deed. If you know that your timing is correct then I would run some seafoam through the pcv, run through some redline in the fuel and see if it improves. Next I would try autorx. If that does not get it then you may have a knock sensor gone bad though I would expect a code from that. I tend to believe that old O2 sensors can play a role in this pinging as well. Let us know what you end up doing and what the results are. But don't take my word for it search on seafoam, redline etc. and see what others have experienced.
 
I have fairly new cap, rotor, wires, air filter, and pcv. I advanced the timing a few months back but got pinging so I reversed it. The CEL came on shortly after that so I checked the timing again (prior to pulling the code). Timing was good. CEL was (is) related to the EGR system. Can't remember the code (it's the common one).

I know my EGR system needs work due to the intermittent CEL (it’s been the same code). I am going to do a little investigating tomorrow to see if I can determine the cleanliness of my EGR sys. If time permits, I’ll also check the throttle body for gunk. I would guess that my O2 sensors are original.

The picture is from my 40. I always had issues keeping the timing in check. One day, driving on the freeway, it started pinging really heavily. I tried to get to the next off-ramp to do some adjustments. Just before I was able to exit, the pinging turned into heavy knocking. I knew it wasn’t good. Don’t need to do the same thing to the 80!

293262928_140d07718d_o.jpg

293262933_73d3932c18_o.jpg
 
I have fairly new cap, rotor, wires, air filter, and pcv. I advanced the timing a few months back but got pinging so I reversed it. The CEL came on shortly after that so I checked the timing again (prior to pulling the code). Timing was good. CEL was (is) related to the EGR system. Can't remember the code (it's the common one).

I know my EGR system needs work due to the intermittent CEL (it’s been the same code). I am going to do a little investigating tomorrow to see if I can determine the cleanliness of my EGR sys. If time permits, I’ll also check the throttle body for gunk. I would guess that my O2 sensors are original.

The picture is from my 40. I always had issues keeping the timing in check. One day, driving on the freeway, it started pinging really heavily. I tried to get to the next off-ramp to do some adjustments. Just before I was able to exit, the pinging turned into heavy knocking. I knew it wasn’t good. Don’t need to do the same thing to the 80!

293262928_140d07718d_o.jpg

293262933_73d3932c18_o.jpg


I have the same problem with my 97 lx. I tried the higher octane but no go. I changed the cap, rotor, wires, plugs, air filter, pcv, o2's, retard timing, and seafoam in gas tank. Still I have pinging issues. Oh and I"m not having my CEL light pop on. My next fix was going to be EGR sys, New Cat's and maybe a fuel pump. I tell you it's been driving me crazy

Danny
 
I recently replaced my 02's and my pinging disapeared but it also cooled down so nothing definitive. I think my pinging is related to carbon build up in the combustion chamber not an easy thing to fix.

here is a post from another thread outlines most of the causes of pinging.

More advanced timing makes it more likely to detonate than less advance. But I would not set the timing to any less than the stock three degrees before top dead center, if you are already at stock then move on to something else.

Higher intake air temperatures make it more likely to detonate than lower intake temperatures, so summertime or other hot conditions you are more likely to detonate than in cool or cold weather, a snorkel or any other cold air intake helps here. The sock intake gets its air indirectly from the engine bay, OBDII reports have seen 30 degree drops in air intake temperature when a cold air intake is used, also a supercharger or turbocharger will drastically increase intake air temperature, an intercooler helps with this on forced induction engines.

At higher altitudes you are less likely to detonate than at lower altitudes

It is more likely to detonate with higher intake manifold pressure than lower, so the more skinny pedal the more likely it is to detonate, forced induction can increase intake manifold pressure higher still per throttle opening and can go above ambient (boost).

Lower octane gas is more likely to detonate than higher octane gas,

Higher compression ratios are more likely to detonate than lower compression ratios, shaving the head or block increases compression ratio. Also excess carbon on piston tops and the bottom of the head can increase compression ratio my decreasing combustion chamber volume. From all the heads that have been off we know that this motor likes to build up carbon, I think excessive carbon build up is an unfortunate side effect of an engine that lasts a long time. Large amounts of funk form the PCV and EGR to not help.

At higher general engine temperatures it is more likely to detonate than at lower temperatures. Overheating even if mild can lead to detonation, check your cooling system.

Higher engine loads can cause detonation,

Fuel cools, leaner mixtures or mixtures that does not atomize well will make it more likely to detonate so slow responding O2 sensors and poor fuel injector spray patterns can cause detonation.

Several instances of any of the above add up, So if you have pinging pick these off one at a time until you fix the ping,

basically what this all boils down to is the temperature and pressure of the intake charge the condition of the cylinder (hot spots carbon etc) as the piston approaches top dead center between the compression and power stroke, if that temperature and pressure go above what the fuel can resist the charge will ignite on its own before the spark,

There are supposedly differences between pre-ignition and detonation, they are related and both cause a ping to be heard, both shorten engine life and come from the same kinds things so I personally don’t really differentiate between the two,

here is my engines story, when I got my 80 I advanced the timing got a notable increase in power, I was using premium gas at the time, no pinging summer or winter for 2 years and about 50K miles. No problems, recently with the sharp increase in gas prices and a matching decrease in my income I tried running regular and mid grade I get pining during acceleration in both, but more so with regular especially in hotter weather, pulling away from a light in heavy Atlanta traffic after idling a long time with the AC on seams to do it every time. same with a fast food drive through.

I put the timing back to stock 3 degrees hoping to be able to run regular without ping, it helped slightly but it needs more, I know from compression testes and by looking with a bore scope that my cylinders have rather high carbon build up, this is probably my biggest problem, high temperatures here in GA add to the problem.

I use good gas and have used the dump in the gas type cleaners (Techron, Redline) , they can clean up dirty injectors and maybe have an effect on the intake valves and intake pockets in the head but seam to do nothing for the cylinders, considering limited funds I think next step will be a decarbonizes using water see if that helps, that or give up and just run premium until the head comes off.
 
Pinging, as I'm sure you are quite aware, can be caused by many different things. I suffer from pinging as well. IIRC, this issue has been kicked around on this board several times but there's never been a consensus "do this and the problem will go away". I tried the fuel treatments recommended, checked the timing, did an OEM parts tune up but no change. I've ordered an OBDII scan tool software online. When I get it, I'm going to hookup the laptop and see what that tells me. I'm hoping to see a "lazy" o2 sensor or the like. I'd rather not contine to throw parts (and money) at it.

I guess I'm saying I can't help you other than to say I think it is something of a common problem. If you figure it out, let us know the solution. Since I have the same symptoms, if anything interesting shows on the scan tool I'll post up as well.

Edit: I've always wondered about an injector not spraying properly. With most of these trucks over 100k miles, pulling the injectors to have them cleaned is probably money better spent then trying the $10 bottle of fuel additive every so often. I think people have had noticeable results when they've pulled injectors in most cases. I don't know that anyone has ever said it cured a pinging problem, however.
 
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I had pinging upon acceleration prior to my head gasket replacement. Higher octane gas did help (sometimes). After my head gasket replacement, I had a valve job done and injector service at Toyota. Pingings gone now. If you do plan to have your HG replaced.... Have your valves adjusted/replaced........
 
did they also clean the carbon off the head and pistons with your HG job? they usually do.
 
I still have pinging @1200-1400 rpm with light throttle.

I have always run Shell, Chevron or 76 Premuim.
I live at 7000ft elevation.
It does not change with the weather. It also does not change when I drive to Phoenix (hot and ~1500 ft elevation)
I have 160k on the engine
I get 17 mpg highway only and 13.5 as a DD.

I have replaced:
Spark plugs
Plug wires
Distributor cap & rotor
EGR valve
EGR valve modulator
Air filter
Most of the vacuum hoses

I have done:
Timing check several times with different guns and one scope.....3 degrees BTDC
Throttle body cleaning
Seafoam x 3
Compression check, 150 across all six +/- <5psi (at 7000ft elevation)


I am considering installing new O2 sensors next. I'll let y'all know if that helps or not.


Dave
 
Oh, and we have a borescope at work and I may borrow it to look in the cylinders to get an idea of the carbon deposits.


Dave
 
I'm also going to to a HG as PM in the Spring or Summer and I will have the head done and injectors cleaned & calibrated at that time. (I may do the injectors earlier though just to see if that fixes it)
 
I've had pinging problems with a few Toyota's and have it as you have all described with my 97 FZJ and it only has 116k on it. I'm ready to blame it all on carbon buildup. Thing is I don't get why Toyota's are so sensitive to it and why it happens so early. I've had two 85 4runner's with realatively low miles that pinged. The only thing that made it stop was pulling the head and cleaning the piston's while I was doing the HG.
 
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