Pinging

[AlexHall]

Hello,

I have an issue with pinging (sometimes part throttle and full throttle) and I would like to have a cure for this irritating problem. I have had it ever since I installed my MSD 6A but only recently have determined it to be pinging. I have done several things which have helped but it is not completely gone. I live in Phoenix AZ where it’s really hot. During the winter time (or driving to cooler climates like L.A.) I don’t have this issue and I can run 89 octane. During the Summer months I get pinging and running 91 octane helps to lessen it. I would prefer not to run octane booster or anything else but gas in the gas tank. Octane booster is pretty expensive too for each fill up.

I drive a 91’ Toyota 4Runner with a 22RE 4 cylinder, 5 speed, 4WD with 210k on the original block. The engine runs and starts great. The cylinder head is a few months old with a complete valve job. I’m running 50/50 coolant with Lubegard Koolit cooling treatment. I use a Stant SuperStat thermostat, stock is rated at 190º.

The timing is set to stock at 5º BTDC. I’m using NGK standard plugs (Stock # 7632, BPR5EA-L); one step colder then stock. Napa Auto Parts tells me that this is the coldest plug available for my engine. The gap is set at .040 (stock is .032)

I have a complete MSD set-up = MSD 6A Box, MSD Tach adapter (Part # 8910-EIS), MSD Super Conductor Spark Plug Wires (Part # 31949), 90 Degree Boots and Crimps (MSD-3311)

I did a compression test a few years back. I have no reason to believe that it’s much different today.

132,500 mi - 5/21/05
Compression test – Rated @ 171 Psi, minimum of 143 Psi, Compression Ratio 9.4:1

Cylinder #1 – Approx 176 Psi
Cylinder #2 – Approx 174 Psi
Cylinder #3 – Approx 173 Psi
Cylinder #4 – Approx 175 Psi

I’ve tried running fuel treatments through the gas tank hoping to clean the injectors out (BG 44K & Seafoam) but it hasn’t really helped. When I Seafoam the engine/cylinders this seems to help a little bit for a short time.

Here’s my questions:
I have seen in some threads here about “the timing coming in to fast”. I’m not sure if I can adjust my timing curve/advance if this is what they refer too. My distributor doesn’t have a Vacuum motor on it, just 2 wires coming out of it, I guess going to the igniter and then to the 6A. Could this be an issue and if so how do I fix it?

I haven’t pulled the injectors off to have them sent out for cleaning so I really can’t say if one of the cylinders or more is running lean. After 200k is this something that should be done?

I’m assuming that the electronics/vacuum side of my EGR system is working properly, I cleaned out the EGR two years ago and it held a vacuum and the valve opened. Could this still be an EGR related issue?

Would using a colder thermostat help? I’m not sure I can get this for my engine as the dealer told me yesterday that they only have one part number listed, so I’m assuming it’s rated for 190º. Is a Toyota/Denso thermostat better then a Stant?

Is there any evidence to support the use of headers lowing cylinder head temps and would this help??

Does spark plug gap have anything to do with this problem?

I’m really not sure what to do at this point besides having the injectors sent out for cleaning. I can’t think of anything else.

Can an MSD tech please respond to this thread? Thank you.

[msdtech27]

sounds like your heat range in your plug is on the hot side. according to the NGK web site 5 is hot and 7 is colder so you might want to buy yourself a colder set of plugs and that should take care of your problem.

[AlexHall]

Hello,

After 4 months of changing plugs to Bosch Super Plus standard plugs (Stock # 7995, Part # WR 6 DC+) and also dropping the timing down to 4º BTDC I still have the pinging problem as described above. It did get alot better but it's still there (not as loud and frequesnt) and as the weather has been starting to cool off that has been helping as well. The Bosch plugs with the "6" heat range rating is the coldest plug I can find.

What should I do for next summer becasue this problem will start again as the seasons change? Will getting headers help with reducing cylinder head temps? Is there anything else that can be done besides removing the MSD 6A from my truck??

[msdtech22]

Usually, pinging poblems are a timing issue. Have you checked the timing for the correct recommended factory value?

What type of timing light are you using when checking the timing?

Use of a digital/dial-back timing light is not recommended when using an MSD Ignition. Use a plain-Jane, inductive, chrome, point/shoot timing light when using an MSD Ignition CD system.

[AlexHall]

Yes I have checked the timing, as mentioned above it is set @ 4º BTDC. Factorysetting is 5º BTDC. Setting it 1º less helped a little with the pinging.

I'm using an Equus Innova digital timing light (part#3568).

Can you please explain to me or send me a link explaing why an MSD can't use anything other then a regular "plain-Jane" timing light??

I thought about trying this one but it says its not compatible with multiple spark ignitions. http://www.summitracing.com/parts/SUM-G1059/

[msdtech22]

The MSD CD ignition is a high voltage piece of equipment and generates at least 470 volts of energy back to the coil. This energy has a tendency to create 'rf' noise in and around the engine compartment. This 'rf' noise is nothing you can hear with the 'naked' ear, it is like static on the radio or 'snow' on a TV screen. This energy will sometime induce itself into the electronics of a digital or dial-back light and cause the light to flash at an 'odd' time. 'Odd' time means that the light will trigger and fire when it isn't supposed to. The human eye sees this flashing on the damper of the engine. Because the flashing is at a time when it isn't supposed to, the eye picks up on and reads that flashing as the possible correct timing. Because the light may not be flashing correctly, the eyes sees the mark as being correct.

By using a 'Plain Jane' timing light we try to eliminate as many of the problems we may encounter with the 'rf' noise as possible. These timing lights are not as susceptable to the high energy 'rf' noise as the electronic timing lights are for the simple reason that there are no electronics in the 'simple' lights to affect its operation.

Use a 'plain-jane', simple two wire hook up to THE BATTERY, pickup to the #1 cylinder, point/shoot timing light to re-check the timing of your vehicle.

DO NOT use or rely on a digital or dial-back timing light when using any CD or high energy type ignition. They tend to give you incorrect readings. Please heed the words or suggestions of MSD and Summit racing on this matter.

[AlexHall]

Ok....last night I got my hands on a "plain jane" inductive metal chrome body Actron timing light. It measured the same as my Equus Innova. I used both to compare and both showed me 4º BTDC @ idle (around 800rpm). I did notice that my timing mark now has a slight bounce to it but this could be becasue the distributor gear is a little worn after 214K miles.

Overall the timing is at 4º. When it gets a little colder here I will adjust it back to 5º.

At this time can you think of any other suggestions??? Any tricks for Toyota's? I really feel now that this has to do more with combustion chamber temps more then anything else. When the ambient temp drops during winter the problem goes away.

[msdtech22]

It could be because the distributor gear is worn. I really don't have any special tricks of the trade for Toyota's.

If the problem tends to clear up with the cooler weather, you might take a deeper look at the combustion chamber temperatures.