Hi;

I've an '85 GSL-SE. Not a great mechanic, but engineer (electrical) by trade. So I understand lots of theory, but, as I said, not a great mechanic.

Problem is a ping, loud and distinctive, starting at 2k if under load, and continuing up to 4k where I usually start to back off a bit. Up to speed in 3rd and up is ok.
Power is excellent, but definitely don't like the pinging expecially in a rotory.

Problem started about 3-5 months ago. Have replaced the distributor cap, rotor, spark plugs, air filter, played with timing, advancing 10 degrees on leading, retarding 10 degrees. Slightly reduced at -10 degrees, but I reset to mark, believing at this point that timing is not the problem.

That leaves distributor wiring (don't think so), and air/fuel.

California is undergoing fuel changes as many of you know, going to ethanol, instead of MTBE to reduce the octane. Still a designer fuel. I've always run lowest octane available, no problems in the last 19 years. But I mention it, as my brothers Audii 4 (2002) has a severe pinging problem which also started about 3-5 months ago. Probably coincidence, but I mention it for what its worth. Vehicle has 153k trouble free miles.

Oil history; used to have a start problem (14 years ago) which I take was carbon. Switched to Rotella T back then, and no problems since then.

So on the fuel/air question, reading a bit, and trying to understand how it works is getting me no where slowly. Not sure where to start, so I'd appreciate any thoughts, suggestions or any other ideas, comments.

Thanks,
Richard Harper
Morgan Hill, Ca

 

Check your timing.

 

Richard,

If this is a real ping (pre-detonation) then you better figure this out before you damage the engine. It doesn't take too many pings to blow your engine's apex seals. Mostly this happens in turbos but can happen it other engines also.

If this new type of gas is causing the problem, I would suggest using a higher octane to hopefully prevent the pinging.

Timing should be set for stock and check your vacuum advance.

Also, if you haven't had your fuel injectors cleaned, I would highly suggest it. Time for a gas filter change? That could help too?

Anything that could make you run lean should be checked or maintained as appropriate.

 

wow first time i heard that a rotary pings.maibe you need to replace your fuel filter or clean your injectors, looks like is leaning out real bad under load

 

First step that I'd recommend is trying some Premium fuel in there to see if it's truly caused by pre-ignition of the A/F mixture. If the pinging goes away immediately (buy on an empty tank), then you know what the problem is.

If it persists, I'd take another look at ignition timing to be sure that it's set correctly. The leading should be 5deg, trailing 20deg for SE (ONLY), and it's safest to stick to factory specs. Rotary Rocket magazine did a write up many, many years ago about advancing leading trailing to get better performance (increasing burn time), but I'd shy away from that in a high-mileage engine such as yours (and mine).

The fuel mix changing from MTBE may be the culprit, and if you still notice pinging after the fill-up with Premium, then not much is lost - any unburned fuel will be consumed in the exhaust system and cats. HTH, and report back,

 

Thank you all for your suggestings.

Your suggestions are fairly clear. So the first thing I will try is replace the fuel filter. That has never been done, so it is a good bet. I'd assumed that I'd get some indication of lack of power, which I don't. Apparently you all believe that I can lean out the fuel mixture with a fuel filter that is "out-of-spec", and further a leaned out fuel mix could be the cause of pinging. Since so many of you think that could be a cause, and since the fuel filter should have been replace by now, I'll do so.

Also, running a tank of premium does seem a reasonable check, so I'll do that.

As to timing, I am sure leading and trailing are dead on. I'd mentioned that I'd played first with delaying the timing (helped a bit), and advancing it (made it slightly worse). I then carefully reset it to dead on. The trailing on this vehicle tracks the leading, so it was not changed, as it was and is set correctly.

There were a few less probable suggestions which I'll follow up on if the first two suggestions don't give me a fix or a clue.

Lastly, I'm retired, spend my days day trading, and don't get off the hill but once every few weeks. But I will report back. Like you guys, I have a certainty amount of feeling for the car, it has been by far the most reliable, and fun car I've owned. I don't drive my Gold Wing much anymore, as I'm getting up there in age, but it is fun to get out and push the Mazda a bit, now and then.

Btw, the car was smogged just recently, under the new California dynamic test method, scoring so low on hydrocarbons etc. that the mechanic commented on it. I assume that simply means the apex seals are still working after all these years... 8-> But I mention it, as it had the pinging problem at the time of the test. Of course the dynamic test doesn't present enough load to produce the ping, so emission effects would not show up.

Thank you all, I will report back when I have completed the two suggestions.

Richard

 

This is so embarassing I probably shouldn't post it.

First, thanks for all the suggestions... I tried them all, with no change in the "pinging".

Here's where you have to try to avoid rofling. I replaced my u-joints on the main drive. Which removed the u-joint problem, but also removed the ping.... ok, ok... stop lauging.

In my defense, (hahaha), for those that have heard a pinging car under load, that is exactly what I was hearing. Started at 2-3k, and kept up under acceleration, in 1st, 2nd and sometimes 3rd.

But after replacing the u-joints, no more "ping".

Frankly, I still can't believe it. But my GSLE runs beautifully. As well as the day I bought it.

Note that in retrospect, normally when you hear "pinging" (pre-detonation usually), you also get a loss of power, which I never did. I did note that in my original query. Should have been a big clue that something else was going on.

Sign me.. Happy in Morgan Hill, Ca, looking for the next 200k trouble free miles.

And thanks to all that tried to make sense of the original problem.. whooda thunk it. Those that are still on the floor laughing, I beg you to get up and carry on!

Richard Harper
Morgan Hill, Ca

 

Glad to hear it's fixed and it wasn't anything serious. At least you got a new fuel filter out of the deal

 

I find satisfaction when an owner posts back on the results of whatever fixed thier problem. Thank you for bringing back your post and reporting your results.

Even if it is over a year later.

I do recommend changing the fuel filter more often though.

Enjoy both your retirement and 7 for many years to come.

 

good to hear you found the problem.

Oh! and