Hi,

I'm having some mild engine ping from my stock 91 Honda Civic LX and was hoping that I might be able to get some help. Here's the details
Currently the car starts fine, and runs fine, but gets a few pings/ticks when accelerating, especially during hard acceleration in 3rd gear (3k RPM -> 5k RPM.) Also, under mild acceleration in about the same RPM range I think I can maybe hear some ping/tick, or maybe its just me. The pinging is not currently severe, but I'm concerned that I will prematurely wear out my engine by driving the car like this. Here's how I got to this point:
- Just after I bought the car, it did have some pinging problems. As I recall I used some Tekron by Chevron and it seemed to help.
- I have occasionally had the problem where the car won't start for a bit, and throws Code 16. It will always eventually start. This is always after it had been running for a while. I don't know if this is related to the ping or not. I'm guessing its not, and that its the problem with soldered connections on the main relay that I read about.
- I've tried a second set of used fuel injectors (of which the the aux injector is supposedly close to being brand new. The resistance of the aux injector is right in the middle of spec.) The car ran better this way and was driven a while.
- I changed my Oxygen sensor a month or two ago, at the suggestion of a kind soul on this website, and that improved my fuel economy by about 2 MPG.
- recently the pinging problem got a whole lot worse, and I pulled the car into the garage to check it out.
- I checked the compression. All cylinders except #3 got to about 180 psi or so after 2 - 3 (maybe 4) cranks. After the 1st crank they read about 90 psi. Cylinder #3 topped out around 150 psi, and started at 60 psi on the 1st crank. After adding oil to #3 and doing the check again, cylinder pressure went WAY up (around 200 - 220 psi). From what I understand that means I have a weak piston ring on the #3 piston. Since the Helms manual states that 185 psi is nominal pressure, and 130 something is the minimum, I'm figuring that compression is not a problem on my motor.
- I checked both the intake air temperature sensor, and the coolant temperature sensor. Both seemed to output reasonable values.
- The timing has been checked and is pretty damn close if not dead on. My car doesn't always idle at EXACTLY 750 RPM, but the tach was showing either just a little over, or a little under 750 while I was testing. Since the Helms manual states an error range of +-50 RPM, and I don't think I exceeded that, I'm guessing the timing is OK. (I don't have a lot of money, and buying a more precise aftermarket tach, just to do the timing is not in my budget. I have to make do with the one on the dash.) The idle on the car isn't always perfect. Sometimes it's a little low and other times a little high, sometimes right on. Speaking of idle, it is sometimes a little rough (i.e. more vibration from the engine than there should be.)
- I believe my ignitor on the distributor to be working properly. The ignition coil was in right at the top of the acceptable range of resistances stated in the Helms manual. Both the cap and rotor are less than 8 months old, and I recently filed all the terminals on them a bit to get them extra clean.
- I have OEM Honda Spark plugs installed. I have "Premium" aftermarket NGK spark plugs wires.
- The previous spark plugs, seemed to show evidence of perhaps running hot/lean. I have been suspecting a mildly lean mixture all along. I didn't think the plugs were bad, but just in case, I replaced them with brand new OEM plugs. I still get the mild pinging I described.
- The main fuel injector is brand new.
- I believe that a while back the car used to run rich, as it fouled the last set of sparks plugs it had in it (the set before the ones I just pulled out) and it kicked some soot (as well as water) out of the exhaust pipe. There is no longer any soot.
- I did discover that I had accidentally been driving the car with the timing adjustment connector (the one on the passenger side of the car that you use when adjusting the timing) jumpered. I have un-jumpered it, and I'm guessing this is the main source of the improvement. (Before this the pinging was under full or partial acceleration from around 2kRPM -> 5k RPM)
- The car has a new radiator, new water pump, and fresh coolant. It has never overheated during the time that I've owned it, nor do I notice it running hot.
- The timing belt is new, and the valve lash was recently done by the dealer.
- I have not tested the MAP sensor as the only way I can conceive to do it is to open the insulation on the wires and stick the electrodes from my multi-meter in it when its still connected to the car, or try and find a way to get 5v to it on a work bench (not impossible as I have spare computer power supplies.)

I still haven't made up my mind yet, but I think I will get some Tekron, and drive the car tomorrow, and see what happens. However, I'm still not sure as I don't like driving a car that even has slight ping.
I'm about at wits end here, and about to take the car to the dealer and have them deal with it. I need this car back on-line soon. However, as I have stated before, my funds are limited, and the dealer is expensive. Does anyone have any ideas? If you folks think it would be helpful, I can post pictures of the last set of spark plugs. Any help that you guys can offer would be GREATLY appreciated.
Thanks so much,
Curt

 

PS: I checked the fuel pressure too, and its within spec.

 

i know u said the the timing is correct...but are you sure that the base timing is dead on?

 

oh i forgot...have u tried running one step colder plugs?

 

Thanks for replying.
I'm about 80% sure that the timing is dead on. It it isn't dead on, its really darn close. I have considered disconnecting the Idle Air Controller, and then using the idle screw to set it at exactly 750RPM. Then set the timing, and once set, return the screw to its previous position, and reconnect the IAC. This saves me having to repair a very mildly malfunctioning idle control in order to get the timing right.
I haven't tried the next step cooler plugs, but I think that I will, now that you mention it. This car is exposed to heavy driving on a regular basis (I use it to deliver pizzas 4 days a week.) I will post as soon as I get the new plugs installed. (Plus I think I'll post the pictures of the old ones for reference.)
Thanks again,
Curt

 

the colder plugs might help you out...but i cant see why a stock engine would need to go one step colder...is it possible the previous owner milled or resurfaced the head?
what octane gas are you using? have u tried filling up with higher octane gas?

some close up pics of ur old spark plugs might help

 

It is unlikely the previous owner did anything to the head. He didn't strike me as the kind of guy to modify the car (unless he had the head rebuilt or replaced and didn't tell me about it.) I have tried higher octane gas in the past, and it did help a bit, but didn't always solve the problem. Unfortunately, I really need this car to run on cheap 87 octane regular gas if at all possible, and from what I understand, its supposed to do that.
I'll try and get some pics of the spark plugs up tomorrow.

 

i feel ya...gas prices are outragous here too...now u say higher octane gas helped but didnt quite solve the problem? can you elaborate?
right now im stumped

 

On the current round of pinging, I have not yet tried premium gas. The last time I had this problem, I did try it, and it helped some. By helping some, I mean that I got less ping, less often. Its been a while, so I don't remember the specifics. This ping problems has cropped up a few times. I thought it had gone away, but now its back.

 

so it only does this occasionaly? would it happen to be after a long/hard drive? hot weather?
my suggestion would still be to try the colder plugs.
weird problem man...seems like you have diagnosed evrything so far
now that code 16 is a fuel injector code? have u tried trouble shooting the code?

 

I've been meaning to update this thread for a while, sorry I haven't done so. The situation is this. I went ahead and put in new stock NGK plugs, and ran a heavy concentration of Tekron by Chevron through the car. This seemed to get rid of the pinging for a while, and I thought I had it solved. Now, its starting to return. It doesn't do it all the time right now, just ocasionally, and there is also a bit of a raspy sound to the engine under acceleration. I do drive this car heavily -- I use it to deliver pizzas, driving around 300 - 400 miles a week, plus my normal driving. Therefore, I'm guessing that I probably do need the colder plugs. I think it might be pinging after having been run awhile, but I can't be sure of that.
I tried to get the colder plugs this evening, but no one has them in stock, so I'll try a few more places, and order them if no one has them. At the end of this post, I will post pictures of my previous set of spark plugs, the ones that were in there when the pinging was taking place. As soon as I've got the new plugs and have driven the car for a bit, I will post results.
A big thanks to "Suck my DX" for the advice and help. I appreciate it.
Cylinders 1&2:

Cylinders 3&4:

 

I know this sounds odd , but , turn your idle adjustment screw on your throttle body counter clockwise a turn and a half . You'll probably see the idle smooth out and for some reason if it's in to far you'll hear a knock in the valves.
I noticed a whistle from my cai and lately my engine has sounded like ****.
So at the advise of other HT members i adjusted the screw. BIG difference !
The whistle went away , and the engine just all around breaths more healthy.
No more knock and a purrrrrfect sounding idle. I could not believe that this simple screw could cause said problems but in my case it's it sure made a 110% difference.

 

I assume you are using the Tekron in an attempt to clean out some carbon build up? Are you using the Tekron from off the shelf at Kragen or Autozone? I have found using "top engine cleaner" from a GM dealership (p/n# 12345104) to work extremely well. Judging by your compression numbers, they dont indicate a build up, but u never know.

Anyways, you could run a step colder on the plugs as already stated, or you could set the base timing to 14 degrees (not sure what you're at now). Whats this talk about 80% sure the timing is dead on? How are you cheking it? Why are you unsure...possibly due to your inconsistent idle?

Does your LX have an EGR valve?

BTW, your description of the problem and what work has been performed is beautiful! LOL.

 

As always, thanks for the posts, and advice

I'll give the idle screw thing a try and see if that helps. I did play with it in an attempt to get the car to idle at exactly 750 RPMs, so it might be off. I recall putting it back where it was before I played with it, but its quite possible I didn't get it right.
As for the ignition timing, the reason I'm not completely, perfectly sure, is that my idle isn't perfect. Sometime's its at 750, but sometime's its a bit low, or a bit high. When I adjusted the timing I checked it frequently to make sure it was right at 750, or as close as I could get it, and it seemed to stay at 750 when I adjusted the timing. The 80% is how sure I am that I got it perfect. If its not prefect, it should be pretty close. Currently the timing is set to the center mark on the crank pulley per the instructions in the Helms manual.
As for an EGR valve, I'm assuming I have one, but I haven't looked into it at all. Is it something I should check?
As for the Tekron, yes, I was using it with the idea that I might have some carbon buildup or something else in there that needed cleaning.
I'm hoping to get the colder plugs today, so I'll post when I've got some more info.

 

If your LX is an automatic, then u probably have an EGR valve. EGR does affect combustion temp, thus affecting ping/knock. If u have a manual car, then u dont have one.

About your idle issue, remove the idle air control valve and clean the screen. Carbon builds up on that screen and can cause idle issues. Also be aware that its possible the idle screw can adjust itself due to the vibration of the motor. Its one of the reasons it comes with silicone/paste over it from the factory. I have experienced this first hand (very frustrating until i figured it out!!).

About the timing, the center mark on the pulley (should be painted red) is 16 degrees. The mark to the right of that, viewed when standing on the driver side of the car is 14 degrees. Retarding timing should help with the pinging, without sacrificing a noticeable amount of performance. BTW, 14 degrees is still within spec.

 

My LX is a manual.
I will try cleaning up the idle air control valve. Thanks for the suggestion. Since I'm going to do that, I'll also try and set the idle screw, and re-verify the ignition timing. I'll have to guess, as I'll be using the tach dash, but I think I can get it pretty darn close. (Tach dash makes it hard to see exactly where 650 RPM is.)
I just ordered the colder plugs, but since no one in town had them in stock, it will be around a week before I get them. I'll update when I have more info.

 

OK, an update for my engine ping problem.
I got the colder plugs, gapped them, and put them in. It actually made the problem worse.
I then put the original plugs back in, adjusted the idle screw per the Helm manual instructions, and I also adjusted the timing, setting it retarded to the right-hand mark. All this improved it somewhat, but it was still there.
I then ran Tekron by Chevron through it some more. This helped, but I was still getting some occasional ping.
I proceeded to get rather annoyed, loosed the distributor, and turned it (the distributor) another degree or two towards retarded, retarding the timing rather ridiculously. This had a noticeable affect. The engine sounded better, and seemed to run smoother. I ran it this way for a while driving the car to CHicago and back (around 400mi). I did start to notice a small but noticeable metallic raspy noise when revving the engine. When I got home, I reset the timing to the standard mark.
I am currently running another tank with the Tekron in it, and mid-grade gas, and currently the ping is about gone, but I still, on occasion, notice it.
I think that I am going to see what happens after this tank runs out. The goal is to get it to run on regular like it should. I am inclined to try testing the MAP, Atmospheric Pressure Sensor, and the throttle position sensor, but this may have to wait another week or so. I may also take apart the IACV and see if I can clean it.
I'd also like to thank everyone who's posted on this thread for their help. I really appreciate it.
If anyone has any pointers or suggestions, they would be most welcome. When I've made more progress, I will post the results.
Thanks again,
Curt