Pinging Again!

[stuntjunkie199]

I posted months and months ago about a pinging problem I had with my 89 Honda Accord. Well it's back. To be honest I haven't paid enough attention to tell whether it came back gradually or all at once. It only does it when it's under a heavy load which it rarely ever is so it could have definitely went unnoticed for sometime.

Something makes me think that it may be something to do with timing. I've noticed if and when I floor it (inducing pinging) that it pings from sub 2k RPMs to about 4500 or 5000k RPMs and then it quits around that 4500k RPM mark. If the distributor/vacuum advance system is advancing too quickly could this cause a potential lean condition and induce pinging? It's like it takes the motor a few seconds to catch up with timing. I may be completely backward on this whole theory? Any input would be appreciated, thanks.

[Dr_Snooz]

The timing is fairly complicated on these cars and given the age, is subject to failures of various kinds. Download the manual and do a complete timing inspection, starting on p. 24-4 and continuing through p. 24-8. If everything checks out (it won't), let us know and we can go from there.

[2geeSEi]

I second what Dr_Snooze said. Also, make sure that you always set the static timing with both hoses connected, do not disconnect and plug them, and make sure you are setting it using the correct mark.

[stuntjunkie199]

Ok guys finally got a chance to start troubleshooting today and I think I've found a definite problem. I hooked my timing light up and starting checking ignition timing first off. I let the car warm up and as the manual says I disconnected the two vacuum lines and I'm not exactly sure which end to plug, I am guessing the line going to the intake manifold not the distributor. Oddly enough with the lines unplugged I was at about 17* which according to the manual should be about 4*. I loosened the distributor and obviously I couldn't even get close to that in fact turning the distributor affecting the engine little to none. I'm thinking that I should at least be able to get a decent rpm change while turning it. Anyways as 2geeSEi said I reconnected the lines into the advance unit and the timing was so far off I couldn't even see the 15* no matter how far I turned the dizzy either way.

Also just for giggles I left those two vacuum lines plugged and since the timing was about 17* with them plugged I took it down the road. It ran exactly the the same with the lines plugged as it does unplugged. Any thoughts?

[Dr_Snooz]

Sounds like your timing belt is off a tooth.

[stuntjunkie199]

Ok that's what I was maybe thinking. I've driven the car 20k+ miles as is though and it runs fine idles fine and gets good mpg- about 32 to a gallon. Do you think it could be masked that well? If so what is the easiest and simplest way to check?

[2geeSEi]

If you can't adjust the timing to spec, it is probably the timing belt off a tooth. You will have to remove the valve cover to check. Turn the crank so the flywheel + TDC mark lines up exactly with the pointer. Then look at the marks on the cam pulley. The main "Up" mark should line up with the mark on the timing cover, and there should be two fine scribed lines that should line up with the top of the head on both sides of the pulley. You can look at the timing belt section of the service manual for a better visual of what you are looking for. If everything is correct, you could have a problem with the centrifugal advance in the dizzy (you may want to verify that is working first though).

[stuntjunkie199]

Ok is this centrifugal advance the same thing as the vacuum advance that the shop manual talks about testing with a vacuum pump? If not how do I test it?

[2geeSEi]

The centrifugal advance has 2 weights with springs in the distributor. If you plug the lines to the vacuum advance and increase the rpm, the timing should advance. I don't remember how much, but if you are following the procedure in the manual, I know there is a part about that. You can also visually look with the cap off to see if the springs are connected to the weights.

[Dr_Snooz]

The centrifugal advance is under the vacuum advance plate, so some additional tear down is required to view it.

If you want to get into the centrifugal advance, try this thread out: https://www.3geez.com/forum/technical...stributor.html

[stuntjunkie199]

So I set the flywheel to the -T- mark and sure enough my cam sprocket was one tooth past TDC so my question is how do you take the belt off just enough to set the cam and then put it back on. I've been trying to loosen the tensioner but I back the adjusting bolt almost all the way before I can slip it off. It's still too tight to get back on. Also the cam gear is almost impossible to turn by hand, is there an easier way?

[2oodoor]

Pull the spark plugs out, engine turns very easy then. Line up marks tdc best you can. Slide belt off being carefull not to let it fall or slip off any other pullys, turn cam gear with wrench just enough to lne up, slide belt back on. Turn motor by hand a little to take up slack then tighten tensioner,

[stuntjunkie199]

Got it back on and timed with a light and it runs great! I've been running one tooth off for years! I'm surprised at how well it ran that far off. Mpg was good and it had plenty of power. Oh well, it's dead on now and there's ZERO pinging.