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| Pinging and it's NOT a lifter or valve?; Diagnose another pinging story | |
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| Tweet Topic Started: Sep 14 2011, 08:25 PM (821 Views) | |
| Bad Bent | Sep 14 2011, 08:25 PM Post #1 |
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Facetious Educated Donkey
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It's been pinging. A JDM engine in the 1991 'Filthy Beast' that I was pretty sure sounded like a lifter. This is vacuum advanced, 1.0-3 cylinder, aluminum underpulley, ram air, catch can, racing header and street/race cam. I had added some Marvel Mystery Oil a month ago. It wasn't affecting my 55-56 mpg at all and performance is really, really good. I figured to do an oil change to Mobil 1 and see if that had an effect and while in the store last Friday I bought a can of spray Carb. cleaner on sale for $2 - impulse buy. But it was a bad weekend so on Tuesday I got motivated and went down to finally determine if I was needing to rebuild my spare engine and replace my JDM for what, $300-$600. I got out the cheap $4 sale priced Harbor Freight Mechanics' Stethoscope* and poked around. Since it sounded like the passenger side I put the scope on and touched the metal end to the water pump; nothing, alternator (for fun); nothing, oil pan; nothing, block at the header; light tapping, valve cover; heavier tapping but not serious, Throttle Body; nothing, Vacuum advance on the distributor; BINGO. And it was loud. But that makes no sense that it would be a lifter like tapping out of the distributor advance, not the cap or body? I pulled the dist. cap and you could twist the rotor a little and hear a tinging. Using a mirror I saw that it was a little piece of metal in the back moving. Undid the vacuum advance (advance) and it was moving, the plate was moving, nothing was binding. Pulled the hoses off and they were clear. Blew and inhaled on the hose connected to the advance and you could hear the diaphragm move and no air was passing through it with light air pressure. So this morning I decided to pull the hoses off the vacuum advance and spray some of that $2 carb. cleaner in it to clean the 'gas filter' (Hood Sticker w/gas filter location)on the #1 intake manifold and the passage at the TB that the hose is connected to and drove 45 miles. At work I did it again before driving home. I got to Job #2 and there was NO tapping. Moral of the story is that it may not be lifters that are tapping. I believe the 'gas filter' (that filters/prevents vapors from getting to the advance) was clogged OR the port at the TB was clogged and the vacuum advance was not working so the little metal piece in the distributor was making a lifter like tapping noise. *My new best friend: Don't leave Harbor Freight without one.
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| metromad | Sep 16 2011, 10:20 AM Post #2 |
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My '97 has a "lifter tap" that is not actually so. L.H. side of the engine, attached to the back side is a vacuum activiated soleniod unit that has something to do with the fuel vapor system. When the solenoid gets activated, sounds just like a lifter. If I am sitting at a light, there will be no noise, then for about 30 seconds I will hear the tapping, then nothing again. Drove me nuts for a while until I figured out the problem. I can get a replacement solenoid from NAPA for about 70 bucks but since it does not seem to be causing any other problems besides the occasional irritating noise, I will live with it. |
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Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.

Don't leave Harbor Freight without one.




7:25 PM Jul 10