naviathan Posted April 4, 2007 Share Posted April 4, 2007 I think clatter is an appropriate description. When I get about 4500rpm and up it sounds like my valves are about to come apart and get some black sooty smoke out of the exhaust, but only when under load. It'll rev fine all the way to 5500 when not under load. I won't push her past that though seeing as how she has 215k miles on the engine. I get the feeling she's dropping lean in the upper rpms, however I richened up my AFM and it helped. My plugs are now looking tan and clean (up from looking white and nasty). Ok so I seem to have the lean problem under control and my fuel pump holds a nice 38psi spike when I rev it at idle. Can't imagine that changes when it's under load. But I still hear the valve train noises and it's not quiet it sounds like it's any minute I'm going to hear one last ping and a crack. Anyhow, it's not like I drive my car this way often, however I'd like to remedy the problem as I do intend to push it getting on the highway and playing with the occasional mustang every now and then. Could I be loosing spark? It's running the stock ignition and I wondered if maybe it was going rich in the upper end because it was blowing black smoke. Quote Link to comment Share on other sites More sharing options...
olie05 Posted April 4, 2007 Share Posted April 4, 2007 Have you pulled your valve cover yet? Thats where I would start. Then I would move on to electrical connections. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 4, 2007 Author Share Posted April 4, 2007 Damn, had every intention of putting that in there, but yes I've done a valve adjustment, Didn't help. Quote Link to comment Share on other sites More sharing options...
datman Posted April 5, 2007 Share Posted April 5, 2007 I had a noise like that, adjusted the valves...made no change. I think it was down to camshaft journals, might be worth checking. Quote Link to comment Share on other sites More sharing options...
linluv84 Posted April 5, 2007 Share Posted April 5, 2007 Are you sure youre not hearing pinging? Mine had a rat-a-tat-tat around 4500 and it was from too much timing under boost with cheap fuel... Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 5, 2007 Author Share Posted April 5, 2007 It's an NA so no boost. Although that doesn't mean it's not pinging. I'm going to pull the plugs again and see where I'm at mixture wise. I richened it up a lot last time because it was so lean the plugs were white all over and there was some kind of debris stuck to them almost like what happens when you get coolant in the cylinders, but I know there's no coolant getting in there, compression is good oil is clean and so is the radiator. It was just that lean. Anyhow, I'm going to look at the plugs again tonight and see where it's at. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 6, 2007 Author Share Posted April 6, 2007 Ok I have it figured out, but not a solution. It's running lean under load in the upper RPM. I richened the AFM up and it stopped clattering in the upper RPM, but it started fouling the plugs at idle and cruise. Now if I could just find a happy medium. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted April 6, 2007 Share Posted April 6, 2007 Ok I have it figured out, but not a solution. It's running lean under load in the upper RPM. I richened the AFM up and it stopped clattering in the upper RPM, but it started fouling the plugs at idle and cruise. Now if I could just find a happy medium. It's called MegaSquirt Seriously though, try Blue's tests for spring tension. The spring might be warn on your afm. Or try another afm. In my experiences the stock tuning has always been on the rich side. Mario Quote Link to comment Share on other sites More sharing options...
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