YoungZOwner Posted September 7, 2004 Share Posted September 7, 2004 Hey, i need your guys advise. I recently put on a 6 to 1 header off one of my spare engines, cleaned it all up and painted it, looked really nice. Got it put on my car(Datsun 260z), car ran really good for a few days. Then was heading farther out of town and the car starts to bog and putter really bad. Kept on getting worse and worse, and then started to backfire through the carbs. Had to come home on a hook. Any suggestions, what to check, and what might be the problem. Should i rip the header back off and put stock manifold back on, i hear that the side drafted carbs can be really finicy, for that. Any advise would help thanks. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 7, 2004 Share Posted September 7, 2004 Your header isn't going to cause your car to run like crap after a couple days. It's either going to run strong or run like crap right away. You might want to double check the manifold bolts and nuts just to make sure they are tight though... Could be anything, but not the header. Check the usual driveability stuff, clogged filters, ignition problems, etc. Maybe you knocked a connection loose (coil wire?) while you were installing the header. The Z SU's are easy to tune and easy to maintain. Check out http://www.ztherapy.com if you aren't familiar with them. Buy the video from ZTherapy if nothing else. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted September 7, 2004 Share Posted September 7, 2004 Only thing I can think of is this; After you put the header on, you might have bumped/broken the adjusters on the botom of the carbs, losening them up. As you drove around for a few days, they rattled themselvs loose, and eventually threw off the mix too much.. maybe? Mine acts like this when its cold, and is next to imposible to drive.. first time it happened I thought I was gona need a tow to get home.. but eventually it ran fine after it got hot.. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 8, 2004 Share Posted September 8, 2004 I used to have this problem when I ran SU's. First suspect is that you're running too lean. For me richening up the mixture got rid of it for a while, then my vacuum advance canister on the distributor went bad, and the problem came back, though only occasionally. Installed a new vacuum advance canister and never heard another pop. Not sure why the vacuum advance causes the 'lean pop' thru the carbs, but I thought I'd mention it as I know a lot of people just disconnect the vac advance and drive that way. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted September 8, 2004 Share Posted September 8, 2004 omg.. I just realized something I should have thought of; I was running NO vac advance (just advanced the dizzy, got a slightly high idle..meh), But recently, I switched to a 'suposedly' good dizzy and started using the advance.. could be why Im poping.. maybe that's your issue as well? Quote Link to comment Share on other sites More sharing options...
Clifton Posted September 8, 2004 Share Posted September 8, 2004 First suspect is that you're running too lean. Same thoughts here. Quote Link to comment Share on other sites More sharing options...
DAW Posted September 10, 2004 Share Posted September 10, 2004 It's not the header, per se, but might be due to the replacement process of manifolds-to-header since they share the same long gasket. Sounds like you might have a fuel supply problem or air/fuel imbalance (leaking gasket?). It may also be an ignition defect which shows up the warmer it gets..,.like around the time you're heading out? A little more history would be useful, but I'd go ahead and replace the fuel filter, run fuel system cleaner through it and clean/replace the screens in the carbs since they can gum up. Then I'd check the quality of the spark while the engine is crumping and rule-out impaired ignition, or not, if that's the culprit. Unless you twisted the mixture knobs on the carbs (and didn't tell us), it's more likely that the chokes/main jets would stick extended; causing richenning, not leaning, of the mixture. Retrace your steps. DAW Quote Link to comment Share on other sites More sharing options...
cheftrd Posted September 11, 2004 Share Posted September 11, 2004 First suspect is that you're running too lean. Same thoughts here. Bingo. Quote Link to comment Share on other sites More sharing options...
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