1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

High RPM power loss

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Old Sep 11, 2005 | 11:38 PM
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From: Columbiana, AL
High RPM power loss

I have an 84 with a 12A. It has a racing beat header and presilencer. I also removed the rats nest and rebuilt the carb a week ago. I have replaced the fuel filter. It still dies off in higher RPM's. It seems quick up untill then, but then it nose dives. I got beat by my brothers 94 1.5 civic the other day. I am running the stock muffler right now and it has an exhaust leak about mid way back. Could these be part of the problem. I also think it is running a little rich. Does anyone have any suggestions of what the problem might be. I have searched and searched and found nothing.




Thanks,
Chris
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Old Sep 12, 2005 | 01:36 AM
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do a fuel pump volume and pressure test.
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Old Sep 12, 2005 | 07:11 AM
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Yep, that's the place to start. If that checks out, you might have to rebuild the carb. If your secondary jets are clogged, you won't be able to get enough fuel into the carb at higher rpms to maintain power.
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Old Sep 12, 2005 | 07:18 AM
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From: Don't you wish you knew....
I wouldn't think he would have to rebuild the whole carb to clean out the jets would he?
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Old Sep 12, 2005 | 07:35 AM
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Probably not, but as long as he's in there....
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Old Sep 12, 2005 | 10:17 AM
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Time for a upgrade...13B
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Old Sep 12, 2005 | 10:44 AM
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From: Columbiana, AL
thanks i will perform the fuel pump volume test today and get back with the results. I thought the carb was the problem, but i rebuilt it a week ago and it still does it.
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Old Sep 12, 2005 | 12:01 PM
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have you checked your timing?
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Old Sep 12, 2005 | 02:13 PM
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and how would timing problems cause those symptoms?
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Old Sep 12, 2005 | 02:44 PM
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it's a fuel problem. any results on that pump test yet?
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Old Sep 12, 2005 | 02:45 PM
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where did you get the rebuild kit? just curious.
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Old Sep 12, 2005 | 06:12 PM
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From: Grand Rapids Michigan
Originally Posted by skrewloose78
have you checked your timing?
Good point, and easy enough to check. You aren't hearing any weird noises at high rpms, are you? Either way, throw a light on there and see where you're at.
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Old Sep 13, 2005 | 12:50 AM
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From: Columbiana, AL
I didn't get a chance to check the pump today. It is not making any noises at high RPMs. I will also check the timing. I got the carb rebuild kit at advance.
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Old Sep 13, 2005 | 09:45 AM
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From: Grand Rapids Michigan
When you rebuilt the carb, did you remove the jets (the ones where you go through the sight window to remove them)? That's where my blockage was, resulting in high rpm power loss.
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Old Sep 13, 2005 | 01:18 PM
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Also make sure your secondaries are working.
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Old Sep 14, 2005 | 12:13 AM
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From: Columbiana, AL
Does anyone have any comments on switching the mechcanical secondaries. I have been thinking about switching it but i was wondering if it helped out that much.
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Old Sep 14, 2005 | 07:41 AM
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From: Don't you wish you knew....
is your vacuum advance hooked up?
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Old Sep 14, 2005 | 08:19 AM
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I put money on you accidently having swapped your primary and secondary fuel jets.
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Old Sep 15, 2005 | 12:29 AM
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From: Columbiana, AL
i only took the jets out one at a time and put them back in as soon as i was done cleaning them, so i wouldn't do that
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Old Sep 15, 2005 | 12:51 AM
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Originally Posted by Mazda12AGS
Does anyone have any comments on switching the mechcanical secondaries. I have been thinking about switching it but i was wondering if it helped out that much.
You can switch them. That's one way to make sure they work, as you can see them open , as opposed to the vacuum secundaries, which you can't see open.
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