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Discussion Starter · #21 ·
It's not hard but you'll need a synchrometer and a NDIR CO meter to do it properly. To balance the carbs, run engine to operating temperature, remove the air cleaner and the mesh funnels, measure the air flow with the synchrometer, then turn the adjusting screw until air flow is the same for both carbs. I use the STE Synchrometer type SK.

View attachment 29525

To properly adjust the mixture screws, you need a NDIR CO meter, but those are expensive so you could fudge it by doing what this fine chap demonstrates in this video:
Oh duh. Ive sync motorcycle carbs before, and i forgot that these cars HAVE motorcycle carbs. lve never used a synchrometer and i dont care to spend the money on one, but its not hard. I just simply don't believe i need to sync them.

I just got a new pcv valve since currently there is not one and the vacuum line is plugged directly into the valve cover. 2 dollars for that little thing! I was happily surprised. They didnt have an air filter, so i just picked up a glasspack instead so i can fix the whole "running open headers and getting angry stares" thing. Also, a 2 1/2" exhaust would be fine right? I know the optimal upgrade from factory pipes is 2 1/4 but they didnt have a 2 1/4 cherrybomb on hand.

And i didnt know how much power these cars had. I was looking at an intercooler for 200 smackaroos on the old marketplace, told the guy its going on a prelude, and his entire demeanor changed and he started talking like he knew me for a decade. He goes "if you get that one, I'll throw in this one for free. The wife'll just throw em away anyway"
 

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Discussion Starter · #22 ·
Good news! I fixed the weird stuttery problem!(i believe). I put the pcv valve in and it immediately stopped missing and ran better than ever. I also put the glasspack in and its like an entirely different car.

Weirdly enough though it still doesnt start easily and it doesnt idle. I have to give it throttle to get it started and it idles horrendously at 200 rpm for a couple seconds before dying. I can hold it at 1500 rpm to engage the high idle but thats it. Its weird because after i hit the throttle when the revs start to come down, it reachs a point where the revs suddenly drop and it goes into the 200rpm idle state.

Would it be the emissions air valve thing killing it? Its like a flip of a switch and the revs drop suddenly.
 

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Discussion Starter · #25 ·
I might tinker with the carb synching but i hiiiiighly doubt its that. When cold this thing runs fine, but warm it idles on about 2 cylinders at 200 rpm before dying and when i shift at 6k or i pin the pedal to the floor above 60 it starts to sputter a little. Not neeeearly as bad as it used to, but still a little.

It still feels like a slight vacuum leak perhaps? Also my brakes are terrible and when i pin the brake pedal to the floor the idle gets worse. Leaky booster maybe? Idk. I'll tinker with carb synching but im fairly certain thats fine. Trying to find a vacuum leak on this thing is harder than trying to find a grain of rice in a landfill.
 

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Also my brakes are terrible and when i pin the brake pedal to the floor the idle gets worse. Leaky booster maybe? Idk. I'll tinker with carb synching but im fairly certain thats fine. Trying to find a vacuum leak on this thing is harder than trying to find a grain of rice in a landfill.
Could be the brake booster. A bad diaphragm in the break booster can cause it to draw excess vacuum.

I might tinker with the carb synching but i hiiiiighly doubt its that. When cold this thing runs fine, but warm it idles on about 2 cylinders at 200 rpm before dying and when i shift at 6k or i pin the pedal to the floor above 60 it starts to sputter a little. Not neeeearly as bad as it used to, but still a little.
One cause for poor idle is badly tuned or unbalanced carbs. Not sure if it's the cause here but it's worth checking.
 

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Discussion Starter · #27 ·
Could be the brake booster. A bad diaphragm in the break booster can cause it to draw excess vacuum.


One cause for poor idle is badly tuned or unbalanced carbs. Not sure if it's the cause here but it's worth checking.
Ive decided to disregard the brake booster at the moment, the drivers side brake piston seals are destroyed so when i hammer the pedal i lose brakes until i fill the reservoir again lol. but im going to check the egr system and carb synching. I am really really trying to avoid pulling the carbs because it seems like a royal PITA and typically they dont just randomly fall out of tune. At some point i want to pull the carbs anyway, but if i can fix the problems without pulling them I'll be more than happy. If i pull the carbs i might as well put webbers in their place.
 
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