Glowlude

So I got a 4th gen prelude for free, because a friend couldn't afford to tow it from Ohio to Alabama. Turns out, it idles real funky, weird, w/e.

The intake doesn't have an extra nipple for a vacuum line, so he cut it and plugged it with a screw. Can this have any effect on the motor after time? Also, is there a way I can get that vacuum line to the intake, to fix the idling problem?

Also, the car seems to run at high RPMs while driving as well(maybe not, Idk). I'll do about 55mph(or I think so at least, Speedometer is off) and its running at around 2500rpms. Could that be because of the massive exhaust leak as well.

As you can tell, this poor 4th gen needs some TLC, and I'm awaiting my job next week. Figured I'd get some advice.

Thanks PO.

slipknot95758

the intake is fine i drove mine like that fr about a year it is just for a 5th gen

the rpm sounds about rgiht aswell but to better know we need to know whant engine tranny it has

there were 3 differant manule and 1 auto tranny in the 4g

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Glowlude

Its an h23, automatic - should have specified that in original post.

Maharajamd

The RPMs sound fine. Since its kinda of a beater, I would make sure the ATF levels are good.

As for the vacuum, just go get one of those $10 little ricer filter things at autozone. Problem solved, and looks cleaner.

I would also do a fresh oil/filter change, possibly some new plugs. But before you do all of that, give her some Seafoam. Then do the maintenance stuff...

Glowlude

Seafoam? I'll try and find that here in the forums...

edit: Found it - just trying to find a reliable post to go by.

slipknot95758

what ever you do do not use seafoam is has killed alot of high milage engins

the carbon deposits it breaks off can actlualy be helping the valves seal

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Maharajamd

Eh, I have seen Seafoam do nothing but wonders. And I'm talking 15+ cars ranging from 40k-250k. If you are scared, just do a compression test first, if your numbers are good proceed.

Just don't go revving it above 4k.

I have actually seen Seafoam get rid of CELs...

Glowlude

Alrighty, sounds good. Thanks for all the help guys.

petern101

fyi, some manual trannies rev almost 4k @ 75-80mph

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Maharajamd

Yea...in this situation I'm not real sure how relevant speed is, just engine stress. The seafoam will burn hot, so don't go too fast or rev too high I guess...

Glowlude

Well, checking to see why the CEL is on now. Just need to find a flippin paperclip.

p2im0

Yeah, I have a 1992 Prelude S with the F22A1 and I swapped it out with the H23A1 engine and tranny. I'm now revving at about 4k RPM @ 80mph or so.

I feel like I'm gonna hurt her if I drive any faster...but the bottom end is great.

When I swapped engines I took a dremel with a sanding bit to the valves to get off some of the carbon, I'd say I only got maybe 1/2 or less of it off. The engine has 180K miles on it. Think it's a worthwhile investment to do the Seafoam?

And Maharajamd when you say "Just don't go revving it above 4k." What exactly do you mean?

petern101

dremel for carbon deposits???

ok...

you rev at 4k @ 80mph is because of the gear ratios.

and maharajamd said that because if you read the original post, you would know the car in question wasn't in teh best shape. so there could be some problems, i wouldn't go and drive the crap out of it.

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"I am a ricer because I have Z3 fenders"
Bless Her Heart ORG

spin_r_g

Are you getting idle surge? Most likely it's causeed from that vacuum hose being plugged. On my old motor it did the same thing. Try taking out the screw and see if the car idles fine. If it does then that's your problem.

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white93

I would guess the idle surge is coming from a vacuum leak on the intake manifold, or the weird one, I have also seen it happen from power steering fluid being low, dunno whyit happened, but filled fluid and tensioned belt, and it was fine.