My '75 2.0 idles fast when hot.

I have replaced all the hoses and injector seals, adjusted the timing, done all the tune-up stuff, etc. I suspect there may be an air leak, but I'm running out of places to find it.

The only place I haven't refurbished yet is around the plenum. I want to take that out next, clean it up, paint the intake tubes, replace any gaskets/seals, etc. But I haven't been there yet, so I'm hoping for some input - photos of the disassembled parts would be nice.

Throttle-body gaskets, the short pieces of hose that connect/seal the intake tubes to plenum (what do you call those???).... what else do I need? Anything tips before I dig in?

You've checked your AAR?

QUOTE (Rand @ Dec 3 2005, 02:53 PM)

My '75 2.0 idles fast when hot. I have replaced all the hoses and injector seals, adjusted the timing, done all the tune-up stuff, etc. I suspect there may be an air leak, but I'm running out of places to find it. The only place I haven't refurbished yet is around the plenum. I want to take that out next, clean it up, paint the intake tubes, replace any gaskets/seals, etc. Throttle-body gaskets, the short pieces of hose that connect/seal the intake tubes to plenum (what do you call those???).... what else do I need? Anything tips before I dig in?

The plenum isn't a difficult task, just a couple bolts/screws, twisting yer haid the right contorsionists position with light directed properly and feeling yer way with the right sized wrench or screwdriver.
I did it with the same intensions. I was hoping to find a leak but din't.

The TB gasket I'm relativly certain is NLA. I used some stuff from a tube that dried but could peel off when necessary. Sealed good.

There's a photo & drawing with the proper sizes of hose for connecting all vacuum hoses. A search for vacuum hoses should bring it up.

Also, ditto what Mark said. Bypass that AAR. It might be open, even a little bit!

Good luck with yers... I gave up the chase

.....b

Thanks guys.

Not the AAR. Every single port that goes into the airbox has been ruled out... except the Cold start valve. Looking at that now too.

I wouldn't have suspected the plenum, but it's just about the last place left to look. I figure I'll enjoy the experience of seeing it apart and cleaning/painting while I'm at it.

Have you changed the injector seals yet? Runners to head gaskets?

I would test for leaks spraying starting fluid lightly around the known leaks spots while the motors running.


Geoff

QUOTE (Bleyseng @ Dec 3 2005, 07:39 PM)

Have you changed the injector seals yet? Runners to head gaskets? I would test for leaks spraying starting fluid lightly around the known leaks spots while the motors running. Geoff

got one better for ya man....

get the canned air that's used to cleaning out computers with...

Dust-Off....

it uses a refridgerant that doesnt burn well....

spray at things...if the idle drops....BINGO!

this is what i use everytime i think i have a leak.....the can even has a little straw so you can get real close without getting real close....

its dry too, no wet anything....


b

I have replaced the injector seals.

Runners to head gaskets? Not yet.

Did the spray test, but used carb cleaner (carefully of course)... Isn't that supposed to work like starting fluid?

it kinda works....I like ole fashion starting fluid as the "leak" shows up instantly. Don't spray much....just alittle here see what happens, then some here etc. If you start spraying alot everywhere it will get sucked into the TB intake and that is why the rpms go up.


Maybe we can hook up....and I'll take a look see.

QUOTE

Maybe we can hook up....and I'll take a look see.

Thanks Geoff. I don't care what Blair says, you're ok!
I'll take you up on that. I'm also curious to find out how healthy my MPS is and would appreciate your evaluation.

Here's a shocker.... I stopped by my local VW shop, where I've picked up great deals on parts before... looking for the little boots that seal the intake runners to the airbox. What do you call them? THESE:



Ok, so, what are four of those worth?





I was quoted $42.00.

Cough, hack, choke. Ok, more than I expected.

What is so special about those? It doesn't get that hot there... Why couldn't regular rubber hose pieces be used there? Maybe use hose clamps to make sure they seal air tight? School me please.

Intake Manifold Hoses

Old manifold hoses have a tendency to crack and leak, causing a variety of fuel injection problems. New replacements are worth more than enough in saved headaches while troubleshooting injection problems. Note, the 1.7 manifold hoses are no longer available, however, the 1.8/2.0 hoses can be used as a replacement if you hose clamp them to the runners and the air plenum. Sold per each.

Intake Manifold Hose, each, 914 1.7 (1970-73)
Brand: Genuine Porsche
022-133-241B-OEM $6.75
Intake Manifold Hose, each, 914 1.8L/2.0L (1973-76)
Brand: Contitech [Photo] [Photo]

039-133-241-M21 $8.50

Manifold hoses Pelican Parts

Thanks Ron.
Ok, $30 or so with shipping is better than $42. But we're still talking about a few inches of hose here. It's not a high-pressure or high-heat application... Seems to me it just needs to be air tight? So what's wrong with using pieces of the rubber hose I have on hand and clamping with hose clamps?

Sorry for I just want to understand how it's justified.

Thanks.