Evap System Delete? Options

[brianp626]

Did some searching around first but wasn’t finding any good information. My 1.7 seems to be running strong now but idles around 2500rpm. Naturally I started at the vacuum lines. The evap lines going into the rocker panel are in bad shape and you can hear it leaking. Rather than pull the panel and replace the lines is there a way to just bypass it? If a route the line from the intake straight to the fan shroud it revs even higher. Obviously this can be done from looking at some of the race setups but how? Is that the right way to route it and you adjust the idle down at the throttle? Any help would be greatly appreciated. (IMG:style_emoticons/default/beerchug.gif)

[ClayPerrine]

Something is plumbed wrong.

The evap system shouldn't be hooked to the intake plenum. It should be hooked tot he air cleaner on one end, and the fan housing on the other. There is no vacuum involved at all.

[SirAndy]

Something is plumbed wrong.

The evap system shouldn't be hooked to the intake plenum. It should be hooked tot he air cleaner on one end, and the fan housing on the other. There is no vacuum involved at all.

(IMG:style_emoticons/default/agree.gif)

The reason you see the rpm go up when you hook it from the plenum to the fan shroud is because that creates an air-leak (air bypassing the throttle body) and you're running lean.

The evap system pushes air from the fan shroud through the carcoal canister and back into the air-filter (pre throttle body!) to burn any fumes.

It should never be hooked up to the vacuum part of the intake!
(IMG:style_emoticons/default/shades.gif)

[worn]

Did some searching around first but wasn’t finding any good information. My 1.7 seems to be running strong now but idles around 2500rpm. Naturally I started at the vacuum lines. The evap lines going into the rocker panel are in bad shape and you can hear it leaking. Rather than pull the panel and replace the lines is there a way to just bypass it? If a route the line from the intake straight to the fan shroud it revs even higher. Obviously this can be done from looking at some of the race setups but how? Is that the right way to route it and you adjust the idle down at the throttle? Any help would be greatly appreciated. (IMG:style_emoticons/default/beerchug.gif)

When you say intake do you mean up or down stream of the throttle butterfly? Normally a small amount of fan pressure drives air through the charcoal and into the air (at atmospheric pressure) going into the intake. That is going into the air filter, not into the intake vacuum.

[worn]

Something is plumbed wrong.

The evap system shouldn't be hooked to the intake plenum. It should be hooked tot he air cleaner on one end, and the fan housing on the other. There is no vacuum involved at all.

(IMG:style_emoticons/default/agree.gif)

The reason you see the rpm go up when you hook it from the plenum to the fan shroud is because that creates an air-leak (air bypassing the throttle body) and you're running lean.

The evap system pushes air from the fan shroud through the carcoal canister and back into the air-filter (pre throttle body!) to burn any fumes.

It should never be hooked up to the vacuum part of the intake!
(IMG:style_emoticons/default/shades.gif)

Seems I was typing when Sir Andy was testifying.

[brianp626]

Thanks all. Yea it sounds like I have it wrong. When I bought the car it was missing some lines so I thought I had it right but clearly it’s not. Sounds like I need to study some more schematics.

[brianp626]

Swapped some hoses around after reviewing a few schematics. No longer has the high idle but runs pretty rough in my opinion. Is 914 ownership always this fun? Lol. I just wanna drive the damn thing.

[SirAndy]

Swapped some hoses around after reviewing a few schematics. No longer has the high idle but runs pretty rough in my opinion. Is 914 ownership always this fun? Lol. I just wanna drive the damn thing.

After 40+ years, many of them have seen better days. The good news is, most parts are still readily available and we have plenty of knowledge here to help you get your car running great again.

When i had my 1.7L D-Jet it took me a good year to sort out all the engine issues it had accumulated over the years but when i finally got it all sorted, it was the smoothest running 914 i have ever driven.
(IMG:style_emoticons/default/driving.gif)

[brianp626]

Appreciate the words of encouragement, Andy.

So, at this moment I’m thinking maybe injectors causing possible misfire? The car has sat for an unknown amount of time. Been throwing money at it since I bought it. Replaced fuel pump, filter, plugs, cap, and rotor. The wife loves this car. Lol