Crunky

Ok, I have finally finished putting everything back together(minus the top of the airbox and filter) after replacing the oil pan on my 84 944. I just tried to start the car and it ran for about a half a second and died. Then I noticed that I hade broke some sort of vacuum fitteng on the brake booster, I think that its the check-valve, but not positive. It has one big hose running downwards somewhere, I don't know exactly, and there is also a small hard vacuum line that plugs into the top of the valve. I busted off the nipple that the small vacuum line plugs into, so I jammed a tiny vavuum fitting/coupler thing into the hole where the nipple was and plugged the line back in.
Then I Tried starting the car again, it almost ran, was running like crap and wouldn't come above 400RPM on its own. So I started revving the motor up to 2-3K RPMs and let off the gas, it fell back down to the 400RPM range and it will idle there by its self, but very rough. The best way I can describe what its doing is that low end stumble that the early cars have, but its doing it worse than normal, and not coming out of the stumble, just sits at about 400RPM. If you blip the throttle or just push it down and leave it down, the car tries to die. You have to pump the throttle to get it above 1K RPMs and then it runs fine above 1k RPMs, until you let off the gas, it falls back to 400RPMs.
The first thing I thought was a vacuum leak somewhere, but I haven't found any so far. But after revving the motor to 3k and leaving it there for a couple minutes to burn off all the oil that leaked onto the exhaust it seems to run a tad bit better.
If your wondering, there is tons of oil on the underside of the car, I smashed my oil pan into a big rock in the road at 40 MPH, so the entire exhaught system is covered in oil. Could it be possible that all that oil coulld had contaminated the o2 sensor?
Any advice would be appreciated, this is really boggling me.....

Cass944

If the big line coming out of your brake booster is broke, you have a BAD vacuum leak. that line connects directly to your manifold which would mean there is no vacuum at all throughout the entire system. and if there is its very little.

make sure you have the air flow sensor plugged in. whenever i take my airbox off i always forget to plug that thing back in and the car will not run. it will start for about a split second then immediately turn off. sounds like it could be that.

i wouldnt worry about small vacuum leaks anywhere. these car will run fine with leak (not perfect but they will run). but if its a huge leak, like one on the brake booster, then no go.

Cass944

I read your post again,

ther fact that you can rev the engine up to 2 or 3k rpm tells me its not the plug on the air flow sensor. you have to ahve a pretty horrible vacuum leak somewhere. The idle is controlled by a valve just under the intake manifold. if you have a leak that is somewhere near that valve it will not idle properly at all. (usualy even if you DONT have any leake it will idle like crap anyway, but still)

i would say you have a bad leak somewhere. also, dont think you can get away with just plugging the lines to fix the problem. those lines (especially the ones ont he brake booster) are important. have you ever tried turning off the car while rolling then tried using the brakes? thats what the brakes will feel like if you dont have any vacuum.

Crunky

Heh, one of the first things I checked was the plug on the airflow meter, I have embaressed myself that way before. I also don't see any breaks in the big line and I can feel or hear a leack where it plugs in at either end.
But this really seems like a vacuum leak, almost exactly how it ran when my J-boot had a colossal crack in it.

Crunky

Is it possible for this valve to become plugged or jammed up? Or possibly go bad somehow?

Cass944

sure i dont see why it couldnt.

oil will make its way into your pcv system (which is where the idle control valve is) and it will over time start filling it with sludgeness.

also, just so you know. Having a hole in your J boot wouldnt cause a vacuum leak. you get vacuum leaks only from anything that is located after the throttle body. which on the 944 engine luckaly is only the intake manifold. BUT basicly, every vacuum line int he car is connected to the intake manifold OR the throttle body itself.

I dont mean to ruin your day or anything. but usualy when looking for vac leaks, the best place to start is just by getting the intake manifold off because most uf them are located under it or around it. It would also be a good time to just run to auto zone and pick up a good 15 feet of silicon vacuum line (super cheap) and just replace all of them. Its really nto that rediculous of a job because (unless you removed it) there is a sticker on your fender near the windshield fluid that shows the detail view of where the vacuum lines are located and what they connect to.

when i replaced all my vacuum lines my car instantly felt much nicer. no shaking at idle, no weird smells, and also it cured that stupid thing all 944s do where the car shakes a little as you come down to idle.

Crunky

Aha! After a short break and some cooling off, I wnet back out to examine all the vacuum lines once more, and there was one BIG line that was unplugged, looks like a heater hose. Probably 5/8" diameter, it was supposed to be plugged into some round shaped thing underneath the intake manifold, towards the firewall, right above cyl. No. 1, or is that No. 4? Anyways the other end plugs into the J-boot. Runs great now, thanks for the help.

Cass944

is your car garnet red? I love that color. mine is that color too.

Cass944

awesome, glad you found it. sounds like the line that plugs into the weird round plug with 2 vacuum plugs sticking out of it. which (i think) is a temp sensor that controls how high the idle is depending on the temp of the engine. so yeah, with that being unplugged it makes sence that your idle would suck.

Crunky

I was told (by the used car salesman) when I was buying the car that it is Marachino Red, or something like that, I don't know if that was an original color or not, but it does look very close to garnet red. I think its an ok color, but I'm planning on painting it soon, its pressy obvious when your up close to it that someone did a cheesey repaint, I almost think they didn't mask anything. Well they didn't take the glass or seals out for sure when it was re-sprayed.
You can't see it in my avatar pic, but the sunroof is awful, huge white fiberglass patch where there is no paint. I usually leave the roof off to keep it from looking so ugly.
Anyways, I just got back from my test drive, I havent driven it for almost 2 months now, and WOW, I can't beieve how much I have missed this car. I don't think I will ever get rid of it, I love it more that ever after not driving it for 2 months.
I think I'll go for some more test drives.

Cass944

heck yeah, Im pretty sure im going to burried in my 944... I'll just be sitting there as the entire car is lowered into the ground. It will be sweet