I don't think this is normal....Help!!

[Jeremy G]

I have a 74 2.0....my ultimate problem is high idle and an off idle engine hesitation (which has got to be a vacuum leak.) I inspected all of my hoses and could not find any leaks BUT the hose that connects to the port directly to the right of the oil fill-up spout is being sucked shut almost completely flat. It stays flat at idle but when I give it some gas it opens up. Is this Normal?????

Jeremy

[This message has been edited by Jeremy G (edited 04-28-2000).]

[Joe Bob]

Hesitation can be a lot of theings...TPS aka throtle position switch can be worn...or the cold start valve...high idle can be leaks in the intake manifolds...the judicious use of carb leaner can find leaks....

[John Rogers]

The hose you are talking about to the right of the filler neck is the PCV line and should go to an open connection on the air cleaner. It lets the crank case breath. Good luck.

[JP Noonan]

Look at the tech refference part of this site for Dave Darlings vac hose diagram. I think you may have a hose hooked up wrong or the PVC is cloged shut. I don't think they make new ones so remove the oil filler assembly. There is a "bail wire" like the ones on the cylinder heads. Clean it out good with carb cleaner, see if that helps. Also the hose may just be shot or the wrong kind. I use heater hose from FLAPS for the breather, it is fairly stiff and the right size.

Hope that helps. BTW the reason not to clean the PVC on the car is you don't want the carb cleaner getting into the oil.

High idle can also be caused by too advanced timing. of coarse timing is affected by dwell so check that first.

[Jeremy G]

......ok, I solved the collapsing hose problem with a new stiffer hose.

I still have a high idle problem and hesitation. I had thought I'd discovered the source of that problem when I took the throttle body off and discovered there was virtually no gasket under it.....replaced gasket, no good, still high. I've replaced all the hoses and endlessly searched for leaks.....still can't find any. Aux. Air Reg. is working properly. Checked timimg...it's OK. Are there any sure-fire ways to find leaks? What's this carb cleaner test I've heard about?

Please help.......I'm spending so much time with my 914 that my girlfriend is reassured in her belief that I love my car more then her.

Jeremy

[Joe Bob]

Carb cleaner in a spray can...most parts stores will carry it...with the engine running, you simply spray short squirts around suspect areas. When the idle changes, you have found a leak.

[John Rogers]

I have hose clamps on most all the vac hoses even though they fit pretty snug. Also, I cut off the amount over the fitting about once a year since finding a leak is much harder than the preventative stuff. I agree with Mike about the carb spray, make sure you use the little red tube so it is directed at specific areas. Good luck.

[JP Noonan]

Other places to look: The small injector seals ($.95 ea) go bad and crack.

The weld aroung the intake plenum, the big black box the TB bolts to. I use Black RTV and glob it all over the seam and in the two tubes going through the center.

The intake boots, the 1 3/4" or so rubber tubes that hold the intake runners to the intake plenum, buy new ones and use hose clamps.

Last are the intake to head gaskets. The tinware and CHT wire have a nasty habit of worming their was between the gasket and the head. I also either use new phenolic spacers or wet sand them on a flat peice of glass.

I aways use new gaskets and spray them with a copper coating from FLAPS.

Also make sure the port that the idle adjustment screw is in is clear. Remove the screw and clean it out with carb cleaner WHERE SAFTEY GOGGLES the carb cleaner can spray out the other ports of the throttle body so be carful (ask me how I know that the emergency room uses a suction cup and an I.V. bag to flush out cemicals from your eyes....$800 later

[AlexO]

Luckily my 914 had this problem too. The first thing I did was to plug the hose from the warmup regulator to the air box, that will stop that thing from causing problems temporarily. Then I took the air box off and covered the TB w/ my hand, and my idle dropped from 2500 down to 1200, so I knew for sure it was a vacum leak. The carb cleaner works well, I used it to find a leak or two. But try moving the injectors in and out. They caused my car to have a real inconsistant idle because the vacum was enough to make somewhat of a seal.

[Jeremy G]

A co-worker said to try a small propane torch(unlit) instead of carb cleaner because it is overall cleaner on the system and it can find its way through cracks easier, so I did but still couldn't any leaks. I tried the hand-over-the-throttle trick but the engine almost instantly stalled so I pulled my hand away real quick before it did. So I don't seem to have a vacuum leak. Maybe.?!
To restate my symtoms: car starts fine when cold, idles at about 1500rpm but within 30 sec. it works it's way up to 2300rpm. Once it warms up it will idle about 1300rpm. It will occasionally raise up to 1600-1800rpm and even less often go down to 900rpm. But it usually hangs out at 1300. My idle screw is all the way in and I can't find any leaks. My car is a 74 2.0 but it has a 73 2.0 engine with stock d-jet FI in it(I always seem to forget that detail).
Could it be my MPS???

Jeremy

[Pritchard]

Jeremy-

I have a '74 2.0L with stock everything. I also had the exact same symptoms as you. What I concluded after trying everything that this board suggested, was that I had a small vacuum leak somewhere. I first replaced every air hose in the engine compartment. No change. Then I started disassembling all the stuff that feeds air into the head looking for any thing that could leak air. If I found something I sealed it with silicone sealer. Some improvement, but still had an idle around 1300 RPM, with idle screw all the way in, of course. Finally I broke down and replaced all the gaskets in the engine compartment. Success. Now I can actually get the idle down to about 400 RPM's if I want to!

Good Luck!

Pritchard

P.S. The intake runner boots (4 large pieces of hose that connect the plenum to the intake runners) appeared to be in good shape until I removed them. Then I found that they were deteriorated on the bottoms. This is most likely where my air leak was.


[This message has been edited by Pritchard (edited 05-03-2000).]

[John Rogers]

One gasket that can cause problems if it leaks is the rectangular cork gasket under the breather box that has the oil filler neck attached to it. I have seem several that are loose as the wire bale gets deformed and will not clamp it tight. Good luck.