1978 280Z Fuel Pouring From Throttle Body

[Irish Wake]

Stock 1978 280Z suddenly won't start and fuel pours out of the throttle body and fills up the air filter housing. If you push pedal to floor, it will start after about ten seconds, backfire and die as soon as you release the pedal. If you partially hold the pedal down it will run but it surges. As soon as you turn the key fuel pours out in a steady stream from the throttle body.

Please help my son is trying to leave for college

Thank You

Randy

[Zed Head]

Sounds like your cold start valve (CSV) is stuck open. It's either getting voltage all of the time, instead of just at start, or it's physically stuck.

Try unplugging the connector and see if it stops. If it stops, the problem is electrical and you can just leave it unplugged. Make sure you insulate the end of the connector though so you don't get a short.

If not, you can remove it, block the intake port, and plug the hose,if you're in a hurry. It's only real value is for cold weather starting. It's more of a convenience than a necessity.

The CSV is the valve/injector on its own separate fuel line up close to the throttle body. Follow the fuel lines if you're not sure where it is.

[Irish Wake]

Thanks is the CSV available for replacement and if it is electrical what part would be bad.

Does anyone have a picture of the CSV?

Where can I find a repair manual for this car?

Could it possibly be the fuel pressure regulator?

Thanks

Randy

[siteunseen]

In a very nice way ZedHead fixed your problem. Google "280z cold start valve" then click images. They're still available too. Use that Google thing again.

[siteunseen]

I apologize for the glib remark. If your Fuel pressure regulator is bad it would dump fuel through return line to the gas tank, no way it would effect the throttle body. Here's a picture and a source for another. http://www.google.com/imgres?q=280z+cold+start+valve&um=1&hl=en&sa=N&biw=1280&bih=644&tbm=isch&tbnid=zXb1Gi5k31XIXM:&imgrefurl=http://www.thezstore.com/page/TZS/PROD/11-3430&docid=aEzH7nAVAFfe4M&imgurl=http://www.thezstore.com/store/graphics/00000001/large113430.jpg&w=320&h=247&ei=WpIVUJGDIoS08AT164GoAQ&zoom=1&iact=hc&vpx=818&vpy=149&dur=126&hovh=197&hovw=256&tx=125&ty=93&sig=103913282402571895353&page=1&tbnh=141&tbnw=214&start=0&ndsp=15&ved=1t:429,r:3,s:0,i:84

[Irish Wake]

No problem site thanks for the help!

[siteunseen]

I've taken some pictures to show what he's talking about. That's the cold start injector hanging down in the mouth of the intake manifold. It'd be more like a garden hose sprayer compared to the 6 injectors which would spray a finer mist like a kitchen sink sprayer. The other picture shows how close it is to the mouth of the throttle body and the tendency to flow with gravity down into the air filter which I think would be dangerous for your son to drive. As hot as it is at Road Atlanta this time of year you should just unplug it and tape the connector up real good. When it gets cold in January it might take a couple more seconds to crank. Ahhh January.

[Irish Wake]

Site thank you so much for the pictures and help.

I discounted the CSV and plugged the fuel line, no more fuel coming out of the throttle body.

It stills takes about 10 seconds to start running with the throttle held wide open. It dies immediately when you release the throttle. What is the proper setting for the Idle setting ( the bolt with the spring on top of the throttle body)?

I also replaced the tempature sensor and the fuel pressure regulator, Any ideas on what to do next?

Thanks

Randy

[Zed Head]

Now it's looking like you might have a vacuum leak, a big one. All air must pass through the Air Flow Meter (AFM) otherwise the mixture will be lean and the engine will die or run funny. The crankcase is connected to the intake manifold through the PCV system also, so any leaks there will also be a vacuum leak. The oil filler cap, the dip stick, all vacuum hoses connected to the intake manifold, all must be intact and leak-free. If you've disconnected anything, thinking that you would re-connect it after you got the engine running, reassemble and try again. And check any hoses that you've reefed around while working on the engine to see if they split or cracked.

The engine should start right up without messing with the idle screw. Counterclockwise gives a faster idle if you get close and need to keep it running.

[Montezuma]

Check the two hoses that connect to the AFM, if you got a break in them it could cause the problems you speak of. I have brand new in the box Nissan CSVs too.

[grantf]

Two questions: have you downloaded the Factory service manual yet? And is there a possibility that the plugs for the water temp sensor and cold start injectors have been swapped? Factory Service Manual at: http://www.xenons30.com/reference.html

[Irish Wake]

Zed thanks for all your help!