Need Help Identifying Leak

[rogerwilcos]

I have an 1983 280ZX. For a while it has been sporadic on starting. It will crank for a while and eventually start, but sometimes it takes a while. I have noticed the smell of fuel as well. I don't see any leak at the fuel pump and the fuel pressure regulator does not have fuel coming through the vacuum line either. The injectors don't seem to be leaking. This weekend while I was working on a separate issue I finally think I found the source of the leak - but I am not sure what the part is. Can someone take a look at the pictures and let me know what this is? 

 

[rcb280z]

The part in question is the cold start valve but, that may not be leaking. From what I can tell in the pic the fuel hose is wet. So it can be the culprit. Try tightening the hose clamp and see if that takes care of it. If not replace it with the proper EFI rated fuel hose. And if that isn't it, it'll more than likely be the CSV

Could also be the result of hard "cold" start ups depending on how much fuel is actually leaking out.

Edited October 21, 2019 by rcb280z
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[siteunseen]

@S30Grit just cleaned his cold start valve. Maybe he has some info that might be useful?

[rogerwilcos]

Thanks everyone!

[S30Grit]

Yeah I did clean my cold start valve (CSV) and after putting it back in, it leaked as well due to old hose/clamps (and because the previous owner not using FUEL hose here).  A quick trip to parts store to get a few inches of fuel hose (I believe the Inside diameter was ~8mm) and some new clamps fixed the leak right up.

You might be able to swap the hose without taking the CSV out of the intake manifold, but it's probably tough/impossible.  If you do unscrew and remove the CSV, there will be a gasket in there that you may want to replace.  Right now I'm running without a gasket: since the intake is under vacuum, I doubt it will leak fuel there, but it may let some extra unmetered air through ?‍♂️

https://zcardepot.com/products/cold-start-valve-gasket-280z-280zx?variant=19280903962737#

[rogerwilcos]

@S30Grit - When you took the CSV out, did you have to do anything special? I was looking in the Chilton manual and it said you might have to jump some electrical connections to get it to depressurize? I just don't want to take it off and have fuel spurting everywhere! ?

[Patcon]

1 hour ago, rogerwilcos said:

@S30Grit - When you took the CSV out, did you have to do anything special? I was looking in the Chilton manual and it said you might have to jump some electrical connections to get it to depressurize? I just don't want to take it off and have fuel spurting everywhere! ?

Most of the fuel rails don't hold pressure forever like a modern car does. If the car is not hot then some fuel loss won't be a huge deal. Just cover it with a rag when you loosen the clamp. then put the rag outside to evaporate off.

[S30Grit]

Yeah, if you wait overnight at least to be safe, it should be depressurized.  Some fuel will come out regardless of what you do, so like Patcon said, be ready with a rag in all scenarios.

If you're curious to follow the manual, or started the car recently, it's easy: just take off the wiring harness to that very CSV that is leaking, then wire +12v and ground directly to the CSV for 10-20 seconds (might test the harness to see which pin is ground).  CSV should open and spray gas into your intake manifold, if you're CSV isn't clogged that is...

[rcb280z]

I would suggest you relieving the fuel rail pressure just to be on the safe side. Many do not hold pressure long after being shut off but some do. Lets just assume yours does and go ahead and release the pressure as per FSM. 

Mine doesn't hold pressure so I've done exactly as Patcon described above.

The other question is do you have a fuel pressure gauge in line? If so then you'll know if there is rail pressure or not and can adjust your procedure.  

Edited October 22, 2019 by rcb280z
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