injectors

[dependencies]

How, might an injector leak fuel into a cylinder .
and cause smoke on start-up

82 SC

thanks

[carrue529]

I dont think that it is fuel that leaks into the chamber, its oil that seeps thru the valve stem bushing (worn out bushings) and gets on the cylinder

[Zef]

Oil will induce blue smoke...not fuel.

[Wil Ferch]

Can't a bad fuel leak induce hydro-lock ??....hope this isn't going too far away from the original question.

- Wil

[911mot]

What colour is the smoke? Black would be fuel, blue for oil.

[dependencies]

Colour,

I'd have gone with blue/oil

Mechanic says with exhaust off, and car on lift
its petrol that leaves the exhaust port though.

I'd not heard or read anywhere, of much in the way of injector problems up till now, at least not on petrols.

have to say not convinced really, as its following a top-end rebuild at same shop,
and using reportedly 'good' but used pistons & barrells.

still, give him the benefit of the doubt for now....




BTW anyone here know who I'm using yet

[chuckr]

I had injector leaks on my 83SC, no smoke but they were leaking.
My mechanic noticed this during a tune up. plugs were wet.
I replaced my injectors and injector 0-ring seals. Very good
thing to replace !
Chuck

[dependencies]

Well Theres a new set of Injectors on their way, as it's an 82' car anyway so overdue.
but the wholw reason the car went in to start with was smoke,
so a rebuild looked set,
when it came back ( after Three months) it still smoked copiously
on start-up, though now intermittently,

which is somewhat confusing,

back it went for another go.

all at first pointed to # 3 by a process of eliminatiion
(removing leads) indeed removing exhaust initially confirmed
an amount of fluid present in port, after standing.

He looked at stem seals next via covers, and thinks their OK

and re-examining fluid, in fact thinks its petrol hence that injector,
which is where you lot come in,
and hopefully someones hand shoots into the air,
'Mine did that too'

except you havent'

bugger...

[911mot]

Try this - run the car and then pull the fuel pump fuse or relay and wait for the engine to stall. Now leave it the usual amount of time that it takes to make it smoke again on start up (e.g overnight). Refit fuse/relay in the morning immediately prior to starting and see if it smokes this time. If it smokes again its probably not an CIS problem as it should have had no residual pressure in the system. (It might take a while to start though until the pressure has built up)

[dependencies]

Interesting,
does this mean (bear with me here)

That in some way fuel is being delivered between key being in ignition?

[LakeCleElum]

On a CIS car, it's pretty easy to pull the injectors, and see if they are leaking.

[911mot]

Sort of.
When you switch the ignition off the pump stops running but pressure is maintained in the system. It sounds to me something somewhere is allowing the fuel to dribble through to the injector.
The SC injectors are different to the 3.2 - the 3.2 injectors are opened and closed electrically with a multiplug on each injector. On the 3.2 its possible to have an injector leak by not closing fully.

I'm not sure how the SC delivers the fuel to the injector but they all inject at once. So if one was leaking I would expect the others too as well? Maybe a CIS guru can help here, I'm better with EFI.

[dependencies]

smoke though?

I'm clutching at straws in an effort tofollow his thinking really.

perhaps I'm wrong here, and would loved to be proved wrong,

but blue smoke (which is what i'd call it)
is widely reported as an oil issue

[911mot]

Is the problem on just the one cylinder?
Has a compression test been done?

all at first pointed to # 3 by a process of eliminatiion
(removing leads) indeed removing exhaust initially confirmed
an amount of fluid present in port, after standing

Does the smoking stop when you disconnect #3 lead??

[dependencies]

perhaps I should explain in outline;

had a top end carried out same place

head, guides, seals & used but reportedly perfect pistons+ barrells.

had it back after work carried out, but smoked (biggg puff) occasionally on starting
hot or cold AM or PM made no odds parked on flat BTW


took it back where it had a compression test
(broken ring on rebuild possibly)
nothing in it to indicate a good starting point
so in order to check car with engine still in it,

removed leads one by one over several days, and thought #3 seemed culrpit.

he popped off the exhaust with it on a lift, and

again started it looking for squirt of oil from exhaust port
instead found it to be petrol.

removed covers and says the stem seals all look in order


and coincidentally marked pulley at start to find it only smoked on starting in 1of6 rest positions

[rick-l]

Every so often my 88 smokes on startup, actually a small cloud. I was told it was due to the cylinder walls being horizontal oil would seep past the rings into the chamber.

[Gunter]

Sounds to me a compression and leak-down test is in order to get the real picture.
CIS system has residual pressure left after ignition is turned off but even a leaking injector (Or leaking Cold Start Valve) should not have an excessive discharge.
Besides, a leaking injector would give you bad idling.
CIS-Injectors can be easily checked for leaks and new ones are relatively inexpensive.
You mention a rebuild but may have some doubts?
Go to a DIFFERENT shop for the Compression/Leak-down test IN WRITING.
Then let us know.

[dependencies]

YHM