Kiwi'79

G'day All,
(This after extensive and imformative search function utilised)
I fired her up after 2month sleep, (battery had remained connected during this time) she ran a little rough until warm up, I did not notice any misfire on the 15k trip home, however I am a newbie and they do run smoothly on seven, I ought to have felt the miss though if it were present.

So... 3 weeks later, battery still connected, I turned on the key, everything lit up as per, except the starter motor. Charged battery up over the next few days, and went through fuses etc, and the grounds that I could get to easily.

So battery back in and beaut she fired right up, but with a miss, so I went for a quiet drive down the road hoping it may clear to no avail.
After a clean with the compressed air gun I pulled the plugs starting at #5-8 then 4-1, all plugs were a nice tan shade, EXCEPT #2- see photo, which is "sooted" up.
I looked down the bore(with a bright pencil style light) no scoring etc, but the top of the piston looked similar to the plug.
Incidentally the plug and piston were dry (no fuel)

Had very small fuel leak from forward R/R tyre well,(accumulator) it has since stopped oddly enough...

I then cleaned rotor arm etc with Deoxit, and tested the offending plug and lead with a tester, it produced a nice fat spark.

I then pulled the injector, well I un-screwed the injector along with the "holder" the lower part of the seal was badly ripped and stayed in its housing, I carefully removed the damaged seal. NOTE the injector contained fuel though nothing "sprayed" out under pressure when I cracked open the line to it, should it have?

I have just picked up the injector after it was tested and ultra sonically cleaned, the technician told me the spray pattern was perfect on the injector opening at 60psi, blast!!!! I was hoping it was clogged!!!!

So NOW WHAT?
My thoughts are to now trace the fuel line back for a blockage?
The part I am having trouble with is the fact that Seven Cylinders are running fine, surely a fuel blockage would cause trouble with all?

Q-the seal against the injector is tight, could air squeeze past the threads of the holder creating an issue? If so would it not produce a lean looking plug?

Thoughts appreciated please

Steve

The Forgotten On

Check the lines to see if they are clogged.

Also, there are small filters inside of the CIS head that go to each injector line. It is possible that they have gotten clogged if a PO hasn't removed them already.

Kiwi'79

Thanks Blake, will do.

Mrmerlin

if any fuel came out of the accumulator then it has failed and needs to be replaced.

NOTE the leak is a warning it has failed

Kiwi'79

Thanks Stan, leak was from that area, upon removal of inner guard cover, leak was no longer visible nor were there any signs of where it had originated from, i will check again tonight, then get one ordered.

Mrmerlin

there is a hole on the top of the accumulator and a rubber plug fitted,
remove the plug and put a piece of wire into the hole see if its wet

Kiwi'79

Ok Stan will do, what should it be like? as soon as I know I can get my order in (or not).
Steve

Mrmerlin

if there is any wetness the part has failed it should be dry as a bone

Kiwi'79

No plug Stan just a non sealed metal screw, however this area is very wet as you can see from the pic, is this what you meant?

Mrmerlin

yes the diaphragm has failed

Kiwi'79

Brilliant thanks I will order a new one.
NOW, could this contribute to the Misfire?

SwedeInSiam

No, The main purpose for the accumulator is to keep the pressure after the engine stop to prevent the fuel from boiling in the lines while the engine is still hot.

Kiwi'79

Thanks Anders

SwedeInSiam

Could be many things. Have you got pressure gauges to check the CIS pressures?

Has the Fuel Distributor been overhauled? The FD have a rubber membrane in it that fails over time. Mine failed to the point that it was impossible to control fuel flow to the injectors (note, I have a Mercedes aluminium adjustable FD). The cylinders were all different from rich to very rich.

Here's a pict of my failed membrane in the FD, it's flat and stretchy when new. This one was wrinkled and hard.

Kiwi'79

Ah ok, no I don't have gauges,yet..., I will call PO and ask about FD, I would think that it is untouched though.
I will refresh it anyway, a process of elimination!!!

I have my first car show in a few weeks, I will be trailering her to it but I need to fire her up to drive into the building, so 7 may have to do as the parts won't arrive in time.
Cheers Anders, pics speak a thousand words (to me anyway).