steps to take when one cylinder seems to be running lean..

[mark '87 930]

What are the first things to check when you find one of your cylinders running lean?

I pulle dmy plugs last night, they all seem fine except number 5, it was white!

should I check the injector first?

[DDDD]

yes.

[mark '87 930]

Is it just a matter of removing it and checking/verifying if it squirts? I guess I could check the manual.

[Craig 930 RS]

Crack pressure, leakage, volume - have a pro check it.

[mark '87 930]

thanks Craig, I'll get around to pulling it later this weekend. Are they easy to remove? i don't have to remove a whack of other stuff as well do I?

[mark '87 930]

I replaced the injector and still nothing. The plug is still lighter than the rest, although seemingly better than before. I have driven the car about 500 miles since I changed it, so I figured the plug is pretty much at the color it's going to be now isn't it?

I guess the next thing to verify is the fuel distributor?

[DonE]

A mile or so would have told you. Be real careful driving it - you could melt a hole in the piston pretty easily.

You might want to remove the fuel line (from the fuel head to the inj) and clean it. The connection to the fuel head (the fitting on the fuel head for that fuel line) should be removed and inspected for garbage.

[Craig 930 RS]

Definitely check the tiny filter at the fuel head - a real pita, but a few of mine were collapsed - available from Imagine Auto (no one else has them AFAIK):





Testing the injectors:

[fredmeister]

Can you explain more the filter location in the fuel head?
Are there six filters, one for each injector line? Or is there one fliter located at the fuel line coming into the fuel head?
Can you show a picture of the plug that was running lean?

Thanks for the info,
Fred

[mark '87 930]

I'll try to get a picture of the plug next to another one? but no guarantees as my camera is not good with closeup shots.

I am also curious about the fuel filter at the distributor. unbolting the line and checking it should be simple enough. Is it safe to assume I should put in new crush washers at he fuel head when putting it back together after having cleaned it? Also, for cleaning, I can use aerosol carb cleaner right?

[Craig 930 RS]

Right inside where the fuel lines connect to each of the 6 banjo bolts.
The filters are miniscule. New washers are also a must, trust me. Imagine Auto,

What are you gonna clean? I wouldn't. The head itself it really fragile, esp on the bottom plunger part.
You screw that up and you are.......screwed. DOn't get 'clean crazy' and spiff it up for nothing.

Clean it up *before* removal, also a must.

Edit: 6 filters

[mark '87 930]

I meant just clean up the fuel line, make sure it's clear.

[Craig 930 RS]

How are the wires, cap, and rotor?

[mark '87 930]

less than 6K miles on them. It was like that the first time I changed the wires/cap/rotor as well, so I'm pretty confident in eliminating that as a potential cause.

[mark '87 930]

I went to take a picture today and noticed the plug that I say is light is actually the right color.. it's all the others that are dark.. now, that being said, it still means that no.5 is leaner than others.

All this fuel distributor inspection is going to wait until winter storage unfortunately. I still ahve anotehr month or so to enjoy her before I put it away.

[WERK I]

When is the last time you put Techron in your fuel tank? Run a full tank of fuel with Techron before you store the vehicle. Then in the Spring, add Techron to the tank and run that through the system.
When the vehicle is in storage, put Stabil fuel stabilizer in the tank to prevent varnish buildup.