Plugs... Not sure what to think...

[Hotrodlincoln]

So I put a new set of plugs in the 85 today. I gave each of the old ones a close check as I took them out.
The first one, cylinder 3 (the hardest one to get to) was actually a bit loose, clean, and looked 100% normal.
Second one, cylinder 2, straight up white. Apparently running pretty lean on that cylinder for some reason (bad intake manifold gasket maybe?).
Third plug, cylinder 1, clean, just like cylinder 3, looked great, not white not black, not ashed up, just clean as you would expect from normal combustion.
Fourth plug, cyl 6, had a fair amount of ash deposit. Not gunky black or green like a bad oil leak or coolant leak. It's a hard crusty tan-ish color buildup on the anode.
5th plug, cylinder 5, had a bunch of crud packed up around the plug on the outside, picked it all away with a small screwdriver and noticed the plug wasn't even close to tight. Didn't even use the ratchet to remove it, just put the socket on it and turned it with the extension. (Who knows.) Anyway, plug was white (big surprise there huh? ) but otherwise clean. New plug in, tightened up just fine.
Last one, cylinder 4, comes out looking just like cylinder 6. Ash deposits, same color as before, about the same amount, just enough to coat the ground anode.
So this has me to wondering, What is causing the ash deposits, and why is cylinder 2 running lean? I'll recheck cylinder 5 in a couple weeks and see how it looks to make sure it's not still running lean too, but in the meantime...
I set plug gaps to .06. Starts great and runs like a purring kitten. Might have to unhook that MSD ignition box tomorrow and see if it still runs without it.

 

[Original_Ranger84]

Sounds like someone should have checked the spark plugs after he put them in to make sure they were tight... hmmm?

I kid, I kid. I love new parts! Its like christmas... sometimes..

 

[Big Jim M]

-Was there a question in there somewhere?- Sounds about NORMAL for a 25 year old engine! You didn't say how long them plugs had been in there.. A little oil use causes the buildup on the plug. Clean and white doesn't always mean too lean.. Just forget about it and go do something else till she starts running badly.
Big JIm

 

[Hotrodlincoln]

Don't know how long the plugs were in there. I just bought the truck at the end of Feb. Not much wear on them though, I'd guess maybe 10-15k miles at most.
I've pulled plenty of plugs in my (short) lifetime, and have seen plenty of variance between one engine and another. But I've never seen two plugs come out normal, then the one between them come out completely white. Not on a carbureted engine at least. If it were a FI engine I would suspect a clogged injector.

Sounds like someone should have checked the spark plugs after he put them in to make sure they were tight... hmmm?

Yeah the PO probably should have, but it appears he didn't. One more check on the list of ghetto-isms I've found on this truck.
Oh and another thing I thought was strange was the plug wires. He had them labeled with hash marks... but they were all wrong. The one he marked 6 was on cyl 1, 2 was on cylinder 6, 3 was on 5, I think number 4 was correct, but the rest were all out of order. He had them on the correct terminals on the distributor, just labeled them all wrong for some reason.

Next up on the To Do list is rebuild the carb, but I'm still waiting to find a non feedback 2150 to throw on it and Duraspark it. Til then I think I'll just enjoy getting 19mpg on the highway.

 

[dangerranger83]

19mpg, why change it over and spend money that you dont need to spend, from the looks of it everything is wroking as it should.

 

[kimcrwbr1]

does it blow smoke when you first start it after it has been sitting for a bit. Depending on the mileage it might be valve guide seals easy enough to change them in the tech library under 2.8 V-6 is a section that tells you how to without pulling the heads.

 

[Hotrodlincoln]

19mpg, why change it over and spend money that you dont need to spend, from the looks of it everything is wroking as it should.

It works for now. I said the same thing with my last truck, I didn't want to mess with it because everything worked fine. Then it left me on the side of a country road at 2am. I got it to run again , not well but it did run, after it cooled down for about 45 minutes. Drove 15 miles and it wouldn't go over 35mph. It got me to my street, which is all down hill, and quit again. I coasted it to the house. Next day it would start but hardly run, and had no power at all.

Durasparked it that weekend and never had a problem with it after that. My mileage went from 15 to 17mpg. It stopped pinging all the time, timing was set the same at 10°btdc. Same plugs and wires, same carb settings just had a few things removed. It would climb hills better, and when it was wet out it would actually break the tires loose if I stomped it off the line. Couldn't even do that power braking it before.

I figure if nothing else changes I at least get a simpler and more reliable ignition system with the Duraspark. But I expect about the same results out of this truck, better mpg, less pinging, and better power with the duraspark over the EECIV TFI.

It does smoke, but it's a greyish brown smoke like what comes from too much fuel. Smells kinda like matches. It has to be turned over about 3 times before it will stay running, and it won't idle on it's own for about 5 minutes until the engine starts to build some heat. Add to that ANY load on the engine before it gets warmed up a little will just kill it. I have to ride the clutch to about 1500 rpm to keep it running if I want to move it when it's cold.

 

[kimcrwbr1]

Yea do the duraspark conversion and be done with it if you dont have to pass emmissions. You can use the stock carb you just need to put a metering block where the feedback solenoid is on the back of the carb and run the vacuum advance off of manifold vacuum. Can you get a vacuum guage for now it sounds like you have a vacuum leak take a vacuum line about 3 feet put one end up to your ear and go around with the other end and listen for any hissing. I like this method because you can pinpoint a leak it works good for exhaust leaks also just stick it in the carb first so you know what to listen for.

 

[Hotrodlincoln]

I've done the vacuum hose trick before not long after I got the truck. I know there are two hard lines that were broken and have rubber line stuck over each end to put them back together. They seem to be tight and holding. I checked the vacuum tree on the manifold as best I could and found no leaks there. And did a quick check of the vacuum mess under the cover on the passenger fender. That does remind me... I had an evap purge solenoid get stuck partially open on my Subaru and made a heck of a leak. I should check all the solenoids on the truck and make sure none are sticking open.

 

[kimcrwbr1]

Also have you checked the egr pull a vacuum on the egr the engine should stall at an idle. If no change in rpm pull it and see if it is leaking. Always get a new gasket before you pull the egr sometimes they stick open and a cleaning will help and check that the seal for the rod that pulls the valve open is not leaking also. I push the valve open and plug it with my thumb and suck on the other hole to test the seal and then release the valve and suck on the hole to check the valve.

 

[Hotrodlincoln]

Might be able to look into this when we finish with our annual memorial day sale at work. 12.5 and 13 hour days don't leave much free time to play with the truck.

 

[Quartermile]

Just to scare you: a very clean plug can be caused by burning coolant in a cylinder

 

[Hotrodlincoln]

None of them were that clean. Just clean in that they had no evidence of abnormal firing conditions (too rich, oil, etc).

I've dealt with a few blown head gaskets in my days and have yet to see a plug come out completely clean, or soaked in clean antifreeze. Usually they're covered in wet green or brown gunk. I could understand clean plugs if someone had just replaced them, and the leak was so bad that the coolant prevented combustion of the A/F mixture entirely, so no ash to settle on the plug. But if the leak were that bad, there would already be buildup on the plug that no amount of water would wash off.