Baffled: 3fe with quick build up on plugs... from what?

[Carlp336]

i have a 89 FJ62 ive been working on for sometime..

i can say she is arguably running the best it has since i got it.. ( lots done to get there) the short version is this..

i had some bucking during load, thought it was driveline. but once all that was addressed i went back into the ignition system.. i was shocked it even ran, crazy build up of hard deposits on all the plugs... ( plugs were not old!! maybe 1-3k miles.) ... pics of 4 of them attached...

that was 500-600 miles ago.
today i pulled one just to see and its happening again...

im down a bit of oil, which i just figured to be consumption, im also down on my overflow tank..
i dont have smoke, no sweet smell or any other signs of a blown HG, my oil is clean and so is the coolant.

what on earth could it be??
1. perhaps my tb is leaking coolant into the manifold? ( had planned to bypass that plumbing and test)
2. maybe moisture in my fuel system
3. to cold a set of plugs? im running NGK BPR5ES
4. weak coil?

anyone seen this before?

 

[YooperCruiser]

i have a 89 FJ62 ive been working on for sometime..

i can say she is arguably running the best it has since i got it.. ( lots done to get there) the short version is this..

i had some bucking during load, thought it was driveline. but once all that was addressed i went back into the ignition system.. i was shocked it even ran, crazy build up of hard deposits on all the plugs... ( plugs were not old!! maybe 1-3k miles.) ... pics of 4 of them attached...
View attachment 3608940View attachment 3608941View attachment 3608942View attachment 3608943

that was 500-600 miles ago.
today i pulled one just to see and its happening again...

View attachment 3608945

im down a bit of oil, which i just figured to be consumption, im also down on my overflow tank..
i dont have smoke, no sweet smell or any other signs of a blown HG, my oil is clean and so is the coolant.

what on earth could it be??
1. perhaps my tb is leaking coolant into the manifold? ( had planned to bypass that plumbing and test)
2. maybe moisture in my fuel system
3. to cold a set of plugs? im running NGK BPR5ES
4. weak coil?

anyone seen this before?

Disconnect the throttle body coolant lines, loop them together and throw a new set of plugs in. It's getting to all 6 cylinders and it's not oil

 

[OSS]

Try chevron gasoline

 

[CruiserTrash]

@Carlp336 My plugs do this on a few cylinders as well, some worse than others, and I’ve never been able to figure out why. I pull them and clean with a wire brush periodically. Following along for answers.

 

[Carlp336]

Disconnect the throttle body coolant lines, loop them together and throw a new set of plugs in. It's getting to all 6 cylinders and it's not oil

was my first thought and easiest test..

 

[Spook50]

Definitely give the throttle body coolant supply a check like @YooperCruiser suggested. There's definitely something getting in, and to all six cylinders. That's some ugly buildup.

 

[CruiserTrash]

What I’m hearing is that this is coolant? Yes?

 

[Carlp336]

What I’m hearing is that this is coolant? Yes?

from my research it could be. among other possibilities.. was hoping someone could chime in as to what..

 

[OSS]

https://www.austincc.edu/wkibbe/plugchart.pdf

 

[Carlp336]

https://www.austincc.edu/wkibbe/plugchart.pdf

yup saw that before too....

 

[OSS]

Here’s another one

 

[CruiserTrash]

@OSS Well, from my wet/dry compression testing, my rings are pretty well fubared, so ... in my case I'm guessing it's not a head gasket issue, but a blow-by issue. Thanks.

 

[SteveH]

@Carlp336 - My '78 2F plugs looked like that when the valve stem seals were shot. The plugs cleared up after seal replacement. Your buildup was very fast and heavy for the miles driven, however. Also check the PCV valve to be sure you're not sucking in too much crankcase goo and use the correct weight oil (10w-30 or 10w-40).