No white smoke with Seafoam treatment / PCV

[6lug]

1998 100
All stock

In a quest for better mileage (dead horse), I installed new 267/75R16's, down from 285/75's, on my newish to me LC.

Thread:
Smaller tires installed, same to worse mileage?

With only one response, I figured I better search some more, and figured tire threads are pretty worthless anymore.

Found some good tune up and mileage threads, so I removed the PCV, soaked it, and poured seafoam in the intake side. I have read 1/2 to a full can. Well, I poured lightly and the engine would rev a bit when it went through, but not one molecule of white smoke. I have seen this stuff being digested by an engine, and figured it would be about the same. Nothing. So I figured, Ive had the stuff for a while, try something else. So I tried some PB Blaster tune up spray, which I KNOW is good, and have used recently, and the same thing...no smoke.

Which means I think I'm doing something wrong or just don't know whats going on. Could the cat's be part of this?

Any ideas?

Took a plug out, checked its condition, and it looked pretty good, gapped at .043". Its one of those fine-wire / pointy tip style (not sure if that's normal for this engine or not). Cleaned the throttle body plate and throat. Disconnected the battery until in the morning.

Going to clean the MAF next, but have to get some cleaner. Air filter looks good.

All stock with 267/75's and getting 13 mpg with 90% interstate driving. 2300 RPM at 74 mph. I'm feeling and hearing some vibs at this RPM, very light, but perceptive. At 2200, where the RPM was at 74 with 285/75's, quiet as a kitten.

That's about it for now. Thanks in advance.

 

[2001LC]

Run a can of 44K in the tank, after you have the fuel injector clean, rebuilt & tested. When to replace fuel injectors

If you really want to see and improvement, try this test. Drive no faster then 65 mph. Keep a very light foot during acceleration.

 

[2003lx470]

 

[6lug]

I guess my main question with a lot of backstory above is:why isn't white smoke coming out? This makes me think I have done something wrong based on what I've experienced before. Thanks

 

[camino70]

You did it wrong jk

I used seafoam on my '98 and when it started to smoke, about 3/4 of a bottle, I shut it down and let it sit. Not sure how long, few hours maybe? When I restarted, it smoked like the neighborhood kid rolling coal in his mid-90's cummins dodge.

I'm not sure what it actually did or got me, so....

 

[2001LC]

You did nothing wrong. Some may say then you had no carbon built up, so no white smoke. Which since you dive 90% highway, makes senses.

I get on highway every chance I get, sometime shifting to 2nd gear hold 4,800 rpm for five minutes, then dropping back to 2,300 rpm for 5 minutes. I repeat this several times. This heats combustion chamber all the way out too cat's, then cools to normal, burning off carbon and oily deposit.

Here is my intake manifold after fogging with SeaFoam, afterword's driving in low/high gear two 5 mile trips. I then split intake manifold inhalf. Look at the pools I found.

 

[codertimt]

Yeah, I've gotten smoke from a sea foam treatment too...not sure which vacuum line I disconnected though. And as above, not sure what it might have helped on a fuel injected engine besides cleaning out the combustion chamber a bit...

Was going to reply on your tire thread, but didn't have any actual advice. While I agree that the vehicle is a brick and mileage drops off pretty badly at 70+, I don't agree that 13 is the best to expect on a mostly stock vehicle in those conditions. Possibly only 10-15% better is to be expected, but IMHO you should be pushing 15 in your scenario versus 13... Again, don't have any idea of what to look at, but unless you just have really, really crappy gas in your region, something besides speed is up. For comparison, I have a 2001 LX with 190K, 295/75/16 tires, and 500+ extra lbs of bumpers/sliders. I can still pull 15 or very near it in your scenario.