Cloud of Smoke

jlglr4

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I stand corrected. That part number for the pump in that diagram pulls up the brake vacuum pump. So, the older model LR4’s must have been using the brake vacuum pump for the evap system. The newer cars have an electric pump built right into the canister itself.

I still don’t see how fuel saturation would give a bunch of white smoke, unless liquid fuel mixed with the charcoal gives something that produces white smoke? Or maybe the system somehow drew water or oil into the canister. I also don’t why this would give white smoke at startup.

I guess OP could disconnect the purge valve from the air intake and see if anything is seeping. Maybe also start it and run it with the purge disconnected and see if the problem persists. Plug the opening on the intake side to prevent a vacuum leak and maybe plug the purge valve side to try to avoid an evap code.
 

gsxr

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I stand corrected. That part number for the pump in that diagram pulls up the brake vacuum pump.
That diagram is not a factory diagram, it's from an aftermarket part catalog used by dealers. It can be trusted about as much as any news story you read on the internet. To find out how the emission system works you need to look in the factory service manual, and/or factory part catalog (MicroCat). I've never researched this so I don't know how the evap system functions, or if it has any connection to the engine vacuum pump.

:2in1:
 

Bodhistt

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I love you guys. This is the most helpful forum.

I do have an earlier LR4 (2010).

https://www.amazon.com/ROVER-VACUUM...eywords=lr4+vacuum+pump&qid=1620737043&sr=8-3

I saw this diagram and thought that maybe the pump could get into a weird over/under pressure condition that could put oil vapor into the intake to give me the white smoke.

I also don’t why this would give white smoke at startup.

I guess OP could disconnect the purge valve from the air intake and see if anything is seeping. Maybe also start it and run it with the purge disconnected and see if the problem persists. Plug the opening on the intake side to prevent a vacuum leak and maybe plug the purge valve side to try to avoid an evap code.

Maybe a slow oil leak allows some to pool in the intake and it gets sucked up at startup? IDK. Not very good at EVAP systems myself.

I'll have to try plugging the hole and recreating the conditions.

I will report back as soon as I have some info on this. Just need to find the time to get under/inside to take a look.

THANKS!
 

jlglr4

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The vacuum pump is a booster pump. The engine pulls vacuum as well. So those two lines you see in the diagram (one to the intake manifold and the other to the pump) are both pulling vacuum to assist the brake (third line).

When the pump goes bad, it should pull less vacuum, not more. So I don’t see how a bad pump would pull more oil into your intake. I know that’s what the one poster commented in that video, I just don’t understand the mechanism by which that was happening.

To be sure, oil can get into your intake from the PCV breather. In fact, I can tell you for certain that the newer cars have a bit of an issue (in my opinion) with how much oil gets past that breather. Most people that have pulled the superchargers have noted the accumulation of oil. The vacuum generated by the engine at the intake manifold might pull some of this down into the cylinders. However, the vacuum is greatest at idle and the throttle plate is closed. It is far less when you accelerate (especially hard acceleration), and even on first startup when the engine is idling fast because the throttle plate is open and air is flowing in freely from the air intakes.

You mentioned that the PCV was changed. I assume this was after the smoke started. How bad was the PCV - was it torn? Just wondering if you got a bunch of oil in the intake while the PCV was torn, and its still draining into the cylinders. Seems like it should be out by now though.

You could try disconnecting the purge valve as mentioned before - just rule out the evap system.

If your thinking of disconnecting the brake pump, be careful as that can be a bit dangerous. Your brakes will not work nearly as well without that pump connected. Might be okay to observe the startup smoke.

Not sure if you’re doing this work yourself or not, but you might just pull the intake manifold and see what’s in there. I don’t think it’s very much of a job on the V8’s (it’s a royal pain in the supercharged cars). With that off, you could see if there’s oil accumulating from the PCV, and you could get a peek at your valves/stems to see if there’s a lot of carbon buildup or even fresh wet oil getting past. Just make sure not to let anything drop down in those cylinders :).
 

Bodhistt

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You mentioned that the PCV was changed. I assume this was after the smoke started. How bad was the PCV - was it torn?

Yeah, I read somewhere else that this was a possible culprit. So I replaced them. They weren't bad really. Nothing torn or especially oily. I did note that the valve cover it clips onto is broke a little bit. All I did was use some RTV sealant and make sure it had a good connection.

If your thinking of disconnecting the brake pump, be careful as that can be a bit dangerous. Your brakes will not work nearly as well without that pump connected. Might be okay to observe the startup smoke.

Nah, I ain't playin that game. The startup smoke is very inconsistent. Not worth it really.

Not sure if you’re doing this work yourself or not, but you might just pull the intake manifold

I pulled the intake when I did the coolant crossover pipe. The pipe had broke and coolant was leaking everywhere. It looked ok when I did that. Can't say I noted any pools of oil, But I was more focused on the coolant.

I also just had a look finally and the vacuum pump is definitely oily. It's the only wet spot on the truck. Gonna order a new one and see how she fairs.


I just don’t understand the mechanism by which that was happening.

Just spitballing here: If the pump "loses its seal" at higher RPMs and no longer creates vacuum. Then the oil could be leaking and pulled into the intake through the intakes vacuum since the pump is theoretically 'open'?

¯\_(ツ)_/¯
 

jlglr4

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Just spitballing here: If the pump "loses its seal" at higher RPMs and no longer creates vacuum. Then the oil could be leaking and pulled into the intake through the intakes vacuum since the pump is theoretically 'open'?

So, the vacuum from the engine is pulling the leaking pump oil up into the intake through the brake assist line. I guess that’s a possibility. Whatever the mechanism, your symptoms seem to be the same as that other poster who reported a bad vacuum pump, and now you find your pump leaking oil as well. Seems like more than a coincidence. Hope that’s it. Let us know.
 

Bodhistt

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Alright! Finally had time to dig in and replace the Vacuum Pump and it was definitely leaking.

Took a little drive right before to confirm the smoke issue was still occurring.

After replacing, I went on a confirmation drive and sure as shit it's fixed now. So whatever the mechanism it was the vacuum pump responsible.

Thanks for your help y'all!
 

gsxr

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Wow. That is crazy! Nice to hear the problem is fixed. I'd love to know how the engine vacuum pump could cause smoking. Never would have thought it was possible.

:oops:
 

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