This is a terrific video of a tech using a smoke test to discover a vacuum leak in 2000 XJ8 4.0.

Gives you a very good example of what a smoke test can do and how it's done.

I'll bet it had a P0174 cade given it appears to be the left side manifold<G>

 

I bought a cheap party fog machine from eBay to identify a sneaky vacuum leak. It ended up being where the brake booster meets the throttle intake. I had replaced the brake booster clip twice then the brake booster pipe. Thinking that there was no way there would be a vacuum leak still there. The smoke test revealed a leak still in that area but very small. Upon inspection for the 4th time I realised the rubber o ring inside the brake booster brass fitting had disappeared. I would not have caught this without the smoke test. No more vacuum leak.

 

Every once in a while we see something new and interesting. Thanks much RD.

 

Fog Machine. That's simply brilliant. Thanks for the idea.

 

I have a fog machine, but am concerned about the oily film from it gunking up my maf. I guess I could remove and block off the maf while smoke testing.
Has anyone had this issue?

 

Remove the plastic intake tube and tape the machine to the aluminum intake.

 

You can make your own
All you need is a sealed tin and a glow plug

I posted a copy of how I made my unit awhile back
https://www.jaguarforums.com/forum/x...-leaks-117917/

Cheers
34by151

 

I took a look and tested all the links.....they're dead and your pics further down are gone.

 

Out of curiosity did it use an oil or water based fluid and what's the downside to using either in our systems? Would an oil based screw with any sensors or would water cause any corrosion.

I would think a water based would be safe as whatever residue it left behind would pretty rapidly evaporate. Don't know for sure.

How much fluid did it take to run the test as fluid appears to be about 40-50% of the cost of the lower priced units with fluid being about $13 a qt. and units starting at about $25+ with shipping. (like inkjet printers<G>)

Oh yeah. What brand did you buy?

 

I think you'll be fine with either water or oil based fluid. I beleive I ended up getting the cheapest I could find which i beleive was oil based. I got the cheapest fog machine I could find on ebay. a Chauvet brand, found used for 25 bucks.
The fluid can be had at a Guitar Center or Musicians store. I beleive I paid about $10 for a bottle. I took the fog machine to Home Depot to find a large enough hose to fit at the fog emitting end then duck tape the hose to the aluminum oval intake after removing the plastic intake. I think the only sensor it would reach would be the MAP sensor located in the elbow under the throttle body. I wouldn't worry too much about that one since it's used to seeing black soot from pcv etc.
Below is a link to a fog machine:
Chauvet DJ Hurricane 700 Fog Machine | eBay

Happy Vacuum Leak Hunting

 

[QUOTE=BlackKat;1684550]I think you'll be fine with either water or oil based fluid. I beleive I ended up getting the cheapest I could find which i beleive was oil based. I got the cheapest fog machine I could find on ebay. a Chauvet brand, found used for 25 bucks.


Thanks for the reply and the info. I had done some looking at smoke generators but after reading your post I started looking at 'fog machines' as you did on eBay. I found several, but the Chauvet looked to be the best combination of price and features and wasn't being shipped from China.

 

what size hose are we looking at ? Hosepipe ? And do you step it down to fit into engine hose

 

Don't know, never bothered to measure. Just take your smoke machine to Home Depot and match it up to whatever flexible hoses you can find, drainage or others; doesn't matter. I used duct tape to then fit to the engine intake. No need to be fancy, as long as she conects and blows smoke without leaking at the machine end you're good.

 

Thanks for that I am in UK so don't have home depot ut I will pick up a fog machine and adapt. I will put in body throttle and stuff a rag round to get a seal and fingers crossed. I did find a part on under tray on driver side looks like it from some type of hose hopefully this is where the problem is and it's not the manifold.

 

An old electrical contact of some sort maybe???

 

I have no idea it was on the underfloor pan on driver side under engine. I was hoping it was what is causing my air leak. There is something at front under wing on driver side looks like something like a heater matrix but I not sure

 

That looks like the screw cap from a AAA battery torch.

 

I wish it was but has a slot on underside more like something to release pressure on a pipe / bleed screw

 

Plug for electrical brushes?

 

Thinking about that, on # 15 post.