Using A Fog Machine For Vacuum Leak Test

[Minty Sauce 2]

I want to do a vacuum leak test and was thinking of using a cheap fog machine to do it. My question is, is it safe for the engine? ie, pumping in liquid vapour (water and glycol I believe) into inlet. I would run the engine after to try and burn/evaporate most of it off.

 

Thanks,

 

Andy.

[Minty Sauce 2]

OK, thought about this a bit more and a fog machine is probably not the best solution, being water based it will probably condense on the inside rather than seep out any holes.

 

So the new plan is to put a smoke pellet used for finding plumbing leaks in a tin, take the AFM off and seal the tin to the inlet, probably using a rubber glove and black tape, lol.

 

Anyone else done DIY vacuum tests?

Edited September 4, 2016 by Minty Sauce

[welshpug 1,657]

TBH there's very little that can cause a leak its probably much easier and quicker to take it apart replace a few gaskets and bolt it all back together.

[Minty Sauce 2]

The reason I thought it might be worth trying a smoke test is because it has just had the head gasket done and has since had a constant misfire at all engine operating ranges. It idles smoothly and revs through out the range but is low on power and has the constant misfire.

 

Passed it's MOT the other day but CO was 0.18% and HC 220ppm so looks very lean.

 

I am guessing as it is lean most likely cause is a vacuum leak or fuel delivery problem. If it was ignition it would most likely be rich (?)

[GLPoomobile 958]

I just asked for advice on making a smoke tester on another forum and plumbers smoke pellets were recommended. Given how cheap and simple it is to knock one up I'm now tending to think it's a useful test on any engine (in my case I'm looking for boost leaks).

[Minty Sauce 2]

Yeh, given that my car is till on it's original rubber hose I think it could be worthwhile anyway.

[steve@cornwall 100]

After just having the head gasket done, I'd check the valve timing first. Especially if the head was skimmed. The timing marks may well line up but shifting the belt one tooth can pay dividends. If you can fully advance the dizzy an not provoke pinking that would be an indicator. My car once belonged to a niece of a local peugeot "specialist" and I have many receipts for "investigate power loss" which turned out to be exactly that problem.

[Minty Sauce 2]

After just having the head gasket done, I'd check the valve timing first. Especially if the head was skimmed. The timing marks may well line up but shifting the belt one tooth can pay dividends. If you can fully advance the dizzy an not provoke pinking that would be an indicator. My car once belonged to a niece of a local peugeot "specialist" and I have many receipts for "investigate power loss" which turned out to be exactly that problem.

Yeh I will look at the valve timing too, Surely if it needed adjusting one tooth is quite alot? I was thinking a vernier cam sprocket might be needed?

[toolie72 67 1 Cars]

You can take quite a lot of a 205 head so it may have had more than one skim in its life

One tooth sounds a lot but it is not much when you think of it as points of a compass/or degrees of a circle

 

Remember if in doubt-wind engine round by hand a couple of times-simple check which should result in no sobbing!