Does propane change with age?

[micky]

Does propane change with age? The web says No, but....

I have a can/bottle of propane that is at least 10 years old.

I'm using it as one of several ways to find the vacuum leak in my car.

I used it 2 years ago and got nowhere, but I'm being more diligent this time. I have an old valve to which I've added some windshield washer tubing, so that I can reach anywhere (although the curve that won't go away from the tubing makes it hard to get to some places).

But I'm used to propane having a strong, distinctive, maybe pungent smell, even just a whiff of it, and this stuff, Berzomatic brand. 14oz. fwiw in a tubular blue can (shaped like a salami), has barely any smell. In fact I wasn't even sure the valve was opening. Only because frost was forming on the valve (that screws to the bottle) was I sure something was coming out.

Also, when I didn't find a leak, I removed a small hose from the air cleaner box and I attached the hose from the propane bottle. Barely any change in the sound of the engine. Wouldn't have noticed it if I were not listening for it. Should I have attached it somewhere else? Or is propane just not a good test substance? I also have MAPP gas if you think that would work better.

This is somewhat complicated because these Toyota engines idle at

2000rpm to start and slow to 750 after 3 or 4 minutes.

So I'm rushing to test while the engine is cold and it's all the time lowering engine speed and changing the sound it makes anyhow.

40 years ago, I had a car that stalled if you didn't give it extra gas until it warmed up some. AFAIK, that car was considered in need of repair. But now it seems, with a microprocessor that can start with a fast idle (better or faster than the fast idle cam) and lower it later, Toyota just covers up this problem by providing 2000 rpm idling, instead designing the engine to not have the problem. Am I too cynical? Do other makes of cars do the same thing?

[Clare Snyder]

Toyota and all other manufacturers of EFI engines enrich the mixture when cold. Even with a richer mixture the engine speed needs to be increased on a cold engine. The IAC sensor end ECT sensor tell the computer it is cold - with the ECT having priority. (Intake Air Temp and Engine Coolant Temp sensors) Speed is controlled by the IAC valve (Intake Air Control) that bypasses the throttle plate.

Inearly Bosch style injection systems they had a CSI (Cold start injector) controlled by a thermo time switch that just shot an extra stream of fuel into the manifold for a certain length of time depending on engine coolant (and sometimes air) temperature.

[rbowman]

Have you been tested for covid lately?

[Anonymous]

BernzOmatic propane should have the same "rotten egg" smell as residential natural gas. Both have Mercaptan added to give it the odor.

See the MSDS data sheet here

[Clare Snyder]

Then againwe don't know what he's using - if he has an old torchwith the teeny tiny orfice half plugged he may not be getting enough flow to get much smell. - which wouid explain why he doesn't get much if any result when he feeds the gas.

[trader_4]

I don't recall Bernzomatic fuel having a strong smell. I've used cylinders that were a decade or more old and they worked for the torch.

Just shows you that what sounds simple on the internet, isn't so simple. Why not just warm it up first?

IDK, but 2000 for warmed up idle doesn't sound right for any car. Around 800 is more typical, for obvious reasons. Yours may be idling faster because of whatever is wrong with it and the computer trying to keep it running.

[trader_4]

I suggested he use a garden sprayer filled with gasoline and spray it everywhere, but for some reason he hasn't done that.