Pay for a smoke test or just replace all vacuum hoses?

[coldweatherblue]

i've been tracking down a lambda 2 CEL for a couple months.

car runs fine but throws CEL at idle, goes away with increased throttle, sometimes (rarely) dies at idle, runs rich (carbon plugs, 18 mpg city 23 hwy).

sounds like a vacuum leak to me. at first I sprayed carb cleaner around everything I could see without any change in the idle. the boots/hoses all look ok but could definitely still have a leak. dipstick o-ring looks ok.

i've tested the o2 sensor and it seems to be working within normal limits (based on multimeter test)

c191 replaced. thermostat replaced.

fuel/air/oil filters all replaced. ignition system (rotor/cap/wires/plugs) replaced. ICV is working.

So now I just want to fix it.. 95% sure it's a vacuum leak.

is it worthwhile to pay someone to do a smoke test ($80) to pinpoint the leak or am I better off just putting that money towards buying new boot/hoses and just replace everything?

[dnguyen1963]

It depends...there are so many places that could contribute to vacuum leaks. Even when you replace everything, it is still worthwhile to do a smoke test to make sure that you have taken care of all vacuum leaks. My suggestion is to build yourself a cheap smoke machine then use it to find, at least, the major leaks. Replace what you need then go from there.

[jlevie]

The complete list
of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hoses, valve, and expansion tank
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

While leaks in some of those can be found by inspection or by spraying carb
cleaner on suspect areas, not finding leaks that way doesn't eliminate the
possibility. Only a smoke test will really work.

[EatsHondas]

If it were me, I'd replace any vacuum/intake/breather hoses that aren't soft and healthy looking just because. This is a good maintenance practice if you don't know the last time they were replaced, if they feel like hard plastic, if they're visibly cracked, etc. It can only do you good and will get you more familiar with the car.

If you or the PO has already done this, then go ahead and smoke it.

[SlamedIAm]

I think its worth it just to smoke it so you know exactly if/where you do or do not have vacuum leaks.

[coldweatherblue]

cool. thanks for the replies.

I replaced the valve cover gasket yesterday as well with no change.. yeah I've removed and inspected intake hoses/boots and connectors several times for routine stuff and they appear in decent shape but will try to make some time this weekend to get a smoke test done.

I hate vacuum leaks. part of me just wants to replace injectors/hoses/boots etc EVERYTHING just for the heck of it but it's good to know where the leak is, etc

[Vtec?lol]

Look up the DIY smoke test on here. all you need is an old pint bucket or glass jar with a metal lid and throw in a burning towel.

[Victor_PR]

^Yup. This is the way I'm going. Just bought the 5 ft of hose to finish the assembly and put it to the test on Saturday.

Here's the link that inspired me: http://www.r3vlimited.com/board/show....php?p=3530331

Good luck and report back please!

Look up the DIY smoke test on here. all you need is an old pint bucket or glass jar with a metal lid and throw in a burning towel.