Just a quick question. Can you use either throttle body cleaner or MAF sensor cleaner to detect a vacuum leak by spraying around suspected area? I've heard of using carb cleaner but don't have any of that. If there is a leak will the idle increase? Cheers Jeff

 

Yes, should do the same. You might also try using a length of hose as a stethoscope, with one end in your ear and the other end probing around the suspect area listening for the tell-tale hissing.

 

As another option, this thread on a BMW forum that I also frequent might be a more satisfactory solution: https://www.bimmerforums.com/forum/s...e-smoke-tester

 

I like to use starter fluid ( the car kind- not the barbecue type ). It evaporates well, and doesn't leave any residue.

 

I had NO LUCK using carb cleaner. The engine sound in my 06 str did not change as the pcm immediately corrected for it. I could see the change on the o2 sensors voltages and currents using SDD using the monitoring function

 

You would be better off watching the STFT while spraying the fluid.

 

I had those up on the screen too. I cant remember which one wiggled the most. But ya

 

You can use plain water in a spray bottle. The motor’s idle will change if there is a vacuum leak, similar to the idle change observed when using the highly flammable sprays already mentioned.

water has several pros, and no cons.

pros+ :

wont catch on fire
is really cheap
easy to find H2O
little to no residue (use distilled water If you want to avoid mineral spotting)

​​​​​​cons :

none

Z

 

Cons: water is not going to go through some tiny leaks so won't help if that's the problem.

 

Ive never had the water test fail yet in 50+ years . But I suppose there’s always a first time.

Z

 

they are tricky on this car I have one I cant find. I have smoked it, soaked it, and throttled it. the damn thing is elusive.

 

Thanks Guys. I have what sounds like a massive leak somewhere around the supercharger. See my other post below. Noticed a small but repeatable idle increase at front of s/c inlet pipe. Ordered another gasket. Spent hours fitting it (with other maintenance). Didn't make one bit of difference! I've never owned such a frustrating car. I love the thing but seriously starting to think that I spend more time rolling round underneath it than driving it!...

 

i hear ya......

 

I feel you on that, definitely spent more time under the hood than driving it.