Cheap DIY smoke machine for finding vacuum leaks
21 - 40 of 72 Posts
Joined
·
413 Posts
That is my battery ground cable I pulled out of my engine bay. Haven't gotten a new one today since I was pretty busy afterwards.
To refresh the thread, Indy:
-Miss at cruise with very very light pedal pressure. Never at WOT
-I can hear through the exhaust this "bubbly" noise at idle, like a miss of some sort. It's not painfully obvious though.
-Hammering the throttle is fine, it missed once and it was around 2,500 rpms. About the only time it ever missed under heavy acceleration.
Thanks for the reply.
Sent from AutoGuide.com Free App
Joined
·
413 Posts
With the stock throttle body on (removed the 70mm), it idles around 900+/- and I can still unplug the IAC where the idle drops. So I know that is working (only about 3 months old). I don't get any idle surge at all. It's pretty smooth when idle is locked in.
Joined
·
24,251 Posts
with a air leak on a speed density car the idle will go up.
Your idle should be 675+- 50 rpm.
the fact that you have a miss at cruise and idle, both conditions with low manifold pressure, suggests air leak indeed.
get a smoke machine and find it, %99.99999 sure that is what it is.
If you watched fuel trims, Im sure they are in the plus range.
Your idle should be 675+- 50 rpm.
the fact that you have a miss at cruise and idle, both conditions with low manifold pressure, suggests air leak indeed.
get a smoke machine and find it, %99.99999 sure that is what it is.
If you watched fuel trims, Im sure they are in the plus range.
Joined
·
413 Posts
I wish I had a smoke machine. Had one at the Ford dealership just before I got out of auto mechanics.
I have replaced every vacuum hose in the engine bay that I can visibly see.
PCV
Manifold to EVR
MAP
Source
Purge valve hose
New intake gaskets (miss is still identical)
A/C is capped
I've tried spraying soapy water around things and I'm not finding anything. To reiterate, this problem was super random. To a car show in May, it did it about 4 times the entire way there and back. Since May to present, it will do it very often. On the 4th of July during a 40 minute return home trip, it never missed once for the last 20 minutes of the ride.
I have replaced every vacuum hose in the engine bay that I can visibly see.
PCV
Manifold to EVR
MAP
Source
Purge valve hose
New intake gaskets (miss is still identical)
A/C is capped
I've tried spraying soapy water around things and I'm not finding anything. To reiterate, this problem was super random. To a car show in May, it did it about 4 times the entire way there and back. Since May to present, it will do it very often. On the 4th of July during a 40 minute return home trip, it never missed once for the last 20 minutes of the ride.
Joined
·
413 Posts
I'd like to..... If I could afford to spend over $750 on a machine. Sadly not an option in present time.
Sent from AutoGuide.com Free App
Sent from AutoGuide.com Free App
Joined
·
413 Posts
My newest creation. Made it my way. I'll be placing the charcoal in a small glass bowl that won't make contact with the plastic inside. All that needs to be made is smoke. I'll test it out tomorrow after work.
Thanks for the inspiration Indy.
Sent from AutoGuide.com Free App
Thanks for the inspiration Indy.
Sent from AutoGuide.com Free App
Attachments
Joined
·
413 Posts
Well, my smoke apparatus (far from a machine) worked like a charm. I used cardboard instead of the charcoal/cardboard combo and it smoked rather well.
What I found was one of the new hoses I installed in March when I put my Cobra intakes on was leaking at the MAP sensor and clearly. I didn't see any other smoke at all besides there. I put a clamp over the hose to tighten it up. I haven't been able to drive it as I ran out steam after a long work day.
I'm hoping this is my issue but only a test drive will tell.
Sent from AutoGuide.com Free App
What I found was one of the new hoses I installed in March when I put my Cobra intakes on was leaking at the MAP sensor and clearly. I didn't see any other smoke at all besides there. I put a clamp over the hose to tighten it up. I haven't been able to drive it as I ran out steam after a long work day.
I'm hoping this is my issue but only a test drive will tell.
Sent from AutoGuide.com Free App
Joined
·
413 Posts
I know this is a bad leak at an important sensor but I'll sure be delighted to know if it solves my issue. Also good to know all the other components are sealed.
Sent from AutoGuide.com Free App
Sent from AutoGuide.com Free App
Joined
·
413 Posts
Update :
I'd like to publicly thank indy2000 for his insistence (and a couple others that agreed with him) that my engine's issue was vacuum related. I've driven it 4 times now since yesterday and it doesn't miss anymore.
This simply proves when we think we've checked properly for vacuum leaks, we can still miss them. I'd easily recommend anyone follow this thread to see how easy it was to make a smoke apparatus. Worked awesome.
Close this case!!
Sent from AutoGuide.com Free App
I'd like to publicly thank indy2000 for his insistence (and a couple others that agreed with him) that my engine's issue was vacuum related. I've driven it 4 times now since yesterday and it doesn't miss anymore.
This simply proves when we think we've checked properly for vacuum leaks, we can still miss them. I'd easily recommend anyone follow this thread to see how easy it was to make a smoke apparatus. Worked awesome.
Close this case!!
Sent from AutoGuide.com Free App
Joined
·
413 Posts
Here's what I used to make mine:
-5lb whey protein tub (used this as its much easier than drilling a hole in glass)
-Spark plug boots from a coil wire (has 2 perfect sizes for the design to work)
-Hi-temp silicone to seal plug boots
-Glass jar to fit inside of the tub
-Cardboard
Instructions:
Take your drill and make a hole just a bit smaller than the diameter of the plug boot so it will fit tight in the LID of your tub. If you happen to have had a Ford coil wire, you'll have 2 different sizes most likely. Use the smaller diameter plug boot and twist it through the lid.
Make a similar hole NEAR the bottom of the tub and twist this through as well. Install the boot so the opening facing out and up is the bigger opening. This is so your tire inflator will fit inside.
Get your silicone and smear a liberal amount around BOTH sides of the plug boots. This ensures there's a tight seal made, no smoke will seep and it will strengthen the boot's ability to hold still. I will suggest you let it sit for a day now.
Now we are ready to use it:
Take you glass jar and fill it with cardboard. Set the cardboard on fire and let it burn for a minute. Let it burn out so it can then kindle/smolder. This is what will produce all the smoke you need to pump through your intake. Place the jar carefully into the tub and seal the lid tight.
Attach a vacuum hose to the boot on the lid but make sure you don't put it in all the way as you'll block the smoke's flow. Now take your tire inflator hose and plug it into the bottom spark plug boot. Have someone hold it in or try it yourself. Mine fit snug.
Connect the vacuum hose from the lid to a vacuum port on the intake. Turn the pump on and now you can search for smoke!
I hope this helps someone who can't afford a real smoke machine but it was free to make and worked perfectly for me.
Sent from AutoGuide.com Free App
-5lb whey protein tub (used this as its much easier than drilling a hole in glass)
-Spark plug boots from a coil wire (has 2 perfect sizes for the design to work)
-Hi-temp silicone to seal plug boots
-Glass jar to fit inside of the tub
-Cardboard
Instructions:
Take your drill and make a hole just a bit smaller than the diameter of the plug boot so it will fit tight in the LID of your tub. If you happen to have had a Ford coil wire, you'll have 2 different sizes most likely. Use the smaller diameter plug boot and twist it through the lid.
Make a similar hole NEAR the bottom of the tub and twist this through as well. Install the boot so the opening facing out and up is the bigger opening. This is so your tire inflator will fit inside.
Get your silicone and smear a liberal amount around BOTH sides of the plug boots. This ensures there's a tight seal made, no smoke will seep and it will strengthen the boot's ability to hold still. I will suggest you let it sit for a day now.
Now we are ready to use it:
Take you glass jar and fill it with cardboard. Set the cardboard on fire and let it burn for a minute. Let it burn out so it can then kindle/smolder. This is what will produce all the smoke you need to pump through your intake. Place the jar carefully into the tub and seal the lid tight.
Attach a vacuum hose to the boot on the lid but make sure you don't put it in all the way as you'll block the smoke's flow. Now take your tire inflator hose and plug it into the bottom spark plug boot. Have someone hold it in or try it yourself. Mine fit snug.
Connect the vacuum hose from the lid to a vacuum port on the intake. Turn the pump on and now you can search for smoke!
I hope this helps someone who can't afford a real smoke machine but it was free to make and worked perfectly for me.
Sent from AutoGuide.com Free App
Thanks for the rundown on how you did it. I thought it would be nice to have one of these myself, but was a little skeptical on how well it would work without any means of pushing the smoke into the intake tract. The second connection for a tire chuck makes sense. Glad to hear it works. I will try making one myself sometime soon!
21 - 40 of 72 Posts
Join the discussion
Join now to ask and comment!