Ford Explorer 4 0L SOHC Rough Idle Part 2 Vacuum Leak Hunting

In this video series, I will show you how I am attempting to fix a rough idle on my 1999 Ford Explorer 4.0L SOHC. I will show you how I used my inexpensive obd2 scan tool (with live data) to troubleshoot my vehicle. I used the fuel trims (long term) to help diagnosis a vacuum leak. Then I will show you how I found the vacuum leak. I tried several methods to find it, and I demonstrate a few of those methods. In this end I found the vacuum leak with a homemade smoke machine that I converted from a fog machine.
To see the videos in this mini series click the links below
Ford Explorer 4.0L SOHC Rough Idle
Part 1 Fuel Trim • Ford Explorer 4 0L SOH...
Part 2 Vacuum Leak Hunting • Ford Explorer 4 0L SOH...
Part 3 Smoke Machine • Ford Explorer 4 0L SOH...
Fog Machine Converted To Smoke Machine
Part 1 Overview • How To Use A Cheap Fog...
Part 2 Modifying • How To Use A Cheap Fog...
Ford Explorer 4.0L SOHC Upper and Lower Intake Gaskets
Part 1 • Ford Explorer 4 0L SOH...
Part 2 • Ford Explorer 4 0L Upp...

[@matthewchandler2470]

Hey, great video man! It helped me a lot. We did the fogger trick, only thing is, my coworker whom I was fixing the mountaineer for, I used him as the fogger. He vapes and blows a big fog everywhere, so why not blow it in there. So anyways, we found the leak at the egr diaphragm on your right in the front

[@dlin1231]

What is speed control flashing light on a 01 mercury mountaineer?

[@debraclifton8213]

Thank you I need to see how to look for...... whether you fixed it at that point or not. To physically SEE WHERE to start looking is GREAT FOR ME. So I personally Thank You

[@figibloom]

Thanks for watching!

[@kenjones2819]

its like building nuclear submarines, only different

[@marlonstubbs727]

On my 1998 explorer there is a vac hose on the drivers side of the car it's a 3/8 hose that runs from it looks like right on the front of the engine and runs down to a, looks like a box it's about 16 to 18 inches long and it was split on both sides and would collapse every time I started the car. I'm a contractor so I just cut a piece of old 3/8 air hose and BINGO fixed. Hope this helps and have a great day.

[@Kingjosh19]

whats the name of the second hose he pulls out attaching to the intake?

[@mikeschminkey8106]

Good luck bud because the tiny vacuum lines or rather need to intake and only way to get to him is pulling the upper intake off which is a pain in the ass I have the same problem with my Explorer on the driver side towards the back you can hear hissing

[@awohaz471]

explore 2008 6v engine jerk at a certain speed of around 60mile i dont know much about reading but the live data shows big drop in vacuum and increase in throttle opening up to 75% please help

[@JesusGodHolySpirit3]

Do you know where the HEATER CONTROL VALVE hose leads to ? It broke so I have to replace it when replacing the heater control valve for 98 Ford explorer?

[@MidnightSky1821]

Was your engine making a hissing sound; basically, was it noticeable you had a vacuum leak with sound alone or did you figure it out by rough idle/start up? Ive spent two days looking for mine which sounds like it is coming from the center area near the rail line/injectors. I sprayed it last night engine sounded great. Tried it today and nothing.

[@rudyramos4816]

I noticed I had a leak but didn't think much now my truck running like shit

[@donniejones3109]

I found your channel looking for vacuum diagram its so odd the diagram on the core support is like what the foc my rig has way more lines than what they show

[@donniejones3109]

Carb cleaner is what i have used in the past it does the opposite it makes the engine bog down

[@greg1629]

I replaced my PCV valve because after watching about every video on KZbin about these codes that usually fixed people's issues however it didn't fix mine. Perhaps I will replace the two vacuum hoses that attach to both sides of the PCV valve next otherwise I will be doing what you did throughout this video with the exception of not using starter fluid.

[@figibloom]

Hope it helps. Thanks for watching!!

[@ronaldbrown9638]

What did you find I'm tearing intake manifold off of moms truck right now been fighting with this silly thing for days

[@MidnightSky1821]

I am having a vacuum leak i cannot find even with starter fluid. Two mechanics and both are stuck. Fixed a bad injector, issue became worse. Rough idle when stop and a lot of shaking/jerking/bucking. Took off Air Flow sensor and wire harness and sounded better tomorrow is hose hunting.

[@bronzechicken4437]

So, I managed to get mine done, and I'm still having lean codes, with no vacuum leaks, I've smoked it and done starting fluid, and I'm getting good MPGs, but it's coding leans, the gaskets helped a ton though

[@figibloom]

Well if you still have lean codes with no vacuum leaks present. Could be lots of things. Could be a fuel delivery issue. Lean conditions are caused by either to much air or not enough fuel. Perhaps a clogged fuel injector. You can do a fuel injector pressure balance test, but you need an injector pulsing tool (I bought mine for 30) Basically what you do is hook up a fuel pressure gauge to the fuel rail, and plug in your injector pulse tool to one injector, and the tool turns on the fuel injector for a precise short amount of time, you do this to each injector and compare the before and after fuel pressure drops of each injector. You have to cycle the key between tests to rebuild the fuel rail pressure. If the fuel pressure drops do not match. Then you have a fuel injector fuel delivery issue (probably needs injectors cleaned) I had the same issue on my explorer. You can can on car injector cleaning or off car injector cleaning. In fact as I write this I am waiting on my fuel injectors in the mail. I sent my injectors out to be professionally cleaned and serviced (internal filters changed, ultrasonic cleaned, new o rings, and new pintle caps) I used this website www.mrinjector.us/ For 6 injectors to be serviced cost around 105.00. 17.50 a piece. Which may seem high, but to replace an injector cost around 100 per injector just for the part. I will be posting a video showing this whole procedure with in the next few days. This is my first time using this service, so I will wait and see and post results when I get my injectors back in the mail. Anyway, so lean conditions are either to much air or not enough fuel. Of course there are numerous things that can cause this problem vacuum leaks, clogged injectors, cylinder misfires (if air does not burn up in cylinder it gets pumped down to the o2 and that creates a false lean), faulty or skewed sensors (map, maf, tp, coolant, o2, iat,) basically any sensor that contributes to fuel pulse width can be suspect, exhaust leaks, bad o2 sensors. Anything that causes unwanted air to get to the o2 sensor can cause a lean or false lean condition. Well I hope this info helps you out. Good luck to you. Thanks for the comment and have a good day.

[@bronzechicken4437]

I found it, right rear of the upper intake is spaced out further than the front and air is going in there, I'm going to attempt loosening all bolts and tightening it in a different pattern.

[@billkrause4585]

Get out a cigar, plug up the air intake and blow in smoke into the brake vacuum line. The price of a cigar is cheap tool to find that vacuum leak. Afterwards, don't forget to unplug the air intake and plug the vacuum line back in. Have fun.

[@Leroy42575]

Do I do that while it's running or off?

[@geraldcoleman6540]

what is the vacuum line called that hooks to the right and left side of the intake?

[@figibloom]

Sorry, I am not sure what it is called. You may try looking on www.fordparts.com sometimes you can find detailed diagrams and part breakdowns. Thanks for the comment and have a good day.

[@E.J.61]

Trying to find ambient temp sensor on 98 ford explorer sport

[@kevincooper7290]

WHERE DID U GET THOSE PLUG WIRES AT MINE DONT LOOK NOTHING LIKE THE ONES YOU HAVE LET ME KNOW ..IT WOULD B A BIG HELP THANKS

[@figibloom]

I think I bought them from rockauto.com or off ebay.com they are motorcraft plugs I believe the part number was WR5944. I remember when I got them they had 5 black plug wires and 1 grey plug wire, which I thought was weird, but that is how they come. Well I hope this info helps you out. Thanks for watching and thanks for the comment. Have a good day.

[@Kingjosh19]

the hose he pulls out on minute 5:10 what does that hose lead to, I have an oil leak thru there

[@Chimonya]

Crankcase ventilation tube I think

[@andowolfy4203]

How would i get the vacume system off to get to the thermostat housing under? Im trying to replace entire thing.

[@andowolfy4203]

Same exact engine.

[@tonycotta31]

Easy to build your own smoke machine get old spray gun take it apart shorten nosel in side get a H.P shut off valve buy a cheap soildering gun drill a hole on side of spay gun can stick iron faceing down get a couple bottles baby oil and an old sock 3 ft. clear hose its cheap so you can put in line with vacume hose coming from break booster second hose to blow smoke threw or use compressor at 5 psi. it should make the leak stick out like a sore thumb there is a fella on you tube that made the same one it works great.

[@figibloom]

Thanks for watching!

[@figibloom]

And thanks for the tip!

[@jerrypeal653]

Best practices is check on cold engine

[@sabrinarojas6103]

What’s the yellow tube for ?

[@djexrayexray4384]

Mercury mountaineer rough Idel

[@anthoneysmith3436]

always start with the pcv cause mine had misfire in 2 cylinders lean code bank 1 and 2 its always the pcv the problem

[@MidnightSky1821]

I replaced mine 2 weeks ago and have just about all cylinder miss fire codes. I definitely have a vacuum leak just not entirely sure where :(

[@MidnightSky1821]

@al carr I'll look into it. Thank you

[@mariomartinezjr.3386]

alarm system reset well not start

[@Magnum5.9360]

I have a 97 4.0 and I have this valve thing that’s above the IAC sensor I have no close what it is it doesn’t look like yours has it.

[@dennylang4165]

Your likely looking at the Variable Induction System on a 4.0L SOHC engine, only a few years have it...

[@David-lh7mm]

Of course I'm not there to say positively, But the sound that you are chasing is the air that is going through your induction tubes.that your throttle body is hooked up to, those two black round cylinders on top of your motor are made of plastic and the air moving through them it sounds like an air leak.

[@josearenas3848]

6:40 show spray gasoline top to the motor

[@RobertLee-rr5wx]

check PCV valve?

[@clintzx10]

can also be a bad brake booster

[@user-ge1sf2us3b]

Can anyone tell me what is the hose name at 5:20 ? My this hose is cracked. Thanks.

[@Chimonya]

crankcase ventilation tube I think. Try a junk yard if you need to replace it.

[@TaxinGigs]

Thank you

[@user-ww4ip8kf8v]

Ok

[@maxxer127]

I have a hate for new cars and trucks. The 1990 4.0 was the best of the 4.0 engines it had NO EGR VALVE It had no Plastic intake and the self-life of the 2002 and later 4.0 with alum heads was short-lived. one major flaw with the dual overhead cam engines is If you have a timing chain issue. Most shops tell you to get a junkyard engine. Now tell me why any shop would tell you that it takes 12 hours to do a timing chain. My old 4.0 I've never dose a timing chain in 15 years with 250,000 miles

[@rudyramos4816]

I'm about to go hunting for a leak on my 2003 explorer

[@MAbid-zt7nm]

I explorer 2008 4.0 v6.rough idle at stop. codes showing four oxygen sensors.egr valve.purge control valve.what I tried is as follow.change fuel pump. change fuel filter. clean throttle body and injectors. change spark plug. change egr vlave. change front 2 oxygen sensor. still the engine hesitate at idle. ac compressor turn off when rough idle. Reply•

[@figibloom]

The trouble is this could be caused by so many things, I think you need to have a simple scan tool that shows live data. The reason is you need to be able to see what your o2 sensors are doing, and to see what the computer is seeing (make sure they are in closed loop and switching properly), need to look at fuel trims (long term and short term) to see if your vehicle is running rich or lean (these numbers can also help determine if you have vacuum leak at idle). I think having 4 o2 sensor codes would be a good place to start,(you said you changed the upstream o2's but did you also check the circuit integrity or did you just swap out the sensor) Could be an o2 circuit issue and not the sensors themselves. Especially if you changed the o2 sensors out, but still have the codes present. Also you said you changed out the spark plugs, what about the spark plug wires, what about your ignition coil (you may want to make sure it is firing properly (use a spark tester, oscilloscope, or a simple test light hooked to ground and check spark at the ignition coil) The test with the test light you can check for spark and also do a cylinder power balance test to see if you have a misfire at idle, and find out if you have a cylinder that is not contributing. Here is a link to a video showing this test. kzbin.info/www/bejne/a5bae3x4iJ5_b5o As I said your problems could be caused by so many things, but you need to be able to see more info to get a better picture of what is going on. I have seen rough idle issues caused by bad plugs, bad plug wires, weak ignition coils, weak fuel pumps, or restricted fuel, air restrictions, exhaust restrictions, timing problems, low compression, weak crankshaft position signals causing idle issues, weak camshaft position sensors, egr flowing at idle will cause rough running engine, I mean the list goes on and on. My advice to you is get a simple code reader one with live data, so you can look at what is going on. You can find simple scan tools online for under 20 and all the way up to 10000 just depends on what you want your scan tool to do, but just a simple generic obd2 scan tool with live data should be able to give you enough info. I have a few scan tool video reviews on my channel if you are interested. Well I hope this info helps you out, and good luck to you. Well thanks for watching and thanks for the comment. Have a good day.

[@felipebautista8222]

I think you have a bad. IAC valve

[@shidukirider]

I found most efi systems are pretty good at maintaining the idle speed even with vacuum leaks, they will maintain even with the introduction of a fuel source to a vacuum leak. My explorer only had a slight change in idle when i sprayed brake parts cleaner around the back of the manifold. I found the pcv had popped out of the hose. I did however see it big time on the fuel trims on my scanner when I sprayed around this area it leaned the fuel out a lot to compensate for the introduction of the brake parts cleaner to the intake tract. I still have a leak, I’ve yet to change the pcv valve so this may be it, maybe the intake gaskets themselves.

[@jeffmartin5843]

Brake booster could also have a vacuum leak

[@maggiealena]

Smoke machines are not the holy grail. WD-40 works. I been using it for 50 yrs. Not good as a penetrating oil but good for most other stuff. What ever works. I hope you got the problem solved.

[@guesswhomartin9249]

Why are you spraying it with starting fluid ?

[@Jh68101]

It’s a way of finding the leak, if you spray starter fluid on the vacuum leak the fluid will get sucked into the engine and cause it to rev higher and signal the leak

[@elitegamer9_182]

If the engine revs higher that means the hose is sucking it in

[@billkrause4585]

Blow some smoke into the vacuum system.

[@anthoneysmith3436]

its always the pcv

[@joepedroza4707]

Not sure if i would do it that way too risky . I prefer the old cigar routine. Beside why not enjoy a cigar while your vacuum hunting. You can look like Groucho Marx the mechanic.

[@figibloom]

Haha. Thanks for watching.

[@angelgjr1999]

I don’t smoke though

[@camocrazy6506]

Find a friend who's into vaping get him to blow clouds at your engine for you. Lol

[@angelgjr1999]

Camo Crazy I already fixed it. It was just a loose air hose.

[@MidnightSky1821]

How can you do a smoke test while working out doors? This is a legit question because i am a beginner at this stuff.

[@djexrayexray4384]

Mercury mountaineer

[@BrunoTOGBE-ml4rw]

Dacomsa

[@kennysanders1900]

sounds like a bad idler pulley

[@figibloom]

+Kenny Sanders You might be right. Thanks for the comment and have a good day.

[@zeusprogods9950]

Ok blue screen red letters you couldn't do white black

[@JamieTransNyc]

So, this was 11 minutes of us watching some guy spray stuff inside the engine bay.... with no results? Not very good.

[@WilliamCarrier-oj4vk]

How are we going to feel for a vacuum leak with gloves on You're sticking your hand in all over the place like a blind kid at a Hooters. 💆🤦🏻