Determining WHICH Fuel Injector is Leaking

[BTR]

2000 Explorer 4.0L SOHC JOB1 2WD 5-Speed Automatic 140,000 Miles

I've determined that one (or more) of my fuel injectors is leaking. For this discussion, please assume this is correct. Also, please assume that I've ruled out everything else. Try to go-with-it. If possible, I'd like to see this discussion stay completely focused on the specific diagnosis of a leaking fuel injector/s.

I realize that I should simply remove all 6 injectors and have them professionally cleaned, or replaced with new injectors. However, that's not the approach I want to take right now (maybe later). Thus, this is more of a scientific discussion and less of a just-do-this-fix discussion.

Before I take anything apart (which I only want to do as the final step), I would like to determine WHICH injector/s is leaking. I realize that determining the EXACT injector/s is not feasible without taking things apart. However, I wonder if I can -- at least -- narrow it down to WHICH BANK the leaking injector/s is/are located in.

I've gathered quite a bit of fuel trim data. I wonder if this data can be used to determine WHICH BANK the leaking injector is located in.

When I analyze long-term fuel trim data (LTFT % Bank1 and LTFT % Bank 2), I see some patterns. The patterns aren't apparent 100% of the time, but they're apparent enough that they stick out as regular, recurring patterns. The patterns show the following:

Pattern 1
Warm engine. All sensors working and reporting properly. Idling smoothly in Park. Bank 1 reports 6.3. Bank 2 reports 4.7.

Pattern 2
Warm engine. All sensors working and reporting properly. Idling smoothly in Drive. Bank 1 reports 0.0. Bank 2 reports -0.8.

Pattern 3
Warm engine. All sensors working and reporting properly. Driving at varying accelerations, decelerations and speeds. When Bank 1 reports a negative number (asking for less fuel to be injected) Bank 2 also reports a negative number. Bank 1's negative number is noticeably lower than Bank 2's negative number.

So -- net net -- I wonder if this data is telling me that the leaky injector/s is located in Bank 2. Yes? No? Your thoughts?

 

[410Fortune]

you need a mechanics stethoscope
You can actually touch the tip of each injector and listen to them fire off with engine running
If you have one that is not "clicking" then that's your "leaker"
Only an injector that is stuck OPEN can leak fuel through, and a stuck open injector will not "click" when you listen to it working.
Usually it is low fuel pressure that is causing an injector to not atomize (spray) the fuel instead it just drips out and will not combust = leaky injector

IN order to replace one injector you must remove the entire fuel rail, so its best to test/clean all 6 while they are out
Do NOT replace one injector with cheapo auto parts store unit or you will be sorry!

 

[fast_dave]

@BTR

Just sayin' - sometimes it helps to establish a baseline, and then use that info along with the info you provided in your original post to get a complete picture.

I'd suggest, with the engine off, individually disconnect the wiring harness from each injector, and utilizing a multi-meter set to OHMS, take & record the resistance of each fuel injector.

Check the resistance of each fuel injector one by one and map it out on a piece of paper - Bank 1 & 2 along with each banks individual cylinders.

Report back with your findings for each bank & cylinder.

Overall, when evaluating the OHM readings, we're looking for consistency.

HTH -

 

[410Fortune]

You wont be able to put a ohm meter on 3-4 of the injectors
You can ohm them out through the PCM connector though

 

[96eb96]

This with a fuel injection pressure tester:
https://www.amazon.com/ALLOSUN-EM276-Fuel-Injector-Tester/dp/B0126MEK3C

 

[boominXplorer]

I'd replace 3 on one side, see if it fixes it. If not I'd do the other 3. They are not cheap but aren't that expensive either.

 

[410Fortune]

you can get 6 rebuilt and flow matched bosch injectors on ebay for under $60
Bosch 6x Fuel Injectors Ford 4.0 explorer sport trac 2001 shipped today | eBay

If you are going to remove the SOHC intake manifold you mine as well replace all 6
Or at least test all 6 of yours on the bench, it is not difficult
good time for plenum O rings as well

 

[BTR]

You can get 6 rebuilt and flow-matched Bosch injectors on eBay for under $60. Bosch 6x Fuel Injectors, Ford 4.0, Explorer, Sport Trac, 2001.
If you are going to remove the SOHC intake manifold, you might as well replace all 6. Or at least test all 6 of yours on the bench, it's not difficult. Good time for plenum O-rings as well.

@410Fortune. Are they any good? What do you think? Have you used them? You've piqued my interest, but it's a job I want to do only once (because of the complexity of the job).

 

[fast_dave]

@BTR

I believe that @410Fortune is trying to offer you a sound path that allows you to continue to drive your Ex, and when the parts arrive, perform the swap.

When I clicked on the Ebay link he provided, I saw that the dealer has been in business since 2007, and has close to a 100% rating for the 1,000's of sets he has sold - so he's good to go in my book. I've had good luck on Ebay - legit sellers want/strive for 100% ratings. I know I do when I sell stuff from time to time. And the one time I did have a problem, Ebay stepped in and the problem was solved to my satisfaction within a week's time total.

OK - so what you are getting off of Ebay is 20 year old used OEM injectors that have had the pintel filters and both o-rings replaced. The injectors have been cleaned and flow tested. The seller is in South Gate, an industrial area of LA, and more than likely has a deal with local wreckers to pull injectors for him, and he refurbishes them. Nothing will change the fact that they are used, BUT, they are OEM/Bosch/German Mfg. and not questionable Chinese Aftermarket.

Your other option is to utilize a fuel injector refurbish service off of Ebay, and they will refurbish your injectors, but the flip-side is your daily driver will have to be parked, and you have the ship time back/forth as well as the refurbish time. Additionally, refurbish services tend to cost more than the Ebay dealer link that @410Fortune provided. You could also find out from the refurbisher that you have one or more bad injectors, and have to spend money to get replacements. It's a roll o' the dice but some guys want THEIR injectors to be refurbished - and I understand that - and it's just another option.

The last option is that you can purchase a refurbish kit off of Ebay for around $15, and refurbish them on your own.
It's pretty simple and easy as long as you're not ham handed and take your time, and as far as I'm concerned it was pretty fun to do. I wouldn't want to do it all the time, but the first time was almost like a high school science experiment ;-) All the info is out there and no special tools are needed.

"Special Tools" are offered - but in reality all that's required is a multi-meter, sheet metal screw held by a set of small vise grips, injector pig tail, 9 volt battery, aerosol carb cleaner, a couple of zip ties, rubber fuel line to place over the injector, a small drill to drill a hole into the rubber line, some super glue to quickly seal around the hole that the red plastic tube from the carb cleaner enters through, and a catch container. You'll also need your wife's hair dryer to heat up and install the plastic spray pattern ring that installs on the end of the fuel injector. Heating up the plastic pattern ring lessens the chance of breaking/snapping it.

I checked my injectors resistance first, saw they were all good, and thus went that route and ordered a kit off of Ebay, BUT I have another car available to drive. Also, if you find out you have bad injector (resistance doesn't match the others) you will ultimately have to buy another which will take time/money. That's why it's advantageous to test them while they are installed on your Explorer.
.

 

[BTR]

2000 Explorer 4.0L SOHC JOB1 2WD 5-Speed Automatic 140,000 Miles

In several discussions, I've read "use only OEM fuel injectors!!!" I would like to use OEM injectors. However, I'm not clear on WHICH brand is OEM. Is the OEM brand Motorcraft... or is it Bosch... or is it some other brand... which one? Thanks.

 

[Turdle]

I would use the spark plug reading method myself. If an injector was truly leaking, that spark plug would look different from the rest.

 

[Mbrooks420]

I would use the spark plug reading method myself. If an injector was truly leaking, that spark plug would look different from the rest.

This. But, of course, if you open it up, replace all 6, they are probably more than due.

 

[410Fortune]

you guys are awesome

Jon is spot on, if you can read spark plugs you can see what cylinder is having issues


Yes I use EBAY injectors all the time, check sellers rating

I also refurbish my own injectors, wellI at least clean them and check their performance with a battery and can of carb cleaner....

I tried to buy 8 injectors at the junk yard recently, they wanted like $19 each and a core charge....was over $350! I laughed and left them on the desk.....silly prices!! came home and ordered some. I can buy an entire v8 engine for $350...........

 

[fast_dave]

@BTR

Your current Fuel Injectors are OEM and manufactured by Bosch for FORD.

The ones that the refurbisher on Ebay is offering have been pulled of a junkyard Explorer, and they're OEM and manufactured by Bosch for FORD.

If you can find New Motorcraft injectors, they will be manufactured by Bosch and have a Motorcraft part number. Make sure you're sitting down when you price those ;-) Probably in the $60 Each price range and many times any one dealer doesn't have (6) in stock.

Everyone is telling you to get the OEM/Bosch because not only are they original equipment, but they are built for the long haul. They have a "service life" just like any auto part, BUT more than often they FAR exceed their service life. That's why you're seeing them offered re-furbished 20 years after being originally manufactured.

If I were you , I would follow the link that @410Fortune provided in Post #7, and drop the $60 on the rebuilt injectors since you/we know they're good to go.

When you swap 'em out, save your old injectors, check them with a multi meter, and if the readings are consistent - buy a $15 refurbish kit off of Ebay, and have fun re-furbishing them on a rainy day.

As things stand, seriously, you're just spinning your wheels in the mud worrying about this - the set of injectors 410 steered you towards is OEM/Bosch and the last set the guy has