What is the REAL fuel injector size for the SOHC engine

[JOEZ33]

I've done quite a few searches on this topic, and have seen more than one person who's "positive" that they know how many lbs per hour the stock fuel injectors are on the 4.0 SOHC, but it's not always the same answer.

I've got a 1998 EB 2wd, stock. I want to replace the injectors with flow matched newer design injectors that fog better for economy in mind. Are they 19lb, 21lb or 24lb?

I've even read four different "Ford" part numbers for the stock replacements, apparantly the parts stores don't know either.

I can't tell the color since they're buried under 175K miles of dirt and old hoses etc.

If anyone's sure or has already replaced them please let me know. THANKS!!

JOE

 

[JOEZ33]

http://www.explorerforum.com/forums/showthread.php?t=173547

Found this thread while searching again, just needed to filter through the hundreds of threads on this topic. Someone PLEASE make this a sticky!!- and I'm talking about the older post that I quoted, not mine.

 

[aldive]

Mine are 19 pounders.

 

[JOEZ33]

Mine are 19 pounders.

just wondering if you read the link to the injector testing post? According to that very well informed post, with extremely detailed flow bench testing, and accurate stock ford/bosch fuel injector part numbers, the injectors are 24 lb/hr, 249cc, 14.5 ohm injectors. They are EV1 connectors, but EV2 style, and are very similar if not exact Bosch "Design III" injectors- which means they're the new style spray pattern.

Or, did you have yours already cleaned and matched- therefore you know first hand what's installed? I'm paranoid of installing the wrong injectors and completely screwing up the truck.

 

[JOEZ33]

Upon speaking with a sales rep for another bosch fuel injector outlet, he says that Ford rates them at 19 lbs because Ford uses 22.45 PSI as the rating pressure, but that same injector is really a 24 lb/hr injector when tested at the "industry standard" of 43 psi. This seems to be where all the confusion is coming from.... leave it to Ford to create another useless standard...lol.

Well, after doing the research and comparing part numbers vs. acceptable replacement numbers, and newer improved design part numbers etc. I found a source on eBay who will sell me a set of rebuilt injectors that are completely 100% exact flow matched for $129. Or for a little more I can get the 8 cylinder set and keep two spares. On my budget I'll just get the set of (6).

Anyways here's what this seller told me:

"these are rated at ford pressure at 22.45lb. They are part # 0280155715 from ford/bosch. If you want 6 they are $129 for the set flow matched. We flow match these 100% of each other.. we buy cores by the 1000's. We flow every one, they are then marked by flow rate, they are then grouped with others that flow the exact cc/mn..."

Anyways, I'm taking the chance and buying them. Wish me luck, and I'll keep updates of mileage changes etc. in case these are wrong and screw everything up.

 

[JOEZ33]

INSTALLATION UPDATE: For anyone who's following this install and who wants to replace and/or upgrade theire injectors. I received my injectors today and pulled the top of the engine apart to get access to the old ones. After getting the old ones out I see that the originals are over 1/2" shorter than the replacement ones. They also have different shape and style of the plastic tip at the spray end of the injector. I'm not sure what purpose that tip has besides giving the o-ring a place to stay seated. That plastic tip on the new injectors doesn't fit very well into the engine, and cracks/breaks off while sliding the injector in. The part that breaks off is a perfect circular shape ring at the very tip. I'm continuing this install anyways, and I'll see what or if any problems come from this. I really don't think the small piece that breaks off is an issue, the O ring still has a ring land to sit in and looks uniform.

One more thing I'm dealing with is the fact that the taller nozzles cause the fuel rail to be over 1/2" above the engine at it's mounting points. Because of this I have to make spacers. Tomorrow morning I'm going to the airport (my job) and getting some bushings to make my own spacers. Right now I just used two #6 plain nuts on top of each other as a spacer. It's perfect height and the rail fits solid.

After seeing the originals and the replacement injectors I can tell that the new and old injectors both have 4 tiny spray holes, this supposedly means we already have the newest technology injectors and won't find a better replacement.

I would strongly recommend using Rogue Performance instead of eBay injectors like I bought. The original replacements from Rogue will literally bolt right in without modifications, and are already flow matched.

While apart I'm scraping out all the caked on oil and carbon deposits from the intake. what a MESS. The only clean part of the intake is immediately below the injectors and also the intake valves are clean.

 

[trucku]

You can eliminate the oil being sucked up into the intake by putting a air/oil separator between PCV valve and intake. I bought mine from home depot (husky) in the air tool section. It works great. I have to drain it every month or so.

 

[JOEZ33]

You can eliminate the oil being sucked up into the intake by putting a air/oil separator between PCV valve and intake. I bought mine from home depot (husky) in the air tool section. It works great. I have to drain it every month or so.

Yeah I love my oil separator! I installed it almost a year ago. While installing it I went a step further than some people and used a piece of that brass or bronze colored metal scrub pad they sell for cleaning kitchen stuff. I cut off a piece of it and shoved it into the pcv hose just before the oil separator. This causes turbulance over thousands of little pieces of surface area, and in turn separates more oil than just the separator alone. I save about a shot glass of oil every month to month and a half which used to get sucked into the intake. So I feel confident that I'm not wasting my time by cleaning the intake runners, after the next 50,000 miles it should still be clean since no oil at all is getting into it.

 

[trucku]

Yeah I love my oil separator! I installed it almost a year ago. While installing it I went a step further than some people and used a piece of that brass or bronze colored metal scrub pad they sell for cleaning kitchen stuff. I cut off a piece of it and shoved it into the pcv hose just before the oil separator. This causes turbulance over thousands of little pieces of surface area, and in turn separates more oil than just the separator alone. I save about a shot glass of oil every month to month and a half which used to get sucked into the intake. So I feel confident that I'm not wasting my time by cleaning the intake runners, after the next 50,000 miles it should still be clean since no oil at all is getting into it.

Thanks for that tip. I will do the same.

Good to know we are having the same results.

 

[JOEZ33]

Do you know what I'm talkin about with that scrub pad? it's the one that crack heads use as a filter when they smoke.....LOL,,, so even though it's sold at every single grocery store in the world, if johnny law pulls you over and finds that pad in your car he can decide to call it paraphernalia and can search the car.

I had read about the separator on this web forum, but am also a member of bobistheoilguy.com and mpgresearch.com. On those forums those guys are insane about getting better mileage and they swear that adding the copper scrubber will help MPG. Supposedly there is a small amount of flammable material left over from the gasoline that gets into the oil, this separator helps make that fuel evaporate back into the air being sucked into the engine. Not sure if it applies to every vehicle or just old school cars that run richer than needed.

 

[JOEZ33]

Just another note about the replacement injectors-

These injectors had a different style plastic tip which breaks off because it fits too tight into the engine. I successfully removed the tip from the factory injectors and popped them onto these new injectors. None of them broke WooHoo!

I've spent hours and hours learning and reading about the factory fuel injectors and learned much more than I really wanted to about them. As a result I found a few great links for anyone interested in fuel injector information. Here's a link http://www.injectorcleaning.co.uk/flow.htm to a very lengthy list of every single part # injector made by Bosch along with flow rate and ohm resistance. The factory injectors BTW are P/N 0280155734.

Everyone in the world rates the Lbs/Hr at a specific 43 PSI as the industry standard. In turn this means the factory fuel injectors for the SOHC 4.0 V-6 engine is 24 Lb/Hr. FORD for some stupid ass reason rates it at 22.45 PSI even though the engine doesn't normally run below 28 psi, and FORD decided that while at 22.45 PSI these injectors flow 19 Lb/Hr, so in turn they're called 19 Lb/Hr injectors. I have no idea why they did this but hey, they obviously know what they're doing or else their stock wouldn't be so valuable....LOL $1.00 a share.....

 

[trucku]

Do you know what I'm talkin about with that scrub pad? it's the one that crack heads use as a filter when they smoke.....LOL,,, so even though it's sold at every single grocery store in the world, if johnny law pulls you over and finds that pad in your car he can decide to call it paraphernalia and can search the car.

I had read about the separator on this web forum, but am also a member of bobistheoilguy.com and mpgresearch.com. On those forums those guys are insane about getting better mileage and they swear that adding the copper scrubber will help MPG. Supposedly there is a small amount of flammable material left over from the gasoline that gets into the oil, this separator helps make that fuel evaporate back into the air being sucked into the engine. Not sure if it applies to every vehicle or just old school cars that run richer than needed.

I am a BITOG member also. Yep them guys are oil gurus...lol. Gary Allen is great.

I was actually going to check out bitog to see if the scrubber had any ill effects on the oil. I have not done a analysis, but wanted to see if anyone else did with the scrubber in for a while.

I was actually thinking of paralleling two oil/water separators at one time. I figure slowing the volume of air is better and will allow the oil to condense into the catch.

 

[JOEZ33]

Tonight I got the top end of the engine all back together and fired it up. After three tries it finally stayed running and coughed a little bit. Then it finally smoothed out. Ran extremely smooth, not one sputter. Before it always had some slight sputtering and shaking at random but now its completely smooth as glass. I let it warm up and shut it down. Tomorrow I'll finish wiring my electric fan and then start test driving it. So far so good, those injectors seem to work perfectly. They are rated at identical cc/min and ohms, and are rated at 24 lb/hour. I suspect that if I had incorrectly changed to a much larger than original injector size it would run like crap.

 

[JOEZ33]

I finished the truck and drove it around tonight. Wow what a blast to drive now. I had figured it would run smoother and maybe feel slightly stronger, but HOLY crap it feels like I swapped in a V8 and a lower first gear ratio. It's insane what a huge difference the injectors made. The idle is pretty good, but when it's in gear if you crack the gas pedal down about half way it will bark the tires and snap your neck back. Now it finally feels like it has the 4.10:1 posi gears in it, I cant wait to tow something. It's always had 4:10 gears but drove like they were 3.23's.

 

[JOEZ33]

So far so good, the newer injectors have helped the gas mileage a little bit. If I set cruise and watch the instant MPG gauge, I always look at the average and usually it's different in the morning vs. afternoon based on outside temps etc. So I've been keeping track of the most common mpg, and it's about 3 mpg better than before. My mileage had taken a dive a few months ago, and its gotten better again. The only difference is that I have power AND mileage now.

Before the injector change I was having a little trouble building speed to merge onto the highway, or passing other vehicles on the highway. Now I barely step on the pedal to pass people, I don't have to force a downshift just to make enough power to pass.

The new injectors are Bosch Design III. I think they might be the same spray pattern as the old ones, just a taller injector body. I read somewhere that the Design III injectors have a more sensitive coil, not sure if that matters. Either way, these are 24LB injectors, they're blue (stocks were blue also), and they work great.