Leaking Injector

So, i was looking at what I can replace these with. I'm pretty sure the fuel is comming from the body where the plastic meets the metal and not from the O-ring itself, So its going to need replaced not just re-ringed. I know alot of people goto the 4.6/5.0L mustang 19lb injectors. Not only are they cheaper, new at schucks for $49 vs $70 for stock or rebuilt ones you can find on ebay for like $80 bucks.

Long story short, my question is, why not? what are the down sides of using the 19lb injectors over stock? What kinda of proformance gains, if any, are there? I'm sure less fuel economy, but what other gains are there? I've done a quick search and didnt see much. Can someone with expreience with these clue me in? If its not going to give me much of a gain in proformance, then i might as well go stock and at least keep some of the mileage.

Also, this will be my first injector replacment, what are some snags I'll run into that I should avoid/be careful with?

~Ed

Downsides? None - the SBFord injectors deliver at right about the same rate as OEM RENIX.

Performance gains? None, unless you use the "four-hole" Ford jobs (which result in a finer mist of fuel. Probably no performance gain, but you may note a slight increase in economy.) Injectors won't increase power output unless you do something to improve air throughput as well.

Replacing injectors is fairly easy, and you should be done well inside of an hour. Tips:

1) Make sure to have new QD seal kits (two o-rings, spacer, new clip, installation thingy. You can also get just the o-rings, but don't get them from the hardware store. You need fuel-rated o-rings, and regular plumber's rings will dissolve over time.)

2) Draw a cupful of clean fuel (easiest to do this by catching the fuel when you depressurise the system.) Drop the o-rings in there before you take things to bits.

3) Remove the fuel rail as a unit, after you've removed the retaining screws and the fuel lines (and vacuum line from the pressure regulator.)

4) Make sure the injector seats are clean, both in the manifold and on the fuel rail.

5) By now, the new o-rings have been sitting in fuel for 15 minutes or so, and have softened considerably. This is a good thing - it helps prevent "skinning" of the things as they are installed.

6) Assemble the upper rings to the injectors (the dealer kit should have 13 rings in it - six of one colour and seven of another. The "upper" rings are the ones that there are seven of - the odd ring goes on the pressure regulator.) Assemble the injectors to the rail, install retaining clips. Change the o-ring on the pressure regulator.

7) Assemble the lower o-rings to the injectors. If you like, apply a very light coat of engine oil or chassis grease to the bore in the intake, where it "flares out" slightly.

8) Wiggle the rail into the intake. It takes a bit of doing to keep everything lined up, but you'll know you're in good shape when you see all of the "feet" on the rail touching the bosses for the screws on the manifold.

9) Change the QD fitting seals.

10) Reconnect the fuel lines and electrical connectors.

First start: Before you crank the engine over, cycle the key to RUN two or three times (at least five seconds in RUN each time) to refill and repressurise the system. Then crank. This will save you holding the starter down until the fuel finally gets there.

This may be a good time to change the fuel filter as well, if you haven't done so recently. Doing so will also allow you to get a good cupful (at least) of fuel to soak the o-rings in as well.

Pour the fuel you used to soak the o-rings back into the tank - it's not contaminated, so no point in wasting the stuff...

NOTE--The O-rings in the dealer kit are all black.
If changing to the Ford style injectors with the plastic tip-clean the hole in the intake real good to remove the carbon --a .45 cal bore brush works well.

Wayne

Awsome guys, great info. I guess my thoughts were higher pressure injectors ment more fuel getting into the chamber for a bigger burn and thus more power. But its all good. Even if its not going to give more proformance its cheaper and just as good as OEM =) I didnt know that I needed to get an o-ring kit also tho, figured they would have came with each injector. Thanks for the info guys =)

~Ed

GinisKratos said:

Awsome guys, great info. I guess my thoughts were higher pressure injectors ment more fuel getting into the chamber for a bigger burn and thus more power. But its all good. Even if its not going to give more proformance its cheaper and just as good as OEM =) I didnt know that I needed to get an o-ring kit also tho, figured they would have came with each injector. Thanks for the info guys =)

~Ed

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"Higher pressure injectors" is a misnomer - fuel injectors are rated for a certain volume of delivery at a certain pressure (for instance, a proper rating would be something like "21#/hour @ 45psig".)

This rating can be corrected to any pressure you like - I don't recall the formula offhand, but it's out there. I'd probably start by looking at Marren Fuel Injection (www.injector.com) or MSD (since they've gotten into fuel injection - www.msdignition.com, I think.)

5-90 said:

"Higher pressure injectors" is a misnomer - fuel injectors are rated for a certain volume of delivery at a certain pressure (for instance, a proper rating would be something like "21#/hour @ 45psig".)

This rating can be corrected to any pressure you like - I don't recall the formula offhand, but it's out there. I'd probably start by looking at Marren Fuel Injection (www.injector.com) or MSD (since they've gotten into fuel injection - www.msdignition.com, I think.)

Click to expand...

Ahh got ya. So this isnt so much as a proformance mod but a "its as good as stock but cheaper" mod Thanks for the info. I'll look closer. The "four-hole" ones you mentioned above that produce a finer mist seem like they might be the better option. With my 89 pushing 198k I'd be alittle worried about them getting cloged tho. I'll keep looking around. Thanks :worship:

GinisKratos said:

Ahh got ya. So this isnt so much as a proformance mod but a "its as good as stock but cheaper" mod Thanks for the info. I'll look closer. The "four-hole" ones you mentioned above that produce a finer mist seem like they might be the better option. With my 89 pushing 198k I'd be alittle worried about them getting cloged tho. I'll keep looking around. Thanks :worship:

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As long as you're running clean fuel, blockage shouldn't be an issue. I dump a four-ounce bottle of acetone in the fuel tank about once a month - acetone is used as a cleaning additive, so you're just upping the concentration for a tankful. It does help to keep things clean, and it's cheaper than commercial additives (which are probably mostly acetone and/or mineral spirits anyhow.)

Are the Ford 4.6/5.0 injectors good for the HO motors as well?

Here is a link to where I have gotten my injectors from in the past: http://www.fiveomotorsport.com/Injector_SetsJEEP.asp

Great service and they come with new o-rings on them as well:thumbup:

Does anybody know if 19# injectors from BMW will work? It seems that everyone prefers the ford set. Is this because the ford injectors were better construction than most other injectors or were RENIX injectors just a bad design and any other set will work. am watching a set of BMW injectors that I could pick up pretty cheap.

Thanks,

ECGTECH

Renix injectors were made by Bosch, and the Ford ones are direct drop ins. I did this 4 years ago using Ford O-rings, and it all never gives me trouble. I got mine from a 5.0 performance internet vendor, ran about $140 the set as they were low mileage takeouts.

If the BMW injectors are the same exact type, flow rating, electrical connection, etc., yes, they should work - but like all things Jeep, BMW = $. The Fords give the same performance and save money.

eBay Motors search for item 260349195168.

Seller is lucky7autoinjectors.

Ships fast, comes with o-rings, work great. Plus you end up with a couple of spares!

um spares, its not a good idea to just change out one or two of these. Its like rotating tires while adding your spare in, that way they all wear about the same rate. They should all have the same resistance value otherwise it will not work correctly. over time thier values will change as a set. Or that is how I have understood it.

By spares, I was referring to a set of eight injectors for a 4.0I6.

Should have made myself clearer. Anything that is mechanical or electrical can fail or become damaged in use, having two injectors in your spare parts kit couldn't hurt.