Fuel Injectors

wkohler · Post by **wkohler** » Wed Apr 14, 2010 1:39 am

Is there a way to replace the hoses on the fuel injectors separately, or do I need to buy new injectors (doesn't seem like a very cost-effective solution)?

Basically, the issue I'm having is that cylinder #2 injector (something around it - entire injector is wet) is dumping a considerable amount of fuel, so I figure it's something in the supply, as for the amount of time the car was running, that much fuel couldn't come from the o-ring side.

Thanks.

Mike W. · Post by **Mike W.** » Wed Apr 14, 2010 12:25 pm

Yes, the hoses can definitely be replaced seperately. I think BMWs recomendation is to burn them off with a soldering iron, but I have this thing about heat and fuel so I cut them off, carefully, with an exacto knife. This is one of those things that mushrooms, if one is leaking badly, by this time they all probably need to be done. It is kind of a pain, the OE hose is ungodly tough, but you want to be careful not to nick up the barbs on either the injector or the fuel rail. It will take far longer than it looks like it should just to replace 6 short pieces of rubber. And again, as long as you're there... do the rest of the hose in the engine compartment.

Now, after all that, before you do anything I suggest you get some carb cleaner and hose off all the injectors so they really clean. Let it dry, it won't take long with that stuff, and start it up. Sometimes it's the actual injectors themselves that leak, not just the hose, and you'll get really upset if you replace all the hoses only to find the injectors themselves leaking.

T.Hanson · Post by **T.Hanson** » Thu Apr 15, 2010 9:26 pm

There's a whole big nice full color FAQ on the subject.

T.Hanson · Post by **T.Hanson** » Thu Apr 15, 2010 9:33 pm

Mike : Are you saying squirt carb cleaner under the manifold, etc., all over the injectors, flanges, bolts, hoses ?

Obviously followed by soapy water, rise, dry as carb cleaner is boom, boom wow wet.

Only curious as I thought injectors leaked internally, as in the little pin sticking out from that nylon nose cover. Other places, to me, would want new O rings, fuel line.

wkohler · Post by **wkohler** » Thu Apr 15, 2010 9:39 pm

Out of curiosity, I started it up again and nothing is leaking. Weird. Its all getting changed regardless, but...

Mike W. · Post by **Mike W.** » Fri Apr 16, 2010 11:35 am

T.Hanson wrote:Mike : Are you saying squirt carb cleaner under the manifold, etc., all over the injectors, flanges, bolts, hoses ?

All over the injector body and the little stub hose.

Obviously followed by soapy water, rise, dry as carb cleaner is boom, boom wow wet.

No, it's all on the intake side and it evaporates off pretty quickly. You don't have to have it running to clean it up anyway.

Only curious as I thought injectors leaked internally, as in the little pin sticking out from that nylon nose cover. Other places, to me, would want new O rings, fuel line.

Nope, there's a seal in the body that leaks too. I've replaced at least half a dozen over the years, that's the injector, not the internal seal which I don't think is replaceable. You can pretty much tell by looking at them, they get an oily look to them where they leak. They don't always even drip, but sometimes just get wet. But it doesn't take much gas to create quite an odor.

Lenny D. · Post by **Lenny D.** » Fri Apr 16, 2010 12:14 pm

wkohler wrote:Out of curiosity, I started it up again and nothing is leaking. Weird. Its all getting changed regardless, but...

All good info. above from Mike, and I'll add that leaky injectors/fuel line are most prone to do their leaking after you shut the engine off. (Proper) residual pressure will tend to reveal a leak so do your checking a few minutes after the engine is stopped.

thomas_m535i · Post by **thomas_m535i** » Sat Apr 17, 2010 5:08 am

Mike W. wrote: [..]

Indeed once again good info. Just to be sure: I can safely try to pry the nylon cover on the pictures of and there should actually be another replaceable gasket underneath?
The outer gasket and rubbers (injector to intake manifold) will be replaced.
Is there anything else advisable to replace on the injector itself while I'm at it?

Mike W. · Post by **Mike W.** » Sat Apr 17, 2010 11:22 am

thomas_m535i wrote:
Mike W. wrote: [..]
Indeed once again good info. Just to be sure: I can safely try to pry the nylon cover on the pictures of and there should actually be another replaceable gasket underneath?
The outer gasket and rubbers (injector to intake manifold) will be replaced.
Is there anything else advisable to replace on the injector itself while I'm at it?

No, while you can remove the nylon pintle cover and replace it if necessary, other than that there is nothing in there to replace. If the injector body starts leaking all you can do is replace the injector, I'm not aware of a way to reseal it. I'm talking the body, not bleeding off past the pintle which can be taken care of by either a professional cleaning or sometimes fuel additives like Techron.