Injector(s) leaking like mad

Recently (last week) I've changed injector o-rings with new ones, got them from stealership, 13 pieces. All black and they are all same. They were really tight fit, but I managed to put them on and assemble thing back.

Everything was working fine, no leaks for a week or so. And last night there was strong petrol smell. One of them is now so badly leaking, that I don't know what went wrong. Checked if anything come loose. But not, everything sits correctly, and it is just leaking at oring. Not the injector itself.

What can I do now ?

BTW, engine is renix type, 4.0L '90. And the part number for orings was 83503637.

Thanks!

did you grease the o rings when you put them in? If not you may have nicked them and now they are leaking.

I soaked them in petrol for 15 minutes before putting them on. Also, when I checked them yesterday, they looked fine - no damage on them.

Is there anything that I can do to them so they sit / seal better ?

Can you see where they are leaking from, when you turn on the key and pressurize the system do they start leaking right away or does the engine have to be running for them to leak ? If you unplug the connectors do they still leak when the system is pressurized.
I know you soaked them in gas but I don't think that lubricates the bores as well as vasoline as you slid them in.

They leak immediately when I turn on the key. Also it seems that it happens on only one injector (#4). Strange thing is that it was working so nice for a week, and then started leaking.

Bad thing is that dealer didn't have orings in stock, so they had to order them .. took 10 days to get those suckers, and pack was $20. That is just plain wrong. I will have to try to find new ones somewhere else. Are they from some special material, or just a matter of right size ?

It's pretty easy to nick those O-ring while installing them. You may not have removed a scallop from the O-Ring, but it may still be attached and not sealing well.

Another trick for installed is to not only soak them in petrol is to also coat them in petroleum jelly (aka Vaseline.)

Huh, being that english is not my native language, I have trouble understanding what 'scallop' means ?

Thanks

Okay... think about digging out a piece of that O-ring with your fingernail. The removed piece will be oval in 2 dimensions and slightly rounded in the 3rd.

I suspect that this piece is still attached on one edge, and isn't immediately obvious when you pull the injector out. It'll be pushed out of the way when it reaches the seating surface in the fuel rail, leading to a leak.

It is also worth noting that the RENIX injectors are known for leaking after 150-180Kmiles (~250-300K kilometres) at the body seam where the metal lower body is crimped to the upper plastic body.

The fix? Get a set of injectors pulled off of a Ford 302V8, a Chevvy 305V8, or a Chevvy 350V8 - making sure they use the same connector (it's fairly common) - and swap in six of those. If one is leaking, the rest aren't far behind - so just replace all six.

I don't know how available those injectors are going to be for you in Serbia, tho, but at least it's a jumping-off point for you to start looking.

Good luck! And don't wait to replace them - engine compartment fires aren't fun...

5-90

Thanks ChiXJeff and 5-90,

It seems that I will order some injectors off ebay, but in the meantime, I need to get jeep running. It started snowing yesterday, and my jeep is now far away.. I can try to put new o-rings at weekend.

However, as dealer doesn't have them in stock, I will have to buy them at local shops. The only problem is that I haven't got one with me, for them to find a matching replacement So I'll have to ask you here for one favour, if anybody can, to find exact measurement - inner + outer diameter, and possibly thickness.

It is sometimes so tricky to find some simple stuff for jeeps.. Seems like I'm living on different planet. Well, it is a different continent at least

I've found some 302 injectors on ebay that can be sent to europe. They are however from '87 engine. Aren't they a bit old ? Or it doesn't matter ?

Thanks

fuel pressure regulator

@delverde

You think it might be shot ? dead ? not regulating correctly ? ... I hope thats not the case.

It seems also that I can find 2nd hand HO injectors here. Will they work on my renix engine ?

Thanks

mr_W said:

It seems also that I can find 2nd hand HO injectors here. Will they work on my renix engine ?

Thanks

Click to expand...

They should - as long as the connection is the same for the electrical (I think they changed it with OBD-II in 1996, but I'm not sure. The early HO will work.) If the connector is different, you'll have to get six male connectors and splice those in. Fuel delivery is at the same rate.

I've not had a fuel regulator failure yet - but you may as well replace that o-ring (from the FPR to the fuel rail) while you've got it torn to bits.

5-90

Temporary solution: take the undamaged o-ring off the bottom end of the injector and use it a the top end, where the injector connects to the fuel rail. Use the leaky o-ring on the bottom of the injector, where it does not have to hold fuel-rail pressure. Check for leaks!! I found I could not get the o-rings to slide in unless I used vaseline on them- without it, the new o-rings caught and twisted (and leaked).

4xBob said:

Temporary solution: take the undamaged o-ring off the bottom end of the injector and use it a the top end, where the injector connects to the fuel rail. Use the leaky o-ring on the bottom of the injector, where it does not have to hold fuel-rail pressure. Check for leaks!! I found I could not get the o-rings to slide in unless I used vaseline on them- without it, the new o-rings caught and twisted (and leaked).

Click to expand...

Soaking them in fuel should also work - it's what I usually do.

However, if it's the typical "RENIX Injector Leak," swapping the o-rings end-for-end won't work - it's a body leak. Just replace the things...

5-90

@4xBob

This is most probably what is causing my problems. Man those were so tight fit, that I started thinking that I got wrong part number. Eventually they went into fuel rail. And now that you say it, I think they might be damaged or twisted a little bit.

@5-90

Thanks for helpful info on HO injectors. I will give these guys which sell them a ring, and if its normal price, I'll just have to give it a try. Otherwise, ebay here I come

Such a pity to have to walk, with all the snow and rain and cold weather, and jeep just sitting in driveway.

mr_W said:

@4xBob

This is most probably what is causing my problems. Man those were so tight fit, that I started thinking that I got wrong part number. Eventually they went into fuel rail. And now that you say it, I think they might be damaged or twisted a little bit.

@5-90

Thanks for helpful info on HO injectors. I will give these guys which sell them a ring, and if its normal price, I'll just have to give it a try. Otherwise, ebay here I come

Such a pity to have to walk, with all the snow and rain and cold weather, and jeep just sitting in driveway.

Click to expand...

I've had to do this job a couple of times - it's a snug fit, but soaking the o-rings in fuel helps to soften them slightly (I usually draw a half-cup or so when I depressurise the fuel rail, and drop the new rings in before I start taking things to bits...) and a bit of Vaseline, petroleum jelly (by whatever name you have it there,) or a small amount of grease on the part where the oring enters might also help. And, take a moment to check the ports in the manifold and the fuel rail - make sure they're clean and there's no bits of old O-ring stuck in there - that could cause trouble. Clean them with a toothbrush (if none,) or a small brass or bronze brush (like a bore brush for a shotgun) if there are any bits in there.

Cleanliness is important here.

However, they are going to be tight, and that's actually a good thing (since you know they'll seal straight away, if they go in right.) Just don't overdo it with the lube, or you'll have things running funny for a little while as you burn the extra lube out. I've honestly tried not to use anything but soaking the new o-rings and a little care, and it's worked for me so far.

HINT - don't just ram the new o-rings straight into the bore - get them started, and gently rock and turn the injector until it's fully seated. You can still turn the injector once the rings are in, so getting the final alignment you need to plug them in is not a problem. Whether to do the fuel rail end (and install the new setup as a unit) or do them individually (and put the fuel rail on all at once) is up to you - but I've found it easier, for me, to install them into the fuel rail, put the clips on, and then put the new injectors/fuel rail in as a unit. That's just me...

5-90

Well, it seems that, as for 2nd hand injectors, ebay is off. They claim that USPS won't ship any fuel system related items, except if they are brand new, never used.

I can buy used HO injectors here, for 20eur ea. So most probably this will going to be my route.

Also, the thing that bothers me a little bit, is this thread : http://www.naxja.org/forum/showthread.php?t=6391
which lists different flow rate for 91+ injectors than 87-90.