leaks around injector o-rings?

[rrubel]

How common is it for newly-installed o-rings to leak vacuum a little? Once again, I have the car all together and was testing it for vac leaks. If I spray carb cleaner onto the manifold by each injector (so far, I'm 6 for 6), the engine revs higher.

These are all brand-new rings, lubed with a small amount of clean motor oil before installation. The fuel rail is tight against the manifold. The injectors will rotate when pushed, but not easily.

What's going on?

Thanks.
[RICHR]

 

[Ken]

How common is it for newly-installed o-rings to leak vacuum a little?

Not common at all Rich. There should be no leaks at all.

 

[The Car Whisperer]

If the o-rings are leaking you would be leaking gasoline there. The fuel systm is presurized, not under vacuum. You may have a manifold leak in the area you are spraying the carb cleaner.

 

[RonJ]

If the o-rings are leaking you would be leaking gasoline there. The fuel systm is presurized, not under vacuum. You may have a manifold leak in the area you are spraying the carb cleaner.

The o-rings that rrubel is talking about never see any fuel pressure, unless maybe if the engine backfires and forces A/F mixture back against them. If they are new and sucking air, somethings not right. Could they have twisted when going in? Could they be wrong o-rings? I always put a bit of silicone grease on them before installing. Slippy is good!!!

Ron ...

 

[rrubel]

Argh. I feel like I'm living a nightmare with this Superram. I'm almost ready to hang it up and get a Mini-ram instead (and hope that I still get good results with the 219 cam).

I can direct the carb cleaner with a tube right at the base of each injector or at the manifold/head seal. I only get the revving engine when I point at the injectors. They are the right o-rings for a stock plenum; this is an Accel Superram base which is *supposed* to be identical; however, with my experiences so far I would not be surprised if the holes are too big. If I have to take everything apart again though, I'm going with a different system.

I didn't use silicon grease, but I did use synthetic motor oil which should lube well enough. I could believe one o-ring could have seated wrong (in fact, that happened) but all of them?

This sucks royally.
[RICHR]

 

[Ken]

Rich, you're not alone (but then you already knew that ). This from my web log folowing my various projects...

10-28-04 - It's on the road again.​

But not without Mr. Murphy having one more shot at me. This time it was an O-ring on the crossover tube that wouldn't seal. As soon as I turned the key it started spraying gasoline everywhere again. Damnit, can't anything ever go right the first time, and not have me rework everything I do. I took my time too, and followed everything to the letter, including lubricating the O-rings before installing them. Sometimes I just can't win!​

Ya know, I had a guardian angel sittin' on my shoulder again today. When I first turned that key and had fuel spraying everywhere, I also had a cigarette burning in my lips; I had just lit the cigarette before attempting to start it. Needless to say I was very lucky!​

Also of note: the stock fuel pump certainly wouldn't meet my current requirements for fuel supply. Before checking after each attempt to find and fix the leak, I pulled the fuse for the Bosch racing pump and just relied on the stock in-tank pump to pressure up the system. That pump barely allowed a trickle from the leak, whereas with the Bosch pump on it was spraying leak a broken fire hydrant! My engine drinks a lot of fuel (45 lbs-hr injectors), but what it doesn't need obviously returns to the tank.​

​

 

[WhalePirot]

I felt that my SR had a leak at the runner/intake joint for Cyl. 2/4. I took my time, mostly as I was PO'ed; took the whole thing apart one day, then took 2 or 3 to carefully reassemble, with a LOT of RTV black to seal the damn thing. Luckily, a friend had new plenum/runner gaskets made for me.

You know what a big job it is, so ENSURE that it is leaking there, hard as it is to access.