Fuel Rail Question

[LT1910]

I have a 1994 Ranger 4.0 OHV 2wd.

Just finished replacing the head gaskets and have been having trouble with rough idle and no power until I hit about 2500rpm.

Before I get too much into detail about that though I have a question.

What are the holes in between the intake ports on the fuel rail for? anything?

Why I ask is I was looking over the engine yesterday and there is a small gap between the upper intake and fuel rail at one of those holes (I can see into the hole. My first thought is that probably isn't right. But maybe someone can shed some light. Thanks.

Russ

 

[BillupsOMally]

If we're thinking of the same thing, the holes are a whole lot of nothing. They only exist to save material on the fuel rail. Since there's a gasket between the upper intake and the fuel rail there SHOULD be a gap there because if I remember right the gasket doesn't have a piece in that gap. However, if the gasket does cover the fuel rail where you see this gap then you have a problem. (I don't recall the particular shape and coverage of any gaskets on that motor because my budget = silicone atm.)

 

[trail B2]

Sounds like a vacuum leak the EGR tube is all hooked up right.

 

[bhawk]

If you see a hole or gap why don't you try spraying some carb cleaner at the gap while the engine is running. If the engine speeds up you have a vacuum leak there. There are other methods to find vacuum leaks, discussed on this site, such as using a propane torch, but not lighting it of course. I think you have a vacuum leak and need to try to find it using those spray down techniques.
You won't find a vacuum leak at the joint between the lower intake manifold and the cylinder head with those methods however. That is because that joint is hidden under the valve covers. I discovered this recently when I installed new valve cover gaskets.
Did you torque the lower intake properly and to the proper torque specs?
My manual for the 94 says you must torque the lower intake in a special sequence, and do it three times, each time you increase the torque setting until you hit the final torque setting. The lower intake bolts straight down into the block, none of the bolts go into the cylinder heads. That is why they are prone to vacuum leaks, albeit under the valve covers where you can almost never find them without tearing down the top of the engine.

 

[LT1910]

I believe you are right Billups. I don't remember seeing the matching holes in the lower intake. Probably like you say, to save material.

I figured out the power issue. I had the O2 sensor plugs crisscrossed (one bank rich one bank lean) Lots of power now, but idle is still a little rough. Cleaned the maf, iac, and tps. No change. might try resetting the maf and seeing what happens. I'm not that concerned really, I'll just keep tinkering with things, atleast its drivable now.

No egr on my engine, that I can see.

Yeah, i did all the funny torque spec things. The heads/intake were interesting, I think that's the most amount of effort I've had to put into torquing. Just one word of advice, never buy a torque wrench from lordco (if you have lordco's where you are).

Thanks All!