Fuel Pump ECCENTRIC...need inputs

RedBarchetta · #1 (**permalink**) 05-05-2008, 06:36 AM

Hi. What I thought was a case of fouled plugs ended up being a zero fuel pressure situation. Pulled the Carter mechanical fuel pump and inspected it but didn't see anything obvious (i.e. torn diaphragm, etc.). Motor is a stroked 392 from RDI with just under 11K miles.

Decided to poke a thin steel rod into the fuel pump cavity and noticed that I can rotate the eccentric slightly (maybe 10 degrees). Given all the friction associated with the valve train, timing chain, etc. I figured I shouldn't get any movement from the eccentric, correct?

I was always under the assumption that fuel pumps either work or they don't. I just don't want to have to tear into the front of the block if I don't need to. And if I do, appreciate any advice for doing same.

Regards,

-Dean

blykins · #2 (**permalink**) 05-05-2008, 06:56 AM

The eccentrics are located and pinned by the cam dowel. So it shouldn't move. However, a fouled plug would be a rich condition.....having no fuel would be lean.

Three Peaks · #3 (**permalink**) 05-05-2008, 06:59 AM

Eccentric shouldn't move at all. It should be indexed with the cam pin and bolted tight with the cam bolt and washer. Sounds like something came loose. Probably a good time to pull the timing cover to check it out before you lose your cam timing gear or drop a bolt or pin into the timing chain and take out even more parts.

Bob

Rick Parker · #4 (**permalink**) 05-05-2008, 07:00 AM

Some of the later OEM (approx 79-82) were 2 piece allowing the outer diameter shell to rotate for less friction. However you may be on to something if the one you have is one piece, it should be clamped tightly to the cam gear. Possibly the camshaft dowel pin is not protruding into the eccentric. Three Peaks is giving you some good advice.

RedBarchetta · #5 (**permalink**) 05-05-2008, 07:20 AM

Thanks, guys. Looks like it's going to be a tear down. :-(

Aside from having to loosen and slightly drop the front of the oil pan, any other tricks that I need to know?

-Dean

Three Peaks · #6 (**permalink**) 05-05-2008, 07:27 AM

Try to keep track of where all the water pump/front cover bolts go. I always get screwed up trying to remember which bolts go where because of all the different lengths. Other than that it is pretty straight forward.

Good luck and let us know what you find out.

Bob

RedBarchetta · #7 (**permalink**) 05-05-2008, 07:29 AM

Thanks, Bob. I have some international travel coming up and I'll be out of pocket for two weeks. May start the tear-down before then, but won't have the car back on the road until the end of the month. :-(

cobred · #8 (**permalink**) 05-05-2008, 10:33 AM

I am pretty sure you dont have to loosen the oil pan to remove the front cover. On my fe I didnt and I think a small block is the same.

blykins · #9 (**permalink**) 05-05-2008, 10:41 AM

FE's are different. The block is skirted, therefore the pan is flat. On a SBF, you have to contend with the end gasket. It's easier to drop the pan a little and get the timing cover perfectly centered with the balancer. Tighten the cover bolts, then draw the oil pan back up.

RedBarchetta · #10 (**permalink**) 05-05-2008, 10:57 AM

I'm really looking forward to this R&R...

blykins · #11 (**permalink**) 05-05-2008, 11:01 AM

You'll be fine. I'm still concerned about your fouled plug issue...it doesn't jive with me that a faulty fuel pump could cause that.

Does the engine run ok, otherwise?

RedBarchetta · #12 (**permalink**) 05-05-2008, 06:38 PM

Quote:

Originally Posted by blykins

You'll be fine. I'm still concerned about your fouled plug issue...it doesn't jive with me that a faulty fuel pump could cause that.

Does the engine run ok, otherwise?

I pulled all the plugs and only one had any hint of excess fuel..the rest were nice and tan. The popping was more so an intermittent delivery of fuel as a result of loss in pressure. It just sounded like I was running on 5-6 cylinders when the car appeared to be loading up coming off the freeway. I was able to keep it at a fast idle at the following light and then pulled over about another 1/2 mile when I realized I wasn't going to make it the last 4 miles home. After that the car was very hard starting and then coughed and sputtered and I knew something was not right. So out came the AAA card and the flat bed tow home.

After changing the plugs, pulling both fuel bowls on the carb (to make sure everything was squeeky clean), filling the fuel bowls up and then pulling the timing back a couple degrees to ease in the cranking, she fired right up and so long as I was tickling the accelerator pump she would run fine. That's when I noticed the fuel pressure gauge on my intake line not moving and then shut it down. So she probably ran lean (at around idle) for all of 10-15 seconds on a cold motor.

-Dean

CHANMADD · #13 (**permalink**) 05-05-2008, 06:44 PM

It is not necessary to loosen the oil pan at all. you can do the job with it in place. That being said, it is really easy to take the oil pan completely off and do the job right. There are no crossmemebers like in a mustang.If you are under there anyway ,what the hell!!

Trueoo7 · #14 (**permalink**) 05-05-2008, 07:40 PM

Don't know how to link a prior thread, but if you do a search in small block forum under Mechanical fuel pump, you'll see some more opinions concerning this subject. My engine is a 1991 and it does have the two rings.... one inside the other. The outer one moves quite a bit. Unfortunately I verified this just last week when I had to rip down the engine due to bearing problems.... another story. I also verified that the eccentric wasn't loose, its made to be that way.

RedBarchetta · #15 (**permalink**) 05-05-2008, 07:55 PM

First of all, have already had the pan out about 6 months ago when I changed out the crank and rod bearings. Easy to drop but I'm not looking forward to breaking the great seal that is on there now.

Second, if I have a two piece eccentric and there is supposed to be a little movement, that concerns me ever so slightly that maybe it was the pump that went bad. Part of me just wants to install the new pump that I ordered from Jeg's, prime the carb and see what happens. Worst case is zero fuel pressure and then I know what's wrong. Would hate to tear into this FORD only to find out that the eccentric is fine. Such a weird arrangement to drive the pump...I was schooled on Chevys and the pushrod that is actuated off the cam...big, thick steel solid pushrods never break.

-Dean

vector1 · #16 (**permalink**) 05-06-2008, 01:22 AM

check your fuel filters & supply lines, change fuel pump, then fire her up, if that doesn't work theeennn tear into the motor.

RedBarchetta · #17 (**permalink**) 05-09-2008, 06:59 AM

Quote:

Originally Posted by vector1

check your fuel filters & supply lines, change fuel pump, then fire her up, if that doesn't work theeennn tear into the motor.

Did just that last night. No fuel coming out of the new pump, so it HAS to be the @#$%& eccentric.

Heading to Asia for two weeks, so I'm not going to have any time to get to this before then. Oh well, at least the rest of the car looks/runs great.

Bonos · #18 (**permalink**) 05-10-2008, 03:20 AM

The oil pan does not need to be loosened. the front 4 bolts on the oil pan screw into the bottom of the timing / front cover.
The timing cover gasket set will have new front oil pan gaskets that you cut to fit.
Bonos

Jac Mac · #19 (**permalink**) 05-10-2008, 05:59 AM

IF the eccentric is a single piece unit and turning or moving then you are on the edge of disaster as it also means that the single bolt retaining the cam gear/sprocket is not tight. The single dowel will not last long if this is the case- I remember breaking one while trying to degree a cam in with all the valve train in place once, with the bolt only finger tight-- dowel snapped off flush with front of cam. That was only winding the crank over by hand, dont think they would go for long in a running situation with the bolt loose!