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  #1  
Old 03-29-2010, 08:29 PM
wolf_walker's Avatar
Zen And The Art Of Diesel
 
Join Date: Dec 2003
Location: Oklahoma City
Posts: 2,050
M110 carb W114 electric fuel pump conversion done

With success so far even.

This Pump

With this fuel filter


The pump is quiet, cannot hear it with the car running. It fit well on the passenger side frame rail forward of the gas tank and to the side of the rear diff mount(and away from the exhaust). It primes quickly from dry also.

The filter is mounted on the inner fender on the forward drivers side, again
away from the exhaust, and near the washer fluid reservoir. This was possible after removing the rack of solid state relays and vacuum valves that I quit using 6 months ago when they started randomly cutting in and out as the car warmed up(which plays hell with the one controlling the vacuum retard).

I retained the updated stock non-vacuum controlled fuel return valve/pressure regulator and it seems to cope fine with the pump, as does the needle and seat. I was able to set the float height lower, it was previously at the +2mm setting spec'd for hard starting.

I finished it up this weekend and only brought it home from the shop this evening, we'll see how it goes. It did start up quickly and with only maybe ten seconds of throttle attention from cold after letting the pump run with the key on for five or ten seconds. This part at least proves my theory that the fuel is either evaporating or something(and I couldn't find it leaking anywhere internally). I suspect I'll see improved hot starts as well. And fuel that is filtered by something other than the laughable inlet screen filter, or the crappy inline parts store pieces.

Next is getting rid of the CDI and points.

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  #2  
Old 03-29-2010, 09:52 PM
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Wolf, is the pump a pusher since you mounted it in the rear? Or, can it be used as a pusher or puller? Did you tie it into the stock fuel system, and does it pump through the stock fuel pump? Let us know how this works after a few weeks, especially the hot start issue. Good experiment.
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  #3  
Old 03-29-2010, 10:21 PM
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Zen And The Art Of Diesel
 
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Location: Oklahoma City
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Most of these type of pumps like to push more than pull, I think it's rated at 12" of lift.
It's mounted close the the outlet of the fuel tank and I simply ran the outlet over to the pump then back into the stock metal feed line. It was more bother running the power wire than anything else. And as you said, beware that short hose right off the tank outlet, it goes from a larger size down to a 5/16 or whatever the metric equivalent is. I used a double sided barbed coupling to go from it to the fuel line going to the pump.

I found an un-used ignition switched source at the two fuse separate block near the firewall on the drivers side. I put an 8 amp fuse in there and powered the pump relay from that. I tapped power for the hidden cut-off switch I mounted form a handy ignition switched source and fused it at 5 amps, it's a low draw being just a turn on for a relay. Mounted the relay on the inner fender aft of the CDI box using a handy hole.
I ran the power wire following the fuel lines pretty much on the drivers side underneath, encased in a length of clearish braided pvc of maybe 1/4" I had laying around for protection. I'm not comfy with just the wire insulation protecting things.
Used some larger version of the same pvc hose for abrasion protection for the fuel line I added underneath for the pump also. It isn't pretty in a romantic sense, but it's secure.
I left the stock pump in place for now with a hose joining the inlet and outlet to keep it clean. It's a good backup I suppose, and I don't think it will hurt anything.
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Old 04-01-2010, 10:45 PM
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Alright, puzzle me this.

It's still vapor locking when hot.
I verified this by pulling the hose off the inlet and it was pressurized after sitting fifteen
minutes by mostly vapor and little spurts of barely fuel. This part isn't so surprising, as it's cramped and hot as heck in that engine bay.

My hope was the electric pusher pump would push this vapor on out and re-fill the system inside a few seconds allowing decent warm starts. BUT, when this business is going on, the pump is loosing prime, indicated by a tell-tale noise, and it cannot re-prime for some reason. It's a heat issue somehow, as it primes fine when cold.
After a looong crank time, it eventually struggles to life, and shortly after the pump quiets down.

So, what the heck is making the pump loose prime and not be able to re-prime, when hot but fine when cold, as in overnight, or even when only sitting a short time?
Thoughts?
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Old 04-02-2010, 11:25 AM
mak mak is offline
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exhaust wrap

I have had good sucsess in reducing under-hood heat by installing a heat exhaust wrap on the exhaust manifolds. It works very well , the engine temp gauge proves the efficacy of the wrap
mak
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Old 04-02-2010, 08:16 PM
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You would be better off with the pump body lower than the center of the tank so that you get it primed via gravity.

-CTH
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Old 04-02-2010, 08:20 PM
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Zen And The Art Of Diesel
 
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Quote:
Originally Posted by cth350 View Post
You would be better off with the pump body lower than the center of the tank so that you get it primed via gravity.

-CTH
I'd be willing to bet it is, but the outlet is at the very bottom, with the pump at center line it still has to climb uphill. The pump would have to be below the bottom of the tank I think to truly gravity feed, don't think that's really possible on a W114. It primed from dry in a scant few seconds, and primes when cold after sitting overnight in about two seconds if that.
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Old 04-02-2010, 08:22 PM
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Quote:
Originally Posted by mak View Post
I have had good sucsess in reducing under-hood heat by installing a heat exhaust wrap on the exhaust manifolds. It works very well , the engine temp gauge proves the efficacy of the wrap
mak
It's a thought, I've used it before in both the wrapped thermo-tech type and the blanket type. Neither are attractive, but hey. I've also considered a reflective shield for that drivers front corner where the fuel filter now sits, that entire area due to the cramped nature of the W114 engine bay has air just through the radiator blown over it constantly.
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Old 04-02-2010, 08:23 PM
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Zen And The Art Of Diesel
 
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I also read a long an interesting thread from some of our domestic car brothers, particularly 30's to 60's era stuff, and they have had LOADS of trouble with percolation and/or vapor lock and some just down right not running worth crap on E10 fuel.
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Old 04-03-2010, 09:30 AM
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I've never had any luck with the solenoid style pumps. I have had them lose prime/pressure/flow while running down the road.

I've tried them mounted on the frame rail and down by the tank (use a piece of 3/8" fuel line on the large tank fuel outlet. Don't piss about with the reduction rubber bit) and no luck. Same story. They work fine for a bit but they just won't flow enough volume , crap out and die.

On my carb'ed engines I use a Carter rotary style pump (Carter P4070 Electric Fuel Pump) and the problems don't occur. There's not enough room to safely mount them at the rear so I mount them on the fenderwell. I'll try to dig up a pic or two and post.
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Old 04-03-2010, 01:02 PM
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How big is the carter? If it's not overly loud I'd not object to mounting it up front, common lore has been to put a small electric pump as near the tank as possible though.
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Old 04-03-2010, 01:45 PM
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How's that common lore workin' out for ya? "Common lore" also doesn't take into consideration the return line system used on your car.

The Carter makes a bit of a whine but not really noticeable. Nowhere near as bad as the solenoid's style hammering when it's losing prime. You KNOW the sound I'm talking about!
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Old 04-03-2010, 02:14 PM
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Zen And The Art Of Diesel
 
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I do, I like being able to hear when it looses prime actually, and I can't hear it otherwise as loud as the car is. It never does it till it sits for twenty minutes when it's hot is what I'm trying to figure out. Do you think even mounted on the passenger side at the rear away from the exhaust it's hot enough that it's effecting it's operation? This particular pump has a pretty good reputation from what I can gather, and it does prime perfectly when cold. I don't really object to throwing another $75 at the thing, but I'm going to be bummed if I have the same BS problem. I assume you mounted yours that you were un-happy with on the fender well(like is says not to)? FWIW it's perfect when driving, I put a hundred miles on it in all sorts of driving and not a hitch. There is more than enough pressure and flow from this thing to keep the carb full near as I can tell.

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