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Re: FUEL PUMP PROBLEMS?
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Home away from home
 
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Your description of the problem doesn't give us enough specific information to point toward the fuel pump. If the engine surges at a constant speed but smooths out with sustained full throttle, that is an indication the surge is not due to low fuel delivery.
However, how long did you maintain full throttle? Just a momentary throttle depression will mask low fuel bowl level with the accelerator pump shot. Bottom line, will it hold full throttle long enough to downshift and run strongly back to the upshift point? If so, it's not the fuel pump. jack vines
Posted on: 2012/8/2 14:57
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Re: FUEL PUMP PROBLEMS?
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Forum Ambassador
 
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If the symptoms you mention occur under quite light acceleration rather than steady speed driving, they're often associated with either a ruptured vacuum advance diaphragm in the distributor, or carburetor main jets that are undersized. The latter has been a not infrequent issue since the introduction of the 10% ethanol gasoline which exaggerates the condition and on request most of the better carburetor rebuilders will compensate for the ethanol (which creates a leaner mixture) by installing slightly larger main jets. Worked like a charm on my 56 Carib which was prone to modest surging under light throttle at road speeds. You might also check the carburetor float level.
I'm not convinced your problem is the fuel pump, why not do a pressure and flow volume test?
Posted on: 2012/8/2 14:58
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Re: FUEL PUMP PROBLEMS?
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Forum Ambassador
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If the arm itself didn't get damaged or bent, I don't think there is much in the pump that can either.
IIRC, a single stem from the diaphragm thru a relatively small opening which fits in a slot but rests on top of the arm. Has a captured plate that the arm lifts up. If all that is intact -- and surely the mechanic would have seem any problems if not -- then doubt there is an issue. What about the level in the fuel filter. Is it staying full? Any puncture or rip of the diaphragm should be finding your oil full of gas because that path would be easier than going thru the filter or being stopped by the float. If you check and all is well with oil level, then doubt any problems there. Also wondering about the used plunger. Maybe it wasn't in that great a shape after all and couldn't stand being put into service again.
Posted on: 2012/8/2 15:12
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Howard
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Re: FUEL PUMP PROBLEMS?
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Home away from home
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Quote:
Sorry I've taken so long to get back, but I was reminded that I was to take SO's '95 Town Car through DEQ - which it passed with flying colors I'm relieved to say. Now for the Packard. The freeway was a little crowded so I was unable to do a sustained full throttle run. It was long enough for a downshift but she downshifts very quickly. It was a short burst from about 60 to 70 but I did it several times. At constant speed it acts like its running out of gas - which is one reason I suspected the pump.
Posted on: 2012/8/2 16:08
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1951 200 Deluxe Touring Sedan
1951 200 Deluxe Touring Sedan (parts ?) 1951 Patrician Touring Sedan 1955 Patrician Touring Sedan |
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Re: FUEL PUMP PROBLEMS?
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Home away from home
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Quote:
The thing is that even with a bad accelerator pump the car ran GREAT before the pin exodus. Another reason I suspected the pump. After it warmed up, I just couldn't believe I was driving the same car as I had before. The symptoms wouldn't show up until I was at a steady speed. any moderate change either up or down but more UP than down and it would smooth out. I called the shop when I got home and asked "What did you do to this car?" The only thing they touched was the pivot pin (and since the pin was still hanging on, I'm not sure how much investigation of the pump was done), the carb for the "new" accelerator pump and a moderate adjustment on the choke for the hard cold start - which I've already changed back to no avail. This morning I did go out and get the "tools" necessary to do the fuel pump test in the FSM.
Posted on: 2012/8/2 16:18
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1951 200 Deluxe Touring Sedan
1951 200 Deluxe Touring Sedan (parts ?) 1951 Patrician Touring Sedan 1955 Patrician Touring Sedan |
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Re: FUEL PUMP PROBLEMS?
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Home away from home
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Quote:
The fuel level in the filter bowl is definitely full and did the sniff test on the dipstick and that seems OK. The used plunger already shows signs that it doesn't want to play in the form of being either "ON" or "OFF". A slow easy acceleration is no longer possible. I just slowly press down on the loud pedal and nothing happens until all at once you're moving rather quickly. Makes backing into the garage really interesting! I plan on doing the pressure/suction test as soon as I get up from this and I'll let you all know what I find out. I will say that will I was running the engine last night I observed that the fuel pump is leaking around the mating surfaces. I also want to thank Jack, O_D and you Howard for lending me the benefit of your knowledge and experience. I do appreciate it. More after the test!
Posted on: 2012/8/2 16:30
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1951 200 Deluxe Touring Sedan
1951 200 Deluxe Touring Sedan (parts ?) 1951 Patrician Touring Sedan 1955 Patrician Touring Sedan |
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Re: FUEL PUMP PROBLEMS?
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Webmaster
 
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I wonder if one of the hoses/lines on the pump is loose and you are sucking in air or something. Or the arm pump got bent and you are not getting enough pressure anymore.
Also when they reattached the pump, did they put any spacer that was there back in place? If not, there could be a change in cam/pump arm geometry that could affect the pump stroke. Also take a moment and blow out that ceramic filter. They can look clean, but the pores can be clogged. So blow it out from the inside.
Posted on: 2012/8/2 16:44
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-BigKev
1954 Packard Clipper Deluxe Touring Sedan -> Registry | Project Blog 1937 Packard 115-C Convertible Coupe -> Registry | Project Blog |
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Re: FUEL PUMP PROBLEMS?
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Home away from home
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Make sure that #5 and #7 plug wires are not touching each other. There needs to be at least 1/2" clearence between them.
I'm assuming the plug wires are routed correctly for the other cylinders. 5 and 7 are usualy the 2 wires that are allowed to touch each other because they are rite next to each other and fire consecutively. Many service tech level mechanics are not aware of this.
Posted on: 2012/8/2 16:47
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VAPOR LOCK demystified: See paragraph SEVEN of PMCC documentaion as listed in post #11 of the following thread:f
https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=7245 |
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Re: FUEL PUMP PROBLEMS?
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Home away from home
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Think we may have found the problem. I hooked a pressure gauge up between the pump and the fuel filter. The reading: 1.5 psi. If I goose the throttle, the needle moves up to about 2.25.
The history of the fuel system since I've owned the car is that I dropped the tank which was found to be beyond repair and after firing up my compressor to about 90psi, blew the fuel line out. The tank was replaced with a newly cleaned and sealed one I got from Mike Dulinski. And, as I say, since I first got the car back in late June up until last week the car has done noting but improve in every way - until the pin problem. However, while I have everything out, I'm going to do the suction test as outlined in the FSM but since the actual "shove" comes from the spring and not the lever, or so it says in the 1955 Chilton's, I'm not sure what that will show but we'll see. While we're at it, wires number 5 & 7 were in the factory looms but right next to each other. Thanks to Packard V8, that has been changed. Speaking of the 1955 Chilton Manual; it has a 4 or 5 page section devoted the Packard's Electromatic Clutch will test procedures, diagrams and pictures with which I finally understand that option. This manual came with my '55 so I don't know how many are out their but if anyone needs to understand the Electromatic Clutch, I can try a scan or have a scan done.
Posted on: 2012/8/2 17:44
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1951 200 Deluxe Touring Sedan
1951 200 Deluxe Touring Sedan (parts ?) 1951 Patrician Touring Sedan 1955 Patrician Touring Sedan |
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