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View Full Version : R2 Fuel Pump Pressure--Woes Continue



wagone
07-06-2005, 06:13 PM
This saga continues and I still need help/advice. I have been gone away from this site for a couple of weeks (maybe 17-18 days!). A vacation interrupted and then my wife has been looking to buy a new house (groan!). Anyway, I'm finally back trying to get the Avanti running (which it hasn't in about three months). Previous advice included making sure the return line from the pump to the tank wasn't clogged. Fair enough, but the intent of the return line originally was not to control or reduce fuel pump pressure--at least I'm pretty sure that it wasn't (my pump pressure appears to range from 7 to ten pounds, or more). However, my return line is badly rusted and someone had done a less than ideal repair to this line by replacing about 5 1/2 feet of it with hose! Not my idea of a proper repair. So I've jerked this line out and replaced it with a new steel line-- not a real fun job as I'm sure most who have done it would agree. And I then checked to see whether the original line was plugged (as per the advice) and the conclusion is that I really don't think so. So the next thing I did was to pull the new ($176) fuel pump and check the angle of the lever arm with the pump which was on the car when I bought it two years ago. My THINKING (watch out for brain damage upon engagement) is that if the arm is not bent right it could affect the pump stroke by increasing (or decreasing it if the arm is bent at too sharp an angle) it which just might increase the pump pressure. Tell me guys--is this thinking right or wrong? The new arm is not bent as steeply as the MOPAR pump which was on the car when I bought it. How critical is this angle? Mine is visually different than the pump I took off the car when this odyssey began this spring. And of course I didn't check this angle until today. Visually the new pump lever arm doesn't even look as though it was rebent (by the supplier). Now this may be hard to see, but the pump I took off certainly looks as though it had been rebent (by the metal discoloration due to heating). How much different is the lever arm angle between the Chrysler and Studebaker application? Only a modest difference or a large difference? How much must the Chrysler arm be bent? Thanks a WHOLE lot for the help--I just gotta get this car running--soon. Oh, one other thing, this new pump was hard to install as it was not the easiest thing to tighten the screws against the pump spring tension and get the pump flange square against the engine mounting pad. Is this normal or is it a possible indication that the lever arm angle is not right? Oh, and does anyone know if Studebaker used a sock strainer at the outlet from the tank--on Avantis?
wagone and Avanti I

Alan
07-06-2005, 06:32 PM
I had trouble with my 63 R2007 I had to go to Summit and get their fuel pressure regulator SUM-G3131 $34.95 and pressure reference it to the blower, not on the fuel pump.

charley norton
07-08-2005, 06:45 AM
I don't recall seeing a sock strainer on my Avanti when I sealed the tank. I wonder that if your pump lever is missized that it would cause high pressure at idle, but cavitate at higher RPMs causing the pressure to drop or fluctuate. If that were the case, a regulator probably wouldn't help much. I take it that you can't get another mopar pump and put your lever on it.

63 R2 Avanti

Mike
07-08-2005, 01:28 PM
I traced the modified and stock arms on 1/4" graph paper, when I replaced the diaphragm and valves in my modified pump with parts from a stock Chrysler pump.
On the modified arm, the bend closest to the cam is increased so that the tip is 3/8" lower.
Mike M.

curt
07-09-2005, 10:49 AM
I rotate the cam and find a cam location that has much less fuel pump spring/arm tension, this makes bolting the pump to the block much less muscle work to hold the pump while starting the bolts. Just be sure the cam is on the proper side of the fuel pump arm.:)

hank63
07-10-2005, 07:50 AM
Might be easier to ditch the mechanical fuel pump entirely and go for an electric one (correctly fitted, of course).
/ H

rickomo1
07-10-2005, 07:54 PM
Just fought with a fuel pump and pressure. I borrowed an electric to use for trouble shooting and the problem was pinholes in my supply line, not easy to find good luck

GTtim
07-11-2005, 09:38 PM
As a way of checking the integrity of my fuel delivery line, I took the flexible hose off the tank and plugged it. Then used a little vacuum pump to put it under vacuum and left it sit. It held the vacuum overnight.
Tim K.