'40 LaS engine tends to quit while accelerating

[John Barry [CLC17027]]

Here's the situation: more than once, recently, while accelerating in second and third gears, my '40 has run rough at first; during successive accelerations (e.g., passing through several traffic lights), it gets closer to quitting and finally stalls, refusing to start.  Yes, the tank has plenty of fuel, since it was about 80% full when starting out and the distance covered was perhaps 20 miles at most.

The points and rotor have all been replaced, and a new coil installed.  Those have helped some but the problem still exists.  Might some rubber tube in the fuel line be collapsing due to the suction of the fuel pump?  (Note that an electric fuel pump is installed in the fuel line to help with vapor lock.)  I should note that the fuel tank was completely cleaned/fixed about two years ago by GasTankRenu, so I doubt that's the issue.

[Otto Skorzeny]

  Might some rubber tube in the fuel line be collapsing due to the suction of the fuel pump? 

Your fuel line should be steel not rubber

The electric pump should be as close to the tank as possible and pushes the fuel - it doesn't suck it.

[John Barry [CLC17027]]

The electric fuel pump is essentially right at the tank but it's used intermittently: I forgot to mention that it's in line with the mechanical fuel pump.  I'm looking at a new, all-steel line, and considering having it such that the mechanical pump and the electric pump are connected in parallel, rather than in series.

[harvey b]

Hi John,i had a similar problem with my 37 60 series caddy,it was running great then it seems like we ran out of gas,it quit and we coasted into a freind of mines driveway,was only about 3 miles from home,he gave me 2 gallons of gas he had for his lawnmower,put that in the tank and it would not suck up the fuel,it would run with a prime,i then thought the fuel pump was bad,towed it home and started to remove the pump,when i removed the fuel line i tried to suck up the gas and none would come,the line was blocked.I had to use compressed air to blow it back into the tank,whatever it was,my tank also has been coated inside with the por-15 tank sealer.it was done 2 years ago?,i think it was a little peice of cork from the float that got into the pickup tube?.i dont think the original fuel pump could flatten the lines unless it was plugged at the pickup tube?I would check the points and dizzy first,then the carb to see if it is dirty inside,it may be a couple of little things and not 1 big thing that is keeping you from running 100%.HTH Harvey B

[35-709]

"I should note that the fuel tank was completely cleaned/fixed about two years ago by GasTankRenu, so I doubt that's the issue."

That would be the FIRST thing I would suspect!  Tank lining stuff coming loose or melting and plugging up the fuel line.  There are those that tell me that no one has come up with anything yet (in the way of a gas tank lining) that will really stand up to ethanol. 
Geoff N. 

[John Washburn CLC 1067 Sadly deceased.]

It still might be a bent or collapsed fuel line. On a lot of these they changed out the metal lines to the rubber gas lines. I have worked on two, one a cad and another a 40 LaSalle where the problem was a bent, replacment, gas line.

Like the previous member stated, if it is not the rubber or metal line (which could also have gotten kinked), then air pressure might clean it up, for awhile...

[John Barry [CLC17027]]

Update: got it to one of our club members who knows how to address these problems last evening.  In the 35 mile drive there, it backfired on me four times (never did that before), and pulled that almost-quitting nonsense practically right out of the driveway.  The fuel line will be all-steel as part of the bargain; not sure what else will be done.  More to follow.

[John Barry [CLC17027]]

Further update: distributor got new rotor and points; timing got readjusted; new plugs and ignition wires; replacement coil.  Not sure where the incumbent ignition wires came from, but they were carbon core (as opposed to copper) and were apparently breaking down/degrading, thus yielding some interruption of voltage to the sparkplugs (just before it went in for work, I got four rather assertive backfires).  Over this past weekend, it ran like a champ, starting with zero difficulty, and operating at interstate speeds without a hitch.

To be sure, the ignition wires aren't correct (blue insulation instead of black) but that may be addressed at leisure.  The key thing was that it ran reliably for a wedding (some very close friends of my daughter and son-in-law) this past weekend.  I'll worry about black insulation on the ignition wires perhaps over the winter.

[John Washburn CLC 1067 Sadly deceased.]

John,

The old saying, "90% of all fuel problems are electrical" still stands.

There are lots of folks who make the proper sprark pluge wires, GM still has Packard 440 metal spark plug wires, so one could make their own.

Glad you found the right guy to work on the LaSalle.