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Stalling 1938 Studebaker? Any ideas?


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John it’s a daily driver as weather in SC is never really bad. Especially for a guy from Chicago!  No sign of mice anywhere in garage. So I don’t think it’s that unless one crawled up into the pipe and died!  

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Dave, how much gas is in the tank?  I was wondering if you could see in there to see if anything is going on with the fuel pickup in the tank. On some similar problems it’s been recommended to use some compressed air  at the fuel line to blow back anything that might be creating a blockage.  Not sure how that would work with your electric fuel pump setup.  Hope you soon find the issue, the weather will soon be good for driving, even here in PA!

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You're not wrong, but if I suspected a blockage in the fuel line or pickup, and based on SC38DLS's description of the symptom I do, I would really want to "catch it in the act" and prove it as these sort of problems tend to be intermittent. Doubly so if it might be caused by sheets of failing tank sealer falling down.

 

SC38DLS: Is there an electric fuel pump on this car? I gathered the electric pump was a temporary measure to see if the mechanical fuel pump was causing the problem. Did I misinterpret?

.

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I have a 4 lb pressure electric fuel pump and the mechanical pump. I always use the electric on startup. If just cruising the area for a ride I’ll switch off the electric. If cursing at speed of 45 or above I switch the electric on. The electric has a filter between the tank and the pump. Then the mechanical has the glass bowl then I have an inline between the mechanical and the carb.  All of these are new and I took the old inline and it does not look like anything of significance is in it. By that I mean I can not see any material that could be clogging the line. That is not to say a microscopic particle couldn’t be clogging the carb. It just doesn’t seem logical with the carb rebuild and new filters that it would happen so fast every time it is driven over 5 mph. 
I will finish the electrical traces then try a temporary fuel bottle/line. 
 

Just so you all know why the electrical is a concern. I checked the following: 
Battery is 6.3 volts 

Coil with key on but not running is 5.4 volts

Coil with engine running at idle is 1.4 volts

Coil with high rpms is 0.3 to 0.4 

I’ve been told that could be a possible cause. Time will tell, hopefully soon. 
Thanks guys, I’ll let you know how it goes. 

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Hello everyone 

are you sure itsfuel related,next time it quits chk your ampmetet for power,try hotwiring the car and take it for a road test,mydadhad a Pontiac that would quit under acceleration he searched for probably six weeks for the problem he finally discovered the ignition switch was bad,changed the ignition switch and the problem went away,     Dave

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I’m in agreement Dave, Electrical seems more likely as all the fuel possibilities have been changed out and it seems to be getting gas. When it Boggs down it still wants to run buts it’s like the brakes are on or it’s pulling a huge weight, not gas starved. Trying to check out each electrical part to see if any effect. 

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Dave, what is the battery voltage at the battery post at high rpms?  
The battery voltage at the coil, not the points side of the coil, should be close to the battery voltage and much more steady across the rpms.  The points side voltage will go up and down as the points open and close.

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TerryB it is 6.3 with nothing on and 6.4 at idle and 6.6 at high rpms. 

Coil with key on but not running is 5.4 volts

Coil with engine running at idle is 1.4 volts

Coil with high rpms is 0.3 to 0.4 

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57 minutes ago, SC38DLS said:

TerryB it is 6.3 with nothing on and 6.4 at idle and 6.6 at high rpms. 

Coil with key on but not running is 5.4 volts

Coil with engine running at idle is 1.4 volts

Coil with high rpms is 0.3 to 0.4 

Something very wrong here.  For a test, remove battery voltage wire from coil terminal.  Replace it with a wire of similar thickness at the battery post or where the battery connects to the starter at one end and connect the other end to the coil battery terminal.  A wire with clips on both ends might be helpful.  Looking to get a test with a steady 6v source to the coil. Start car and see what you get.  Note, here you are bypassing the ignition key with this test. Be careful not to touch ground with your temporary wire connections.

Edited by TerryB (see edit history)
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Does this car have the battery voltage connection on the base of the coil or does it have the two posts like most later cars use?

 

Edit-Duh it must be a two post coil since you were able to measure it with the car running.

 

 

D19EB80F-DF56-4C46-A7C6-432C8F078B99.jpeg

6D919046-B14E-485C-AFAC-57BEF79E29A2.jpeg

Edited by TerryB (see edit history)
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Hi Terry. I will have to try it tomorrow. I did do it by taking the positive wire off coil then running wire from pos battery to coil. But that did not work car would not start. It is a two post and car is 6 volt positive ground. 
 

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How old is the gas in the tank?  If it's more than a few months old, especially if fuel stabilizer wasn't added, that may be the problem.  I've experienced my cars having off-idle hesitation, and no power under load and general sluggishness issues that were cured by draining the old gas and adding fresh. 

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2 hours ago, SC38DLS said:

Hi Terry. I will have to try it tomorrow. I did do it by taking the positive wire off coil then running wire from pos battery to coil. But that did not work car would not start. It is a two post and car is 6 volt positive ground. 
 

Ok, car is pos ground, need to take NEG battery post or from the NEG battery connection to the starter connection to the battery voltage terminal on coil with your jumper wire. Regardless of the marking on the coil, the side of the coil that does NOT go to the points needs to have the NEG 6v connected to it.  If you ran the POS battery terminal to the coil directly it would not be able to run as you would have 0 volts to the coil.

Edited by TerryB (see edit history)
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Ok I took the neg wire off the coil. Se pic it’s one on left (far side of coil) and ran a wire from battery neg side to this post. 
Same readings on volts 

Coil with just key not running 5.6 

Running at idle 1.4 -1.5 

Running at speed 0.3 fluxing up and down a bit. 
 

 

51CDAFAC-857A-46FA-956F-D82260069E60.jpeg

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Just now, SC38DLS said:

Ok I took the neg wire off the coil. Se pic it’s one on left (far side of coil) and ran a wire from battery neg side to this post. 
Same readings on volts 

Coil with just key not running 5.6 

Running at idle 1.4 -1.5 

Running at speed 0.3 fluxing up and down a bit. 
 

 

51CDAFAC-857A-46FA-956F-D82260069E60.jpeg

If I put jumper on neg coil (far side again) and put it down on starter again left side brass plate (see starter solenoid next to steering column and dip stick) it runs but only if I keep the starter button on solenoid depressed. I assume that is just hook up wrong. 

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Yes, that starter connection only has volts when you have the starter button pushed.  You need to connect to the big nut where the battery cable is connected to the starter solenoid.  That is where 6v is on all the time.  I think you are close to getting it.

 

Edited by TerryB (see edit history)
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Hi guys. In case any of you that have tried to help me are still reading this thread — just call me an electrical dummy!  Thanks to TerryB I now know I have been doing the voltage readings totally wrong. I will take new readings the correct way both on the way the wiring is now and the bypass way TerryB and Ed have suggested. 
At least I’m learning something from all of this frustration. 
dave s 

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5 hours ago, SC38DLS said:

Hi Terry. I will have to try it tomorrow. I did do it by taking the positive wire off coil then running wire from pos battery to coil. But that did not work car would not start. It is a two post and car is 6 volt positive ground. 

Yep, not correct for a positive ground vehicle...

 

Put the positive (red) lead of the DMM on the engine block. Put the negative (black)  lead of the DMM on the negative terminal of the coil. That should read 6 volts. Should always read about 6 volts. Let us know when it does not read about 6 volts. 

 

The + terminal of the coil should connect to the distributor (points). This voltage varies with engine speed and dwell of points.

 

You can also put the positive lead of the DMM on the positive battery post, and I mean the actual post, not the terminal. Put the black lead of the DMM on the engine block. With the engine running, does the DMM read anything? This test is for the voltage drop from battery to engine block. I would not think this is an issue, since the car cranks fine, but as long as you are looking.....

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Posted (edited)

Ok I’ve metered the coil ( the correct way now) and it is 5.8 with key on only ( not running

Running at idle it show 6.2 - 6.4

Running high rpms 6.2 - 6.4 

 

with the jumper on and key side (not points side) of coil disconnected I get the same readings. 
 

So I took it out with jumper on and it bogged down the same way. 
 

Does this mean the electrical could be ok and it might be a clogged fuel line or tank pickup. I do have a drain plug on tank but of course the tank is 3/4 full. I can always syphon off most then drain rest to see if junk comes out. 
 

Any ideas?  
 

I’ll try Frank’s battery test now 

Edited by SC38DLS (see edit history)
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Frank’s battery test shows a 0.02 on the meter. 
hookup was red-meter lead to pos on battery black-meter lead to block with engine running. This was done with coil being hooked up normally not with jumper. 

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1 hour ago, SC38DLS said:

Ok I’ve metered the coil ( the correct way now) and it is 5.8 with key on only ( not running

Running at idle it show 6.2 - 6.4

Running high rpms 6.2 - 6.4 

 

with the jumper on and key side (not points side) of coil disconnected I get the same readings. 
 

So I took it out with jumper on and it bogged down the same way. 
 

Does this mean the electrical could be ok and it might be a clogged fuel line or tank pickup. I do have a drain plug on tank but of course the tank is 3/4 full. I can always syphon off most then drain rest to see if junk comes out. 
 

Any ideas?  
 

I’ll try Frank’s battery test now 

Some things to try, and yes they might sound unusual.

1. Drive with air cleaner off to see if it might be blocked or clogged.

2. Pull choke on when bogging starts happening, does it help?

3.Disconnect distributor vacuum advance line at carburetor or intake manifold. Plug the vacuum source on carb or intake to prevent vacuum leak.  Test drive it.  Better /worse/same?

4. Pull over when bogging starts, let it idle. Is idle rough or smooth!?  If you let it idle continue does it run better?.  If yes pull out again and see if it bogs.  This is a fuel supply test, idling might refill float bowl.

5. Fuel pump test for gas tank flow. Using output of your electric fuel pump, run the gas line into into a 2 gal or larger can. Does the gas come out fast and then trickle off as the pump runs?  
6. This is another maybe, do you have a heat riser in the exhaust manifold?  Is it stuck closed?

 

Reading back over the posts it does sound more like a fuel delivery problem but have to explore all possibilities first.

 

 

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Ok I’ll give these a try. Not sure about heat riser but will see if mentioned in shop manual. I will get back to you. 
 

Padgett - had the carb rebuilt and if I look down it (single barrel carb) the fuel flows well so I don’t think it’s the blockage at needle. I have no idea how to check the float. 
As Ed says diagnosis is the key then fix. So I’ll try these test then go from there. If you can tell me how to test & adjust the float I am all ears. Thanks. 
dave s 

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2 hours ago, SC38DLS said:

Ok I’ll give these a try. Not sure about heat riser but will see if mentioned in shop manual. I will get back to you. 
 

Padgett - had the carb rebuilt and if I look down it (single barrel carb) the fuel flows well so I don’t think it’s the blockage at needle. I have no idea how to check the float. 
As Ed says diagnosis is the key then fix. So I’ll try these test then go from there. If you can tell me how to test & adjust the float I am all ears. Thanks. 
dave s 

 

I think Padgett might have a point, to rule that out . Can you look down the throat of the carburetor? With the engine off, pull on the linkage to wide open throttle, the gasoline should spray hard, almost a forceful mist, if it trickles or is wet there is a piece of dirt somewhere.

Did you test the carb base/manifold for a vacuum leak? Or the intake for a leak? The problem appears to be that the engine is either starving for fuel or getting leaned out.

It idles nice and smooth correct?

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1 Air cleaner has been off thru all of this so tried it on no difference 

2 Automatic choke so can’t control. 
3 Disconnected vacuum advance no change 

4 pulled over and as soon as I do the bogging down stops but as soon as I go it starts. It garage not under load idles fine runs a little rough but not real bad. Even when it bogs down the engine isn’t missing it just has no power like someone slammed on the brakes. 
5 fuel flows great - I did it after electric pump and just before carb both flowed very well. Did not see any residue in the bucket either. 
6 The plot thickens! The shop manual says it has one- all models have one -  mine does not have a spring on it. So does that mean it’s alway open or always closed?  
 

I honestly do not know if it has ever had a spring or worked. 

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2 minutes ago, SC38DLS said:

1 Air cleaner has been off thru all of this so tried it on no difference 

2 Automatic choke so can’t control. 
3 Disconnected vacuum advance no change 

4 pulled over and as soon as I do the bogging down stops but as soon as I go it starts. It garage not under load idles fine runs a little rough but not real bad. Even when it bogs down the engine isn’t missing it just has no power like someone slammed on the brakes. 
5 fuel flows great - I did it after electric pump and just before carb both flowed very well. Did not see any residue in the bucket either. 
6 The plot thickens! The shop manual says it has one- all models have one -  mine does not have a spring on it. So does that mean it’s alway open or always closed?  
 

I honestly do not know if it has ever had a spring or worked. 

 

Is the choke open when the engine is warm?

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Posted (edited)

Ok I wired the heat riser weight in the opposite position than what it was. Took it out and it seemed to run a little better but was still bogging down. Probably my imagination. I have no clues what’s next

Edited by SC38DLS (see edit history)
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Given that "If you can tell me how to test & adjust the float I am all ears" my next step would be to try a different carb. Jon: will anything else fit a single barrel Stromberg bolt pattern like a Rochester Monojet ? Corvair ?

 

To me that the carb was rebuilt makes it suspect and I'd have it apart on the bench, wire/blow out all of the passages, check needle and seat, and weigh/set the float but have been playing with carbs for a loong time (particularly trips and dual quads).

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36 minutes ago, SC38DLS said:

Ok I wired the heat riser weight in the opposite position than what it was. Took it out and it seemed to run a little better but was still bogging down. Probably my imagination. I have no clues what’s next

Did it take a lot of force to move the heat riser from its old position to the opposite position?  Trying to determine if just the weight moved or entire heat riser baffle inside the pipe moved.  Put the heat riser in old position and with car at fast idle go to exhaust pipe and feel the amount of air coming out.  Then put the heat riser in the new position and repeat, can you feel more air moving in one setting versus the other?  Might be tough to gauge but not sure how else to test it.  Heat risers like to rust in position because the shaft they move on doesn’t get lubricant often.  
 

I’ll also go back to scratching my head some more....

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If you jab the accelerator pedal a few times when it’s bogging or slowing down does that make a difference? The jabbing on the accelerator pedal should force the accelerator pump to squirt some extra fuel into the carb and help overcome a lean running situation.  Yes, we are getting into the oddball tests now.

Edited by TerryB (see edit history)
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Padgett. The car has run great for the last 7000 miles in three years. The rebuilt was done just to be sure nothing was wrong or plugged and done by a guy that has been rebuilding them for over 40 years. Knew the carb backwards and forwards when I brought it into him. It shows good flow when I look down it and pump it. I just have a hard time thinking that’s the problem. Replacing it with something else is not going to happen. The car is original engine, trans just rebuilt and even original paint. I’m not swapping out parts for the heck of it. Not trying to be a turkey just don’t want to throw anymore undiagnosed solutions at it. 
 

Terry it flopped back and forth. It may just be the rod and weight with the internal parts gone who knows when. I’ll try the accelerator trick and also check the exhaust tomorrow. The legs and back are shot from all the ups and downs today. 
 

Thanks guys, I know this is going to get solved and probably be some goofy problem but it sure is frustrating. 
dave s 

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How about the hose for the vacuum wipers? I am presuming that there are vacuum wipers

The way I test for vacuum leaks is not the safest, but while the engine is idling I spray brake clean along the intake and the carb base, not a lot! and notice if the idle changes. Never failed me yet, but just need to be careful not to spray too much.

Edited by John348 (see edit history)
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Posted (edited)

I’ll recheck the vacuum at the distributor ( comes from carb and is only thing on that line) for automatic advance. i will plug vacuum for wipers. I need to go get break clean or starting fluid to do the leak test. Forgot to get it today. 
Two things seem wrong right now that may or may not be the problem. 
1 distributor does not move (that these old eyes can see) when I give it gas. So I don’t think the spark is advancing. 
2 the heat riser does not have a spring so it’s either always open or always closed. I just don’t know which it is. Hopefully TerryB’s test at exhaust will tell me. 
 

I just have to keep testing until something makes sense and gets results. 
Thanks for the help and suggestions one of these is going to solve the problem so please don’t give up thinking it’s useless 

dave s 

 

Edited by SC38DLS (see edit history)
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  • Peter Gariepy changed the title to Stalling 1938 Studebaker? Any ideas?

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