The Stovebolt Site Forums The Shop Area Engine Shop Climbing Hills?

I don't like the performance I'm getting climbing hills. When I approach a hill I have to really give Lucille gas to build up speed, however, once I am maybe half way up the hill she starts cutting out on me. I let my foot off the gas slightly and she reacts and catchs up with power a bit, then I give her a little more gas and she'll start cutting out a bit more. It's this back and forth thing we go through. I've got her set to the correct RPM (475 approx), new points, condenser, distributor cap and plugs. Should I be playing with the throttle as I climb a hill? Can someone explain to me the usage of the throttle? Or do I have another obvious problem that I don't understand? This old technology stumps me sometimes. Especially on the performance side of things.

The throttle is used to bring up the idle when it is warming up. I also use mine to set the idle a little higher as a convenience starting on hills. If you engine is running correctly there shoudl be no need to back off the gas pedal on a hill.

Something similar happened to me once. Turned out to be a vacuum leak. After I found the problem and fixed it everything was fine.

I don't know if that's your case, but its something to check into.

I would check the fuel filter and fuel pump.

Nope, I can lug my 216 with the Carter W-1 down in fourth gear
to 20 mph on a hill and floor it and it's a steady pull right up
to cruising speed.

DG

You mentioned changing everything but plug wires. They're definitely a possibility when dealing with a miss under load. If it's a sharp loss of power, not a gradual loss and a surge back to normal pulling, it's probably ignition, not fuel. Try a new set of plug wires before you chase any more gremlins.
Jerry

Mine did that when it was running lean, check float level, fuel supply, and for a vacuum leak. I bet your milage is decent having to let off all the time !

Joe

Jerry, I just installed new ignition wires this morning. I think I may be firing on all cylinders but its hard to tell. Sounds and feels like it. At idle I get these little fart sounds out of the tail pipe like something is a little off. Anyway I took her out and tryed to do Denny's trick of climbing a hill at 20MPH and then accelerating to gain speed. No such luck she still is lacking the power to climb. I got her on level ground and ran her a couple of miles. At one point when I was turning around to come back she back-fired through the carb one time in second gear going really slow. So I thought that it must be the timing. I had her advanced quite a bit, so I retarded her to 4 degrees. Tested her again and kept playing around with the distributor thinking I'll eventually find the sweet spot. It seemed to work the best at about 2 degrees advanced. Still the power is lacking. I'm thinking of removing the vacuum line to see if its gunked up. It's really got me scratching my head. I mean these are basic machines. It shouldn't be that difficult to figure out but I'm really stumped. Any further tests or suggests about where to go next? Was there ever a standard setting to retard the distributor a couple degrees as they came out of the factory? Just curious.
Oh, one other thing. This afternoon when I was out making distributor adjustments, when I would gun her I'd get a whole bunch of back-fire farts out of the exhaust no matter where I set the distibutor. What does that mean?

Maybe put a vacuum gauge on it and see what it says? Have you adjusted the valves lately? You could always do a compression test and see what it says? The a couple of ideas ......

If you've got a manual choke, try pulling the knob out a little to create a slightly rich mixture. It's possible the power valve in the carburetor isn't opening up and the drop in manifold vacuum as you go to open throttle is causing a lean-out. Have you checked the fuel volume to see if the pump is delivering enough gas? Disconnect the fuel line at the carb, run the line into a 1-quart catch can, and crank the engine up. It should flow at least a pint in 30 seconds at idle speed, running on the fuel in the float bowl.

Also, try a cylinder balance test, where you run the engine at a constant 1,000-1,200 RPM with a tachometer and a vacuum gauge connected. Disconnect one spark plug wire at a time and record the RPM and vacuum drop for each one. If you've got one with a leaky valve, etc. the RPM and vacuum will not drop as much as a healthy cylinder.
Jerry

Perhaps a check on the mechanical and vacumn advance would be in order also?

Jerry,
This morning I performed three of the tests that you suggested and here is the outcome.

First I let Lucille warm up really good to about 150 degrees. The idle with choke fully in finally settled down to 475 RPM after I disconnected the wiper vacuum and hooked up my vacuum gage. Vacuum at idle was 12-13 inches. Dizzy was 2 degrees advanced.

Test #1 was for fuel pump flow rate. You said it should be 1 pint (16 oz) in 30 seconds. My gas volume was 5-6 oz in 30 seconds at idle .

Test # 2 was the RPM/Vacuum drop test at 1100 RPM.
Cylinder #1 = 1100 RPM and 17.5"
Cylinder #2 = 1050 RPM and 17.5"
Cylinder #3 = 1100 RPM and 18"
Cylinder #4 = 1100 RPM and 18"
Cylinder #5 = 1050 RPM and 17.5"
Cylinder #6 = 1000 RPM and 17-17.5"

Test #3 I pulled out the choke about a half inch and it seemed just slightly better but no strong acceleration on a hill.

Your opinion?

Which degree of advance in your timing gives you the highest amount of Vac?
Does Vac increase any with more advance?

Hello: How new is the gasoline in the tank? Fuel that is old usually doesn't run well in an engine.

Caso.....vacumn, wether ported or manifold is what increases advance along with the flyweights and springs ...it's a combination of both that helps control ignition within the combustion chamber .
Good advance curve is required too make good power and fuel mileage.

I've been following this and I'm stumped.

If its not a vacuum leak, or a wire on a wrong cylinder or two - or any of the other stuff posted here - I'd be ready to tear my hair out. (what's left of it).

Let us all know what it turns out to be!

Find the restriction in the fuel system. You've either got a pinched line, a collapsed flex line, or something in the tank that's keeping the gas from getting to the pump. It's also possible the check valves in the pump aren't working right. The pump should produce 3-4 PSI pressure on the carburetor side when deadheaded into a gauge, and hold the pressure for at least a few seconds after shut down, and the fuel tank side of the pump should produce 8-10 inches of vacuum minimum, and the vacuum should stay put for a short time after shutting down. Failing either the pressure or vacuum test is reason to replace the pump. You could also try pulling from a container other then the fuel tank, and see if the volume improves.

With as low a fuel volume as you're getting to the carb, you'll never be able to produce much power.
Jerry

I should have been more specific referring to initial timing. I was asking because the vac seemed low to me and was curious the effect of advancing the initial timing has of the idle Vac reading.
I seem recall being advised advancing the IT several degrees past the book to compensate for today's octane levels.

Jerry,
Thank you for your input. I'm going to look at the lines from the gas tank to the fuel pump tomorrow. I don't believe there are any restrictions, but I haven't looked yet so I may be surprised. Hopefully not. On Monday I'll go buy a new fuel pump and install it. Your test suggestion made that a no brainer! I'm looking at this pump from NAPA:
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?A=AFP429_0252755411&An=0&Ar=AND(P_RecType%3aA)
I'll let you and everyone else know how things turn out.
BTW, you didn't comment about the RPM/Vacuum drop test numbers. I assume you didn't see any big issues, right? Just curious.

Those cylinder balance numbers look good. An obviously bad cylinder would have little or no RPM drop, and the vacuum wouldn't change much. Since the cylinder isn't making much power, killing the ignition won't make much difference in the power it's producing.

Just for grins, before you start swapping parts, rig a small gas can to the fuel pump with a piece of flex tubing, and see if the performance improves. I've done a bunch of test drives with a lawn mower gas can on the front floorboard and a long rubber hose out the window and over the fender to the fuel pump.
Jerry

Set the timing one or two degrees more then the book says and leave it, you are creating more then one problem at a time. Its not going to effect it much from one end of the scale to the other.

First order of business is to get fuel flow and volume. Low pressure can really mess you. I finished up a hotrod Pontiac last month that wouldn't run quite right. Idled OK and run around town with out much problem, but was low on power much like yours. Turned out the fuel regulator had backed off to 1.5 psi. I set it back up to 4.5 and the thing came alive. You could even here to difference in idle.

I would bet if you shut your engine off half way up the hill when its cutting out, you would find the carb half full or less of fuel. Add a pressure gauge where you can see it and monitor the fuel pressure at the carb inlet. You could also add a short piece of clear tubbing in the fuel line where you can see it and go for a drive, I would bet not much fuel is flowing when needed.

Joe

Joe

I had a similar symptom with a 47 Mercury with a flathead V-8 back in the early 1960's. After all the diagnostic tests I've described, including changing to a Carter fuel pump, it still had 14" of vacuum on the fuel line where it entered the tank. The problem turned out to be a 2" long grasshopper in the pickup tube in the bottom of the tank. The car would run about a mile, stall, and refuse to start for 10 minutes or so while enough gas leaked past the restriction to refill the fuel line.
Jerry

Now I'm scratching my head.

I have pulled the fuel pump and noticed that the screws around the perimeter of the pump which hold the two halves of the pump together were loose. You could see evidence of a small amount of gas that had leaked. I took the pump apart and everything was clean inside. No small particles at all. I reassembled the pump and made sure that the screws were tight. I attached my vacuum gage and on the inlet I was easily able to get 8-10 inches of vacuum just by hand pumping. Over on the pressure side I could get 3 1/2 pounds once again by hand. Now I know this was air pressure/vacuum, so does that mean anything because its air pressure and not liquid? Wouldn't they produce the same results?
I also disconnected the fuel line from the gas tank and blew it out with my hand tire pump into a container. Clean gas and just a few very tiny particles.
I'm suspicious of those pump screws. Could that be the problem. Just those small screws on the pump? I don't know the make of the pump, but it does say "Made in the USA" on the pump casting and there is a tag with the number 429 on it.

yes the loose screws could have been the whole problem, that would have caused the diaphragm to be moving less and less effectively, as well as the leaking

Bill

I stand corrected....14" vacuum and 3 1/4 pounds pressure!

Hand-pumping can often make a tired pump look good, because you're moving the diaphragm further than the camshsft lobe does. Loose screws will definitely cause problems- - - -air leaks. Try the volume check again after the teardown/reassembly, and I'll wager you'll get a lot more volume. Then it's time for a test drive.
Jerry

what Jerry says makes me think of another possibility: you may have a worn actuator arm on the pump or a worn lobe, either one resulting in not moving the diaphragm far enough to keep up with full load demand

Bill

OK, here goes! This morning I decided that I would take apart this old fuel pump, clean it up and reassemble it then install it back in Lucille figuring that maybe those loose screws were the issue. So I took her for a run and struggled to get her up the hill in my development when she was still not all the way warmed up. Choke slightly out. Well, I thought hey, I'll try to make some adjustments to see if I can improve the power performance. I played with the carb and the dizzy to try and get a good vacuum reading at the intake manifold. After several ajustments I finally was able to get 17" of vacuum with the idle at 750 RPM (should be 475). The dizzy ended up at approximately 6 degrees advanced with the choke pulled out slightly. Didn't sound too bad even though I think it was racing too much. I have one of those see-thru fuel filters just ahead of the carb and I could see fuel flowing into to it. With those conditions I took her for a run on a level road and she had plenty of get up and go. I turned onto a road that starts with you going downhill and then there is a good half mile uphill grade. Not that steep. Lucille was still cutting out on me and I had to let off the gas slightly for her to resume. When I got to the stoplight she was racing like crazy because of the choke being slightly out. I pushed it back in and headed back home. When I reached another small hill I pulled out the choke slightly again until I came to a stop sign. Once again shes racing like crazy. Went back to my garage and shut her down. I looked at her fuel filter and it was full of gas.
It's that cutting out and having to increase the RPM's to get a decent idle vacuum that concerns me. So, I went out and picked up a new fuel pump I had ordered from NAPA yesterday and will swap the pumps out tomorrow. With the old pump there must still not be enough back pressure on the carb thus the reason that Lucille cuts out on the power demand side. I really should not have to use my choke or set my RPM's that high to get the performance I'm looking for, right?

I read the thread and did not see if you have a fuel filter, and if you do, have you tried changing it? I have had the symptoms you describe with an old filter.

Have also had the symptoms you describe with old gas.

also with bad sparkplugs (bad out of the box)

and with a bad vacuum advance.

Can you tell I've had my truck a long time?

Interesting day to say the least. This morning started with looking at the information that came with the new fuel pump. Its manufactured by Airtex (#429) for NAPA and its assembled in Mexico. No problem. For all you folks out there, here are two interesting "Caution" notices that came with the fuel pump.
#1) CAUTION, To insure long life and leak proof service with this fuel pump, tighten all exterior bolts and screws before installation.

And the next real important "CAUTION" is: ( was worrying about this at 4:30 this morning)

#2) CAUTION: If the old pump had a ruptured diaphragm gasoline may have leaked into the crankcase. Check and change engine oil if necessary to prevent engine bearing damage due to poor lubrication.

Well needless to say I did both. Tightened bolts and screws and did an oil change.

Installed new fuel pump.

Lucille started with little effort with the choke pulled out slightly. Good! Ran up the hill out of my development before I really let her warm up good. Choke pushed in. Struggled a bit but we got to the top and then I pulled over to check out readings after 5 minutes run time.
Manifold vacuum 15.5"
RPM 700
Temp 140

After 10 minutes run time.
Manifold vacuum 16.5 to 17"
RPM 750
Temp 160

After 20 minutes run time.
Manifold vacuum 17-18"
RPM 800
Temp 170

Time for a ride! 8 miles. Lucille cut out on me three times when I was trying to climb a hill. Just enough where I had to let off the gas and she would immediately "catch" and resume power.
Came back to my starting point. The readings were:
Manifold vacuum 18.5"
RPM 925
Temp 170

So here we go again, she racing like crazy, so I'm thinking I've got to adjust the throttle on the carb to slow her down.. After throttle adjustments she was:
Manifold vacuum 16.5 - 17.5"
RPM 650
Temp 180

Now it gets really interesting!!
I put her in gear and can't move!!! My left rear brake has locked up due to an incorrect adjustment. It's overheated and all I can do is let the wheel cool down. I have all new relined brakes, new brake cylinders and stainless steel lines with new master cylinder and the system is leak tight. I will pull that wheel and adjust the pads. No problem.

So today, in the end, I believe my power performance had improved as long as I would have let Lucille warm up a bit more at the start. It was quite warm today (got to 85) and that surely helped the tight brake pad/drum to over heat. An easy fix that may have also contributed to Lucille not being able to perform at her peak.

I still have to figure out how to maintain good vacuum and the correct spark advance.

Another gremlin in the system may be my vacuum windshield wipers. I may try to run Lucille without them and just temporally cap off that connection to the intake manifold and see if the truck performs any better. Gotta get that vacuum right! Trying to get everything RIGHT! I just want to enjoy my truck more and get her out more often so folks can see her. She's a beauty!

In response to Kurt_51carryall,:
I have a fuel filter just ahead of the carb that is not very old. Gas is new. Sparks are all new and vacuum advance is 6 degrees.

To all, any words of wisdom would be greatly appreciated.

I had a problem with my truck and no power. I checked the timing and changed the fuel pump with no change. It wound up being the ethanol gas. I put the additive in the tank and fixed the problem.

Thinking you have a intake manifold gasket leaking?

You might try plugging the wiper port, check the vacuum, and then plug the port going to the vacuum advance, and check the vacuum.

Kurt

This morning I made an adjustment to the left rear brake pads ( the old hucks). When I had them relined I think the new pads were us a bit too thick. I have very little room for ajustment inwards. Guess I'll just have to wear them in a bit.

On another point I noticed that since I installed the new fuel pump my see thru fuel filter ahead of the carb is totally full of gas. That was never the case before! Maybe I won one battle....

Also this morning I hooked up my vacuum gage and tac so that they are on the inside of the cab.

OK, time to see how things are running!

Time is 11:52 - Start cold engine.
Choke all the way out and then quickly back in to about a 1" after she is running.
Vacuum 19"
RPM 1150
Temp Ambient 67degrees

After one minute slowly pushed choke to about a 1/2" out.
Vacuum 15-16"
RPM 475
Temp <100 degrees

Time is 11:56
Pushed the choke in all the way.
Vacuum 15-16"
RPM 600
Temp 130

Time is 12:00
Vacuum 16-16.5"
RPM 650
Temp 140

Time is 12:05
Vacuum is 17-17.5"
RPM 700
Temp 160

Ride time up the hill in my development.
Time 12:07
Went up hill in second gear. Vacuum drops to 6". Drove through the development and noticed that as I shifted gears the vacuum would drop to 6" (sometimes 0") and then climb to 22". Needle was all over the place.

To be honest with all you folks out there, I don't have a clue about what I am looking at!! Can some explain to me in laymans terms just what this engine vacuum means? Are the fluctuations I'm seeing normal or is it telling me something that is wrong? Its not only vacuum but timing and carburation. What would be the logical approach to getting these under control? Step one...step two...etc.

BTW, when I got back home (only drove her about a mile) I saw that the fuel filter was half empty. I think it will recharge itself after cool down. The other thing I noticed was what appeared to be gas on the outside of the carb. That kind of bother me. I surely don't want an engine fire!

Oh, you know what I just thought as I write this? I haven't checked the vacuum line from the dizzy to the carb. Gotta do that. And also Lucille is being run by a 216. Just an FYI in case no one knew.

I'm exhausted over here!!

Will the "Truck Gods" please help me??

The Vac drop when the throttle opens is normal and then it finds it's new equilibrium so to speak.
Your numbers are more like I would expect, and you should find out about the moisture on the carb... mop it with a kleenex and take it out side and put a match to it... If it poofs you know it isn't water!!!

You didn't really mention how the truck ran up the hill and that's really why I'm writing cause like others watching I want to know if it's any better!

check this out
Using a Vac Gauge and what it means

Have you tried putting it 4 wheel drive? Works for me.

Seriously, if you have gas on the outside of the carb, you may have found your problem. How new is your fuel pump?

Sounds like you have your fuel delivery issue solved. Thats good

your vacuum reading looks low.
I believe your fast idle should be set at 450 to 500 rmp once the engine is warm.(check your manual)

your vacuum reading should be between 17-21 at that rpm.

Have you put a timing light on it?

IIRC it was last set @ 6 BTDC

CASO,
I just ran up on hill in my neighborhood. All I had on my mind was reading the gages. I didn't take her out on the run I did yesterday (8 miles). So, your right, I don't know if its better. Will do that now! Also, no I haven't put a timing light on her. Will try and do that later.