Problems Fuel pump in high temperature.

Harylufa

Harylufa

Senior Member
Dear Friends!

Yesterday where I live was 38ºC so driving on the road to my home my car begun to loose power, and stop.
I remember that 13 years ago happened in the same way. I imagined that the fuel pump diaphragm expand, I knew this because the previous owner told me to wrap with wet cloth. Before this I had an electrical pump but I preferred the original one.
Fuel pump is separated from block it is high. It is strange because this must not happen.
I took my radiator out to a professional to see if it is blocked, I tested with different product but no go!

I attach a picture of fuel pump, what do you think?
 
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You had me baffled for a few minutes. The 38C is 100F. I wondered how things got hot at 38F. Raiseing the fuel pump should lower the temperature of the fuel in the pump some but heat also rises so the engine heat is all going up under the top of the hood so it may not help. I don't know what kind of gas you have in Argentina but we have ethenal and other blends of fuel that are causeing problems in the pumps in hot temperatures here. Just to try to pin the spot where the problem is I would put a plastic bag of ice on top of the pump and see if it helps. The other problem with the same effect is a hot coil or condensor. Again a bag of ice on the coil and condensor will cool it in about 10 minutes. A coil or condensor will usually cool in about a half an hour. This is about the same time it takes to change the fuel pump. The pump is changed, the coil cooled and the engine starts. This fooled millions of people for years. Skip Haney an old Ford coil rebuilder has rebuilt 1,000s of coils and "fixed" the vapor lock problem in the pump. But for the past few years real vapor lock is back forming in the pump from this new fuel. I had it on a 1,000 mile trip at 100F or 38C 10 or 12 times. I finially found that if I was moveing above 55 miles per hour I didn't get it and below it started. At 55 there was enough fuel being used that fuel was cool enough that it didn't lock. Below 55 the fuel was in the pump longer and got to hot. I was thinking of a small adjustable return line to the tank to keep the flow higher to coll the pump. The carb has a metering hole at the needle valve of about .100 and the hole in the fuel line is much larger so a small return line with a .060 hole would still allow enough fuel to the carb. I have been involved in a few large projects for the past year and haven't had time to try the return. On my 1,000 mile return trip the temperatures were below 90 and I didn't have the problem. G.M.
 
If it is heat at the fuel pump causing the problem we call it "vapor lock" here in the states meaning that the fuel in the pump vaporizes and won't pump. Mine does that after sitting in the hot sun for 20 minutes after driving in the hot sun and the engine real hot. I can get it going again by pouring water on the fuel pump but I'm installing an electric fuel pump back by the gas tank to "prime" the mechanical stock pump when I have that problem in the future.

As G.M. said, try cooling the fuel pump with ice or water when you have a problem. If that fixes it then you know you need to put the electric fuel pump back in. You don't need to replace the mechanical stock pump you have, just put the electric pump in the fuel line back by the gas tank so it won't overheat and have the same problem as the mechanical one. Then just use it momentarily to "prime" your stock mechanical pump when needed rather than running it all of the time.
 
Walt it don't get to 100 very often where you live. I wasn't a believer in vapor lock very often when we had good gas but this new stuff has got worse the past few years. I changed a lot of fuel pumps myself before finding the real coil problem. The thing is, when you have a problem like this or any problem do only one thing at a time to find the sourse of the problem so you know where the problem really is. Look back 12 or 14 years ago at how I got laughed at when I first said vapor lock was a bad coil. I said time will tell and now when someone mentions vapor lock people will come on and say you have a bad coil. G.M.
 
Old Henry said:
As G.M. said, try cooling the fuel pump with ice or water when you have a problem. If that fixes it then you know you need to put the electric fuel pump back in.
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If that doesn't fix it then you have a different problem to figure out. If you have a fuel filter that could need replacing. Or, it could be an ignition problem to troubleshoot.
 
Too me the obvious would be to see what and how much push rod or rods are in place,that has to be about 16"-20" above cam you have there.Someone over the years has probably rigged an extra length and it has worn,warped,bent or whatever. A theory that fuel pump was getting to hot from being to close to engine block? led to this? Man,they even notched into the firewall to clear for the breather cap.
 
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I don't believe in vapor lock ,but maybe I have something to learn ,if your engine runs above the Boiling point of water 212 F, then yes , I am with Walt ,or GM .Coil /ignition ,or Faulty pump .Ford tested these cars every new model in the dessert ??.
 
Dear Forumer!

I tell you that my mechanical Fuel Pump was installed this year in winter, so I have never had troubles, but read this sequence.

1) When I bought my car 15 years ago the Fuel Pump was near the block, I think as original from Factory.

2)The previous owner (Death today) warned me that the car always had this problem in summers.

3) So in my first year as owner in summer I really proved what he told me. My car left me in middle of the road, so all the traffic behind me remembered my family, I can not forget it.

4)When I convert my car 6V to 12V, the electrician advise me to install an electrical fuel pump. So, during 14 years no problems.

5)Nowadays thanks to internet I discover which parts are original and which are not.

6)This year I install the fuel pump again , but with that modification that you see in the picture attached above. Electrical fuel pump is sleeping below my car and laughing of me.

7)Bingo, the fuel pump failed again in this Summer.

In this case, you have desert there in your country, In summer, in my country the heat raise at 40ºC or 104ºF.

Please, I read over there about coil heat. What must I do to test the coil heat?

Thanks all for your post.

Harylufa.
 
Harylufa, To "test the coil heat", the next time your engine fails, pull a plug wire and hold it to a head stud to test spark while you crank it over. A good coil will deliver a strong blue spark about 1/2" long. A weak coil will show a smaller orange spark or none at all. This same weak coil may show strong when it is cool again.

Generally, a fuel pump diaphram should not stretch when it gets warm, as they are made of reinforced material. An older diaphram may be subject to permanent damage by fuel containing alcohol. Newer diaphrams are made of fuel resistant material.

Your modified pushrod may be of an incorrect length. Check the pump's rocker pivot for damage that may indicate a rod that is too long. A rod that is too short will not depress the rocker sufficiently to actuate the pump. Remove the fuel delivery tube from the carburetor and direct it to a glass jar while you crank the engine with ignition off. You should get a strong pulsing flow from the pump to the jar.

As was said earlier, both a fuel related problem and an ignition related problem will produce identical symptoms, but it is important to address one problem at a time so you will not inadvertantly create a problem where none exists. Don't jump in and do several things, as you will not know which was succesful and which was not.
 
ford38v8 said:
Harylufa, To "test the coil heat", the next time your engine fails, pull a plug wire and hold it to a head stud to test spark while you crank it over. A good coil will deliver a strong blue spark about 1/2" long. A weak coil will show a smaller orange spark or none at all. This same weak coil may show strong when it is cool again.

Generally, a fuel pump diaphram should not stretch when it gets warm, as they are made of reinforced material. An older diaphram may be subject to permanent damage by fuel containing alcohol. Newer diaphrams are made of fuel resistant material.

Your modified pushrod may be of an incorrect length. Check the pump's rocker pivot for damage that may indicate a rod that is too long. A rod that is too short will not depress the rocker sufficiently to actuate the pump. Remove the fuel delivery tube from the carburetor and direct it to a glass jar while you crank the engine with ignition off. You should get a strong pulsing flow from the pump to the jar.

As was said earlier, both a fuel related problem and an ignition related problem will produce identical symptoms, but it is important to address one problem at a time so you will not inadvertantly create a problem where none exists. Don't jump in and do several things, as you will not know which was succesful and which was not.
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ford38v8!

I forgot to mention something concerning what happen with the fuel filter, I attach a picture where you can see a the fuel filter FULL of gasoline (nafta)
This happen a day after using my car in the road, so when I am in the road the fuel filter is almost empty, I think it is normal, but it fill with gasoline when the engine is cool.

In one of the picture you can see near the bolts a liquid color green, did not exit before.

Thanks

Harylufa.
 
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ford38v8 said:
Harylufa, To "test the coil heat", the next time your engine fails, pull a plug wire and hold it to a head stud to test spark while you crank it over. A good coil will deliver a strong blue spark about 1/2" long. A weak coil will show a smaller orange spark or none at all. This same weak coil may show strong when it is cool again.
Click to expand...

If you get a spark from that test then you know you have spark and that the coil, condenser, points, and wires all work. If you don't get a spark, however, that can be because any one of those things has failed and you will only know be testing each one individually as follows:

To truly test the coil to see if it is the problem it must be isolated from all other components that make it fire. To do that, I always carry a spare high tension coil to distributor wire (the one that looks like a short spark plug wire). Then I unplug the fat wire from the bottom or end of the coil and plug the test one in. Then, crank the engine while holding the end of that test wire close to a head bolt. If it fires then when it didn't through the spark plug wire then you know that the spark is stopping somewhere between the coil and the spark plug and isn't a problem with the coil. It could be the short fat wire from the coil to the distributor, the distributor rotor, the distributor cap, or, most likely, the spark plug wire. If the coil still won't fire I then isolate the coil from any problems with the points or condenser by disconnecting the small wire from the top of the coil that goes to the distributor. I then connect a jumper wire from ground that I'll use for this test. Then, with the end of the short fat test wire near a head bolt and the ignition turned on I intermittently tap the small grounded jumper wire on the terminal that I took the other wire off of. That creates the same on/off switching that the points do. If I now get a spark I know it's the points and/or condenser. If I still don't get a spark (and I'm sure power is getting to the coil from the ignition switch) that only leaves the coil as the problem.

I tell you all of this because in the past I too many times jumped to the erroneous conclusion that my ignition problem was a coil problem and replaced the coil without fixing the problem that has always turned out to be something else.

Hope this helps.
 
Henry, good thinking. More difficult to do with an earlier distributor mounted coil. Any thoughts on your test with that application?
 
ford38v8 said:
Henry, good thinking. More difficult to do with an earlier distributor mounted coil. Any thoughts on your test with that application?
Click to expand...

Sorry. Not familiar with that set up. I was telling Hary about my car 'cause it's the same as his.
 
I have seen the rubber hose between the pump and the solid line have a soft spot ( caused by engine movement).The hose when hot would suck together. My 2cents lee34
 
Lee the soft spots in the flex hose is caused by this new fuel. If you get soft spots you more than likely are sucking air into the fuel. This could be Hary's problem also since his filter get low on fuel, vapor lock will also leave the fuel bowl low. I asked what kind of fuel they have down there?? Gadgiteer@aol.com makes fuel hoses that are not effected by this new fuel. G.M.
 
Those AC type diaphragm fuel pumps on almost any vehicle-except old fords,are mounted low on the engine because they are better at pushing the fuel rather than sucking it from the tank.Where Henry placed the pump wasnt one of his better ideas. I think that having the pump mounted so high is only making the problem worse.Even with the standard fuel pump stand,there is very poor oiling for the FP linkage& with the axtra tall stand,I would think oiling is almost non existent.The push rod is very likely worn too short.I think its a good idea to have an electric pump-the type that can push the fuel thru the stock pump & use the electric to prime the carb when sitting for a long time & also for when vapour-lock occurs.Years ago I never had vaper-lock even when it was 105* F. Nowadays I even get vapor-lock with my model A,s if I stop for 15 min on a hot day to gas up.For the 1st block or so it will run crappy untit the cooler gas replaces the heat-soaked gas in the carb.
 
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