New Electric fuel pump can't keep up on freeway. RV stalled

50YrOlNoob · August 09, 2021, 01:05 AM

Blessings all,

I installed a V8 electric fuel pump and it works fine driving around on the streets but when I go with traffic on the freeway it can't keep up and shuts down my RV and then I can't get it started. I called my mechanic friend and he told me to just add another pump midways. In other words he's telling me to have two fuel pumps because the tank is too far away. Is there any truth to that? Has anyone found the original pump somewhere? Any help is greatly appreciated.

Thanks!

Elandan2 · August 09, 2021, 07:59 AM

Does your engine still have the mechanical fuel pump on the engine? Are the fuel filters new?

50YrOlNoob · August 09, 2021, 11:55 AM

Hello Elandan2,
The engine still has the mechanical fuel pump on. I didn't remove it. I just added a new V8 universal fuel pump. The filters are new.
Thanks!

Elandan2 · August 09, 2021, 03:33 PM

What is the flow rate for your electric pump? If it is not high enough, the mechanical pump may not be able to pull fuel through it to feed enough to the engine.

Ray96480 · August 10, 2021, 10:25 PM

You may have rust flakes or debris blocking the fuel pickup tube in your fuel tank. The mechanical fuel pump alone should be enough to supply your engine with fuel.
Some elec fuel pumps are rated at continuous duty while others are rated at intermittent duty.
What do you mean by a V8 fuel pump exactly?

50YrOlNoob · August 12, 2021, 03:18 AM

Thank you for that comment Elandan2. I didn't realize the mechanical fuel pump was on the engine. Good thing I purchased the parts manual from this site. I thought it was inside the gas tank. Because of your comment I omitted that electric pump and placed a new mechanical pump. It worked fine idle for 10-15 minutes but when I took it around the block it died again while running. I could get it to start but it dies if I try to switch gears.

50YrOlNoob · August 12, 2021, 04:11 AM

Thank you for your comment Ray96480. The first thing my mechanic friend did was he dropped the gas thank and washed it. He also cleared the fuel lines because they were plugged up bad.

I will list the things I upgraded to new before I started this post on the engine only because I can't figure out why it's stalling on me. I rebuilt the carburetor. New fluids (Transmission, Motor, Brake, antifreeze). New radiator (re-cored). New radiator hoses and gas hoses. New spark plugs, cables, air filter, oil and transmission filters.

Later after I installed the new mechanical fuel pump it still died on me when I drove it 1 mile. I contacted another mechanic friend (Don't quite trust the first one any more) to tell him the symptoms after all the upgrades. He told me it might be the coil and to also replace the cap and rotor since it was some of the last things left to do so I upgraded them........ And...... Well, same thing happened but the vehicle seems to be loosing power the more I drive it because I was able to take it a few miles into the freeway when it first died on me. The second time after I installed the mechanical pump I took it about 1 mile then it died. The last time it died on me just 3 blocks away. I then replaced the coil, cap and rotor but it keeps dying. I believe when it gets hot it just dies and won't go any more for some reason I can't figure out.

This vehicle has been sitting for 20 years. Do you have any other pro-tips before I seek professional help in my area?

https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/fuel_pumps/carbureted_fuel_pumps/carbureted_electric_fuel_pumps/parts/42S
The fuel pump on this link is for 4 and 6 cylinder cars. The one I had was for V8's only. I removed it and installed an original mechanical fuel pump. It only had two screws. Easy upgrade that my mechanic friend didn't want to deal with.

Elandan2 · August 12, 2021, 07:36 AM

You've replaced most everything that could affect the engine when warmed up. As far as fuel delivery, after the distances you are talking about, there would be no chance of vapor lock. I'm leaning toward ignition, there is still the pickup in the distributor and the ignition module itself. The pickup is in the same spot inside the distributor where the points would be in an old style ignition. Fairly easy to replace and gap with the reluctor. The ignition module is also easy to replace, not sure where it will be positioned in a van, but probably will be mounted to the firewall under the hood. Both of those components are readily available at auto parts stores. Here's a couple of listings from Rock Auto.

https://www.rockauto.com/en/moreinfo.php?pk=942986&cc=1074765&pt=7176&jsn=887

https://www.rockauto.com/en/moreinfo.php?pk=1186723&cc=1074765&pt=7172&jsn=891

Elandan2 · August 12, 2021, 09:07 AM

Thinking about this further, are the floats set properly on the carburetor? There may be too little fuel in the bowls to keep up when driving.

Raceluvr · August 12, 2021, 05:52 PM

Quote from: Elandan2 on August 12, 2021, 09:07 AM
Thinking about this further, are the floats set properly on the carburetor? There may be too little fuel in the bowls to keep up when driving.

I think Rick hit the nail on the head. The rebuild kit should have had a paper guide to measure the float level. Definitely check that. Another annoying thing is the ballast resistor - they can have cracks in them that will only affect the motor as they heat up and the cracks expand. I have the 440-3 motor in my MH, not sure where yours are located, but the ignition module & resistor are to the rear of the engine near the distributor, mounted on a plate. Good luck!

PLUM72 · August 12, 2021, 10:27 PM

Taking a different approach, how was the pump wired? Small gage wire with the electric fuel pumps can be problematic. Between the small wire gage and the length of the wire, the fuel pump may not be operating effectively.

Some of these pumps might need 8 or 10 gage wire for the power feed depending on distance. With the energy draw it's often best to wire these using relays.

Just a different thought....

50YrOlNoob · August 15, 2021, 01:11 AM

I appreciate your input PLUM72. Thank your for that information. I'll keep it in mind for the future since I have a few more RV's to repair. I actually eliminated the electric fuel pump and replaced the original mechanical pump with a new one. My fuel problems are gone but it's still stalling when hot

50YrOlNoob · August 15, 2021, 02:16 AM

Elandan2, I appreciate your suggestions. I did replaced those two components (Ignition pickup and module) plus the vacuum advance since I was there and it was rusted/aged since the vehicle's been sitting for 20 years. I did managed to drive it around for 3 blocks again then it stalled. Once the car dies it does not want to turn over again even if it's parked.

Raceluvr, I also appreciate your suggestions. I'll look into the measure of the float level that you and Elandan2 mentioned along with the ballast resistor since I'm going through the process of elimination. I've replaced most things so what's a few more

I had noticed the ignition switch getting hot before but now it gets VERY hot. I touched the ignition wiring and it was very hot as well. I hope it's not an electrical problem Hm?

Thank you all for your help and suggestions

Elandan2 · August 15, 2021, 08:43 AM

The ignition switch getting hot is caused by high resistance in the circuit. On Dodges, it is usually caused by a bad connection in the plug partway down the column. Check there first.

PLUM72 · August 17, 2021, 05:30 PM

Quote from: 50YrOlNoob on August 15, 2021, 01:11 AM
My fuel problems are gone but it's still stalling when hot

Is it possible there is a vapor lock issue? It can get pretty hot under those engine covers. Is the fuel line routed near the exhaust? That would be enough to give you the issue. Reroute fuel line or they sell a heat shrouding for the fuel line which might help depending on proximity of the heat source. In the 60's-70's some muscle cars with the big engines came with a fuel filter/vapor separator combo. This was placed after the mechanical fuel pump and before the carb. It was like a fuel filter with an extra port that went to the vapor recovery system. If you google fuel filter vapor separator you'll see what I mean.

50YrOlNoob · August 19, 2021, 02:16 AM

Thanks again for the tip PLUM72. I appreciate y'all sharing your knowledge with me. I've learned so much but it's time for me to throw the towel.

50YrOlNoob · August 19, 2021, 02:20 AM

Thanks again Elandan2. I did replace the ballast resistor because it was pretty much out of that white material on one of the pockets and had many cracks on the other one. It was getting supper hot and that's what was causing the ignition and cables temperature to get hot.

I did take the carburetor back to the shop and they calibrated everything again for me. They even tested it on a jeep they have on the back of the shop. It's amazing to see them test 4, 6, & 8 cylinder carburetors on the same car using custom adaptors. I installed it on my RV but I had the same problem. The car just won't stay on now i??

I replaced pretty much all that has to do with the ignition and fuel system. I went as far as I could but I bit way more than I can chew. It has to be something simple that someone with the right knowledge can fix. I'm thinking now it has to be a vacuum or something simple like that that I might've connected wrong. My mechanic friends don't want to help me any more because they don't like getting their hands on some one else's work even if all the components are new Hm? i?? OOPS!

Time to call in a pro. Is there a mechanic listing on this site? I live in California next to the Ontario airport.

Raceluvr · August 19, 2021, 10:12 AM

You mentioned a possibility for a vacuum issue. Is it possible to post a short clip of the engine running and stopping or cutting out? Might help the knowledgeable mechanics who hang out here help diagnose the issue. I have the 78 440-3 motor in my motor home, and a vacuum leak can certainly cause issues if not connected to the right source or have a leak. Good job with all of your efforts, many people would have given up long ago. Vacuum leaks, blown head gaskets, ignition issues and fuel delivery can all cause similar problems like you are experiencing.

50YrOlNoob · August 20, 2021, 12:01 PM

You're right Raceluvr. I came this far to just quit now. I will start a new post adding videos and pictures to troubleshoot. I'm almost there and it's gotta be something simple.

Admin. Can you please set this post as solved since the original fuel issue was solved.

Thank you all for your great advice and expertise!

God bless!

Eyez Open · August 20, 2021, 12:44 PM

Somtimes frustration can blur fundamental issue's. Using that electric fuel pump to prime the system is quite telling. If I was in your shoes I would pull it, next stop would be to get a vacuum gauge dismount the mechanical pump and see if the pump can actually hold a vacuum. Don't take it for granted it can, lots of junk out there...lots of junk.

If your fuel pump can hold a vacuum, next step would be take off the fuel line hooking up a hose a pump a 1/2 gallon into a glass container. If that works heat the engine up and Repeat. These old trucks are extremely simple and very primitive make each work step by step.

Personally I suspect you have a fuel line issue, or a tank fuel pick up issue. Don't assume old metal fuel lines are still ok. I assume you have a old Holley carb, is that correct?

I thought I might add, I am well aware I'm not in your shoes...good luck.

Eyez Open · August 21, 2021, 11:55 AM

Quote from: 50YrOlNoob on August 19, 2021, 02:20 AM
Thanks again Elandan2. I did replace the ballast resistor because it was pretty much out of that white material on one of the pockets and had many cracks on the other one. It was getting supper hot and that's what was causing the ignition and cables temperature to get hot.

I did take the carburetor back to the shop and they calibrated everything again for me. They even tested it on a jeep they have on the back of the shop. It's amazing to see them test 4, 6, & 8 cylinder carburetors on the same car using custom adaptors. I installed it on my RV but I had the same problem. The car just won't stay on now i??

I replaced pretty much all that has to do with the ignition and fuel system. I went as far as I could but I bit way more than I can chew. It has to be something simple that someone with the right knowledge can fix. I'm thinking now it has to be a vacuum or something simple like that that I might've connected wrong. My mechanic friends don't want to help me any more because they don't like getting their hands on some one else's work even if all the components are new Hm? i?? OOPS!

Time to call in a pro. Is there a mechanic listing on this site? I live in California next to the Ontario airport.

did take the carburetor back to the shop and they calibrated everything again for me. They even tested it on a jeep they have on the back of the shop. It's amazing to see them test 4, 6, & 8 cylinder carburetors on the same car using custom adaptors. I installed it on my RV but I had the same problem. The car just won't stay on now

You need to find a new carb shop, it is beyond any reasoning a professional would attempt to calibrate a carb or verify a carb using a jeep as a bench mark. Unless of course they transplanted a big v8 into a jeep and that should speak volumes if they actually did such a mod
. That is the most a absurd thing ive ever heard of. Now being frank is not being negative...but merely a attempt to bring you some clarity.

50YrOlNoob · August 26, 2021, 03:20 AM

Ernie did an excellent job. He even recalibrated and cleaned my carb again at no extra charge after I ran some of that dirty 20 year old gas through it and moved things around.

He thinks outside of the box by using different spacers in order to verify every type of carburetor on the same car. Genius if you ask me and not absurd at all. I even recorded him testing my carb. I highly recommend him!

https://erniescarburetors.com/

50YrOlNoob · August 26, 2021, 03:37 AM

Eyez Open. I agree with you and will look into your suggestions. The engine works fine now that I made sure everything was right. I installed a clear fuel pump to see the gas level. I managed to keep it running idle for over 10 minutes with no change on the fuel flow or gas level. I then drove it around and noticed the gas level getting smaller and smaller the more I drove until the car stopped.

Raceluvr · August 26, 2021, 01:19 PM

The bottom photo may be a roll over valve, designed to shut off the flow of fuel in the case of a roll over.

Elandan2 · August 28, 2021, 08:35 AM

Thinking about this, you have definitely narrowed down your problem. The mechanical pump can supply enough fuel at idle. When you had the electric pump in the system, it acted exactly as it does now. That indicates to me that the problem is upstream of the location where the electric pump was installed. I am leaning to a problem inside the tank, but it could also be a pinched or obstructed fuel line restricting the flow from the tank. I think the best course of action is to remove the fuel tank and check for any problems.