1987 Coachmen Crusader Class C Stalls while driving

[Ksouers]

Hi Everyone. I have an update and questions.

1. After changing the spark plugs and wires it runs much better and allowed us to drive a few miles further before stalling.

2. When driving the RV today it sounded like the transmission was only shifting through 3 gears and then started whining and that's when it stalled. After putting in park and starting again it goes a few more miles, shifts through 3 gears and whines. We checked the transmission fluid it is was really low.

3. We attempted to run the siphon hose in the gas tank to remove the gas and drop the tank, but the siphon hose is hitting something and won't run into the tank. Any ideas on draining the tank if I can't get the siphon hose into the tank?

Any help will be appreciated. Thanks Roxanne

The pickup for the tank is supposed to go very near the bottom of the lowest point in the tank. Disconnecting the hose coming out of the tank and adding an extension should provide a path for siphoning, though with that small of a hose it will take a long time to drain without a pump.

An alternative is to use the electric fuel pump to help drain the tank. Disconnect from the carburetor and lead the hose to gas cans. Don't try to start the engine! Just turn the key to on, you should be able to hear the pump clicking away and see fuel coming out the hose. This will be faster than the siphon. It will also allow a visual inspection of the pumps output; is it weak? Is it strong? That sort of thing.

Put a battery charger on the battery the entire time!!! Oh, make sure the batteries are topped up with water. This not part of the issue but yet another general maintenance item. They should be checked on a regular basis, more frequently if they are old (greater than 2-3 years).

Ok, new stuff...
Was the engine running when the transmission fluidl was checked (engine needs to be running)? Do you see fluid on the dipstick? If not, toss in a quart for starters. What color is the transmission fluid? Bright red or dark, like it was burned? Does it smell burned? If you added fluid you need to run it a few minutes before relying on the color/smell test.
Tranny fluid and filter change may be the next item on the periodic maintenance checklist.


Kevin

 

[toneandrox]

The pickup for the tank is supposed to go very near the bottom of the lowest point in the tank. Disconnecting the hose coming out of the tank and adding an extension should provide a path for siphoning, though with that small of a hose it will take a long time to drain without a pump.

An alternative is to use the electric fuel pump to help drain the tank. Disconnect from the carburetor and lead the hose to gas cans. Don't try to start the engine! Just turn the key to on, you should be able to hear the pump clicking away and see fuel coming out the hose. This will be faster than the siphon. It will also allow a visual inspection of the pumps output; is it weak? Is it strong? That sort of thing.

Put a battery charger on the battery the entire time!!! Oh, make sure the batteries are topped up with water. This not part of the issue but yet another general maintenance item. They should be checked on a regular basis, more frequently if they are old (greater than 2-3 years).

Ok, new stuff...
Was the engine running when the transmission fluidl was checked (engine needs to be running)? Do you see fluid on the dipstick? If not, toss in a quart for starters. What color is the transmission fluid? Bright red or dark, like it was burned? Does it smell burned? If you added fluid you need to run it a few minutes before relying on the color/smell test.
Tranny fluid and filter change may be the next item on the periodic maintenance checklist.


Kevin

Hi Kevin.

1. We checked the transmission fluid while the RV was running and it was bone dry. We added transmission fluid and now it is at the proper level. We drove the RV afterwards and it still stalled after about 7 or 8 miles. Better than the 1 mile we would make it to before.

2. We would love to take your advice and drank fuel from the tank at the hose leading to the carburetor, but for some reason our in-tank fuel pump doesn't start until the RV is started up all the way. Just putting the ignition in the start position doesn't start the fuel pump. When the RV is fully started, we can hear the pump running strong but I feel like we should just replace the pump.

It is so weird that the RV runs fine and after a few miles it will stall as though it is not getting fuel but if we pull over while the RV is still running and shift to PARK and let it idle for a minute, it will run again for about the same number of miles. It's like fuel is filling up the float bowl and lines and then the pump is turning off for some reason and we are able to drive far enough to use the fuel in the float bowl and lines. Then we pull over and restart the RV which might restart the pump and fill the lines and float bowl back up and that's why it stalls about the same time each time we drive. I was wondering if the fuel relay is getting hot and shutting off the pump or the pump is shutting off for some other reason but it's weird because it shuts off like clockwork each time and we can drive about the same distance each time upon restarting. It's like we can time it now because we take the same route and we are stalling at exactly the same spots each time.

 

[Rene T]

Can you look underneath and see if there is anything in that general area like maybe a fitting for a vent hose. You may have to go with a smaller siphon hose to get by what’s there.

 

[toneandrox]

Hi Everyone.

We want to test driving our RV by bypassing the existing fuel tank and in-tank pump. As you know, we recently installed an external electric pump on the fuel rail up near the fuel filter. We were wondering if we can use that external electric pump and a 5 gallon tank to run the RV. If it stalls then we would know it is something electrical, but if it doesn't stall then we would know that the in-tank pump is going bad and needs to be replaced. Any ideas on this type of test?

 

[toneandrox]

Can you look underneath and see if there is anything in that general area like maybe a fitting for a vent hose. You may have to go with a smaller siphon hose to get by what’s there.

The siphon pump hose is really narrow already so I'm not sure where we would find a hose more narrow. Thanks

 

[toneandrox]

You never mentioned how fast you are driving. You do realize it was built during the 55 mph speed limit days from 1974-1987. The gear ratio is much lower on anything built during those years. Have you tried driving 50 mph to see if it lasts longer?

We have been mainly going 45 to 50 miles per hour. Our top speed has been around 55 mph

 

[Ksouers]

Roxanne,
Did you disconnect the fuel line when you tried running the pump to drain the tank? The line must be disconnected. There is a pressure regulator that stops the pump when the pressure gets high enough. So the discharge end of the hose needs to be free so pressure doesn’t build up if you want to use it to drain the tank.

Kevin

 

[toneandrox]

Roxanne,
Did you disconnect the fuel line when you tried running the pump to drain the tank? The line must be disconnected. There is a pressure regulator that stops the pump when the pressure gets high enough. So the discharge end of the hose needs to be free so pressure doesn’t build up if you want to use it to drain the tank.

Kevin

Yes we removed the discharge end to drain the fuel.

 

[toneandrox]

Ok everyone. We are now trying to replace the in carb filter. As you know there is a bottom bolt, then a spacer, and then a top bolt. We have sprayed that bottom bolt with wd-40 and let is sit overnight, but it is not loosening. I was wondering if we are turning the wrench in the wrong direction. Should we be turning that bottom bolt left or right?

 

[Ksouers]

WD40 is the wrong product. It is not a lubricant in any way, though it may act that way when it is still wet. WD40 is a water displacer, a mild solvent and a protectant. It contains fish oils that will repel water, the oils evaporate and leave behind varnishes when it dries to (mildly) protect metal. WD40 is ok stuff when used properly, unfortunately most people do not.

You should probably be using PB Blaster. It is a penetrating oil and lubricant, it is very thin so it will seep into any corrosion and help break it up. It won't dry so it will stay lubricating the parts.


Kevin

 

[TheBar]

Before you break something I said back in post #6 to test your fuel flow but I never saw where you did. This will tell it all. Your mechanic said the fuel pressure is good. On these older vehicles people forget fuel flow is more important than fuel pressure on a carburetor engine.

This could start a fire if you are not careful. Take the fuel line loose at the carb, put a hose over the line to drain into a container, and have someone turn the key on but do NOT start the engine. You should see a healthy stream of gas with no bubbles into the container. A good flow is like turning a water faucet part way on. If you can take a short video of the gas coming out I can tell you if it is good enough.

If you have a good flow without bubbles then the problem is in the carb. Either the in-carb filter you didn't think you have is plugged up, the float needle is restricted or sticking, or the float is set way too low.

If you do not have a good flow or do have bubbles go back to the electric pumps, take the gas line off, and test the fuel flow there. If you have a good flow there your restriction is between the pumps and the carb. If not then your problem is either the pump(s) or in the gas tank.

Let us know what you find.