1987 Coachmen Crusader Class C Stalls while driving

[toneandrox]

My last class A had two fuel pumps. One was located inside the fuel tank.

My RV had a mechanical pump but the previous owner removed it and ran an in-tank pump only. We added an external fuel pump yesterday just in case the in-tank pump is too weak. Our mechanic said adding the external pump would help and would pull fuel through the in-tank pump even if the in-tank pump dies completely. We were questioning how the external pump could pull fuel through a dead in-tank pump but the mechanic said it would. We are still hesitant about that.

Thanks

 

[ChasA]

This could be an exhaust blockage problem. Have the mechanic check it.

 

[Ksouers]

I have a story someone told me many years ago in a bar. Take it for what it's worth.

Said guy was relating a story about a car he had. It would intermittently die on the road. It would only die while driving. After sitting for a few moments the car would start back up and run fine for awhile. Maybe 10-20 minutes, maybe hours or days. This was back in the 70's or 80's, so before electric fuel pumps were common.

After several visits with the dealer they finally decided to inspect the gas tank. Lo and behold when they emptied the tank a plastic sandwich bag came out. I don't recall, but this may have only been an issue when the gas was below a certain level, as in the bag had a tendency to float and only got caught below a half tank.

Seems it would float around until randomly covering the pickup screen, when the engine died and the pump was no longer creating suction at the pickup the bag would float off until the next random event.

I don't how much trouble it is to drain your tank for a detailed inspection but at least you can rule out any scenario similar to above. I don't think dropping the tank but if you could get it empty and inspection with a bore scope may prove helpful.

I would not recommend going through this trouble until you've exhausted the more common problems and remediation.


Kevin

 

[toneandrox]

I have a story someone told me many years ago in a bar. Take it for what it's worth.

Said guy was relating a story about a car he had. It would intermittently die on the road. It would only die while driving. After sitting for a few moments the car would start back up and run fine for awhile. Maybe 10-20 minutes, maybe hours or days. This was back in the 70's or 80's, so before electric fuel pumps were common.

After several visits with the dealer they finally decided to inspect the gas tank. Lo and behold when they emptied the tank a plastic sandwich bag came out. I don't recall, but this may have only been an issue when the gas was below a certain level, as in the bag had a tendency to float and only got caught below a half tank.

Seems it would float around until randomly covering the pickup screen, when the engine died and the pump was no longer creating suction at the pickup the bag would float off until the next random event.

I don't how much trouble it is to drain your tank for a detailed inspection but at least you can rule out any scenario similar to above. I don't think dropping the tank but if you could get it empty and inspection with a bore scope may prove helpful.

I would not recommend going through this trouble until you've exhausted the more common problems and remediation.


Kevin

Hi Kevin. We feel like we've tried everything except dropping and inspecting the tank. We are planning to siphon the gas out and drop the tank today. We were even thinking of replacing that metal tank with a plastic tank to prevent rust issues in the tank. It is a 1987 so who knows what I might find in the tank. Thanks for your advice

 

[TheBar]

Good point. You said originally it was only lasting a couple of miles but after the mechanic installed a new filter it went 10 miles, now you said it is back to a couple of miles. After 34 years the gas tank may be so full of rust that it has already stopped up the new filter. Take the new filter off and see what comes out the suction side. I prefer clear filters where you can see what is in the filter without taking it off. You can also see air bubbles going through it if there is a suction leak.

 

[toneandrox]

Hi Everyone. I have an update and a question. My husband and I changed the spark plugs and wires today. We noticed the wires and plugs were in very bad shape. That could have been a major part of the issue. We didn't really check that in the beginning because the previous owner claimed he did a tune up, but looking at those wires and plugs, it appeared they had never been changed. We also replaced the ignition module early this morning but that didn't fix our issue. It did improve our issue because although the RV stalled it never cut off.

Our question is about the manifold. When we were looking for the fuel filter at the carburetor, we didn't notice a filter on our carburetor. We did notice that air was coming from 2 spots on our manifold where 2 bolts were missing. We are wondering if those 2 bolts are supposed to be missing on each side of the manifold. We felt air coming from those spots where it appears bolts should be.

We are planning to siphon the gas from the tank tomorrow and clean the tank and get fresh fuel.

I will come back with an update tomorrow after we clean the tank out.

Thank you all

 

[TheBar]

To see if you have a fuel filter inside the carb, click on the picture below. The gas line is red and screws into #12 in the carb. You unscrew #12 out of the carb and #15 is the filter behind it. It has a spring behind the filter but if it has been there for 34 years it may be hard to get out. Your carb may not be original or it may not have a filter even though RockAuto shows it does. I should mention a lot of people throw these bronze filters away since the gas should already be filtered.

 

[billwild]

I had the same syptoms in an Chev truck I had. Turned out the fuel cap was not vented and everytime I took it off there was a release of pressure. Replaced the cap and all was well. A goofy fix but worth a try.

 

[toneandrox]

To see if you have a fuel filter inside the carb, click on the picture below. The gas line is red and screws into #12 in the carb. You unscrew #12 out of the carb and #15 is the filter behind it. It has a spring behind the filter but if it has been there for 34 years it may be hard to get out. Your carb may not be original or it may not have a filter even though RockAuto shows it does. I should mention a lot of people throw these bronze filters away since the gas should already be filtered.

Thanks. We don't have a filter on our carb. We removed the line leading to the carb and next is the casing around the float. There was no filter.

 

[toneandrox]

I had the same syptoms in an Chev truck I had. Turned out the fuel cap was not vented and everytime I took it off there was a release of pressure. Replaced the cap and all was well. A goofy fix but worth a try.

We tried that yesterday. We removed the gas cap and drove it as a test but the issue continued. Thanks for your advice

 

[toneandrox]

Today we read that the issue might be the catalytic converter. We plan to check that and clean out the gas tank. If anyone has advice about the catalytic converter, please share. Thanks

 

[toneandrox]

This could be an exhaust blockage problem. Have the mechanic check it.

We checked today and there was no blockage in the exhaust. Thanks

 

[John From Detroit]

Rubber lines, if the wrong type can collapse under suction from the fuel pump. The right type of line won't do that but the wrong type can... Sorry can't help you with how to tell save that if you pinch the line with your fingers it's way easier to pinch the WRONG type.

 

[toneandrox]

Rubber lines, if the wrong type can collapse under suction from the fuel pump. The right type of line won't do that but the wrong type can... Sorry can't help you with how to tell save that if you pinch the line with your fingers it's way easier to pinch the WRONG type.

The rubber lines are really really stiff lines that can hardly be pinched at all. Thanks for your advice

 

[Ksouers]

Re: missing bolts.

It is unlikely that is the root of your issue. If those were leading to the intake plenum (the channels guiding air/fuel to the combustion chambers) the engine would just barely run, if at all. Even with small bolts that would be a massive vacuum leak. But worth inspecting and closing off.

However, if they help anchor the intake manifold to the heads/block there could be a small vacuum leak around the gasket. Again reason enough to inspect and fix.

The work you've been performing has primarily been routine maintenance. Though it has not resolved your primary issue it has not been a waste of time. The previous owner seems to have ignored this part of ownership.

My money is still on fuel delivery. I'm hoping the tank inspection proves fruitful.


Kevin

 

[toneandrox]

Re: missing bolts.

It is unlikely that is the root of your issue. If those were leading to the intake plenum (the channels guiding air/fuel to the combustion chambers) the engine would just barely run, if at all. Even with small bolts that would be a massive vacuum leak. But worth inspecting and closing off.

However, if they help anchor the intake manifold to the heads/block there could be a small vacuum leak around the gasket. Again reason enough to inspect and fix.

The work you've been performing has primarily been routine maintenance. Though it has not resolved your primary issue it has not been a waste of time. The previous owner seems to have ignored this part of ownership.

My money is still on fuel delivery. I'm hoping the tank inspection proves fruitful.


Kevin

Thanks Kevin. We will put the 2 missing bolts in the manifold just to rule any leaks out.

 

[toneandrox]

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

 

[Rene T]

How far down into the filler pipe does it go?

 

[TheBar]

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.

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?

 

[toneandrox]

How far down into the filler pipe does it go?

About 1.5 feet and then it is hitting something that is blocking it.