Your assistance is much appreciated here. Please note that I'm not too knowledgeable about vehicle mechanics, and have kind of been learning on the fly as we drove the 8000+ km from Toronto, Canada to where we are now (Arizona).

The vehicle: 1989 Ford Econoline 24 ft RV, with an E350 engine.

Symptoms:
1. Complete lack of power - on a straight road, I can get it up to maybe 55mph on a good day, or only 35-40mph when it's running badly. On a hill, the speed can drop to as low as 10 or less, to the point where it drops to 1st gear and seems like it's going to stop (but hasn't yet). When the car is running badly, I can even lose speed going DOWN a hill.
2. The lack of power is constant, but it does vary - sometimes, when I go down a long steep hill, I can get it to over 65 mph and it seems to kind of reset the engine for a while, at which point it'll run well (ish) for a short period, but then start to run bad again after a large hill or if I stop.
3. When running badly, the engine heats up really fast and almost roasts the driver and passenger - particularly the passenger, where the floor mats have actually become singed and partially melted. During these times, the engine often leaks a lot of smoke into the passenger compartment. Note that we recently paid a LOT of money to get the exhaust manifolds re-bolted, as they were apparently loose and accountable for leaking fumes into the driving compartment and also making it noisier. Since they were fixed, the fumes have been less and the noise less, but they're still there.
3. This may or may not be related, but when it rains hard enough, the engine also tends to run really bad, as if water is getting into the electrics somewhere. This is a very old engine with a lot of loose wires etc, so it's very hard to say where this might be.

A few other things to consider:
1. I was told by a mechanic that the timing was off by 10 degrees (it's set to 0, rather than 10 BTDC. He, and subsequent mechanics after him, couldn't change the timing as the bolt was rusted on. I've since managed to loosen the bolt with liquid wrench/pb, but now I can't move he distributor at all, despite soaking it in liquid wrench daily and tapping it and using an adjustable wrench to try and turn it.
2. I believe the fuel pump may have been replaced 3 months ago at the start of our trip, but can't find the receipt to confirm that. It's possible that it wasn't.
3. I possibly recall my mechanic a long time ago saying that the cat converter was a little small for the size of the vehicle, but this may also be my imagination.

Would really appreciate your thoughts on what you think could be causing the power issues with this thing. We really don't want to spend any more money going to mechanics and asking them to fix the problem, as no doubt they'll just go ahead and replace the cat converter, fuel pump etc and there's a good chance that they're not the problem. We've already spent upwards of $6000 on this thing in the past 3 months and really don't want to spend any more if it isn't guaranteed to fix the problem.

It seems like the 3 likely problems are timing, cat converter being plugged, and fuel pump, but would appreciate your thoughts. I'm still trying to plug away at the distributor to free it up. Also, any other advice on how to improve power and/or fuel efficiency with this thing would be much appreciated!!

 

It does sound like the converter is restricted. If you place your hand near the end of the exhaust pipe , you can pretty well determine if the exhaust system is restricted. You will not feel the definite positive pressure coming out of the tail pipe. A mechanic , or you, could place a simple vacuum gauge connected to any vacuum source on the intake manifold and raise the engine speed up to 1/3 accelerator pedal travel , around 2500 RPM and if the vacuum reading continues to drop lower and lower while holding that engine speed you can be reasonably assured the converter or exhaust system is restricted. An engine that has been running rich for many miles will contribute to that problem. Speaking of converters, the converters for that year and model were huge !
Approx 6in diameter by about 15 -20 in long.
If the fuel filter has not been replaced in a while , it is worth changing just for the peace of mind. If the vehicle has the original coil, they were troublesome also.
Hope we gave you something to consider and hopefully will end the problem.

 

clogged cat would be easy to verify....remove the upstream 02 from the exhaust. this will allow a path for exhaust gases to pass.

your timing was probably set by someone who did not put the vehicle into base timing mode before setting the timing. retarded timing will cause it to fall on its face when starting from a stop and over all lack of power.

 

Thanks a lot Hanky. I ran the RV as you said and checked the exhaust - there's positive flow from the exhaust and this increases from revving, so not sure if would be the cat being plugged? Should I still get it checked?

Good call on the fuel filter, will probably get that replaced tomorrow when I get an oil change and ask them to check the cat (assuming that won't cost too much for them to do?).

So you think that it's probably not the timing? The power issue seems to be getting progressively worse over time, so perhaps you're right. Today we hardly even made it 60 miles to Vegas, with fumes spilling from the dog house into the passenger compartment and the dog house cover itself actually showing singe marks. Quite alarming. Vehicle could hardly get up to 45 on the highway, was revving really high and overheating quickly.
I guess the question is - should I ask them to try to fix the timing (thereby risking them breaking the distributor and needing to replace it for many hundreds of dollars), or get them to focus on the cat and fuel situation?
Thanks

 

Thanks P, will prob leave that up to the mechanic to do unless it's super easy?

As for the timing, power from stopped actually isn't too much of an issue, initial pickup is ok, it's more the lack of top speed that's an issue. Doesn't do more than 40mph comfortably now.

 

Hey guys. Update:
Took the RV to a shop last week and it turns out that the exhaust manifolds had once again warped and come apart due to heat. They bolted them back down as best they could (not ideal, but better than paying a few more thousand to remove the head again) and replaced the plugs and wires which had been partially melted, and managed to advance the timing (he said to around 12, guess it was too stiff to get it exact). Then in ran a little better but was still overheating and slowing down when it got into third gear. So we took it to a muffler shop today and they replaced the muffler and cat converter (both were horribly undersized and of course partially clogged), and it now runs a lot better on the open highway.
Problem is: it still overheats REALLY quickly. Too quickly. And when the engine gets hot; performance seems to drop.
What could this possibly be? Could the coolant not be moving around freely enough? Also heard something about the fan not working as it should?
What can I do myself to check this and potentially remedy it? Really don't want to take it back to a mechanic again!!!

 

What temp is it running at?

does it run hot only when stopped?

Things to start checking are:

-bad thermostat
-inoperative fan clutch
-loose waterpump drive belt
-blocked radiator fins restricting air flow through the rad
-clogged radiator restricting coolant flow through the rad
-bad rad cap not allowing the system to pressurize...this lowers the boiling point of the coolant by as much as 30*
-bad head gasket...with a pressure tester on the rad, you will see a pressure jump from the leaking cylinders as they leak pressure into the cooling system

 

You may now be getting to the real cause of the problems.
That engine is working hard to move that box up hills and against any wind.
It generates loads of heat and any kind of problem not allowing that heat to get out makes it to the list.
If you run the engine a few minutes the temp gauge should go up to slightly past mid point then when the thermostat opens you should be able to see the needle go down slightly. If it does not do that , but keeps going up , we usually suspect a defective thermostat.
The fan clutch should have some slight resistance if trying to turn the fan blades when cold. When you first start the engine the fan blade should spin pretty fast for around 30 seconds then slow down because the engine is cold. Once the temp gets to mid point you should see that fan speed pick up and really start to pull air across the radiator and you will hear the fan roar. If it doesn't do that it has a problem and should be replaced. Don't know how long you had the vehicle, but if the water pump has never been replaced It could cause an overheating problem.
Not to cause you unnecessary concern but There has to be a reason the converter has been clogging and exhaust manifolds warping , possibly something like an overfueling condition and the converter is working overtime trying to clean up the exhaust.
It is difficult and nearly impossible to diagnose engine problems over the net.
We are aware you invested a lot of $$ in the vehicle, but we need to know what that was for and what has been done.

 

Hi guys, thanks a lot for your feedback.
I don't think the temp gauge is bad, as it corresponds directly to the heat I can feel coming through the engine compartment. Plus on start up it starts on cold then moves to the mid point.
I checked out the fan and don't think that's the issue either. As you say there's a slight resistance when the engine is cold, and it did what you said with initially spinning quickly, slowing down, then speeding up again as the engine warmed up.
Is the rad cap the same cap as where the coolant goes? If so, I'd say the seal is fine.
One thing with the coolant which has struck me as strange is that whenever the engine gets hot, you can hear the coolant bubbling away like crazy in there and if I stop the car on a slight angle the coolant gushes out through the overflow pipe, even though I'm very careful not to overfill the tank. Could this suggest that there's a blockage preventing the coolant from being distributed throughout the engine, and then it gets ultra pressurized and has to exit through the overflow?
As to what's been done on this thing so far:
Last week they re-bolted the manifolds and replaced a couple of the plugs and wires, and advanced the timing. Yesterday they replaced most of the exhaust system (they showed us a length of the exhaust and the diameter was tiny - way too small for this size of vehicle they said), installed a new converter, and re-attached some loose exhaust connections on the manifold.
Prior to that, there's been all manner of things done to this in the past three months, including transmission work, new distributor cap, new plugs and wires, oil changes. That's all that I can remember, but I think there's been a lot more done. No other major engine components replaced to my knowledge however.
Water pump may not have been replaced in a long time, so yes that could be an issue.
Any other basic checks I could do to see what might be causing the overheating? Keep in mind that I'm on the road so only have basic hand tools to use. Any point replacing the fuel filter? That shouldn't be causing overheating should it?

 

the noise of coolant flowing is a sign of air in the cooling system.

when it overflows out of the reservoir, it is a sign of overheating....a cap that will not pressurize could cause this. if the system does not pressurize the vehicle will exhibit overheat conditions at a lower temp. The cap may or may not be part of the problem but You can't visually see a bad cap.

You need tools for testing to rule things out. Below are a few tests you can do without equipment.

At what temp does the upper rad hose get hot...an indication of when the thermostat opens.
with a ir heat gun you can measure the inlet and oultlet temp of the rad hoses...an indication of a blocked rad. did you have a look at the rad and condenser or debris clogging the fins?
when cold, remove the rad cap and start it up till the thermostat opens....you should see good coolant flow. if the upper rad hose is squeezed you should feel retriction to flow. Is there bubbles seen at the rad opening after the thermostat opens....signs of a bad headgasket leaking into the cooling system.