HELP! Stuck in Guatemala - can't go uphill

[Hedgeman]

Hi Everyone - I'm currently stuck in Antigua, Guatemala with a tricky engine problem. I've been working on this for a while but with no luck.

The only relevant post I could find on the forum was this one: http://toyotamotorhome.org/forums/index.php?showtopic=4533&st=0&p=26643&hl=uphill&fromsearch=1entry26643

It's an 81 Toy Sunrader 18ft. Federal and Canada emissions model. 22R

Here is what happens. The car idles smooth and runs well with ok power under hard acceleration on flat land (it does experience throttle hesitation though). When you attempt an uphill of moderate grade, it accelerates normally as you increase the throttle until the revs go up and you have it at full throttle. At that point, it suddenly stalls and lurches until you put in the clutch. Then, (if you did it soon enough) it will return to idle, you can bring up the throttle again and resume uphill briefly before the same stall will happen again. Here is a video of what happens.

For a while now we've had throttle hesitation and I've felt like power has diminished over the course of our 3500 miles traveled since a tuneup. At that time, the following things were done:

oil and filter change, new air filter, new distributor cap and rotors, new spark plugs and wires, new fuel filter (in engine compartment), new belts, new radiator hoses, timing checked, fuel/air mixture screw on the carburetor was adjust by feel (not to any kind of specification).

Most of the time since that work was done, all was well. During the last 500 miles or so, the throttle hesitation problem has been increasing (throttle lag when you depress gas quickly). Otherwise, no significant problems.

Then, while not travelling for a while, I had a mechanic do some things and now I can't go uphill. Here's what he did.

- clutch job

- lowered the fuel tank to fix a crack caused by the cabin frame sitting on the tank. Reset the tank to a lower position that doesn't interfere with cabin now(wow - that crack gushed fuel all over the road on an uphill)

- replaced the mechanical fuel pump (engine compartment) and the fuel filter.

- adjusted the carburetor (I think that he just adjusted the fuel/air mixture screw but it's possible he made another adjustment that my bad spanish couldn't determine from him)

- replaced the exhaust manifold which had a crack and was leaking (as well as vibrating up a very weird sounding hum that was pretty embarrassing while pulling into little Guatemalan villages)

- installed some Firestone air assist springs (oh man did we need those)

- he changed vacuum hoses (this one's a doozy) without consulting the vacuum hose diagram under the hood, he made several changes to the routing of the vacuum hoses that were in error. Since that happened, I have reconfigured them back to spec and a good mechanic has just verified that they are correct.

After I rerouted the vacuum hoses, I tried the hill again thinking that the problem was related to the vacuum advance. No luck. It failed in the exact same way.

It is now at a better shop but the mechanic still seems stumped. He has:

- checked the fuel pump pressure and found it be within spec (I don't have a number)

- verified the vacuum hose layout and that the vacuum advance is operational

I (and the mechanic) now suspect that it might be a carburetor float problem. I'm about to start digging into the manuals and see if it's possible that the old (bad) mechanic has made an adjustment to the float and caused the problem but I thought I'd post this now and see if anyone has any thoughts as I continue troubleshooting.

While we're not on a tight timeline, we're beginning to wonder if we'll be able to get our beloved rattlevan out of here. It's all hills around here so if she won't go uphill, she'll have to stay here and I'm not leavin' her!

If you're interested, you can read a more interesting (but less technical) version of the events that have taken place on our blog on this post: http://rattlevan.blogspot.com/2012/03/why-rattlevan-cant-go-uphill.html

Thanks in advance for any advice you might be able to offer.

Chuck

[Hedgeman]

I just checked the float level sight glass with the engine running and it does seem to be low. The fuel level is just visible in the window but not above the line. I'm not quite sure if I'm interpreting the sight window correctly. It appears on the front of the carb and looks like an hourglass laid on its side. The fuel level is barely visible at all but definitely does not rise to the area between the two necked portions of the hourglass (or the waist of the hourglass). If I'm reading the Chilton's manual correctly, it still appears that I have to remove the carb to adjust the level. 1. this sucks (why put a window to make it easy to see the level if you can't easily adjust it?) 2. If you have to remove the carb to adjust the level then it's not likely that my bad mechanic adjusted it. (Which would imply that the level has been the same the whole time and I would have had the uphill problem before my visit to said evil mechanic.)

UPDATE: Here's a video of the float level sight glass with the engine at idle. (vehicle not perfectly level, tilting to the right about 4-5 degrees, not sure if that matters).

Seems low right?

Edited March 8, 2012 by Hedgeman

[5Toyota]

you should be able to just remove the top of the carb itself. and yes the idle fuel level is right in the middle of the window. how is the filter and the fuel pump. are you shure that the clutch is not slipping.

[Maineah]

The fuel should be in the middle. There is a nut on the top of the metal fuel line going to the carb if you remove the nut you can lift the fitting, the fitting is called a banjo fitting because it looks like a little banjo under the fitting lives a filter it's a tiny screen that fits around the top of the brass fitting going into the carb. have a good look at the screen I probably would leave it out and try it. You can change the float level by changing the washer under the fitting if it's low you'll need a thicker washer (or another thin one) likely as not there is nothing wrong with the float level as you say there is no reason for it to change and to this point it has been running fine. I'm guessing Mexican fuel is not the cleanest.

[Derek up North]

You've checked the fuel PRESSURE. Is there a procedure in the manual to check the FLOW? I'm on dial-up, so it would take me days to download it to look myself. I'm wondering if a fuel line might be crimped while the tank was being moved.

[Hedgeman]

@maineah I'm inclined to agree with you about the float level. I'm reading that the stall is caused by flooding as the float dumps the gas directly into the carb when it tilts. Some off-road enthusiasts actually set it low to avoid this problem. I would think that setting it even higher would just exacerbate the problem. I do suspect bad gas but would it get past the fuel filter? We started the trip with a new one and I changed out that one recently to an even newer one.

@Derek up North no we haven't checked the flow rate. There is a simple procedure in the manual. We'll try it. I'll also check the lines for problems too.

@5toyota the pump and the filter are new and the clutch is not slipping.

I've also received the following offline from a friend of the family:

I'd say the problem is in the tank. Fuel pressure may be fine under static conditions but the pump may not deliver the required volume when needed. I know this might be a bit dangerous but how about using a gas can to make a "temporary" gas tank that is located above the engine level. Let gravity feed your fuel pump and see what happens.

Has the gas tank been drained? Might be worth a shot. Some in-tank pumps have a "sock" around the intake that can get gummed up as well.

Another thing to check is for a clogged exhaust system. That is easier to check, just disconnect the line to the cat converter (if it has one).

One last thought, what happens if you jack up the front of the van, does the engine still quit even if in neutral. Or jack it up against a tree and gently apply gas to make it run under load.

I'll check on the exhaust constriction issue too. I'm hesitant to jack up this thing that much as it's fully loaded and seems a little scary. I also would like to check the fuel sender unit and its sediment filter to see if it's a mess.

Thanks a bunch guys - I'll update when I get more info. I think I'll tackle the things mentioned next instead of messing with the float.

[Derek up North]

... Some in-tank pumps have a "sock" around the intake that can get gummed up as well.

..... and its sediment filter to see if it's a mess.

Blowing back through the gasline, as suggested by 5toyota, would probably unblock it long enough to see if the sock/strainer is plugged up. Then more drastic steps could be taken for a permanent fix.

[Hedgeman]

Guys! It's fixed! I just drove it straight up a hill under full power. It's a little embarrassing but it turned out to be something simple. The previous shop hooked up the fuel pump wrong. The fuel return to the tank was hooked up to the carb. Neither I nor my new mechanic noticed the routing problem as the hoses disappeared into a blind spot (and, more importantly, I was insufficiently diligent in tracing them). I did a flow rate test and discovered that the flow rate was 60% of the specification. Further investigation revealed the routing problem with the fuel hoses.

Special thanks goes to @Maineah for keeping us from cracking that carb open for no reason to mess with the float level and hats off to you @Derek up North for pushing the flow rate test.

Thanks so much for your help guys. I never cease to be amazed by this forum's sense of community and support. Thanks also from my girlfriend who is ecstatic that we will be moving on with our adventure (and not attempting the impossible task of getting home without ever going uphill).

Edited March 9, 2012 by Hedgeman

[Derek up North]

So you were 'running out of gas' going up hill. Pump wasn't keeping up. Glad it's fixed. Happy trails.