Vanagon Syndrome (I think)

[NateTheSkate]

My 87’ Vanagon has been misfiring a few days ago after driving for 12 hours from Lima to cusco Peru. I’ve finally been able to connect to a WiFi to make this post but with limited service I’m unable to search the forum for solutions so easily. When the misfire or bucking first happened it was in 3rd when I hit around 3500 rpm and eventually it failed in second and first until it shut off. I had to wait for the car to cool down to get it running again and was only able to get another 20 minutes for an hour of rest.

After diagnosing as much as I’m mechanically able to, I replaced the fuel pump, ignition coil, coil cable, cleaned the throttle body, checked the spark plus, and checked the distributor cap. After speaking to another Vanagon friend, he suggests that it might be the notorious Vanagon syndrome. I have no yet unplugged the o2 sensor to see if that helps but wanted to know if anyone has any other thoughts.

Things to mention, after changing coil, the bucking was not as significant but had a even greater problem keeping idled. Van would shit off at stop lights or after slowing down where as this didn’t occur when the bucking first stared, my thoughts is that the issue is just getting worse.

Before and after I replaced the fuel pump, the pump would make a very irritating noise almost like it’s steigflimg to get fuel. So we changed the fuel pressure regulator and fuel filter, still squeals like a pig so to get her to start, we turn the ignition 3/4 to get some fuel in, and then she starts right up.

Due to the fact that we’re in Peru and parts are very limited, will unplugging the o2 sensor get me through the rest of my voyage (30-45 days/3,000 miles). How do I know if I need a new AFM vs. a sensor. Assuming of unplugging doesn’t help it will be the AFM.

Thanks everyone and apologize If i don’t respond right away it’s because I have limited service in this country. However I’m able to text pretty easily so if ou leave your number you’ll be able to reach me better

Merry Christmas

[Wildthings]

It sounds to me like the outlet screen in the tank might be clogged or the outlet tube/hose is clogged. Does the problem get worst as the tank empties? If so maybe the outlet tube in the tank may have come apart and you are sucking air.

Get hold of a 0-60 psi pressure gauge and following the instructions in the manual see what your fuel pressure is doing. It would be nice to get a 4' + long hose so that you can read the pressure while your partner is driving.

What happens when you remove the gas cap after driving a ways? Do you hear air rushing into the tank as you do this? If so maybe the ventilation system for your tank is bad?

[DometicLover]

I second, sound like a fuel supply issue. I had a similar issue once, it would buck when accelerating, turning, braking... ended up being crap in the tank blocking the flow.

[AZ Landshaper]

Hit up the taller mechanico for a pressure gauge. They have those down there. Should at least allow you to rule out the fuel pressure possibilities.

I once loved a Peruvian woman. aahh the language of love.
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[borninabus]

fuel pressure & a compression test would be the place to start with symptoms like this.
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[NateTheSkate]

It’s hard to believe it would be the tank as it was replaced brand new last March but then again I’ve done 17,000 miles so far this trip coming from NYC. I’m going to check the hose itself to see if there’s any defects and the screen for a clog. Bad gas down here happens so it very well may be it. If it’s not that I will check the ventilation by removing the cap while driving.

I will also have the mechanic here test the fuel pressure and rule out the ACM and/or o2 sensor for now. Will keep everyone posted on the results later today.