Itinerant Air-Cooled

Hi all,

I'm currently in Colombia and I am acquiring a few spare parts before I venture further south. I am looking to acquire a spare fuel pump since the gas is terrible.

I have an 82 Federal aircooled, FI, vanagon. The normal Bosch fuel pump number is 580 463 016

The pump available in Colombia is the 580 464 070. This pump has a higher pressure rating (43 psi vs 36psi) than the 016.

Can I run this pump or should I be ordering one from the USA?

Doesn't really matter. The pressure is regulated by the fuel pressure regulator, not the fuel pump. Use it as a spare.

ohmydarlingcharlie wrote:Hi all,

I'm currently in Colombia and I am acquiring a few spare parts before I venture further south. I am looking to acquire a spare fuel pump since the gas is terrible.

Just keep up on the filter. You can rinse the filter out many times if it should clog. The pump will be fine with a clean filter.
I have cleaned out the same fuel filter up to ten times before replacing it.

I have 13,000 miles on my new fuel pump since October, and it only "sings" if the filter clogs.
Colin

Hi Colin.

Thanks for the reply.
The reason I was asking about the pump is because I have gone through 3 filters very quicky recently (2000miles) after leaving Panama and driving in Colombia. The fuel pump wasn't making any noise but I was getting buckling.
When I changed the filters the buckling went away. The first two I opened had some white powder on the inside of the can. A collected some fuel from the second filter and there was a bit of water.

The third filter was changed and it didn't look very dirty and the gas I collected from the tank and filter(1/2 galon) didn't have any water.

I thought my pump was maybe loosing some of its power hence the reason for carying a spare.

Any thoughts appreciated.

Randy in Maine wrote:Doesn't really matter. The pressure is regulated by the fuel pressure regulator, not the fuel pump. Use it as a spare.

Thanks Randy. This is good to know. There isn't a max pressure the pressure regulator can handle?

Usually the crud in the filter is from rust in the fuel tank.

Assuming you are running the stock FI.......If you continue getting the bucking, I would have a good look at the Temp Sensor II over by spark plug #3. It has a 13mm head and a black wire headed into the engine wiring harness. Clean the electrical connection and make sure the TSII is snug to the head. Don't reef on it or you will wish you had not.

If the resistance is too high when measure at the "Big Plug" at the ECU with your ohm meter, the computer thinks the engine is cold and runs too rich of a mixture and it will choke out the spark plugs. Feels just like the fuel pump is dying.

Randy in Maine wrote:Usually the crud in the filter is from rust in the fuel tank.

Assuming you are running the stock FI.......If you continue getting the bucking, I would have a good look at the Temp Sensor II over by spark plug #3. It has a 13mm head and a black wire headed into the engine wiring harness. Clean the electrical connection and make sure the TSII is snug to the head. Don't reef on it or you will wish you had not.

If the resistance is too high when measure at the "Big Plug" at the ECU with your ohm meter, the computer thinks the engine is cold and runs too rich of a mixture and it will choke out the spark plugs. Feels just like the fuel pump is dying.

Thanks Randy for the reply. I do have stock FI.
The latest symptoms I have been having with my FI are that the engine speed will suddenly drop a few hundred rpms while in first gear and then jump back to where it was(observed on the tach on also felt in the van) . This started yesterday. With constant pressure on the gas pedal the rpms drop but only in first gear. In all other gears this does not happen. The van idles fine.

ohmydarlingcharlie wrote:

Randy in Maine wrote:Usually the crud in the filter is from rust in the fuel tank.

Assuming you are running the stock FI.......If you continue getting the bucking, I would have a good look at the Temp Sensor II over by spark plug #3. It has a 13mm head and a black wire headed into the engine wiring harness. Clean the electrical connection and make sure the TSII is snug to the head. Don't reef on it or you will wish you had not.

If the resistance is too high when measure at the "Big Plug" at the ECU with your ohm meter, the computer thinks the engine is cold and runs too rich of a mixture and it will choke out the spark plugs. Feels just like the fuel pump is dying.

Thanks Randy for the reply. I do have stock FI.
The latest symptoms I have been having with my FI are that the engine speed will suddenly drop a few hundred rpms while in first gear and then jump back to where it was(observed on the tach on also felt in the van) . This started yesterday. With constant pressure on the gas pedal the rpms drop but only in first gear. In all other gears this does not happen. The van idles fine.

Warm or cold?
Heavy load or light load?

Do you have a temp sensor resistance reading to share with us?
Colin

Warm or cold?
Heavy load or light load?

Do you have a temp sensor resistance reading to share with us?
Colin

This happens warm and cold.
With a light/medium load it is the most pronounced. The rpms drop and jump back up frequently but only in first gear whenever I am going up any kind on infline.
With no load (flat) it is hard to tell. It feels more like a lag in the acceleration but I can't say what the symptoms are with certainty. Without a load the rpms do not drop like they do when there is a load.

Temp 2 readings
At 23C ambient: 2340 ohms
At 34 C ambient : 1570 ohms
With warm engine : 114 ohms

I happen to have another temp 2 sensor on cylinder (long story-head but back on wrong side) and the numbers were almost the same.

Colin
I tried swapping the temp2 sensor by using my sensor on cylinder 2 and the problem did not go away.

I tried changing the AFM with my spare and the problem did not go away. I changed the AFM because the resistance readings between 6-7, 7-8 were way off. What does #7 control?

Before having the problems I drove 600km up and down the Andes without problem. I drove a week in the city, without load, without problem. When I got on a rough dirt road I noticed the problem.

Before doing the 600km drive I repaired a large hole in my exhaust. The spark plugs were a slight white before the hole was repaired.

These plugs were pulled a week ago. New plugs were installed.

Plugs look fine. Your AFM swap rules out the AFM. Your temp sensor swap rules out the temp sensor. We are now down to the grinding little details that you must keep a record of.

For example, I did my spark plug connector resistance readings in March, and the day before yesterday, I replaced one of them that had "infinite" resistance. THAT was the cause of all number of stumbles and backfires at idle and low speed.

Check wires, spark plug connectors, distributor rotor, look for insulation fraying on the spark plug wires themselves, especially if yours are in clips, check double relay ground, transaxle ground, ECU grounds . . .

Think comprehensively and creatively. I once had a distributor that was shorting out the breaker point wire whenever the distributor advance rotated the breaker plate.
Good Luck.
Colin

Amskeptic wrote:Plugs look fine. Your AFM swap rules out the AFM. Your temp sensor swap rules out the temp sensor. We are now down to the grinding little details that you must keep a record of.

For example, I did my spark plug connector resistance readings in March, and the day before yesterday, I replaced one of them that had "infinite" resistance. THAT was the cause of all number of stumbles and backfires at idle and low speed.

Check wires, spark plug connectors, distributor rotor, look for insulation fraying on the spark plug wires themselves, especially if yours are in clips, check double relay ground, transaxle ground, ECU grounds . . .

Think comprehensively and creatively. I once had a distributor that was shorting out the breaker point wire whenever the distributor advance rotated the breaker plate.
Good Luck.
Colin

Thanks for the reply Colin.
My plan of attack right now is to check fuel pressure next and see what the fuel pressure is when I am driving and have the problem.
I will do look at replacing the spark plug wires. I will see if I can do compression as well.

The spark plug wire were showing a resistance of 1000 ohms on 2 and 4, and 1500 ohms on 1 and 3. When I recently checked.

The coils resistance readings were in spec as per the Bentley.
I tried running a different cap and rotor. Problem persisted.

From your above write up, you figure it is something electrical?

With the new AFM I am running very rich. I can smell gas in the exhaust when I stop and my rpms drop at stop lights to as low as 500. I have read your procedure for adjusting the AFM and I wondering if I should tackle this or put back my old AFM (even though some of the readings are not in spec-very out of spec 6-7 and 7-8 show readings that keep increasing every time I check. At first they were 500ohms, then 1500 ohms, 5000 ohms and now as high as 30 000 ohms).

ohmydarlingcharlie wrote: coils resistance readings were in spec
different cap and rotor. Problem persisted.
new AFM I am running very rich.
old AFM readings keep increasing every time I check.
At first they were 500ohms, then 1500 ohms, 5000 ohms and now as high as 30 000 ohms.

Let me know your fuel pressure readings.
Lean out the new AFM with a nice big adjustment at the mixture screw.
First, COUNT how many turns to bottom the mixture screw.
THEN add one full turn counter-clockwise to your initial reading. Test drive.
Add one turn counterclockwise between each test drive and let me know if you experience improvement.
Colin