Sticking Double Relay

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chitwnvw
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Sticking Double Relay

Post by chitwnvw » Fri Jul 17, 2009 8:23 am

Is there anything that can be done for a relay that sticks? Every time I drive my bus the fuel pump keeps running even after I remove the key. I give the double relay, the drivers side portion, a rap and it stops.

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dtrumbo
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Post by dtrumbo » Fri Jul 17, 2009 8:38 am

If it's the old style with the metal can, you can gently unbend the tabs on the bottom side and remove the circuit board. Once it's open, you can file the contacts on the relays and clean the carbon off. This is the same thing as filing your points.

If it's the new plastic style, I believe it's sealed and you're SOL. Perhaps you can gently crack 'er open and then RTV it back shut when yer done.

Let us know how it goes.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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chitwnvw
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Post by chitwnvw » Wed Oct 07, 2009 10:47 am

So I took apart my double relay and tried to get it unsticky. Gently filed the contact points, reassembled, reinstalled. Started the motor, shut it off, the fuel pump continued to run.

Ordered a new double relay. Installed it, turn the key, engine fires up...and then dies. Sometimes it will run for 30 or 40 seconds, cycling the rpms until it putters out and stops. It will continue to run if I give it gas. WTF is going on?

The fuel pump no longer runs after I shut the bus off. Another question, I read Ratwells double relay spiel, and it seems like the double relay is used to power the fuel pump only until the vehicle has started, would my driving the bus with the relay stuck, and therefore supplying power to the fuel pump have messed anything up?

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hambone
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Post by hambone » Wed Oct 07, 2009 11:20 am

You sure it's not vacuuuuuum?
http://greencascadia.blogspot.com
http://pdxvolksfolks.blogspot.com
it balances on your head just like a mattress balances on a bottle of wine
your brand new leopard skin pillbox hat

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chitwnvw
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Post by chitwnvw » Wed Oct 07, 2009 12:09 pm

hambone wrote:You sure it's not vacuuuuuum?
It works with the other 'sticky' double relay, unless that relay was masking some odd vacuum leak, or weirdness with the AFM. I reread the thread below and I did a good going over of the hoses.

Other odd notes, the battery I had in it wouldn't hold a charge after awhile with the 'sticky' relay. I am racking that up to me forgetting to knock on the relay and un-stick it, therefore draining the battery totally. It was an older battery.

I swapped the series resistor and double relay when I had this problem:

http://itinerant-air-cooled.com/viewtop ... sc&start=0

Now if I go back to that original double relay, it won't start at all.

Replaced temp sensor 2 and no difference.

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justgimmecoffee
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Post by justgimmecoffee » Wed Oct 07, 2009 12:28 pm

hmmm...

A bad AFM?

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Ritter
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Post by Ritter » Wed Oct 07, 2009 7:10 pm

Bad new relay? Is your fuel pump wired correctly to the relay? Mine was hacked into the coil by some idiot mechanic in its past. Good cranking power? Mine wouldn't start once due to a low battery condition--not dead, just low. Bump any wires to the coil whilst monkeying around in there? I dunno. Just tossing out ideas.
1978 Westfalia 2.0 FI

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chitwnvw
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Post by chitwnvw » Wed Oct 07, 2009 7:19 pm

I suppose I could swap in the one known-good double relay I have. It is a brand new battery. If I swap the sticky relay back in it runs. The way the engine runs it seems to me that it is having a hard time figuring out how much fuel to deliver, kind of like when I had my temp sensor 2 disconnected on my other FI bus.

I'm thinking of swapping in the double relay and then the AFM from my weekender in the morning, just to see what happens.

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hambone
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Post by hambone » Thu Oct 08, 2009 7:30 am

Chitown has bad luck with AFMS!
You guys are way above me with those type4s. It's interesting to read about though.
http://greencascadia.blogspot.com
http://pdxvolksfolks.blogspot.com
it balances on your head just like a mattress balances on a bottle of wine
your brand new leopard skin pillbox hat

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chitwnvw
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Post by chitwnvw » Thu Oct 08, 2009 7:56 am

So I swapped my '75s known-good, metal jacketed, never given me a second of grief double relay in this morning and it was still hinky, wanted to die if I gave it gas and then let off of the gas, until it warmed up, but then I drove to work with out a problem. I parked and then I hear a familiar whirring. WTF. The fuel pump is running on after I shut the car off with this double relay also. Tap on the relay and it stops. It had never done that before with the '75.

Swapped to my new, plastic encased double relay. Try and start it, it starts, but then the rpms start to cycle up and down. Turn it off and fuel pump shuts off.

Are the internals any different between the older metal jacketed double relays and the newer plastic ones? Like a vacuum tube/transistor type of difference. The metal ones are the ones that seem to stick with the fuel pump running, but the bus runs with them. The plastic ones don't allow the bus to run, but the fuel pump doesn't run after the bus is shut off.

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hercdriver
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Post by hercdriver » Thu Oct 08, 2009 8:43 am

Could the problem be with the fuel pump itself? or a combination of relay and pump?
66 Beetle
75 Westy

Remember that there is nothing stable in human affairs; therefore avoid undue elation in prosperity, or undue depression in adversity. -Socrates

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dtrumbo
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Post by dtrumbo » Thu Oct 08, 2009 10:05 am

chitwnvw wrote:So I swapped my '75s known-good, metal jacketed, never given me a second of grief double relay in this morning and it was still hinky, wanted to die if I gave it gas and then let off of the gas, until it warmed up, but then I drove to work with out a problem. I parked and then I hear a familiar whirring. WTF. The fuel pump is running on after I shut the car off with this double relay also. Tap on the relay and it stops. It had never done that before with the '75.

Swapped to my new, plastic encased double relay. Try and start it, it starts, but then the rpms start to cycle up and down. Turn it off and fuel pump shuts off.

Are the internals any different between the older metal jacketed double relays and the newer plastic ones? Like a vacuum tube/transistor type of difference. The metal ones are the ones that seem to stick with the fuel pump running, but the bus runs with them. The plastic ones don't allow the bus to run, but the fuel pump doesn't run after the bus is shut off.
Have you done anything with the starter lately? If you've mixed up the wires on the starter, that will cause issues with the double relay. There is a red/white wire that should connect to terminal 50 on your starter. If it's connected to terminal 30 by mistake, weird stuff happens.

In the words of Randy In Maine, "Have you been here?". http://itinerant-air-cooled.com/viewtop ... ay+diagram
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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chitwnvw
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Post by chitwnvw » Thu Oct 08, 2009 10:32 am

Hmmm. It sounds like for the double relay to supply power to the fuel pump the wiper must be in the parked position. Once the wiper arm moves the relay should open and no longer power the pump.

Has anyone else noticed that the plugs that connect to the DR are reversed on the metal vs. plastic DR?

I haven't been messing with the starter, but I like your line of thinking, Dick.

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dtrumbo
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Post by dtrumbo » Thu Oct 08, 2009 12:23 pm

chitwnvw wrote:Hmmm. It sounds like for the double relay to supply power to the fuel pump the wiper must NOT be in the parked position.
The voltage going to the starter solenoid when the key is in the start position energizes the relay to run the fuel pump. Once the key is released and the engine is running, the microswitch in the AFM must NOT be in the park position in order to keep the relay energized and therefore, the pump continues to run. If the key is turned off and/or the engine dies, the relay de-energizes and shuts off the pump.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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chitwnvw
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Post by chitwnvw » Thu Oct 08, 2009 12:32 pm

Randy weighed in on TS. A loose ground. 85. I jammed another wire up where 85 came from, grounded it and started the bus. It ran for a few seconds and sputtered out, but the fuel pump didn't keep running. I tried all of my DR's and they were now all behaving the same. You'd start it, it would run for a few seconds and then die. I monkeyed around with the AFM and things got better, it would idle but I had no power. I played with it some more and it is drivable.

1. How do I permanently attach a wire to that white plug?
2. How did a loose ground give me these symptoms?
3. Where's that AFM mixture adjustment guide?

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