1979 CA Bus - Fuel Pump Issue?

[ez2bmyself]

Hey Everybody!

I am not a mechanic (yet!) but I'm doing my best to learn how to maintain my beloved VW. Colin has spent a couple of days of with me and that has helped considerably, although I still have a long way to go. ;) Anyway, to the task at hand...

I'm troubleshooting a no-start for my 1979 California Westy (Jenny). I have done my best to search the forum so I apologize if this has been covered, although I must admit I'm having a little trouble with the search function.

I finally got her home after having the engine rebuilt (twice - long story) but immediately went on vacation and she had to sit for over 3 weeks before I could drive her again.

After sitting for 3 weeks, I tried to start her up and there was this loud popping noise coming from under the left side of the car near cylinders 3 & 4. I had my neighbor try and start the car so I could pinpoint the location and it seemed to be the the fuel pump. I tried starting again and the popping stopped, but now she wouldn't even turn over. Next I took the battery to my FLAPS and had them test it, they said it was dead so I bought another one.

After replacing the battery the engine turns over just fine but never starts. By using the Bentley and this FI manual I dowloaded here http://dl.dropbox.com/u/2066612/AFC_FI_ ... Manual.pdf , I narrowed it down to what I think is the fuel pump.

Here's what I did:

I put a pressure gauge on the FI and did not receive any pressure while cranking. I removed the air filter, and with the ignition on, moved the flap inside the air flow sensor to trigger the fuel pump but did not hear it. Following Bentley, I made my way to step 5 of 4.10 (Sec. 10 Page 21). Which states "if the pump failed to supply pressure, attach a test lamp to the fuel pump connector" then 5. Operate the starter, if the test lamp lights, the fuel pump is faulty and should be replaced. I did this test and the lamp lights up, so the fuel pump is getting power when I turn the ignition.

So two questions - Was the loud popping I heard due to some other issue like the pump not getting gas and then breaking because of it? Also, are there any other tests I should do before ordering a new fuel pump?

I have been searching the boards and did follow the advice here > http://itinerant-air-cooled.com/viewtop ... =46&t=7041. Everything seems to be connected properly so I guess if it's time for a replacement, is the Bosch 251-906-091 the best way to go??

Thanks in advance for any suggestions!

[dingo]

the simplest test for the fuel pump is to briefly put 12V across the terminals and see whether it runs or not

[Gypsie]

I agree that "jumping" some power over to the fuel pump will tell you if you have a functioning pump though you have described a thorough test procedure thus far. One thing I haven't heard is that you confirmed that the ground for the fuel pump is solid.

How loud was this 'popping'? very curious

I recommend checking the ground and jump power to the pump to eliminate any doubt about it's failure. I presume that it is the failure point.

If you get a new one, please check the entire fuel circuit for crud in the system. remove the filter and cut it open to see the upstream side (this will let you know what is coming out of the tank). cruddy rusty particles can prevent flow. Make sure all the fuel line is sitting straight and there are no kinks that might prevent flow or create cavitation issues.

I have a feeling that a new pump will settle the issue though.

[ez2bmyself]

OK! So the test lamp does not verify that the ground is good? Or am I checking the ground to ensure a certain amount of current is available?

I think the only method I have for jumping power will be to run a wire from the battery and touch it to the positive terminal on the pump, will that suffice?

The popping noise (or clicking noise) was pretty loud when I was under the bus, although I couldn't pinpoint it at the time, it definitely seemed to be coming from the pump area.

I will check the fuel filter for crud when I replace the pump, and then take it from there.

Thanks so much for the advice, I really appreciate it!

[RSorak 71Westy]

If you grounded the test lead at the neg fuel pump wire then yes you tested the ground and it's good. No real need IMO to test the pump on the bus at this point. Remove it and them put power to it as a final test, before ordering the new pump.

[ez2bmyself]

I got her going y'all! Thanks so much!

I had only tested continuity to the positive side of the pump, when I tested the ground, it did not light. Then I ran 12V to the pump and it started! I used the Bentley to begin checking the Double Relay and the engine started while I had the test probe on there, but stopped when I pulled it off. It seems I had a loose connector on Terminal 85. Tightened it up and she started right up!

Thanks again for all the help!

Cheers!

[Sylvester]

I got her going y'all! Thanks so much!

How about some pictures of the Bus?

[ez2bmyself]

Well of course! Everybody meet Jenny...

[ruckman101]

Wow, nice bus there. Jenny be stridin' proud and shiny. Dig the Oregon plate up front.


neal

[ez2bmyself]

Thanks Neal! She came from your neck of the woods. I left the plate on the front to show my love for that beautiful state of yours.

[airkooledchris]

welcome and like Neal said, very very nice looking bus. looks to be in really good shape.

[ez2bmyself]

Thanks Chris! I was checking out your website. That Maupin shindig looks sweet! I'm gonna have to try and squeeze that in next year...