TheSamba.com :: View topic

Fri Jul 07, 2023 5:59 pm

wherbusche, Best to know what year the Vanagons are as there are different relay wiring(s) and relays on some of them.

Tue Dec 03, 2024 3:38 pm

Help! I almost have the wiring bypass built but ran into a snag. When testing the diodes pictured below (50V, 10A), I cannot get voltage to flow through either diode regardless of orientation. 12.8V flows through my test leads hooked in series to my volt/ohm meter, but it quickly drops to 0V when I insert either diode in series. Am I doing something wrong or are these diodes bad? I must admit that I am a rank amateur in the electrical category.
Puzzled, Busfixer

Tue Dec 03, 2024 3:43 pm

Digikey RARELY makes a mistake but those are NOT diodes!!! those are capacitors. here's what that part number should look like:

Tue Dec 03, 2024 3:46 pm

Busfixer wrote: Help! I almost have the wiring bypass built but ran into a snag. When testing the diodes pictured below (50V, 10A), I cannot get voltage to flow through either diode regardless of orientation. 12.8V flows through my test leads hooked in series to my volt/ohm meter, but it quickly drops to 0V when I insert either diode in series. Am I doing something wrong or are these diodes bad? I must admit that I am a rank amateur in the electrical category.
Puzzled, Busfixer
Does your Meter have a Diode testing position on its dial? Not all do, but, so many do that I need to ask.
It will look like an Arrow, with a line drawn across the arrow.
Here's a Fluke Meter as an example, the Diode test is one to the right of the Middle/Top OHM symbol, like 1 o'clock on the dial.

https://www.grainger.com/product/4EB18?gucid=N:N:P...d6f729eac6

Tue Dec 03, 2024 7:31 pm

I made the tool with a Posi-Lock fuse holder, and a diode that fits in like a fuse...

https://www.amazon.com/Littelfuse-02400104P-Diode-...&psc=1

https://www.common-motor.com/posi-lock-blade-fuse-...lkQAvD_BwE

Posi lock brand connector info

https://youtu.be/Yiimgl-Rdmw?si=zVx31hbxa2M2ECPF

Tue Dec 03, 2024 7:48 pm

Thanks Dan, jlr and TJet - I believe Dan is right and these electrical components are capacitors. Dan, when I put them in series as described previously, they would show 6V, 3V, 1V then 0V, allin about 1-1/2 seconds. 0V steady after that. So your recognition of them being a capacitor combined with the quick voltage falloff to0V sounds like you are correct. I will call DigiKey tomorrow. JLR, attached below is a pic of my fine Harbor Freight multimeter in the Diode test position and it reads “1”. Apparently this means no flow. Confirms capacitor idea. Thanks for teaching me that function. TJet, if I don’t get satisfaction from DigiKey, then I may go your route. Thanks for the links.
Thanks again to all - I love the Samba! Busfixer

Wed Dec 04, 2024 6:46 am

DigiKey is 80 miles from my house... a company of over 5,000 employees in a town of 8,800!! 3 million sq ft. i've been ordering from them for 40 years and have never had a wrong order but mistakes happen.

frustratingly, before Amazon and DeJoy ruined the USPS, i could order parts in the afternoon and have them in my mailbox by 10am next day for $2.99 USPS 1st Class shipping. now it takes a week to get here and has pretty much circumnavigated the state of Minnesota before arrival.

Fri Dec 06, 2024 5:52 am

There is an emergency bolt on box that fires random sparks into the distributor.
Not seen another one and there is nothing on the Internet about it. Just connect to 12v and King lead. In cap.
Useful diagnostic tool bypass the distributor.
Unfortunately no one makes it now

Sat Dec 21, 2024 12:57 pm

Follow-up: I finally received the correct diodes from digi-jet and built the diagnostic wiring harness. I added an optional short lead in case I wanted to power the harness from the alternator stud instead of the positive battery post.

I originally built the harness to diagnose a hard shutdown problem at highway speeds. While I was waiting on DigiJet diodes, I replaced the original ignition switch, changed coil power tap on fuse panel from D15 to D23, and cleaned several relay, coil and distributor connections on 2 yr old parts. The problem disappeared.

But I now feel a lot better having the diagnostic harness in my 88 Bus wherever I go.

Another issue will pop up at some point in the future and the harness is ready!

Thanks, Busfixer

Sat Dec 21, 2024 1:02 pm

If you have it,, you won't need it!!
The inverse; If you don't have it, you're gonna need it, REALLY REALLY BAD!!

Sat Dec 21, 2024 1:37 pm

those diodes can break pretty easily so cut a section of chopstick longer than the leads and wrap electrical tape around the whole mess to bind them to the chopstick support.

Sat Dec 21, 2024 3:48 pm

Dan I was going to wrap the diodes with electric tape but thought the reason they were bare in previous photos was that they get hot. How about a popsicle stick and electrical tape?
Busfixer

Sat Dec 21, 2024 4:28 pm

Busfixer wrote: Dan I was going to wrap the diodes with electric tape but thought the reason they were bare in previous photos was that they get hot. How about a popsicle stick and electrical tape?
Busfixer

you've got 2 - 10 amps diodes in parallel... 20 amps of service for something drawing less than 10 amps so you'll be fine with them wrapped in tape. popsicle sticks are fine as long as it was grape flavor.

Tue May 13, 2025 2:28 pm

Your device helped me to fix my vanagon today. Thank you, thank you, thank you!!!!

83.5 with a 2.1L engine (replacement) and digijet ignition system. Was having a hot start issue that could have cancelled our trip to Moab.

Coil wasn't get enough current. DIsconnected the fuel pump jumpers first, then the coil feed. Then it would not start again. Reconnected the coil feed; boom fired like a champ.

Thank you, thank you, thank you!!!!

Thu May 15, 2025 7:36 am

I just bought a nice Fluke recently to keep onboard.

https://www.fluke.com/en-in/product/electrical-testing/clamp-meters/fluke-362

Ive been looking for a good clamp meter to help troubleshoot draw issues.

Wed Oct 22, 2025 6:15 pm

I've been posting in the topic Stupid and Lazy, but I've completed the full test harness and now have some dialogue that direct me here for further reflection and advice.

I hooked up all connections as in the original post. I then pulled out of the garage, and let the bus idle while dealing with a few Family matters outside of my VW realm. Around 18 minutes of idling the engine stalled, and I felt around the engine compartment for hot spots. The coil was warm, not hot. Everything else was either cool, or about the same temp at the engine case. On key to start, it fired up immediately, so I went back in the house, but as I closed the door, my wife said 'it just died again' because she can hear much better than me. So again I went out and keyed it to start, again success on running. For a few times over the next 10 minutes, it cut, I restarted without switching off the power to the test harness.

I pulled it back into the garage and cut power to the test harness to shut down. Thus, I am hopeful that this entry to Mark's topic can lead to the resolution.

Thank you, one and all.

-bobby

Thu Oct 23, 2025 4:15 pm

87 Westy riddle might be solved by one or more of the following: cleaned grounds, tightened (more) all connectors to the coil AND temporarily hung my new-in-box lifetime warranty coil (same as the one in place) and like magic, no hiccups whatsoever on my commute home today.

Pie in face, I guess..

Good results I likely should have tried the first day it started getting under my skin.

Still glad to have built and used the test harness!!

-bobby

Thu Oct 23, 2025 4:22 pm

bobbyblack wrote: I've been posting in the topic Stupid and Lazy, but I've completed the full test harness and now have some dialogue that direct me here for further reflection and advice.

coupla things... it would be helpful to describe *exactly* how the engine dies. does it bobble and bibble then snuff out? just a dead cutoff?

you need to know if it is fuel or spark. to that end, put a timing light on the coil wire and observe the flash during death. is it erratic? solid flashing even when the engine is dying? you are looking for the flash presence in the 1/2 second between the start of engine death and rotation stop.

it would be useful to observe fuel pressure during death also. something like a plugged charcoal canister may trigger a low fuel pressure just as the engine dies. or just try idling while the gas cap is loose.

it would also be good to observe a noid lamp during the death spin down. to give a little more time for observation, wedge some cardboard in the throttle to get the idle speed up to around 2000 rpm.

these data points, IF observable, will give you a sense of whether it is the Hall, the ECU, the coil, or a fuel issue during the death rattle. in short, you need to be with the patient at their last breathing moment and not duck into the house for a cold one!

at least it is repeatable!