Hi all.

So I replaced the OEM Jetta ECU and fuel pump relays with these
generic relays: http://www.picocanada.com/en/product/928.php The
engine starts and runs.

But I recalled Dicks' comment on his Scirocco fuel pump relay running
hot, so this got me thinking.    .......

Edit:

I started to write in this post that after reading more about relays,
specifically on relay coil resistance, I went and measured my relays
again. The Jetta fuel pump relay appeared to have a fairly high coil
resistance of ~ 560 Ohms. (as opposed to 60-70 on other automotive
relays). Then I wondered if the higher current draw of the lower
resistance generic relay (60 Ohms) I swapped in place of the OEM part,
would be a problem for the ECU components supplying ground to it.
Before posting here though, I measured the Jetta fuel pump 167 relay
again. I saw 560 Ohms but then saw ~ 60 Ohms. What? Figuring the DMM
probes were dirty (why would they be?), I cleaned them. Most readings
were 560 Ohms but then a few were 60 Ohms so I had a closer look at
the relay terminals. One felt slightly loose.

Can you see it? Image:

https://lh6.googleusercontent.com/-WvTxzJmkhQ8/URigfe_8VtI/AAAAAAAAG3A/V-0gTtMlEQk/s720/Jetta%2520Fuel%2520Pump%2520Relay%2520CRACKAGE.jpg

It gets better  (higher resolution ~ 150 kb):

https://lh5.googleusercontent.com/-gcffbJDC6OM/URigfRKbqVI/AAAAAAAAG28/NdUpjGTonmo/s576/Jetta%2520Fuel%2520Pump%2520Relay%2520CRACKAGE%25203.jpg

https://lh5.googleusercontent.com/-CEuRWyb95Ho/URigfro2m5I/AAAAAAAAG3E/YAOjkReFvDk/s640/Jetta%2520Fuel%2520Pump%2520Relay%2520CRACKAGE%25202.jpg

These issues I've seen are almost certainly due to incorrect relay
install. I mention this b/c I don't want people with WBX engines
thinking this is a relatively common occurrence. AFAIK, this would
RARELY happen under normal circumstances.

Cripes. Sure am learning a lot though!

Neil.

On Tue, Feb 5, 2013 at 11:44 PM, Dick Wong <sailingfc@dslextreme.com> wrote:

> With my old Scirocco, the fuel pump relay will get hot to the touch and has
> actually melted the side of the plastic case.  After filing and cleaning the
> contact, it typically runs cooler.  I also keep a spare fuel pump relay.

> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> neil n
> Sent: Tuesday, February 05, 2013 10:43 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: No Start Cause: Relay Failure. PICS, Thoughts.
>
> Hi all.
>
> This isn't for a stock Vanagon, but I figure it's worth mentioning here.
> (it's Jetta engine powered)

......

> With my engine, the fuel pump and ECU relay are mounted "loose"
> (actually they're packed pretty tight in a Vanagon junction box); they're
> not mounted in relay blocks.
>
> Close up images of the cracked solder joint:
>
> https://lh4.googleusercontent.com/-h3JODsFUDHM/URHsPfqBbZI/AAAAAAAAGy4/5DkyK
> weHpnc/s576/Jetta%2520Power%2520Supply%2520Relay%2520Solder%2520Crack.jpg

etc.

--
Neil n

65 kb image Myford Ready For Assembly  http://tinyurl.com/64sx4rp

'88 Slate Blue Westy to be named.

'81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/

Vanagon VAG Gas I4/VR Swap Google Group:

http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines