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 |
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