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VW_Jimbo 
Samba Member
Joined: May 22, 2016
Posts: 9967
Location: Huntington Beach, CA
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 Posted: Tue Aug 08, 2017 10:40 pm Post subject: Re: Failed smog today |
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Hey Kevin! Sorry to hear there is a wiring issue somewhere in the system. No worries on getting back over to you. I will get over as soon as I am able to.
Check those grounds! Voltage drop check back to ECU. Ohming them is not good enough.
Make sure that tranny ground strap is in place and clean. You can voltage drop that as well.
Make sure battery terminals are clean and not dropping voltage.
Check voltage supply to fuel pump. Filter is good?
Texted this to you as well.
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Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
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EVfun
Samba Member
Joined: April 01, 2012
Posts: 5481
Location: Seattle
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| Posted: Thu Aug 10, 2017 1:02 pm Post subject: Re: Failed smog today |
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| EVfun wrote: |
| busdaddy wrote: |
Back to Amskeptic's diagram:
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I've got one of these relays from KKiley open and am reading out the internals. The actual schematic is just slightly different.
1. Between terminal 86b and the relay coil there is a diode and then a 2.7 ohm resistor, before 86b connects to the relay coil.
2. 88y and 88z both connect to the moving contact, though this doesn't circuit effect function on a single pole relay. (88a and 88c and 88d connect to the stationary contact.)
3. I'm not finding continuity between 88z and 88y, though it is not clear in the schematic if that is supposed to be internal or external (though it would be easy for me to make it internal.)
4. I cannot find continuity between 88b and 88a. This appears to be a blown board trace!
5. I cannot find continuity between 88z and either relay contact. This appears to be a blown board trace! |
The first results, above, are from the relay KKiley sent with the case cut open. That was very helpful as it allowed me to figure out how to pop the case apart without destroying anything, using 2 small screwdrivers.
Unit #2 is open and tested. It is the same in construction so observations 1, 2, and 3 apply. Like the first relay, the 3 diodes are working The trace between 88b and 88a is NOT blown, the only defect in this unit is item 5, the trace between 88z and its relay contact is blown open on the board. It will be an easy repair.
Unit #3, that came in a box, has suffered from water intrusion resulting in significant internal corrosion. The wire for the fuel pump relay coil (under 88y) floating loose because of this corrosion, so this unit is a write-off. However, it suffered the same circuit board trace failure, cutting off 88z, as the other 2 units. This appears to be the one that was in the car when he got it, and is constructed identically to the 2 replacement units. The case can be reused to make the first one complete again, after 2 circuit board repairs.
I will carefully make a total of 3 board repairs and send these back. You will have 2 good relays and some junk. Now we have to figure out what wiring problem has been shorting 88z to ground. I suspect that the relay blew the board trace as soon as ignition power was turned on. I think the cause was previous tampering by someone trying to make the car work. The original relay was never going to work because of the rotted off fuel pump relay coil lead, but I bet someone started chasing the circuit that goes from 88a, to 35 and 36 on the AFM, and then to 86b. Something didn't get back together right and as a result this circuit path most likely has a direct short to ground, possibly only when the AFM flap moves.
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KKiley
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Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Thu Aug 10, 2017 7:18 pm Post subject: Re: Failed smog today |
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Ev, thanks for the update. Here is a little background on these. The one with the water damage is from it sitting outside and the relay filled up with water. It was upside down, and the water ran down the wire and filled the case. That relay went bad and that is when the issues actually started.
When I replaced that relay, the fuel pump would run all the time when the key was on. It didn't do that before, tt operated correctly, would work when I stuck a screwdriver in the AFM.
Right now I have another DR bypassed so that it powers the ECU and the fuel pump when I turn on the key, so the car runs correctly. I look forward to tracing back the issues and finding where this fault is.
Thanks EV!
Kevin
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EVfun
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Joined: April 01, 2012
Posts: 5481
Location: Seattle
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| Posted: Fri Aug 11, 2017 1:02 pm Post subject: Re: Failed smog today |
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| KKiley wrote: |
Ev, thanks for the update. Here is a little background on these. The one with the water damage is from it sitting outside and the relay filled up with water. It was upside down, and the water ran down the wire and filled the case. That relay went bad and that is when the issues actually started.
When I replaced that relay, the fuel pump would run all the time when the key was on. It didn't do that before, tt operated correctly, would work when I stuck a screwdriver in the AFM.
Right now I have another DR bypassed so that it powers the ECU and the fuel pump when I turn on the key, so the car runs correctly. I look forward to tracing back the issues and finding where this fault is.
Thanks EV!
Kevin |
Could you describe the current connections for this alternate relay you are using to power the pump?
If I was to take a guess I would think that you have the relay coil getting power from 86c and ground from 85 in the double relay wiring harness plug. Then you have the one contact connected to either 88z or 88y and the other contact going to 88b, 88c, and 88d in the plug. Then for cold starting you have a jumper in the plug connecting 86a and 86.
I'm looking at the failure mode and it tells me that 88z saw a short to ground on all 3 units. That burned out a narrow spot in the circuit board trace that went from 88z to the relay contact. A short to ground is about the only way to get the kind of current that blows copper off the board. The one relay blew 2 spots out that suggest the short to ground might be, or might have been, from terminal 88b to ground. Either way, once that trace on 88z burned out the ECU would not be powered (no power to 88b or 88a when the relay turned on) so the engine was never going to start. The fuel pump could run while cranking only but only the cold start valve would deliver fuel. Find what could allow 88b or 88a to short to ground and you have found the problem.
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| Wildthings wrote: |
| As a general rule, cheap parts are the most expensive parts you can buy. |
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KKiley
Samba Member
Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sat Aug 12, 2017 9:40 am Post subject: Re: Failed smog today |
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See below
I just checked it and it has 9.72 volts when the key is on.
Let me know your thoughts.
Thanks
Kevin
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Last edited by KKiley on Sat Aug 12, 2017 11:35 am; edited 1 time in total |
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rockerarm
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Joined: December 16, 2009
Posts: 3552
Location: Los Angeles
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| Posted: Sat Aug 12, 2017 10:51 am Post subject: Re: Failed smog today |
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Hi Kevin.
I think you may have your numbers crossed somehow.
85 is the ground for the DR and it should exit the DR white plug as a brown colored wire and go directly to ground.
Looking at your pic I seem to see the brown wire exit the white plug and go into the black sheath.
Hope this helps, Bill. |
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KKiley
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Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sat Aug 12, 2017 11:05 am Post subject: Re: Failed smog today |
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Bill,
You are correct. It was too early and I wasn't reading the numbers right. 86C is the switched hot wire that I have jumped to 88d and 88b.
I do want to check these wires again, something is not right and we should be able to fix it.
Kevin
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KKiley
Samba Member
Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sat Aug 12, 2017 11:29 am Post subject: Re: Failed smog today |
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88b has continuity to ground. I will trace it back and see what I can find.
Kevin
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KKiley
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Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sat Aug 12, 2017 12:03 pm Post subject: Re: Failed smog today |
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I am trying to trace the wire from the plug back to the ECM, but many of the terminals indicate continuity with my VOM, and the bentley does not show the ECM plug in detail. I am trying to figure out exactly which wire is 88b at the ECM plug.
Kevin
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rockerarm
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Joined: December 16, 2009
Posts: 3552
Location: Los Angeles
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| Posted: Sat Aug 12, 2017 12:06 pm Post subject: Re: Failed smog today |
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| KKiley wrote: |
88b has continuity to ground. I will trace it back and see what I can find.
Kevin |
88b will have "some" continuity to ground. It goes to the ECU and to the injectors via the series resistor. I would think if you unplugged the ECU and also the series resistor that wire 88b should have no continuity to ground.
Think about a simple lite circuit. 12v source, to the bulb, thru the element, then to ground. There will be some continuity to ground on this simple circuit. |
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rockerarm
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Joined: December 16, 2009
Posts: 3552
Location: Los Angeles
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| Posted: Sat Aug 12, 2017 12:11 pm Post subject: Re: Failed smog today |
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| KKiley wrote: |
I am trying to trace the wire from the plug back to the ECM, but many of the terminals indicate continuity with my VOM, and the bentley does not show the ECM plug in detail. I am trying to figure out exactly which wire is 88b at the ECM plug.
Kevin |
88b goes to two locations. One is terminal 10 at the ECU and also to the injectors series resistor.
Look at this color wiring:
https://www.thesamba.com/vw/archives/info/wiring/76-79111wiring.jpg
The majority of what you need is on the right side. J40 is the DR and J21 is the ECU |
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KKiley
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Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sat Aug 12, 2017 12:31 pm Post subject: Re: Failed smog today |
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Thanks Bill. Unfortunately, we have 2 issues. That print and my eye site do not match, lol. It's hell to get old. And the Bentley does not have a wiring diagram past 1974.
Also, I am not good with schematics. Not sure what I would be looking for from this chart.
I will just wait until VW Jimbo gets back and have him help me trace this down. This is above my pay grade, lol.
Kevin
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EVfun
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Joined: April 01, 2012
Posts: 5481
Location: Seattle
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| Posted: Sat Aug 12, 2017 1:17 pm Post subject: Re: Failed smog today |
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| KKiley wrote: |
Bill,
You are correct. It was too early and I wasn't reading the numbers right. 86C is the switched hot wire that I have jumped to 88d and 88b.
I do want to check these wires again, something is not right and we should be able to fix it.
Kevin |
Wow, that is brutal on your ignition switch. It is now carrying a lot of load it was not intended to; the ECU, fuel injectors, the AAR, and fuel pump.
If you check terminals 88a and 86b in the plugs that go into the DR do either of those show continuity to ground? Then test 88a with the AFM flap held open a little. You should find no continuity to ground.
Oh, on a side note, will the DR be mounted upside down in the vehicle? (the mounting tab for the bolt facing down) If so I could include a 1/16th inch weep hole in that end of the case by the mounting tab to help prevent future water logging. They way they are built makes it fairly immune to light moisture but sure to fail if it starts to fill with water.
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| Wildthings wrote: |
| As a general rule, cheap parts are the most expensive parts you can buy. |
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KKiley
Samba Member
Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sat Aug 12, 2017 2:45 pm Post subject: Re: Failed smog today |
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88a and 86b do not show continuity to ground. 88a no continuity either with AFM opened.
And I learned to make sure the DR was facing up so the water cannot run directly into the unit.
Kevin
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garyt
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Joined: June 14, 2015
Posts: 763
Location: Burgundy
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| Posted: Sun Aug 13, 2017 10:47 am Post subject: Re: Failed smog today |
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| The Bentley wiring diagrams are good for 74 and later, including 79 and FI models. They take a bit of understanding though. |
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EVfun
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Joined: April 01, 2012
Posts: 5481
Location: Seattle
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| Posted: Sun Aug 13, 2017 1:07 pm Post subject: Re: Failed smog today |
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| KKiley wrote: |
88a and 86b do not show continuity to ground. 88a no continuity either with AFM opened.
And I learned to make sure the DR was facing up so the water cannot run directly into the unit.
Kevin |
If you move the flap in the AFM do 88a and 86b have continuity between them? That is required for the double relay to keep the fuel pump running after the engine starts. There should be no continuity between them if the engine is off.
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| As a general rule, cheap parts are the most expensive parts you can buy. |
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KKiley
Samba Member
Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sun Aug 13, 2017 7:57 pm Post subject: Re: Failed smog today |
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| Quote: |
If you move the flap in the AFM do 88a and 86b have continuity between them? That is required for the double relay to keep the fuel pump running after the engine starts. There should be no continuity between them if the engine is off. |
Yes, I have verified this. Robbie adjusted it when he was here, but it was too far apart to make connection. I adjusted it so it will work correctly when we get the DR working without blowing up, lol
Kevin
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KKiley
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Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Sun Aug 13, 2017 10:16 pm Post subject: Re: Failed smog today |
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Hey EV, was doing some clean up and removed this from the car today.
Old school, think I should have sent this one to you?
I am guessing that is original, lol
Kevin
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VW_Jimbo
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Joined: May 22, 2016
Posts: 9967
Location: Huntington Beach, CA
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| Posted: Mon Aug 14, 2017 7:34 pm Post subject: Re: Failed smog today |
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Hey Kevin!
Just got back in town. Looks like I missed a little bit of fun!
Going to reread everything that has transpired and get a feeling for what is and is not going on. The Bently has the correct schematic in it for your car.
I will set up a date tomorrow after I get a chance to play catch up on phone calls, paper work, and all of employees short comings!
Will shoot you a text tomorrow.
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Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
| TDCTDI wrote: |
| Basically, a whole bunch of fuckery to achieve a look. |
| 67rustavenger wrote: |
| GFY's Xevin and VW_Jimbo! |
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KKiley
Samba Member
Joined: March 08, 2016
Posts: 662
Location: Aruba, Jamica, nope, Kokomo
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| Posted: Mon Aug 14, 2017 8:11 pm Post subject: Re: Failed smog today |
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Sounds good! Could use some help tracking this down.
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