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kamzcab86
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Joined: July 26, 2008
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Location: Arizona
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 Posted: Tue Sep 10, 2019 4:48 pm Post subject: '89 Westy - no start (no power to fuel pump) ~ solved |
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Parents' van: 1989 Westy with 2.1L, Digifant
Was running fine up until last week, when it all of a sudden wouldn't restart after driving across town. After about 30 minutes, finally started. After stop #2, again wouldn't start, but eventually did. Now, it's dead in the water: cranks no problem, but no start.
Fuel pump is not getting power... as in 0 volts and no 5 second prime. At the T2 connector behind the air filter: 0 volts, but continuity on both wires (additional oddity: continuity at ground point and at red/white wire at that T2 connector, and vice versa).
All tests on pages 40-41 of the Pro-training Manual pass (except for the O2 sensor, airflow sensor potentiometer, and cranking voltage tests... haven't done those yet).
ECU:
pin 14 has 12V when ignition is switched on
pin 23 has 12V when ignition is switched on
pin 3 has 12V when ignition is switched on
pins 3 and 13 jumped run the pump
Digifant Relay:
pin 30 has 12V constant
pin 87a has 12V when ignition is switched on
pin 85 has 0V when ignition is switched on
pin 86 has 11.3V when ignition is switched on
pin 87 has 12V when ignition is switched on
Fuel Pump Relay:
pin 30 has 12V constant
pin 86 has 12V when ignition is switched on
pin 85 has 8V and drops when ignition is switched on
pins 30 and 87 jumped runs the ISV and fuel pump (ISV control unit disconnected with this jump yields no power to ISV and fuel pump)
One brand new fuel pump relay and the 53 relay from the main panel have had no effect. A rebuilt ECU has had no effect. A new ignition switch has had no effect. All grounds and alternator connections are shiny. Terminals 15 on the coil have 12V.
Anyone have any insight as to what is going on? Van was scheduled to get a tint job tomorrow, but is dead in the water... 
Edit: Skip to https://www.thesamba.com/vw/forum/viewtopic.php?p=9167841#9167841 for what was the ultimate solution. If you have an '88-'89 van, you might want to seriously consider doing the same relay modification while your van is at home so that you're not left stranded somewhere out on the road. 
_________________
~Kamz 
1986 Cabriolet: www.Cabby-Info.com
 1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子
Last edited by kamzcab86 on Fri Sep 13, 2019 9:22 am; edited 3 times in total |
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djkeev
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Joined: September 30, 2007
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Location: Reading Pennsylvania
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kamzcab86
Samba Moderator
Joined: July 26, 2008
Posts: 7917
Location: Arizona
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| Posted: Tue Sep 10, 2019 5:10 pm Post subject: Re: '89 Westy - no start |
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All the connections are clean... no corrosion. Only PO add-on was a dummy alarm light, which has been removed.
_________________
~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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djkeev
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djkeev
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crazyvwvanman
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Joined: January 28, 2008
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| Posted: Tue Sep 10, 2019 6:02 pm Post subject: Re: '89 Westy - no start |
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Fuel pump prime with key on is more like 1-2 seconds max.
If you hold fingers on the 2 relays and someone turns the key on and then 10 seconds later off, what do you feel? Repeat 5 times.
Look very closely at the red wires attached to the alternator stud.
Mark |
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kamzcab86
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| Posted: Tue Sep 10, 2019 6:04 pm Post subject: Re: '89 Westy - no start |
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Correct; ground is inaccessible. But, the ground passed the ohm test.
When the FPR is jumped, it still doesn't start.
Bypassing the coil, still no power to the fuel pump.
_________________
~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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kamzcab86
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Joined: July 26, 2008
Posts: 7917
Location: Arizona
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| Posted: Tue Sep 10, 2019 6:09 pm Post subject: Re: '89 Westy - no start |
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| crazyvwvanman wrote: |
If you hold fingers on the 2 relays and someone turns the key on and then 10 seconds later off, what do you feel? Repeat 5 times.
Look very closely at the red wires attached to the alternator stud.
Mark |
Digi relay clicks when key is turned on. No action from the FPR.
Alternator wire terminals were dirty, but are nice and shiny now. Wires themselves are in good shape.
_________________
~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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crazyvwvanman
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Joined: January 28, 2008
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| Posted: Tue Sep 10, 2019 6:22 pm Post subject: Re: '89 Westy - no start |
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Hopefully you meant the ECU relay clicked exactly once with key on and exactly once more with key off, every time.
Every time the ECU powers up it should briefly pulse a ground to pin 85 of the FP relay. This should make the relay briefly engage and the pump briefly run, as well as the ICV briefly buzz.
Mark |
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Abscate
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| Posted: Tue Sep 10, 2019 6:30 pm Post subject: Re: '89 Westy - no start |
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Kam if you jump the fuel pump or relay direct does it start and run?
Sometimes the first part of diagnosing is figuring out how many things are wrong... 
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crazyvwvanman
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| Posted: Tue Sep 10, 2019 6:39 pm Post subject: Re: '89 Westy - no start |
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In around 88 and later the fuel pump relay powers everything but the ECU. I think Kam was saying something different than what you read into it though.
This change is a safety improvement IMHO. The "everything" above includes the PS switch power wire, injector power, ICU power, FP power. All will power down when engine stops turning even with key on since the ECU wants to see continuous hall pulses or it assumes the engine isn't turning thus those things aren't needed.
(The diagrams are wrong for 88/89 and that relay wiring is really more like 90/91 diagram shows. But there are other errors in the relay area for 90/91.)
Mark
| djkeev wrote: |
.....
The ISV relay is powered by the fuel injection relay....... unplugging it should not cut off jumped power to the fuel pump.
Thinking out loud here........ |
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kamzcab86
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| Posted: Tue Sep 10, 2019 6:41 pm Post subject: Re: '89 Westy - no start |
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| crazyvwvanman wrote: |
Hopefully you meant the ECU relay clicked exactly once with key on and exactly once more with key off, every time.
Every time the ECU powers up it should briefly pulse a ground to pin 85 of the FP relay. This should make the relay briefly engage and the pump briefly run, as well as the ICV briefly buzz.
Mark |
Yes, the ECU relay. It clicked once, key on; clicked again, key off. Every time.
Nothing from the fuel pump relay. Pin 85 on the FPR is now showing 11.9V, and after 5 seconds or so, voltage dropped. But fuel pump still not powering on.
_________________
~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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crazyvwvanman
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Joined: January 28, 2008
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| Posted: Tue Sep 10, 2019 6:51 pm Post subject: Re: '89 Westy - no start |
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Until the ECU is grounding pin 85, pin 85 will show the power that is fed to pin 86. So yes, it is at times normal to see 12v at both pin 85 and 86 since they are each tied opposite ends of the same wire, that is the winding of the relay coil. The winding wire is very long and thin. Once the ECU grounds pin 85 some current will flow so the long thin coil winding wire becomes a resistor between 12v and ground and so then it has 12v at one end and 0 volts at the other with the 12 volts dropped to zero by the wire resistance.
Mark |
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childofthewind
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| Posted: Tue Sep 10, 2019 6:57 pm Post subject: Re: '89 Westy - no start |
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Can you throw a good spare ignition switch in there?
_________________
1987.5 wolfsburg hardtop; 2.1
“As for me, I am tormented with an everlasting itch for things remote." - Melville |
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E1
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| Posted: Tue Sep 10, 2019 6:57 pm Post subject: Re: '89 Westy - no start |
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Total shot in the dark, but has he/have you tried swapping the relays?
We had two mismatched relays at one point, both looked the same but had different parts numbers stamped on them. Can't recall the effect that had, sorry, but putting in two from the same batch with the same part numbers cured it.
Say Howdy to your folks for us.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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kamzcab86
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| Posted: Tue Sep 10, 2019 7:15 pm Post subject: Re: '89 Westy - no start |
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| crazyvwvanman wrote: |
Until the ECU is grounding pin 85, pin 85 will show the power that is fed to pin 86. So yes, it is at times normal to see 12v at both pin 85 and 86 since they are each tied opposite ends of the same wire, that is the winding of the relay coil. The winding wire is very long and thin. Once the ECU grounds pin 85 some current will flow so the long thin coil winding wire becomes a resistor between 12v and ground and so then it has 12v at one end and 0 volts at the other with the 12 volts dropped to zero by the wire resistance.
Mark |
So, that means the ECU isn't grounding the relay? If so, that means two ECUs, including a rebuilt one, aren't functioning properly?
Could a faulty coil be a part of the problem? We're now getting inconsistent power readings from it.
| childofthewind wrote: |
| Can you throw a good spare ignition switch in there? |
Already done multiple times... no go. That is to say, a new switch, operated via screwdriver, has no effect on the problem.
| E1 wrote: |
| Total shot in the dark, but has he/have you tried swapping the relays? |
Brand new relay tried. Swapped in the #53 relay from the main panel and no go.
There is a disconnect somewhere in the system, we just cannot figure out where and how. Dad is about ready to just chuck the Digifant system for aftermarket.
_________________
~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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E1
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Joined: January 21, 2013
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| Posted: Tue Sep 10, 2019 7:22 pm Post subject: Re: '89 Westy - no start |
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I meant swapping relay 1 for relay 2 to discount one of them being bad.
If the little white plastic plug into the coil is shorted or otherwise not making good contact, that kept us from firing for quite some time last summer. Acted like it had no spark, as it didn't, and could smell fuel.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman
Last edited by E1 on Tue Sep 10, 2019 7:25 pm; edited 1 time in total |
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kamzcab86
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| Posted: Tue Sep 10, 2019 7:25 pm Post subject: Re: '89 Westy - no start |
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| E1 wrote: |
| I meant swapping relay 1 for relay 2 to discount one of them being bad. |
Can't do that with an '89. Digi relay is 5-pin, FPR is 4-pin. Thank you, Volkswagen. 
_________________
~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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E1
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| Posted: Tue Sep 10, 2019 7:26 pm Post subject: Re: '89 Westy - no start |
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Ah, okay.
Post amended while you were posting.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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crazyvwvanman
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| Posted: Tue Sep 10, 2019 7:38 pm Post subject: Re: '89 Westy - no start |
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If you unplug the green wire 2 pin connector from one side of the coil that should remove the coil as a factor in the ECU power up.
But keep in mind the ECU needs power and ground, and a sufficient amount of both.
If the ECU isn't switching on it's ground for the FP relay it may be that the ECU doesn't have enough power/ground to really function. Are you getting any ignition spark when the engine is cranking? Pull the center lead out of the dizzy cap and set it where the end will be very close to engine metal. Sparks should jump from the wire end during cranking. Firing the ignition coil is another function of the ECU and it triggers the coil to spark by providing ground pulses on one of the green wires to the coil.
Caution: Please use only a digital voltmeter set to volts for any measurements other than ohms. Also, probing the FP relay socket wires is potentially damaging to the ECU if you short the wrong 2 pins while the ECU is powered up. Pin 85 is the vulnerable pin as far as potential damage to the ECU transistor that provides ground for the FP relay coil. One slip-up and the ECU is done, for that function anyway.
Mark
| kamzcab86 wrote: |
So, that means the ECU isn't grounding the relay? If so, that means two ECUs, including a rebuilt one, aren't functioning properly?
Could a faulty coil be a part of the problem? We're now getting inconsistent power readings from it...... |
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