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BrownLoaf
Samba Member
Joined: January 21, 2021
Posts: 94
Location: Bellingham, WA
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 Posted: Thu Mar 17, 2022 9:10 am Post subject: Digijet ECU - Bellingham, WA |
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Are there any Digijet Vanagon (83.5-85) owners in the Bellingham, WA area who would be willing to help me troubleshoot a Digijet fuel injection ECU?
I received a remanufactured ECU this week that cuts out at about 2000-2500 rpm, regardless of engine load or temperature (happens during both closed and open loop). Before I send it back, I'd like to plug it into another van and see if the issue still happens.
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83.5 Vanagon Riviera WBX 2.2 "Brown Loaf"
87 Vanagon Syncro Tin Top WBX 2.1 "Bubbles" |
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the_benjamin_effect
Samba Member
Joined: May 31, 2010
Posts: 197
Location: Gateway to the North Cascades, Washington State
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| Posted: Thu Mar 17, 2022 3:08 pm Post subject: Re: Digijet ECU - Bellingham, WA |
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Sorry, I cant help you as I have an 87, but...
Have you tried Josh at Reference Automotive https://www.referenceautomotive.com/?
He is in your area.
He is very helpful and knowledgeable of the Vanagon, and generally just a good guy that likes helping others out.
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-1967 Sundial Camper 1914cc "Sunny"
-1978 Deluxe Westfalia Jake Raby built PowerStroke 2109cc "Westy"
-1987 SYNCRO Westfalia GoWesty 2400cc "Ruby"
-2000 Subaru Impreza Sport EJ22 ¼ million miles "Trusty"
International Association of Machinists and Aerospace Workers. I.A.M. 751
International Brotherhood of Naval Flight Engineers. I.B.N.F.E. LOCAL 8251
My other ride has 18,400 horsepower! |
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BrownLoaf
Samba Member
Joined: January 21, 2021
Posts: 94
Location: Bellingham, WA
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| Posted: Thu Mar 17, 2022 5:21 pm Post subject: Re: Digijet ECU - Bellingham, WA |
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Yup, Josh is great! He's helped me with other tricky vanagon issues. I'll give him a call about this one.
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83.5 Vanagon Riviera WBX 2.2 "Brown Loaf"
87 Vanagon Syncro Tin Top WBX 2.1 "Bubbles" |
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BrownLoaf
Samba Member
Joined: January 21, 2021
Posts: 94
Location: Bellingham, WA
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| Posted: Sat Mar 19, 2022 6:56 am Post subject: Re: Digijet ECU - Bellingham, WA |
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Reference is on Spring break this week, so I'll try them next week.
For context, it's an 83.5 with original Digijet ECU still in mostly working condition. The reason I tried a re-manufactured ECU is that the van has always had intermittent rich starting issues. So much so that my dad added a fuel pump cutoff switch to get the engine started back in 2006 or so. That switch still works and is a great anti-theft device (thanks Dad!).
In recent years, I've tested, serviced, or replaced just about everything on and including the engine. 99% of the time, the van runs great, has plenty of power (for a WBX), does not hesitate, etc. This one issue, occasional rich starting, persists after all these years.
The issue seems to only occur when the van is warm (not hot) and sometimes happens when cold. The engine cranks longer than normal and then starts with a cloud of unburned fuel smoke and rich smell. It seems that once hot and in closed loop using the O2 sensor, things run predictably. Temp II sensor is the obvious culprit but is not to blame in this case.
I've tuned the AFM using the O2 sensor signal (at full temp) and found it at the rich end of adjustment, almost unable to get it lean enough. The O2 sensor has about 10k miles on it.
The ECU and the AFM are the only two fuel injection components that have never been replaced. And that is what brought me to trying the remanufactured ECU.
Has anyone else had a similar issue? Any other ideas?
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83.5 Vanagon Riviera WBX 2.2 "Brown Loaf"
87 Vanagon Syncro Tin Top WBX 2.1 "Bubbles" |
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RawUmber
Samba Member
Joined: June 23, 2019
Posts: 223
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| Posted: Sat Mar 19, 2022 8:22 am Post subject: Re: Digijet ECU - Bellingham, WA |
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| Considering that you have two ECUs now.. Does the re-manufactured ECU exhibit the original warm start issues? I realize that it may have a problem between 2000-2500 RPM, but if you still have the warm start issue, chances are it's not caused by the ECU. |
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bajabones
Samba Member
Joined: April 17, 2019
Posts: 134
Location: Tacoma, WA
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| Posted: Sun Mar 20, 2022 9:51 am Post subject: Re: Digijet ECU - Bellingham, WA |
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I live in Tacoma if you are ever in the area
I have a perfect running 1990 2.1 digijet
I also have 2 good spare ECU's
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1990 Syncro Doka
2.1 DJ
Triple Knob
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BrownLoaf
Samba Member
Joined: January 21, 2021
Posts: 94
Location: Bellingham, WA
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| Posted: Sun Apr 10, 2022 4:33 pm Post subject: Re: Digijet ECU - Bellingham, WA |
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| bajabones wrote: |
I live in Tacoma if you are ever in the area
I have a perfect running 1990 2.1 digijet
I also have 2 good spare ECU's
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Very much appreciated, Bajabones! I may have sorted the issue for good...
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83.5 Vanagon Riviera WBX 2.2 "Brown Loaf"
87 Vanagon Syncro Tin Top WBX 2.1 "Bubbles" |
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BrownLoaf
Samba Member
Joined: January 21, 2021
Posts: 94
Location: Bellingham, WA
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| Posted: Sun Apr 10, 2022 5:15 pm Post subject: Re: Digijet ECU - Bellingham, WA |
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| RawUmber wrote: |
| Considering that you have two ECUs now.. Does the re-manufactured ECU exhibit the original warm start issues? I realize that it may have a problem between 2000-2500 RPM, but if you still have the warm start issue, chances are it's not caused by the ECU. |
Thank you for this suggestion! The re-manufactured ECU did in fact exhibit the same warm start issue, ruling the ECU out as the culprit.
Josh at Reference Automotive graciously allowed me to try the re-manufactured ECU in another 1.9 Digijet van and the starting issue persisted in that van. No doubt the ECU was bad. Back it went for warranty.
While at work one day it dawned on my that I'd never tried replacing the fuel relays in the engine compartment. I'd tested them per the Bentley in years past and they'd always tested good. They were likely original and better quality than modern replacements. A relay wouldn't fail partially, would it? That's what I thought, anyways.
So I went outside on my lunch break and swapped the fuel injection relay (the LH of the two) with a new spare I'd been carrying around in the van. Well, it's been two weeks and the van has started perfectly in every situation so far. Time will tell, but so far the relay does seem to have contributed to inconsistent starting.
Why would a relay that tests good behave this way? My theory is that during cranking the voltage supplied to the fuel injection system drops because most of the current is going to the starter. Reduced voltage supplied to the relay combined with more voltage drop through the old relay and perhaps the ECU inputs were skewed enough that the ECU "thought" the coolant temperature was lower than it actually was, thus enriching the mix.
By ohms law, if the ECU voltage is reduced, the resistance measured by the ECU through the temp II sensor would be increased, meaning the ECU thinks the coolant is colder than reality and the engine needs more fuel to start, flooding the engine and failing to start. That's my idea anyways!
Anyone have any other theories or had similar issues?
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83.5 Vanagon Riviera WBX 2.2 "Brown Loaf"
87 Vanagon Syncro Tin Top WBX 2.1 "Bubbles" |
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DigiMatrix
Samba Member
Joined: April 20, 2010
Posts: 450
Location: Up North Canada
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| Posted: Mon Apr 11, 2022 8:41 am Post subject: Re: Digijet ECU - Bellingham, WA |
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I bet the relay contacts were causing a voltage drop to the ECU. The ECU has a voltage drop table to compensate for injector response vs voltage. If the voltage drops too much it has a tough time controlling the fuel. My bet is, at a certain RPM the relay wasn't providing the required current/voltage.for the ECU.
You could try filing the contacts in the bad relay to see if it solves the issue.
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'91 Syncro Westfalia
soon to be 2.5 liter stroker WBX 10:1 comp
Digifant ECU with knock sensor and custom
cylinder selective knock control by me |
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Vanagon Nut
Samba Member
Joined: February 08, 2008
Posts: 10381
Location: Sunshine Coast B.C.
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| Posted: Tue Apr 12, 2022 8:50 am Post subject: Re: Digijet ECU - Bellingham, WA |
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I’ve had 3 different Bosch type relays have intermittent internal failures. Not saying it’s a common issue but if you use a magnifying glass closely inside the relay you might see a hair line crack at on a part. Try slowly moving each leg during inspection while looking for a fail point.
The relay failure mode I saw was quite random.
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1988 West DIY 50º ABA
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