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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Sun May 16, 2021 6:51 pm Post subject: No spark @ plugs on 2.1. Update: Spark, still no start [Solved] |
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using a jumper wire to ground the center wire of the Hall sensor connector produces a spark at the wire coming from the coil (detached from dist cap and lying on block). In theory, this should mean the ECU and coil are good, indicating a bad Hall sender.
This Hall sensor is exceptionally new looking. Nevertheless, I swapped in the distributor from a running van. Still no spark at the plugs.
I have tried four sets of caps & rotors, and three sets of cables just to make my kid shut up about the cables. Still no spark at the plugs.
To understand how simple the Hall sender is = understanding that this simply makes no sense. The spark from the coil wire should be mechanically distributed to the cables via the cap and rotor. Unless I'm simply spacing out from tunnel vision, the only way for this to make sense is that the coil is putting out *insufficient* spark or somehow BOTH Hall senders are suddenly bad. They don't go bad that often.
I swapped in a good coil just to be sure. And then a good ECU. Still no spark.
I'm at my wit's end.
Any ideas? |
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xoo00oox Samba Member
Joined: February 11, 2010 Posts: 2672 Location: East Nassau, NY
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Posted: Sun May 16, 2021 7:04 pm Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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Did you check the power AND the ground at the hall sensor? |
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DanHoug Samba Member
Joined: December 05, 2016 Posts: 4770 Location: Bemidji, MN
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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Sun May 16, 2021 7:16 pm Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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xoo00oox wrote: |
Did you check the power AND the ground at the hall sensor? |
touching points to the outer two wires in the Hall sensor wire connector shows between 6-9V
that’s sufficient, right? my brain has slowed waaay down in the past 20min |
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xoo00oox Samba Member
Joined: February 11, 2010 Posts: 2672 Location: East Nassau, NY
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Posted: Sun May 16, 2021 7:21 pm Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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wehrbüchse wrote: |
xoo00oox wrote: |
Did you check the power AND the ground at the hall sensor? |
touching points to the outer two wires in the Hall sensor wire connector shows between 6-9V
that’s sufficient, right? my brain has slowed waaay down in the past 20min |
It should be full battery voltage. If your battery is good check the positive to a known good ground, the ground to a known good positive (test each of them tight to the batttey posts ideally) MAKE SURE THE ENGINE IS GROUNDED TO THE BODY GOOD! |
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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Sun May 16, 2021 7:24 pm Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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DanHoug wrote: |
between these two things, you can pinpoint your problem. |
that is a very cool tool. profuse thanks for bringing it to my attention |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50334
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Posted: Sun May 16, 2021 9:21 pm Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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The wires in the Hall circuitry are tiny and subject to breakage. Wiggling them around to test the Hall pickup can make the system work momentarily. |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17110 Location: Retired South Florida
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Posted: Mon May 17, 2021 4:32 am Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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Have you visually watched the distributor shaft turn while the engine cranks? _________________ ☮️ |
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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Mon May 17, 2021 7:45 pm Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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wow i love you guys. i was about to keel over when i posted and ive spent the last 18hrs doing like 7 convoluted tax returns, I majorly appreciate your brainpower injections and feedback. I’ll be done w this stupid desk crap in a bit! |
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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Thu Feb 10, 2022 9:00 pm Post subject: Re: no spark @ plugs on 2.1. am I hallucinating? |
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xoo00oox wrote: |
[(...) If your battery is good check the positive to a known good ground, the ground to a known good positive (test each of them tight to the batttey posts ideally) (...) |
you mean on the hall sensor connector?
I just used Dan's hall tester to confirm that both distributors are fine. The fact that I get a spark when grounding the connector's center wire would seem to eliminate ground issues. I'm stumped. |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50334
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Posted: Thu Feb 10, 2022 10:45 pm Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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Check the voltage at the Hall Unit when cranking to both the engine block and to the body/frame. If the engine/starter has a wacky ground to the body it might still crank, but the Hall unit might not see enough volts to fire. |
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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Fri Feb 11, 2022 11:07 am Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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when you say check voltage at the hall unit, you mean at the connector? i measured 12V between the outer two contacts last night. but the power to the plugs comes from the coil anyway, such that it shouldn't matter right? |
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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Fri Apr 29, 2022 10:43 pm Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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the hall sender tested fine using Dan’s unit. i have spark at the plugs as evidenced by a spark tester from napa. i just sprayed starter fluid *vapor* into the S boot where it attaches to the MAF sensor. engine cranks but absolutely will not start.
do I understand correctly that if there were a bad ground somewhere, the ECU simply won’t send the signal to the hall sender to create the spark? in other words doesn’t the presence of spark confirm that grounds are fine? I guess I already know the answer to this but maybe someone can help it make sense for me. this van has been broken down now for a solid YEAR. |
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crazyvwvanman Samba Member
Joined: January 28, 2008 Posts: 9920 Location: Orbiting San Diego
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Posted: Sat Apr 30, 2022 4:06 am Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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I think you are misunderstanding how the ignition spark works in your Digifant van.
The Hall unit doesn't make the spark.
The Hall unit tells the ECU that the engine is turning.
The Hall unit tells the ECU when the engine is in a certain position as it is turning.
So the Hall unit is the base timing source for the ECU.
Once the Hall has sent its small timing pulse to the ECU the Hall has no further role in the spark creation and distribution.
The ECU uses these small base timing pulses from the Hall to determine when the ECU should trigger the ignition coil to make Sparks.
The sparks go from the ignition coil to the center of the distributor cap.
The spinning rotor points to one of the 4 spark plug wires to direct the spark from the center of the cap to a given cylinder plug wire.
The Hall unit has nothing to do with the spark itself.
It merely is the INITIAL source of the small TIMING pulse used by the ECU to trigger the ignition coil to make the spark.
Then the distributor cap and rotor direct the spark to a given cylinder plug wire.
The low voltage Hall lives a quiet life in the lower part of the distributor while the high voltage spark activity passes through the upper part where the rotor and cap steer the spark to a given plug wire.
Mark
wehrbüchse wrote: |
the hall sender tested fine using Dan’s unit. i have spark at the plugs as evidenced by a spark tester from napa. i just sprayed starter fluid *vapor* into the S boot where it attaches to the MAF sensor. engine cranks but absolutely will not start.
do I understand correctly that if there were a bad ground somewhere, the ECU simply won’t send the signal to the hall sender to create the spark? in other words doesn’t the presence of spark confirm that grounds are fine? I guess I already know the answer to this but maybe someone can help it make sense for me. this van has been broken down now for a solid YEAR. |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32574 Location: Reading Pennsylvania
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Posted: Sat Apr 30, 2022 4:21 am Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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crazyvwvanman wrote: |
I think you are misunderstanding how the ignition spark works in your Digifant van.
The Hall unit doesn't make the spark.
The Hall unit tells the ECU that the engine is turning.
The Hall unit tells the ECU when the engine is in a certain position as it is turning.
So the Hall unit is the base timing source for the ECU.
Once the Hall has sent its small timing pulse to the ECU the Hall has no further role in the spark creation and distribution.
The ECU uses these small base timing pulses from the Hall to determine when the ECU should trigger the ignition coil to make Sparks.
The sparks go from the ignition coil to the center of the distributor cap.
The spinning rotor points to one of the 4 spark plug wires to direct the spark from the center of the cap to a given cylinder plug wire.
The Hall unit has nothing to do with the spark itself.
It merely is the INITIAL source of the small TIMING pulse used by the ECU to trigger the ignition coil to make the spark.
Then the distributor cap and rotor direct the spark to a given cylinder plug wire.
The low voltage Hall lives a quiet life in the lower part of the distributor while the high voltage spark activity passes through the upper part where the rotor and cap steer the spark to a given plug wire.
Mark
wehrbüchse wrote: |
the hall sender tested fine using Dan’s unit. i have spark at the plugs as evidenced by a spark tester from napa. i just sprayed starter fluid *vapor* into the S boot where it attaches to the MAF sensor. engine cranks but absolutely will not start.
do I understand correctly that if there were a bad ground somewhere, the ECU simply won’t send the signal to the hall sender to create the spark? in other words doesn’t the presence of spark confirm that grounds are fine? I guess I already know the answer to this but maybe someone can help it make sense for me. this van has been broken down now for a solid YEAR. |
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This^^^
Plus
The hall unit tells the ECU to fire the injectors too.
Plus
You don't have a MAF
Rearrange the letters.....
You have an Air Flow Meter.
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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DuncanS Samba Member
Joined: October 17, 2013 Posts: 4583 Location: New Hampshire
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Posted: Sat Apr 30, 2022 5:09 am Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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I have heard of them referred to as a Mass Air Flow unit.
Great post by Mark, as always. Sometimes we need to be reminded of the obvious, which we already knew, and or learn something new we didn't before.
Duncan |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32574 Location: Reading Pennsylvania
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DanHoug Samba Member
Joined: December 05, 2016 Posts: 4770 Location: Bemidji, MN
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Posted: Sat Apr 30, 2022 7:18 am Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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djkeev wrote: |
DuncanS wrote: |
I have heard of them referred to as a Mass Air Flow unit.
Great post by Mark, as always. Sometimes we need to be reminded of the obvious, which we already knew, and or learn something new we didn't before.
Duncan |
Actually VW calls it an Air Flow Sensor in the ProTraining manual.
I learned AFM from Mercedes School back in the early 1970's. |
we have an Air Flow Meter but NOT a Mass Air Flow sensor. our AFMs only measure the volume of air flow but does not take into account the mass of the air charge. a MASS Air Flow sensor measures the mass of the air charge by noting the temperature drop of a hot wire strung across the air intake. this takes into account both the volume and density (affected by temperature and pressure) of the air charge. designers can then accurately tune to an exact charge of oxygen, injecting a more precise squirt of gasoline to completely use up that oxygen, no more nor less than is needed. it's not a perfect system but it is better.
important to keep that hot wire clean in a MAF in your other cars. dirt collects on the air creating an insulating layer that interferes with measuring air density. _________________ -dan
60% of what you find on the internet is wrong, including this post.
'87 Westy & '89 Westy both 2.1 4spd
Past projects can be found at--
www.thefixitworkshop.com |
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wehrbüchse Samba Member
Joined: January 04, 2010 Posts: 501
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Posted: Sat Apr 30, 2022 7:39 am Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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crazyvwvanman wrote: |
I think you are misunderstanding how the ignition spark works in your Digifant van.
The Hall unit doesn't make the spark.
The Hall unit tells the ECU that the engine is turning.
The Hall unit tells the ECU when the engine is in a certain position as it is turning.
So the Hall unit is the base timing source for the ECU.
Once the Hall has sent its small timing pulse to the ECU the Hall has no further role in the spark creation and distribution.
The ECU uses these small base timing pulses from the Hall to determine when the ECU should trigger the ignition coil to make Sparks.
The sparks go from the ignition coil to the center of the distributor cap.
The spinning rotor points to one of the 4 spark plug wires to direct the spark from the center of the cap to a given cylinder plug wire.
The Hall unit has nothing to do with the spark itself.
It merely is the INITIAL source of the small TIMING pulse used by the ECU to trigger the ignition coil to make the spark.
Then the distributor cap and rotor direct the spark to a given cylinder plug wire.
The low voltage Hall lives a quiet life in the lower part of the distributor while the high voltage spark activity passes through the upper part where the rotor and cap steer the spark to a given plug wire.
Mark
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Believe it or not I understand all of this but i still don’t understand why I can’t get this motor to start. I apologize for saying MAF sensor. |
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DanHoug Samba Member
Joined: December 05, 2016 Posts: 4770 Location: Bemidji, MN
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Posted: Sat Apr 30, 2022 11:36 am Post subject: Re: No spark @ plugs on 2.1. Am I hallucinating? |
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ok, we gotta get you going. you're still at no spark, correct?
Knowns, correct if wrong:
- Hall sensor good
- spark test grounding center connector on dist results in spark coming out *coil* lead.
Info needed:
- using a remote switch or an assistant, connect the Hall tester to the dist and have someone crank the engine. does the tester flash? this test tells you the distributor is rotating with the engine.
if the tester flashes, next eliminate the cap and rotor as a spark interrupter. pull the coil lead out of the dist and using your remote starter switch (see how handy that'll be now?!), hold the coil lead close to the block. spark? if yes, your problem is in wrong cap/rotor combinations. if no, report back! well, report back anyway. _________________ -dan
60% of what you find on the internet is wrong, including this post.
'87 Westy & '89 Westy both 2.1 4spd
Past projects can be found at--
www.thefixitworkshop.com |
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