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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Tue Apr 05, 2022 8:36 pm Post subject: 1989 starts, idles, then dies after a couple minutes |
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Hi guys,
I’m a Bay window guy but am working on a water cooled, standard shift, 1989 Vanagon. The issue is that when the coolant is below 140 degrees or so, it will die a bit after idling with no throttle. Once warm, it works fine.
My buddy and I spent 6 hours today troubleshooting. Used the fuel injection manual as well as the Bentley. We cleaned numerous grounds and connectors. I’m not going to list everything we tried but it was a lot.
It was running great at 4pm after our work today but after sitting 4 hours I started it up without any throttle. After about 2 minutes it died.
I’m here asking for help. Our next step is to smoke test and put a scope on it to watch the injector pulses. It’s probably something we overlooked and in the end we’ll feel like dummies.
Anyone have a similar problem that was solved?
Thanks in advance-Gary _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
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VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
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DuncanS Samba Member
Joined: October 17, 2013 Posts: 4583 Location: New Hampshire
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Posted: Tue Apr 05, 2022 9:37 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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Sounds like an open loop problem with it running too rich. Check to see if the O2 sensor wire is grounded. Not the shielding which should be grounded, but the core which can not.
There are many who far better at this than I am, so this may be way off base.
Duncan |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22639 Location: NYC/Upstate/ROW
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Posted: Wed Apr 06, 2022 3:17 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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Does that car use an auxiliary air regulator to control warmup air/ fuel? The time frame sounds correct for that. _________________ .ssS! |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 5:11 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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I’d like to test the o2 sensor. We cleaned the connectors.
This engine has no AAR. It has a brain and a idle speed gizmo to control idle based on the coolant temp I believe. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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DanHoug Samba Member
Joined: December 05, 2016 Posts: 4772 Location: Bemidji, MN
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Posted: Wed Apr 06, 2022 5:28 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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how does it die? idling smoothly and then just dead? does it starting bobbling about, sounding like a Harley then die? what is the exhaust odor-- sweet and overly rich? acrid stink?
with that time frame, i would focus on two areas... the O2 sensor and the blue Type II coolant sensor.
try the cold start without the O2 senor hooked up. _________________ -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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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 5:53 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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DanHoug wrote: |
how does it die? idling smoothly and then just dead? does it starting bobbling about, sounding like a Harley then die? what is the exhaust odor-- sweet and overly rich? acrid stink?
with that time frame, i would focus on two areas... the O2 sensor and the blue Type II coolant sensor.
try the cold start without the O2 senor hooked up. |
How does it die? Start cold engine. Idles fine for a couple minutes. Starts missing, then dead. Fires right back up and once warm runs great. Don’t notice any odd smells. Checked O2 wires and cleaned them. Tested coolant sensor with ohmmeter. Fell into chart so it probably is ok.
Would like to explore the O2 testing/troubleshooting _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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danfromsyr Samba Member
Joined: March 01, 2004 Posts: 15144 Location: Syracuse, NY
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Posted: Wed Apr 06, 2022 6:43 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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just a wild hair but I've had this fail on mine
check the vacuum line off the back of the fuel pressure regulator.
if the regulator fails internally it can allow extra fuel to pass into the intake.
at cold idle that'd be enriched but once the engine comes to temp and the O2 tries to regulate, it won't be able to compensate enough. _________________
Abscate wrote: |
These are the reasons we have words like “wanker” |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 6:51 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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danfromsyr wrote: |
just a wild hair but I've had this fail on mine
check the vacuum line off the back of the fuel pressure regulator.
if the regulator fails internally it can allow extra fuel to pass into the intake.
at cold idle that'd be enriched but once the engine comes to temp and the O2 tries to regulate, it won't be able to compensate enough. |
We installed a gauge on the fuel rail test port. Engine running = about 28-30 psi. Engine off = 36 and held. That sounds good to me. It did not bleed down _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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Aryana Samba Member
Joined: November 09, 2015 Posts: 568 Location: Southern CA
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Posted: Wed Apr 06, 2022 7:45 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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I'm in SD and an A&P/PPL based out of Montgomery Field.
I have a Bluetooth emulator installed in the ECU of my 1986 tintop and we could swap that in to be able to see what's happening with that vehicle real time and record logs to go back and see why it's shutting down.
I'm leaving out of town and back next Monday. If you haven't figured this out by then and want to try this, hit me up.
It's a great tool letting you see everything happening with this engine.
https://youtu.be/Oz7YROvXQpc |
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SCM Samba Member
Joined: January 26, 2011 Posts: 3115 Location: Bozeman MT
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Posted: Wed Apr 06, 2022 8:05 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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aeromech wrote: |
Would like to explore the O2 testing/troubleshooting |
I think the easiest way to troubleshoot it is to unplug the O2 sensor. If the sensor is bad the engine should continue to run with the sensor disconnected, albeit running rich. _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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DanHoug Samba Member
Joined: December 05, 2016 Posts: 4772 Location: Bemidji, MN
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Posted: Wed Apr 06, 2022 11:25 am Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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aeromech wrote: |
Would like to explore the O2 testing/troubleshooting |
couple of simple tests... with the sensor connected, slip a DVM probe under the rubber boot to make contact with the spade connector. start it and with a warmed, normally functioning O2 sensor AND ECU feedback, you'll see voltage readings oscillate above and below 0.5VDC about every second or two. this tells you that the O2 sensor is responding to mixture changes and that the ECU is able to modify the dwell time of the injectors to richen/lean.
now, disconnect the O2 sensor and connect DVM to free hangin spade on sensor. see what the output is doing without ECU feedback. if the voltage is slammed above 0.5v, the base mixture is rich. if below 0.5v, it is lean.
if you take the cover of the AFM off, you can push the wiper around while it is running and see the effect as you make it rich by increasing the wiper vane movement and lean enough to die. _________________ -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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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50337
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Posted: Wed Apr 06, 2022 12:34 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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The idle control valve will get sticky over time. Some carb cleaner sprayed through it MAY or may not help.
Once you get a miss the O2 sensor will read the miss as a lean condition and enrich the mixture which can cause all the cylinders to miss and the engine to die. Sometimes you can fix this with just new plugs or plug wires.
These engines have a TSII sensor that can give bad readings as it ages. It is also very sensitive to bad connection. |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 12:40 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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Aryana wrote: |
I'm in SD and an A&P/PPL based out of Montgomery Field.
I have a Bluetooth emulator installed in the ECU of my 1986 tintop and we could swap that in to be able to see what's happening with that vehicle real time and record logs to go back and see why it's shutting down.
I'm leaving out of town and back next Monday. If you haven't figured this out by then and want to try this, hit me up.
It's a great tool letting you see everything happening with this engine.
https://youtu.be/Oz7YROvXQpc |
That sounds like a great offer. I'll follow up on our progress when we jump back onto the Vanagon tomorrow. Thanks _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 12:47 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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SCM wrote: |
aeromech wrote: |
Would like to explore the O2 testing/troubleshooting |
I think the easiest way to troubleshoot it is to unplug the O2 sensor. If the sensor is bad the engine should continue to run with the sensor disconnected, albeit running rich. |
This is the first thing I'll try _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 12:48 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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DanHoug wrote: |
aeromech wrote: |
Would like to explore the O2 testing/troubleshooting |
couple of simple tests... with the sensor connected, slip a DVM probe under the rubber boot to make contact with the spade connector. start it and with a warmed, normally functioning O2 sensor AND ECU feedback, you'll see voltage readings oscillate above and below 0.5VDC about every second or two. this tells you that the O2 sensor is responding to mixture changes and that the ECU is able to modify the dwell time of the injectors to richen/lean.
now, disconnect the O2 sensor and connect DVM to free hangin spade on sensor. see what the output is doing without ECU feedback. if the voltage is slammed above 0.5v, the base mixture is rich. if below 0.5v, it is lean.
if you take the cover of the AFM off, you can push the wiper around while it is running and see the effect as you make it rich by increasing the wiper vane movement and lean enough to die. |
I'll wait for my buddy tomorrow and maybe try this after disconnection the O2 altogether today. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 12:52 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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Wildthings wrote: |
The idle control valve will get sticky over time. Some carb cleaner sprayed through it MAY or may not help.
Once you get a miss the O2 sensor will read the miss as a lean condition and enrich the mixture which can cause all the cylinders to miss and the engine to die. Sometimes you can fix this with just new plugs or plug wires.
These engines have a TSII sensor that can give bad readings as it ages. It is also very sensitive to bad connection. |
We did put the idle control valve on the bench and cleaned it with Mass Airflow Cleaner and shop air.
We cleaned and gapped all the plugs to spec. Cleaned the cap and rotor.
We looked for a standard TSII but did not find one. Either we missed it or it's not installed on this 1989 water cooled engine. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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riceye Samba Member
Joined: March 09, 2006 Posts: 1661 Location: Caledonia, WI
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Posted: Wed Apr 06, 2022 1:13 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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aeromech wrote: |
We looked for a standard TSII but did not find one. Either we missed it or it's not installed on this 1989 water cooled engine. |
On the side of the thermostat housing below the thermostat. The blue one pictured is for the ECU. The black one on the front side of the tower serves the gauge.
My money's on a fault in the o2 sensor coax based on when and how the problem arises. _________________ '87 Westy Weekender - daily driver on salt-free roads
There's gonna be some changes made.
“I find that things usually go well right up until the moment they don't.” - Ahwahnee
"Quality isn't method. It's the goal toward which the method is aimed." - Socrates, later quoted by R.M. Pirsig |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 1:23 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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riceye wrote: |
aeromech wrote: |
We looked for a standard TSII but did not find one. Either we missed it or it's not installed on this 1989 water cooled engine. |
On the side of the thermostat housing below the thermostat. The blue one pictured is for the ECU. The black one on the front side of the tower serves the gauge.
My money's on a fault in the o2 sensor coax based on when and how the problem arises. |
The blue connector on the drivers side is the one we fultz with.
PS- Our coolant sensor is a light green, not deep blue like yours
Today I unplugged the green coax from the O2 sensor. The engine started but died after one minute.
Reconnected, I started and it died again after about a minute. So no affect from the O2 _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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SCM Samba Member
Joined: January 26, 2011 Posts: 3115 Location: Bozeman MT
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Posted: Wed Apr 06, 2022 1:41 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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aeromech wrote: |
PS- Our coolant sensor is a light green, not deep blue like yours
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I vaguely remember replacing a green sensor with a blue one one I first bought my van. I think they're interchangable. _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16959 Location: San Diego, California
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Posted: Wed Apr 06, 2022 2:03 pm Post subject: Re: 1989 starts, idles, then dies after a couple minutes |
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I vaguely remember changing a sensor years ago on some car. The color changed to indicate the upgraded sensor. Can’t remember the details _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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