| Author |
Message |
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
 Posted: Mon Oct 22, 2012 10:00 pm Post subject: 2.1L barely idles; much better with AFM boot opened allowing |
 |
|
Trying to fix a non-idling '90 syncro and think I need a fresh approach.
Symptoms are rough/almost non-existent idle both cold and warm and very hesitant throttle response. I can "milk" the throttle and eventually the van will kick up in RPM (if it doesn't die first). I've done a lot of the normal first steps (Temp II, engine grounds, O2 disconnected just in case) and I have a pretty healthy list of fairly new parts (including the air sensor).
I did notice one thing that surprised me: if I unhook the rubber boot leading to the AFM (from the TB) and allow unmettered air into the intake, this does allow the engine to at least idle (but obviously its not 100% happy). I've tried 2 different air sensors and they both behave the same.
Before I start yet another session staring at that engine, what does this tell you about my problem? Tomorrow I was planning on looking for vacuum leaks, but honestly this is a gigantic leak and yet this improves my idle. Seems counter intuitive to me.
I also found some tests (page 18 of the Digifant pro guide) from the air sensor to the ECU wiring harness; that will be my next move unless somebody has something obvious that I'm missing.
Thanks for any help!
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
 |
denwood
Samba Member
Joined: July 29, 2012
Posts: 1047
Location: Thunder Bay, Ontario, Canada
|
| Posted: Mon Oct 22, 2012 10:49 pm Post subject: |
|
|
Hmm. What have you done in terms of checking your ISV operation? Checked the throttle position switches for correct operation? If it runs better with the boot off, then this would suggest you have a lot more fuel going to the injectors at idle than normal.
Made any timing changes?
This digitool manual explains the operation of the components so may be helpful: http://www.van-cafe.com/shop/images/ecumanual.pdf
_________________
Cheers,
Dennis Wood
The Grape
Last edited by denwood on Tue Oct 23, 2012 12:19 pm; edited 1 time in total |
|
| Back to top |
|
|
Jake de Villiers
Samba Member
Joined: October 24, 2007
Posts: 5911
Location: Tsawwassen, BC
|
| Posted: Mon Oct 22, 2012 11:56 pm Post subject: |
|
|
Does it smell rich? Does it run okay at speed but not idle?
If so, it could be that the fuel pressure regulator has failed and is providing too much pressure at the rails. This will make for a super rich idle which would improve with more air.
_________________
'84 Vanagon GL 1.9 WBX
'86 Westy Weekender Poptop/2.5 Subaru/5 Speed Posi/Audi Front Brakes/16 x 7 Mercedes Wheels - answers to 'Dixie'
@jakedevilliersmusic1
http://sites.google.com/site/subyjake/mydixiedarlin%27
www.crescentbeachguitar.com
www.thebassspa.com |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Tue Oct 23, 2012 10:31 am Post subject: |
|
|
| denwood wrote: |
| Hmm. What have you done in terms of checking your ISV operation? Checked the throttle position switches for correct operation? |
Other than connecting/disconnecting the ISV to a battery on my workbench and seeing it actuate, I haven't done anything else. I'll look at the Bently and see what the spec for testing it is before I assume it's good.
TSP is less than a year old and is the "modern" version sold by Van Cafe. It is also positioned correctly (per my LED indicator on my digitool).
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Tue Oct 23, 2012 10:34 am Post subject: |
|
|
| Jake de Villiers wrote: |
Does it smell rich? Does it run okay at speed but not idle?
If so, it could be that the fuel pressure regulator has failed and is providing too much pressure at the rails. This will make for a super rich idle which would improve with more air. |
It is fairly rich and has been down on MPG. Generally lacking power. I was taking each one of these issues in order (figured it barely idling was top priority).
Tested the fuel pressure both at the T-adapter and it read 30psi. Could this still be a bad regulator?
I replaced it within, say, 3 years, but that's no guarantee that its still any good. 
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
Brungeman
Samba Member
Joined: July 25, 2010
Posts: 187
Location: Pittsburgh
|
| Posted: Tue Oct 23, 2012 11:20 am Post subject: |
|
|
are there any obstructions in your snorkel/intake? a collapsed snorkel tube can cause the choking off sensation that was remedied by your opening of the rubber boot.
but, I have also had a problem with my idle position switch on the bottom of the throttle body, did you check that?
and have you looked at your injectors for leaking conditions?
_________________
87 multivan
84 transporter for sale
86 scirocco RIP
71 Baywindow RIP
1972 Super RIP
1969 Bug RIP
1974 Super RIP |
|
| Back to top |
|
|
PDXWesty
Samba Member
Joined: April 11, 2006
Posts: 6245
Location: Portland OR
|
| Posted: Tue Oct 23, 2012 11:23 am Post subject: |
|
|
I'd take it over to Halsey and get a diagnosis. They got mine to idle well.
_________________
89 Westy 2.1 Auto |
|
| Back to top |
|
|
[email protected]
Samba Member
Joined: August 03, 2002
Posts: 12785
Location: Salt Lake City, Utah
|
| Posted: Tue Oct 23, 2012 11:34 am Post subject: |
|
|
sounds like a clogged air filter, or intake tract (mice or leaves?)
_________________
It's just advice, do whatever you want with it!
Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net
"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net |
|
| Back to top |
|
|
denwood
Samba Member
Joined: July 29, 2012
Posts: 1047
Location: Thunder Bay, Ontario, Canada
|
| Posted: Tue Oct 23, 2012 12:38 pm Post subject: |
|
|
You have a digitool, correct? Can we assume then that all components are checked and working correctly as per the digitool tests? Would help if you provided some history on when the problem occurred as it sounds like you've done some work.
Open up the air box cover or disconnect the air intake. Any change? I did deal with a collapsed air tube but it had no effect at idle with my setup.
Removing the AFM connector should permit start/idle, so pulling the boot shouldn't change drastically air flow through the TB. (Correcting myself from last night!). You did say it idles better this way though..so assuming no blockages, you need to figure out why so rich.
What is the 02 sensor wire voltage read when disconnected and measured at ECU side of plug in the engine bay? Should be a steady .5V. What does the o2 sensor voltage (disconnect from ECU) read when fully warm at idle? My guess is .8 or greater...
Have you adjusted the AFM at all?
_________________
Cheers,
Dennis Wood
The Grape |
|
| Back to top |
|
|
Jake de Villiers
Samba Member
Joined: October 24, 2007
Posts: 5911
Location: Tsawwassen, BC
|
| Posted: Tue Oct 23, 2012 2:21 pm Post subject: |
|
|
| zippyslug31 wrote: |
| Jake de Villiers wrote: |
Does it smell rich? Does it run okay at speed but not idle?
If so, it could be that the fuel pressure regulator has failed and is providing too much pressure at the rails. This will make for a super rich idle which would improve with more air. |
It is fairly rich and has been down on MPG. Generally lacking power. I was taking each one of these issues in order (figured it barely idling was top priority).
Tested the fuel pressure both at the T-adapter and it read 30psi. Could this still be a bad regulator?
I replaced it within, say, 3 years, but that's no guarantee that its still any good. |
30 psi at cold idle is in the neighbouhood. With a dead regulator you get more like 70!
_________________
'84 Vanagon GL 1.9 WBX
'86 Westy Weekender Poptop/2.5 Subaru/5 Speed Posi/Audi Front Brakes/16 x 7 Mercedes Wheels - answers to 'Dixie'
@jakedevilliersmusic1
http://sites.google.com/site/subyjake/mydixiedarlin%27
www.crescentbeachguitar.com
www.thebassspa.com |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Tue Oct 23, 2012 7:11 pm Post subject: |
|
|
| Jake de Villiers wrote: |
| 30 psi at cold idle is in the neighbouhood. With a dead regulator you get more like 70! |
Ok, this evening's round is done with: me-0, van-1 (or is that 2, 3, 4, ...)
This is pretty weird, but a couple days ago I tested the fuel pressure and found that the pump's check valve was not holding pressure in the system so I replaced it. After that the pressure held steady.
Today I checked the fuel pressure again and now it looks like the regulator doesn't hold pressure. Running the van is seeing about 30psi, shut it off and I loose all pressure within 1 minute. I'll pick one up tomorrow and throw it in the van.
I'm not anywhere close to the 70 psi you are talking about, and I know a bad regulator is a strong symptom, but would a regulator that only appears to not hold residual pressure be such a major problem?
Either way I'll put a new one in tomorrow and either I'll be fixed, or I'll move onto the next symptom.
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Tue Oct 23, 2012 7:15 pm Post subject: |
|
|
| Brungeman wrote: |
are there any obstructions in your snorkel/intake? a collapsed snorkel tube can cause the choking off sensation that was remedied by your opening of the rubber boot.
but, I have also had a problem with my idle position switch on the bottom of the throttle body, did you check that?
and have you looked at your injectors for leaking conditions? |
I pulled air filter housing open (with AFM still connected) and tried running the van; did not seem to make a difference so I don't think the snorkel is blocked. That was a good idea though and had high hopes on that one!
Yep, "idle position switch" (aka throttle position switch, or simply TSP) is set correctly.
While I was retesting my fuel pressure this evening, I pulled both banks of injectors and pressurized the system (had to clamp the return line for my leaking pressure regulator) and not a single drip from any of the 4 injectors, so those check out.
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Tue Oct 23, 2012 7:44 pm Post subject: |
|
|
| denwood wrote: |
| You have a digitool, correct? Can we assume then that all components are checked and working correctly as per the digitool tests? |
Yeah, I have a digitool... but in my process of debugging I was starting to think that my soldering to the board could have been causing me some problems so I removed it. Guess I'll have to resolder it since this doesn't seem to be the issue.
| denwood wrote: |
| Open up the air box cover or disconnect the air intake. Any change? I did deal with a collapsed air tube but it had no effect at idle with my setup. |
No discernible difference for me.
| denwood wrote: |
Removing the AFM connector should permit start/idle, so pulling the boot shouldn't change drastically air flow through the TB. (Correcting myself from last night!). You did say it idles better this way though..so assuming no blockages, you need to figure out why so rich.
|
I think my current vote is toward my pressure reg; will know more when I install a new one tomorrow.
| denwood wrote: |
| What is the 02 sensor wire voltage read when disconnected and measured at ECU side of plug in the engine bay? Should be a steady .5V. What does the o2 sensor voltage (disconnect from ECU) read when fully warm at idle? My guess is .8 or greater... |
I did do some earlier diag checking voltage around this. Seems not to have been a factor so I temporarily disconnected my O2 sensor just to remove it as a factor to my symptoms.
| denwood wrote: |
| Have you adjusted the AFM at all? |
No. I have newer AFM that resolved some earlier running problems but haven't messed with it (yet).
| denwood wrote: |
| Would help if you provided some history on when the problem occurred as it sounds like you've done some work. |
The complete history would be pretty long and I was trying to spare the reader with TOO much unrelated info... I'm seeing this is getting deeper now so here's the slightly longer version:
Been sluggish and occasional dying when coming to stops. Down on mpg for about the past 6 months, yet it was running ok (I'll be honest, it's never really purred). Lately its just too difficult to keep running so I've parked it until I can get to the bottom of it.
Done very recently: tried 2 Temp II sensors, cap/rotor/plugs, air filter, fuel filter
Within the last 2 years due to various problems: Van Cafe rebuilt throttle body (have not moved the idle speed screw), brand new AFM, rebuilt ECU (actually 2 of them) and a likely 3rd good ECU, CAT, O2 sensor, plug wires, distributor.
That's the stuff that comes to mind.
Yes, at times I've been throwing parts at it... my cupboard is full of little bags of cookies from VC. 
For sure one of my problems is that my timing isn't set spot on because it's hard to set with the thing running so poorly. Fundamentally I think its more than simply being out of time as I've had it timed and it didn't help and have moved it some to advance/retard it... neither seem to help.
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Tue Oct 23, 2012 7:45 pm Post subject: |
|
|
Side note: thanks for all the replies, guys.... its times like this I need moral support! 
Keep the advice and ideas coming!
...and I'll update if the fuel pressure reg helps the situation.
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
denwood
Samba Member
Joined: July 29, 2012
Posts: 1047
Location: Thunder Bay, Ontario, Canada
|
| Posted: Tue Oct 23, 2012 9:10 pm Post subject: |
|
|
With regard to fuel pressure, spec is 33 with vacuum on and 36 off. if residual is Zero, looms like check valve or regulator. Hope this fixes it for you..otherwise read on.
Vacuum level from your intake at idle. What is it?
I think I sound like a broken record on this one sometimes, but please read this on AFM tuning: http://www.thesamba.com/vw/forum/viewtopic.php?t=356377
Also, a grounded o2 sensor somewhere between ECU and connector (if unplugged) would give you nasty rich 100% of the time. Check as I suggested previous.
Throwing parts at is tempting but expensive and qualifies in my book as the "ball peen hammer approach" ha.
Soldering in a digitool to the board...hmm. This evidently wasn't a plug in.
_________________
Cheers,
Dennis Wood
The Grape |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Wed Oct 24, 2012 9:42 am Post subject: |
|
|
| denwood wrote: |
| With regard to fuel pressure, spec is 33 with vacuum on and 36 off. if residual is Zero, looms like check valve or regulator. Hope this fixes it for you..otherwise read on. |
Belive the Bently said 29/36, but I don't have it in from of me.
Here's hoping the latest part thrown at it shows at least some improvement!
That's a fantastic thread; thanks for pointing it out!
I'm definitely with the author though on not taking the info lightly... I will look into that only after the more obvious issues have been tested. Heck, hopefully when I have the thing running I'll still look into it as I'd love to have the van purring and having improved MPG.
| denwood wrote: |
| Also, a grounded o2 sensor somewhere between ECU and connector (if unplugged) would give you nasty rich 100% of the time. Check as I suggested previous. |
Sorry, may have failed to mention that early on in my tests I did verify that the sense wire is not grounded out; checked with VOM and it was an open circuit.
| denwood wrote: |
| Soldering in a digitool to the board...hmm. This evidently wasn't a plug in. |
Sounds like we are talking about two different things. I have the Shoebox Electronics one that is soldered into the ECU:
http://shoebox-electronix.com/id17.html
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Thu Oct 25, 2012 9:09 am Post subject: |
|
|
Ok, so I replaced my fuel pressure reg last night. Now I can confirm that I have truly good fuel pressure and also holds after shutting off the motor.
Fuel supply..... CHECK.
This allowed the van to run a bit more stable, but still not road-ready. I really do believe I'm at the mercy of a few problems and I'm picking through them slowly.
With the fuel pressure back to normal the van does run and idle now, albeit roughly. With it at least running on its own I was able to get the timing at least in the ball park so I can diagnose the serious lag in throttle response when I'm turning the throttle body. With it still cold I did unplug the ISV and it died pretty quickly so at I believe its, at minimum, helping the idle.
Now for a silly theory....
For quite some time my power steering pump has been a leaky mess. Bad on me for neglecting it, I know, but it hasn't affected steering; always been a back-burnered project.
In more recent times lately the belt has started to squeal even though its plenty tight. So.... a thought..... is it possible that a failed pump would be so hard to turn that it would cause excessive resistance to an idling motor?
Tonight I'm going to remove the belt, turn the pulley by hand to see if its binding, and try running it with the pump disconnected.
Is this a silly diversion and waste of time?
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17122
Location: Retired South Florida
|
| Posted: Thu Oct 25, 2012 9:30 am Post subject: |
|
|
Seems like an easy enough test and yes, excessive load could cause the engine to die at idle. The silver lining to this is once you have it figured out, you will be an expert on your Vanagon's engine management system and will be much more at ease owning and driving it. mark
_________________
☮️ |
|
| Back to top |
|
|
Navy_Flyer
Samba Member
Joined: January 08, 2012
Posts: 474
Location: Charlottesville, VA
|
| Posted: Thu Oct 25, 2012 9:41 am Post subject: |
|
|
I remember reading, in the Bentley (I think), that unplugging and plugging in the ISV while the engine is running is not recommended, because there is a possibility of causing a spike at the ICM and burning it out - an expensive part, and not always available.
_________________
1987 Westfalia, Automatic. EJ25 VANARU Conversion |
|
| Back to top |
|
|
zippyslug31
Samba Member
Joined: July 20, 2007
Posts: 799
Location: Central Oregon
|
| Posted: Thu Oct 25, 2012 11:10 am Post subject: |
|
|
| Navy_Flyer wrote: |
| I remember reading, in the Bentley (I think), that unplugging and plugging in the ISV while the engine is running is not recommended, because there is a possibility of causing a spike at the ICM and burning it out - an expensive part, and not always available. |
Last thing in the world I'd want to do is cause myself more problems! Good to know; thanks.
_________________
previous:
'80 westy
current:
'90 syncro westy 2.5L subi, triple knob, 16" wheels.
'84 sunroof van, 2.1L motor. |
|
| Back to top |
|
|
|
