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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21519
Location: Oklahoma City
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 Posted: Sat Jul 22, 2017 11:17 am Post subject: Re: Fuel injection relief here! |
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| Tram wrote: |
| raygreenwood wrote: |
| Tram wrote: |
| Pmhaupt wrote: |
After some more investigation, I found out this is a digifant system.
That's the good news, the bad news is, that even after adjusting some parts, including the timing, the bus still wouldn't pass the Portland emissions test.
So now, I'll either have to put in a catalytic converter (which won't fit on the current exhaust) or move out of town 
I appreciate your help guys!!! |
Not so fast.
Do you or do you not have an oxygen sensor? Digifant systems on Vanagons were notorious for lean conditions caused by the O2 sensor. |
Yes.....what Tram said.
I do not know from Vanagon experience.....but the same basic system on Rabbit.....also had this lean running problem. Its also why the rabbits came equipped with a Lambda probe tube.....usually to double check the actual downstream mixture as compared to data the single wire 02 sensor was sending.
One has to remember that in digifant.....everything was tied together into the ignition unit. Downstream mixture readings changed injection pulsewidth. As injection pulsewidth changed and result was re-read.....the timing advance was adjusted by the ignition function......and it was all backstopped by the knock sensor (I cannot remember if the Vanagon digifant had a knock sensor yet.....I dont think so). The knock sensor was a major failure point in the later models. Just a few ft. Lbs of extra torque on its puny bolt would crack the inside crystal and cause a wide range of malfunctions.
If it is digifant 1 you have instead of digijet.....it "should" have an 02 sensor at least. Ray |
IIRC Digifant had the 3 wire O2 sensor with a heater. There is a double and a single wire lead. The double is the heater and the single is the sensor itself.
The heater seemed to cause the issue. |
Yep...you are correct. Its been so long I forgot. I kept thinking it had a single wire...simply because it was just about as inaccurate as a single wire.
Its actually good to hear your comment about the heating circuit being the possible cause. I heard LOTS of speculation about this being a BIG part of the cause of high variation.....but never any real "written" conversation.
It makes sense....and I do know this for sure....the Bosch 02 sensors had the most issues. The last time I bought a new 02 sensor for a Digifant 2 car...about 7 years ago (and it was the third sensor in 4 years)....everyone I bumped into that was knowledgeable....swore by the Denso brand 02 sensor over the Bosch...but could not explain the difference.
I had not used any Denso sensors at that point in time (only Denso plugs which are excellent quality). i put a Denso sensor in it....and with a tweak to CO (back to normal)....part throttle issues cleared right up.
That its the heater element..... could explain quite a bit because the Bosch sensors would pass easily when checking via inert gas....but would fail to provide proper fuel mixture when installed in the car.
Ray |
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OKType3Tim 
Samba Member
Joined: April 30, 2011
Posts: 279
Location: Northeast Oklahoma
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| Posted: Thu Aug 03, 2017 6:52 pm Post subject: Re: Fuel injection relief here! |
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Never Mind.
_________________
'69 Squareback restoration
'69 Fastback restoration
'66 Type34
Last edited by OKType3Tim on Fri Aug 04, 2017 6:50 pm; edited 1 time in total |
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itsallparticles
Samba Member
Joined: June 27, 2017
Posts: 6
Location: Seattle
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| Posted: Fri Aug 04, 2017 3:00 pm Post subject: Re: Fuel injection relief here! |
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| my 70 FI square is running too lean. I've spoken to an individual and i'm out of my element here.. was advised that the fuel regulator should have a service screw on it.. if it's coated in plastic I need to torch the plastic off of it and adjust the service screw... No images... I don't even know what I'm looking at. Am brand new to this world and would like to get an idea about what's going on here? |
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trythis
Samba Member
Joined: September 11, 2016
Posts: 145
Location: St Louis MO
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| Posted: Fri Aug 04, 2017 4:24 pm Post subject: Re: Fuel injection relief here! |
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| itsallparticles wrote: |
| my 70 FI square is running too lean. I've spoken to an individual and i'm out of my element here.. was advised that the fuel regulator should have a service screw on it.. if it's coated in plastic I need to torch the plastic off of it and adjust the service screw... No images... I don't even know what I'm looking at. Am brand new to this world and would like to get an idea about what's going on here? |
Wait! There are a hundred things you should do before you mess with that. I am not the expert here, but they will all tell you not to do that.
A vacuum leak, an old wire, a missing gasket, etc will more likely be the cause.
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Laverne, our Squareback project:
http://www.thesamba.com/vw/forum/viewtopic.php?t=664462 |
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Mike Fisher
Samba Member
Joined: January 30, 2006
Posts: 17970
Location: Eugene, OR
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| Posted: Fri Aug 04, 2017 4:27 pm Post subject: Re: Fuel injection relief here! |
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| itsallparticles wrote: |
| my 70 FI square is running too lean. I've spoken to an individual and i'm out of my element here.. was advised that the fuel regulator should have a service screw on it.. if it's coated in plastic I need to torch the plastic off of it and adjust the service screw... No images... I don't even know what I'm looking at. Am brand new to this world and would like to get an idea about what's going on here? |
Figure 10.8 on page 26 in Section 4 FUEL SYSTEM in the brown 68-73 Type 3 Bentley manual. It's NOT coated in plastic. Fuel pressure should be 28-30 lbs but you have to test it to know what it is. I rigged up a water pressure gauge from Home Depot to test my fuel pressure.
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69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold
Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey |
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Donnie strickland
Samba Member
Joined: December 21, 2009
Posts: 2403
Location: Moody, AL
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| Posted: Fri Aug 04, 2017 6:03 pm Post subject: Re: Fuel injection relief here! |
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He's talking about the MPS.
As stated above, do NOT mess with that. Do some reading and searching, and you'll want to check all your FI electrical components, and check all your vacuum hoses for leaks.
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71 Elm Green FI A/T Squareback |
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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 34013
Location: Conejo Valley, CA
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| Posted: Fri Aug 04, 2017 8:50 pm Post subject: Re: Fuel injection relief here! |
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| itsallparticles wrote: |
| my 70 FI square is running too lean. |
How do you know it's running lean?
| itsallparticles wrote: |
| I've spoken to an individual and i'm out of my element here.. was advised that the fuel regulator should have a service screw on it.. |
Who is this genius? He's got the wrong part, and the wrong advice about that part. You need to avoid this person like the plague.
Timing, vacuum leaks, fuel pressure... among many other things, all should be set 100% right before you even THINK of touching the MPS. |
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22728
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Sat Aug 05, 2017 11:23 am Post subject: Re: Fuel injection relief here! |
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| KTPhil wrote: |
| itsallparticles wrote: |
| my 70 FI square is running too lean. |
How do you know it's running lean?
| itsallparticles wrote: |
| I've spoken to an individual and i'm out of my element here.. was advised that the fuel regulator should have a service screw on it.. |
Who is this genius? He's got the wrong part, and the wrong advice about that part. You need to avoid this person like the plague.
Timing, vacuum leaks, fuel pressure... among many other things, all should be set 100% right before you even THINK of touching the MPS. |
Agreed. Temp sensors too.
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Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
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OB Customs
Samba Member
Joined: January 16, 2011
Posts: 128
Location: Washington
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| Posted: Mon Aug 21, 2017 8:44 pm Post subject: Re: Fuel injection relief here! |
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Hello everyone,
So, I have my 69 Square on the road again and it seems to have an odd issue it’s a little hard to start I know the cold start device is bad so that makes sense but as it warms up it starts to pulse? Almost like the ignition is shut off for a second. I have the factory analyzer and all systems get the go light any ideas I thought about posting a video of it running but thought I would just post this to start.
Thanks
Spencer |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21519
Location: Oklahoma City
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| Posted: Tue Aug 22, 2017 7:44 am Post subject: Re: Fuel injection relief here! |
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| OB Customs wrote: |
Hello everyone,
So, I have my 69 Square on the road again and it seems to have an odd issue it’s a little hard to start I know the cold start device is bad so that makes sense but as it warms up it starts to pulse? Almost like the ignition is shut off for a second. I have the factory analyzer and all systems get the go light any ideas I thought about posting a video of it running but thought I would just post this to start.
Thanks
Spencer |
What do you mean by start to pulse?
Does the idle go up and down.....or is it a misfire......or does it just stop running for a split second .....which is what it sounds like from your description.
This sounds like....many things. All of them electrical.
You need to pull every plug from every fuel system part and check that the connectors in the plugs have no frayed wires, cracked wires....and you need to find an old male pin from a broken injection part....and insert it into each female connector inside the plugs.
You are checking that the female connectors fit onto the male connectors tightly.
We are not talking about checking if a harness plug fits tightly into a part like an injector. That means nothing. The connectors inside must fit tightly.
If you find a fit with loose fit....its worth it to remove all lf them from the plugs one at a time and tighten the rolled edge portions with a small pair of pliers.
Then make sure the connectors and ground to the EFI system power relay are tight and clean. Make sure the ground connections under the intake manifold are tight and clean.
Go through the ignition system. Make sure the copper ground braid on the points plate is clean and not frayed. Check points gap and clean the points and grease the rubbing block. Make sure the points plate rotates when the vacuum advance unit gets vacuum.
Pull the trigger points from the distributor. Check that each side or channel works, clean them and check resistance. Grease the rubbing blocks. Inspect cap and rotor for cracks.
Get a volt meter and do the bend test on each spark plug,wire and check for high resistance, cracks and breaks.
Start here. Ray |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22425
Location: Kimball, Mi
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OB Customs
Samba Member
Joined: January 16, 2011
Posts: 128
Location: Washington
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| Posted: Tue Aug 22, 2017 7:23 pm Post subject: Re: Fuel injection relief here! |
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Thanks Guys,
I should have said I have a new FI harness, and yes it's like it shut off for a split second. under load it seems fine but as you roll up to a light it acts like it wants to dye. I will work throught the point and check all the grounds again. Also I will check vac lines as well.
Spencer |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22425
Location: Kimball, Mi
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| Posted: Wed Aug 23, 2017 4:38 am Post subject: Re: Fuel injection relief here! |
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| OB Customs wrote: |
Thanks Guys,
I should have said I have a new FI harness, and yes it's like it shut off for a split second. under load it seems fine but as you roll up to a light it acts like it wants to dye. I will work throught the point and check all the grounds again. Also I will check vac lines as well.
Spencer |
Also check where the runners meet the head, and where they connect to the plenum (IAD).
But it does sound like your idle is too high, in that the ECU is shutting off the fuel for a brief second (letting the rpms drop), then turning on the injectors until the rpm reaches that point again, where it shuts of fuel. In gear, you probably don't notice it doing that at all, and it's because the engine is under load (from the torque converter).
That's the catch 22 with AT and FI, in that you set the idle speed with the car in gear and the parking brake on, but when it's put in neutral or park the idle speed increases to the point of it cycling on and off (especially if you set the idle too high while in gear). There's a fine line to getting it right, and we're talking about 50 rpm 1 way or the other can make it cycle or not cycle.
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71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
| "Friends are God's way of apologizing for relatives." |
| Tram wrote: |
| People keep confusing "restored" and "restroyed". |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21519
Location: Oklahoma City
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| Posted: Wed Aug 23, 2017 8:01 am Post subject: Re: Fuel injection relief here! |
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| Bobnotch wrote: |
| OB Customs wrote: |
Thanks Guys,
I should have said I have a new FI harness, and yes it's like it shut off for a split second. under load it seems fine but as you roll up to a light it acts like it wants to dye. I will work throught the point and check all the grounds again. Also I will check vac lines as well.
Spencer |
Also check where the runners meet the head, and where they connect to the plenum (IAD).
But it does sound like your idle is too high, in that the ECU is shutting off the fuel for a brief second (letting the rpms drop), then turning on the injectors until the rpm reaches that point again, where it shuts of fuel. In gear, you probably don't notice it doing that at all, and it's because the engine is under load (from the torque converter).
That's the catch 22 with AT and FI, in that you set the idle speed with the car in gear and the parking brake on, but when it's put in neutral or park the idle speed increases to the point of it cycling on and off (especially if you set the idle too high while in gear). There's a fine line to getting it right, and we're talking about 50 rpm 1 way or the other can make it cycle or not cycle. |
Bob is spot on.
Really it should not feel like a dead cut off when the ECU shuts down fuel for high idle. It should be almost imperceptible...just a dropping of rpm....BUT....if you have other issues and your fuel mixture is say...already lean....and the ECU cuts off fueling....since there is less reserve fuel in the ports than there should be....it can feel like a "hard" miss.
The effect Bob pointed to with the automatic transmission and idle...is why VW installed an active vacuum throttle kicker on the 411 and 412 with D-jet and automatic transmission. They put the same kicker on some buses with L-jet.
The type 3 had a spring loaded one that actually worked quite well to lessen throttle closed transition idle drop. A lot of mechanics remove it because they do not know what it is.
It does snot help as much as the one on type 4 because its not keyed to vacuum. Ray |
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Greenfasty
Samba Member
Joined: September 12, 2017
Posts: 1
Location: United kingdom
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| Posted: Tue Sep 12, 2017 12:06 pm Post subject: Re: Fuel injection relief here! |
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| hi have had my 73 automatic fuel injected fastback for 5 years and the engine was starting to get a tired so have rebuilt it but after 4 months of trying am unable to start the thing have new plugs points condenser but still nothing I have good fuel pressure and a strong spark would be very grateful for any help |
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Mike Fisher
Samba Member
Joined: January 30, 2006
Posts: 17970
Location: Eugene, OR
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| Posted: Tue Sep 12, 2017 1:49 pm Post subject: Re: Fuel injection relief here! |
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| Greenfasty wrote: |
| hi have had my 73 automatic fuel injected fastback for 5 years and the engine was starting to get a tired so have rebuilt it but after 4 months of trying am unable to start the thing have new plugs points condenser but still nothing I have good fuel pressure and a strong spark would be very grateful for any help |
Maybe the engine rebuilder installed the distributor drive rod like a Type 1 engine, which is the opposite for a Type 3 engine.
_________________
https://imgur.com/user/FisherSquareback/posts
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold
Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey |
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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 34013
Location: Conejo Valley, CA
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| Posted: Tue Sep 12, 2017 1:50 pm Post subject: Re: Fuel injection relief here! |
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| Mike Fisher wrote: |
| Greenfasty wrote: |
| hi have had my 73 automatic fuel injected fastback for 5 years and the engine was starting to get a tired so have rebuilt it but after 4 months of trying am unable to start the thing have new plugs points condenser but still nothing I have good fuel pressure and a strong spark would be very grateful for any help |
Maybe the engine rebuilder installed the distributor drive rod like a Type 1 engine, which is the opposite for a Type 3 engine. |
Yes, very common, and your spark plug wires will be wrong. Find TDC for 1, and put its wire above the rotor. Then follow around 1-4-3-2. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21519
Location: Oklahoma City
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| Posted: Tue Sep 12, 2017 3:08 pm Post subject: Re: Fuel injection relief here! |
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| And.....along with that....there are MANY things that can keep it from starting. Pictures and tell us what has been done. Ray |
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DE Type 3
Samba Member
Joined: September 14, 2017
Posts: 23
Location: Wilmington, Delaware
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| Posted: Wed Sep 20, 2017 3:33 pm Post subject: Re: Fuel injection relief here! |
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Hi i just started working on my 1973 squareback and trying to get familiar with the car....can some tell what this is? It is at the back of the engine compartment...it has a cable thats not connected to anything....can someone tell what it should be connected to?
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rockerarm
Samba Member
Joined: December 16, 2009
Posts: 3552
Location: Los Angeles
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| Posted: Wed Sep 20, 2017 5:12 pm Post subject: Re: Fuel injection relief here! |
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Hi and WELCOME.
That wire end is part of the old VW Diagnostic Service Program back in the '70's. It attached to cyl #1 and it told relayed this spark signal to the "computer" for ignition timing.
If you refer to the samba technical section and pull up your wiring diagram you will see "T20" which is the multi-plug for this system and all the small orange dots are where the wires terminated and measured a signal for this system.
As far as I know nobody uses any of this for any diagnostics. Many cars still have the majority of the wires still installed in their cars. It is not a "stand alone" system which could be easily removed. Many will tape up wire ends that lead to a 12v positive source.
Hope this helps, Bill. |
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