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KTPhil 
Samba Member
Joined: April 06, 2006
Posts: 33986
Location: Conejo Valley, CA
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 Posted: Mon Nov 16, 2020 3:51 pm Post subject: Re: Fuel injection relief here! |
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| knewknew wrote: |
...on another note, I have noticed that when I first start the car, the engine is running on 3 cylinders when I take my foot off the gas and let it idle. When I rev it up, it all four seem to be firing.
Only once the car has warmed up (a few minutes) will it idle on all four. I know this probably isn't normal, but is it to be expected with these old systems? Any idea what the issue could be? |
This was exactly my symptoms of a bad connector at one of the injectors. When cold, it didn't fire the injector. When it warmed up, it made better contact and ran. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Tue Nov 17, 2020 7:28 pm Post subject: Re: Fuel injection relief here! |
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| KTPhil wrote: |
| knewknew wrote: |
...on another note, I have noticed that when I first start the car, the engine is running on 3 cylinders when I take my foot off the gas and let it idle. When I rev it up, it all four seem to be firing.
Only once the car has warmed up (a few minutes) will it idle on all four. I know this probably isn't normal, but is it to be expected with these old systems? Any idea what the issue could be? |
This was exactly my symptoms of a bad connector at one of the injectors. When cold, it didn't fire the injector. When it warmed up, it made better contact and ran. |
Which is exactly ONE of the issue main issues with the original D-jet connectors. With age...when the female connector gets loose at the edges.....heat expansion and vibration cause intermittent issues......which is exactly why I have been working to get away from those to modern connectors for a LONG TIME!
Check this out if you have not already:
https://www.thesamba.com/vw/forum/viewtopic.php?t=745841
Ray |
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KollynnBlackpaw
Samba Member
Joined: October 19, 2016
Posts: 528
Location: Hubbard, Oregon
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| Posted: Tue Nov 17, 2020 7:35 pm Post subject: Re: Fuel injection relief here! |
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Hey y'all! I threw up a question on my build thread and facebook, but almost forgot about this sticky which is perfect!
I got my '71 AT/FI Square back from a friend who rebuilt the motor to 1641, fixed some wiring gremlins, and welded up some holes. He runs like a champ! Sounds fantastic, looks great and I'm so happy to have him back - however I've run into an issue, he won't rev! This is both at the pedal AND the actual throttle on the motor - actuating either changes nothing about how the motor is running, it has both of us completely stumped. His gear lever is also one position off, IE Park is actually Reverse, Reverse is Neutral, etc. I was told that may just be an out-of-adjustment linkage, which I can't get to yet as it was POURING outside today!!!
Some things:
Yes, I checked and both doing it by-hand so I can make sure the throttle is moving, as well as doing it from the pedal of the car, does not do anything for it.
All wires are connected as they seemingly should be, they match the photos I have of when he was last running before we took it apart.
It idles PERFECT, I've tuned the timing and the fuel pressure to be perfect with the help of the neighbor's pressure gauge, he sounds fantastic, he
was surging, however I pulled off the cold start and he stopped it. I remember specifically having this issue when I very first got him, and just pulled it off as it was when he was running last time. At least my buddy hooked it up! 
The reason we rebuilt him was not a non-running motor, it was the electronic points went out and the motor was at 100k original non-rebuilt motors. Otherwise he ran like a champ, but we decided it was time for an overhaul finally.
Thanks y'all!
_________________
'71 Shantung Yellow AT/FI Squareback |
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Wed Nov 18, 2020 1:42 am Post subject: Re: Fuel injection relief here! |
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Tale the air cleaner boot off and make sure the throttle lever is actually moving the butterfly.
Next step would be to see if the advances in the distributor are frozen, but that should at least make it try to rev when you hit the throttle.
_________________
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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KollynnBlackpaw
Samba Member
Joined: October 19, 2016
Posts: 528
Location: Hubbard, Oregon
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| Posted: Wed Nov 18, 2020 6:14 pm Post subject: Re: Fuel injection relief here! |
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| Tram wrote: |
Tale the air cleaner boot off and make sure the throttle lever is actually moving the butterfly.
Next step would be to see if the advances in the distributor are frozen, but that should at least make it try to rev when you hit the throttle. |
Aye, I can definitely see the butterfly moving. Someone on Facebook mentioned the vac line from the auto trans to the motor, which I need to check and see if it's in the right spot.... which is where?
_________________
'71 Shantung Yellow AT/FI Squareback |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22396
Location: Kimball, Mi
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| Posted: Thu Nov 19, 2020 10:28 am Post subject: Re: Fuel injection relief here! |
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| KollynnBlackpaw wrote: |
| Tram wrote: |
Tale the air cleaner boot off and make sure the throttle lever is actually moving the butterfly.
Next step would be to see if the advances in the distributor are frozen, but that should at least make it try to rev when you hit the throttle. |
Aye, I can definitely see the butterfly moving. Someone on Facebook mentioned the vac line from the auto trans to the motor, which I need to check and see if it's in the right spot.... which is where? |
If it has a true FI plenum on it, it'll have a tube off the back of the plenum for a hose to attach to it from the vac modulator on the trans.
Definitely check that the advances in the distributor work. Mechanical should snap back when twisted and released, and vacuum should move the plate when you suck on the hose.
_________________
Bob 65 Notch S with Sunroof
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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KollynnBlackpaw
Samba Member
Joined: October 19, 2016
Posts: 528
Location: Hubbard, Oregon
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| Posted: Thu Nov 19, 2020 3:56 pm Post subject: Re: Fuel injection relief here! |
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| Bobnotch wrote: |
| KollynnBlackpaw wrote: |
| Tram wrote: |
Tale the air cleaner boot off and make sure the throttle lever is actually moving the butterfly.
Next step would be to see if the advances in the distributor are frozen, but that should at least make it try to rev when you hit the throttle. |
Aye, I can definitely see the butterfly moving. Someone on Facebook mentioned the vac line from the auto trans to the motor, which I need to check and see if it's in the right spot.... which is where? |
If it has a true FI plenum on it, it'll have a tube off the back of the plenum for a hose to attach to it from the vac modulator on the trans.
Definitely check that the advances in the distributor work. Mechanical should snap back when twisted and released, and vacuum should move the plate when you suck on the hose. |
Checked both and we're good, however, I noticed the MPS wasn't fully plugged in... Anyone wanna bet that's the issue? The connector cover was over the connector so I hadn't realized it wasn't all the way in. Gotta throw a battery in it today and see how it does.
Edit: Still no revving, but man it starts RIGHT up, barely any cranking! Also, the throttle seems to hit my return spring, which is connected from the air regulator? (thing over the Type 1 Fuel Pump hole) and the accelerator cable barrel nut.
_________________
'71 Shantung Yellow AT/FI Squareback |
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knewknew
Samba Member
Joined: July 06, 2007
Posts: 217
Location: Alexandria, VA
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| Posted: Fri Nov 20, 2020 6:43 am Post subject: Re: Fuel injection relief here! |
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| raygreenwood wrote: |
| KTPhil wrote: |
| knewknew wrote: |
...on another note, I have noticed that when I first start the car, the engine is running on 3 cylinders when I take my foot off the gas and let it idle. When I rev it up, it all four seem to be firing.
Only once the car has warmed up (a few minutes) will it idle on all four. I know this probably isn't normal, but is it to be expected with these old systems? Any idea what the issue could be? |
This was exactly my symptoms of a bad connector at one of the injectors. When cold, it didn't fire the injector. When it warmed up, it made better contact and ran. |
Which is exactly ONE of the issue main issues with the original D-jet connectors. With age...when the female connector gets loose at the edges.....heat expansion and vibration cause intermittent issues......which is exactly why I have been working to get away from those to modern connectors for a LONG TIME!
Check this out if you have not already:
https://www.thesamba.com/vw/forum/viewtopic.php?t=745841
Ray |
Thanks for the info, I was unaware of that thread and those new harnesses. Will definitely look into them!
The guy who makes the harnesses mentions a limited stock on the ECU connectors.
That got me thinking about the ECU itself... has anyone ever attempted to recreate the T3 ECU board?
Perhaps there isn't much of a demand to warrant the effort, but I imagine it can be replicated on a modern PCB with updated components (fairly) easily. There are no 'chips' that I am aware of, just resistors, capacitors, and transistors, no?
...or is there even a need? I haven't read about any of them failing. Only electrolytic caps would go bad in time.
When I see them being sold online as being refurbished, does anyone know what is being done?
_________________
1970 Squareback |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22396
Location: Kimball, Mi
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| Posted: Fri Nov 20, 2020 9:54 am Post subject: Re: Fuel injection relief here! |
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| knewknew wrote: |
| raygreenwood wrote: |
| KTPhil wrote: |
| knewknew wrote: |
...on another note, I have noticed that when I first start the car, the engine is running on 3 cylinders when I take my foot off the gas and let it idle. When I rev it up, it all four seem to be firing.
Only once the car has warmed up (a few minutes) will it idle on all four. I know this probably isn't normal, but is it to be expected with these old systems? Any idea what the issue could be? |
This was exactly my symptoms of a bad connector at one of the injectors. When cold, it didn't fire the injector. When it warmed up, it made better contact and ran. |
Which is exactly ONE of the issue main issues with the original D-jet connectors. With age...when the female connector gets loose at the edges.....heat expansion and vibration cause intermittent issues......which is exactly why I have been working to get away from those to modern connectors for a LONG TIME!
Check this out if you have not already:
https://www.thesamba.com/vw/forum/viewtopic.php?t=745841
Ray |
Thanks for the info, I was unaware of that thread and those new harnesses. Will definitely look into them!
The guy who makes the harnesses mentions a limited stock on the ECU connectors.
That got me thinking about the ECU itself... has anyone ever attempted to recreate the T3 ECU board?
Perhaps there isn't much of a demand to warrant the effort, but I imagine it can be replicated on a modern PCB with updated components (fairly) easily. There are no 'chips' that I am aware of, just resistors, capacitors, and transistors, no?
...or is there even a need? I haven't read about any of them failing. Only electrolytic caps would go bad in time.
When I see them being sold online as being refurbished, does anyone know what is being done? |
The ECU is pretty bulletproof. If you think about it, the newest ones are almost 50 years old (1973 vintage), and are still working. About the only thing that really goes bad in them is the transistor for the fuel pump ground circuit. Jim Adney offers a replacement for these if you want to install one yourself, or will go thru your ECU if you want. There's not really much of a demand for these, as they don't really fail that often. What does kill them though is getting wet inside (caught in a flood for example).
As for the rest of the "hard" parts, places like AutoAtlanta offer parts for the 914 crowd, as does Pelican parts. But you're paying Porsche prices for them (same bits as VW used). I hope this helps.
_________________
Bob 65 Notch S with Sunroof
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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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 33986
Location: Conejo Valley, CA
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| Posted: Fri Nov 20, 2020 9:54 am Post subject: Re: Fuel injection relief here! |
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Bosch and Beru used to refurbish ECUs... probably more due to abuse than failures.
They are close to bulletproof and the analog circuits actually would be hard to duplicate with modern electronics. If you want that, go with Megasquirt or other programmable digital ECUs, and still re-use many of your components and look. |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22396
Location: Kimball, Mi
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| Posted: Fri Nov 20, 2020 9:58 am Post subject: Re: Fuel injection relief here! |
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| KTPhil wrote: |
Bosch and Beru used to refurbish ECUs... probably more due to abuse than failures.
They are close to bulletproof and the analog circuits actually would be hard to duplicate with modern electronics. If you want that, go with Megasquirt or other programmable digital ECUs, and still re-use many of your components and look. |
Yup, a few people are doing just that. Building their own ECU's and using some of the VW parts. Some are even using modern injectors as well.
_________________
Bob 65 Notch S with Sunroof
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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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Fri Nov 20, 2020 2:32 pm Post subject: Re: Fuel injection relief here! |
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It's actually fairly easy to diagnose and repair ECUs by opening them up and using a jeweler's magnifier. You can clearly see where solder has burned away or the PC is interrupted and reflow the solder, repair the PC, or replace a component like a cap or resistor, etc.
I recall one ECU that was smoked so badly that it was irreparable. The others were all solder re- flows. I'll never forget the owner of a Mercedes 280SE 3.5 Cabriolet with D-Jet that was quoted something stupid like $10K by the dealer for an ECU, trigger points, throttle sensor, and MAP.
It didn't need a MAP, the triggers just needed to be cleaned up, the throttle switch was out of adjustment, and the ECU needed solder reflowed in two spots.
I also replaced rubber fuel lines, injector seals, cam oiler nipples, and adjusted the valves, then I sent him home for under $2K happy as a clam. It's still running a decade plus later. You'd think that the solder would do what it does because there's another problem, but that hasn't seemed to be the case. I think it's just simple heat cycles plus vibration that causes oxidation and a break. I say the solder "burns" but that's really a misnomer- probably more like corrodes and gets weak, then fails under electrical load.
_________________
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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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 33986
Location: Conejo Valley, CA
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| Posted: Fri Nov 20, 2020 4:24 pm Post subject: Re: Fuel injection relief here! |
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My junior high school electronics shop teacher, who was as straight and geeky as they come, gave out sound advice in his lecture on soldering: "A tight connection is a necessary prerequisite for a solid joint." He looked clueless as the whole class roared with laughter. It was the 70s, after all.
Solder is a lousy mechanical connector. A loose component will unsolder itself from vibration. |
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galencurrington
Samba Member
Joined: March 16, 2004
Posts: 426
Location: bowling green, ky
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| Posted: Thu Dec 03, 2020 11:41 am Post subject: Re: Fuel injection relief here! |
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| KTPhil wrote: |
My junior high school electronics shop teacher, who was as straight and geeky as they come, gave out sound advice in his lecture on soldering: "A tight connection is a necessary prerequisite for a solid joint." He looked clueless as the whole class roared with laughter. It was the 70s, after all.
Solder is a lousy mechanical connector. A loose component will unsolder itself from vibration. |
That's the funniest thing I have heard in a long time you made my day lol.
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"asking and getting are two different things" |
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tbb
Samba Member
Joined: July 26, 2017
Posts: 84
Location: Van Nuys, CA
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| Posted: Sat Dec 12, 2020 8:32 pm Post subject: Re: Fuel injection relief here! |
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| Does anyone know where I can find a guide to rebuilding an ECU? |
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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 33986
Location: Conejo Valley, CA
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tbb
Samba Member
Joined: July 26, 2017
Posts: 84
Location: Van Nuys, CA
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| Posted: Sun Dec 13, 2020 5:25 pm Post subject: Re: Fuel injection relief here! |
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Thanks KTPhil! I'm looking to get a bit more familiar with the inner workings of the ECU and these resources are perfect.
I'm also hoping to figure out what the problem may be with my current ECU(s)
ECU #1 Fuel Pump does not ground, engine runs and idles well.
ECU #2 Fuel Pump does ground, engine will not run unless the hose to the MPS is disconnected (signaling to the injectors to give maximum load). Runs poorly.
ECU #3 Exact same as ECU #2
How is it the ECU that seems to be in the worst shape allows the car to run the best? Could there be an issue with a component outside of the ECU?
Gonna do a little more digging to see if I can find any issues with the circuits themselves. Any thoughts? |
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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 33986
Location: Conejo Valley, CA
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| Posted: Mon Dec 14, 2020 9:20 am Post subject: Re: Fuel injection relief here! |
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I wonder if someone bypassed the ECU #19 wire when the circuit failed. This is one of the few and rare but known failure points. A PO's "hot-wiring" the pump may explain why it runs with ECU#1.
Bu then that rewiring may foul up running with the good ECU#2 and #3, if the wiring wasn't set back to stock first.
Last edited by KTPhil on Fri Dec 18, 2020 2:47 pm; edited 2 times in total |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Tue Dec 15, 2020 9:26 pm Post subject: Re: Fuel injection relief here! |
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| tbb wrote: |
Thanks KTPhil! I'm looking to get a bit more familiar with the inner workings of the ECU and these resources are perfect.
I'm also hoping to figure out what the problem may be with my current ECU(s)
ECU #1 Fuel Pump does not ground, engine runs and idles well.
ECU #2 Fuel Pump does ground, engine will not run unless the hose to the MPS is disconnected (signaling to the injectors to give maximum load). Runs poorly.
ECU #3 Exact same as ECU #2
How is it the ECU that seems to be in the worst shape allows the car to run the best? Could there be an issue with a component outside of the ECU?
Gonna do a little more digging to see if I can find any issues with the circuits themselves. Any thoughts? |
Yes....95% of the time...faults have nothing to do with the ECU.
Ray |
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tbb
Samba Member
Joined: July 26, 2017
Posts: 84
Location: Van Nuys, CA
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| Posted: Wed Jan 13, 2021 3:39 pm Post subject: Re: Fuel injection relief here! |
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My '68 square ("B" FI system) starts right up when cold and idles smoothly. Maybe 1 or 2 cranks and she gets going. But the warmer the engine gets the worse the idle becomes (oil pressure light flickers in and out) and the rpms move up then down, up then down repeatedly at stoplights. It's not drastic, but definitely noticeable. I opened up the idle screw just a tad and it definitely smoothed out the idle a bit. But I'm not sure I should open it much more as the idle sounds to be a bit high. I suspect the TPS position may be a player in this issue. with the idle screw allowing less air to pass, the idle surges up and down more intensely, but when the plug to the TPS is disconnected, it smooths out.
My first guess was a vacuum leak but all my hoses and connections seem to be in good shape. Is there a better method for testing vacuum leaks?
Also when starting the engine when warm, it takes about twice as long to start (maybe 2-3 seconds of cranking).
Any thoughts? |
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