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udidwht
Samba Member
Joined: March 06, 2005
Posts: 3779
Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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 Posted: Fri Apr 11, 2014 10:47 pm Post subject: |
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| Wildthings wrote: |
| grailtown wrote: |
| asiab3 wrote: |
| rory66 wrote: |
-1600 engines work hard, make heap big heat.
pause at the top of big grades to cool a bit. |
Cresting a hill and driving down the backside will cool the engine much faster than letting it idle.
Drive on Ben, you're doing it  |
Completely agree, just finished round trip from Colorado to San Diego..many many long steep grades; packed all my road tools, never opened my tool box, never 'paused' at hill crests....keep the air moving...cooling...  |
I will often downshift a minute or so before I reach the top of a grade so my heads will have cooled a bit before it starts down the backside. If anything you want to avoid the thermal shock of having a hot engine begin to cool too rapidly when you let off on the throttle. In over 40 years of driving VW's, I have never once stopped to let an engine cool. |
I believe Colin had shown on more than 1 occasion that downshifting to 3rd gear on a grade compared to not downshifting made no difference whatsoever in CHT's. Perhaps he'll ring in on this and reconfirm his findings.
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airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12721
Location: on a bike ride somewhere
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| Posted: Fri Apr 11, 2014 11:12 pm Post subject: |
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| udidwht wrote: |
| Wildthings wrote: |
| grailtown wrote: |
| asiab3 wrote: |
| rory66 wrote: |
-1600 engines work hard, make heap big heat.
pause at the top of big grades to cool a bit. |
Cresting a hill and driving down the backside will cool the engine much faster than letting it idle.
Drive on Ben, you're doing it |
Completely agree, just finished round trip from Colorado to San Diego..many many long steep grades; packed all my road tools, never opened my tool box, never 'paused' at hill crests....keep the air moving...cooling... |
I will often downshift a minute or so before I reach the top of a grade so my heads will have cooled a bit before it starts down the backside. If anything you want to avoid the thermal shock of having a hot engine begin to cool too rapidly when you let off on the throttle. In over 40 years of driving VW's, I have never once stopped to let an engine cool. |
I believe Colin had shown on more than 1 occasion that downshifting to 3rd gear on a grade compared to not downshifting made no difference whatsoever in CHT's. Perhaps he'll ring in on this and reconfirm his findings. |
I think that was in his late FI bus with full-throttle-enrichment. The 2.0 engines are powerful enough to kill themselves so the engineers gave them a rich tendency at full throttle. The (stock) early buses are so limited in power that they run out of steam before they run out of cooling.
On my T1, the grade combined with throttle and speed all play in. Since it's stock and happy, I can floor it up any hill and the engine will give up before heat becomes an issue. When the speed drops below the torque peak of the current gear is when the heat starts to come. Around 45-50mph is 4th gear torque peak for an early bay, so let's use that.
I started the Indio grade last week at 68mph, and it's 10 miles pedal to the floor. CHTs were 355 when I started, and 403 when I crested the top at 50mph. Oil pressure was a solid 10psi/thousand rpm. Speed dropped pretty early on in the climb, and temps plateaued with the speed. When the bus dropped to 50mph the temp stayed around 390-395. The last bit was the steepest, and 45mph (torque peak) saw 403. Then it was flat for the next 200 miles, and temps got back to the 350 than they cruise at within a mile.
Now the week before, I climbed the grapevine full of camping gear and friends. Again I approached at the factory maximum speed, and as speed dropped I laid it on the floor and didn't let up. Same exact temps at same speeds, except this time the hill became much steeper. As soon as 4th gear floored dropped me under 45-50, the temps rose at a much higher rate than before. 395 was the maximum until the speed dropped below 45, and then it was instantly 405. I kept my foot in it to observe temps, and saw 410 and 415 almost immediately- Way higher than I've ever seen keeping the engine above the torque peak. I downshifted to third, and INSTANTLY saw a 15* drop in temps as I did 38-40mph. As I neared the HP Peak in third (about 45) up the grade, temps continued to drop, and they settled around 375.
Point is, at or above the torque peak makes a tiny difference for me. If at any time you drop below, downshift or go shopping for head work. These are the two hardest hills in Southern California, so I feel like they're good examples; ambients were 80-85f for both, no wind.
I'll be doing both of these this summer in 110* heat, and I'll post that too.
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HastaAlaska
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Joined: November 22, 2012
Posts: 1420
Location: Off Grid
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| Posted: Tue Apr 15, 2014 10:56 am Post subject: |
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Hey I am heading into towards the Mountains between Caribbean Mexico and Pacific Mexico.
I have the problem where the bus just dies on the highway again, stops for 5 minutes then goes again for a few miles then stops.
I checked that there is spark getting to the plug (but not the plugs themselves) and I checked that enough gas is getting to the injectors (but not the injectors themselves)
No idea what is wrong, anyone have a clue? It just wont start for like 5 minutes.
Seems to be heat related, happens more in the heat of the day. Mexico long hot roads, what is the cause?
H E L P?
Thanks guys
Ben
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Wildthings
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Joined: March 13, 2005
Posts: 50337
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| Posted: Tue Apr 15, 2014 12:55 pm Post subject: |
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How hot is the fuel in your tank getting to be when this happens? Maybe try adding a 1.5 ohm power resister (like an old fashion ignition ballast resister) in the power feed to your pump and see if you can slow it down. Less fuel flow should equal less heat building up in the fuel. This worked with early Vanagons to quite up their pumps and they still made sufficient volume to run the engine.
Are you sure your fuel tank is well vented, though I seem to remember it didn't make any difference when you removed the gas cap. |
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Busdriver79
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Joined: July 22, 2011
Posts: 1655
Location: The Peoples' Republic of "No" Jersey
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| Posted: Tue Apr 15, 2014 1:16 pm Post subject: |
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| I had the no start problem when hot caused by the electronic module inside the distributor failing with excessive heat buildup...let it cool down and it ran like new...run it hard and it would shut off the engine...solution ??..replaced the bad ignition module with a new unit...problem solved...now I do not know whether you have a points dizzy or an electronic unit, but I thought I would throw this out there anyway. |
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HastaAlaska
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Joined: November 22, 2012
Posts: 1420
Location: Off Grid
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| Posted: Wed Apr 16, 2014 7:25 am Post subject: |
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| Wildthings wrote: |
How hot is the fuel in your tank getting to be when this happens? Maybe try adding a 1.5 ohm power resister (like an old fashion ignition ballast resister) in the power feed to your pump and see if you can slow it down. Less fuel flow should equal less heat building up in the fuel. This worked with early Vanagons to quite up their pumps and they still made sufficient volume to run the engine.
Are you sure your fuel tank is well vented, though I seem to remember it didn't make any difference when you removed the gas cap. |
Yeah you are right it doesn't make a difference when I take off the cap. Yesterday I drove all day without seeing the problem 
I need to confirm that it is a starvation problem. Previously the problem was 100% vapor lock (i.e starvation) but since I moved the pump that shouldn't be happening any more. Also when the bus cuts out I am seeing decent fuel delivery quantity at the injector rail and also a spark to the plugs.
I wonder if it could be an electrical fault (the ignition wire next to the key) has been getting pretty hot....
| Busdriver79 wrote: |
| I had the no start problem when hot caused by the electronic module inside the distributor failing with excessive heat buildup...let it cool down and it ran like new...run it hard and it would shut off the engine...solution ??..replaced the bad ignition module with a new unit...problem solved... |
What ignition module did you replace?
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Busdriver79
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Joined: July 22, 2011
Posts: 1655
Location: The Peoples' Republic of "No" Jersey
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| Posted: Wed Apr 16, 2014 11:23 am Post subject: |
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| I have a 1979 Bus w/California spec engine...factory installed electronic dizzy...swapped out the firewall remote mounted module. |
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Danwvw
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Joined: July 31, 2012
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Location: Oregon Coast
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hopkin 
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Joined: June 25, 2012
Posts: 2480
Location: Ottawa, Ontario
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| Posted: Wed Apr 16, 2014 1:22 pm Post subject: |
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Maybe the Air intake, here's some text from a document found on www.1600i.de (just a guess ):
Adjusting the Throttle Butterfly Valve:-
The idle speed adjustment screw is normally preset at the factory and should never be changed unless it really is necessary. If however the screw has either been accidentally adjusted or has come loose then the air intake unit must be adjusted correctly.
Fig.1 Air Intake Unit viewed from its left-hand side.
Key to fig. 1:-
1 = Accelerator Lever End-stop
2 = Idle Speed Adjustment Screw
5 = Accelerator Cable Clamp Bolt
6 = Accelerator Cable
To adjust the throttle butterfly valve correctly, unscrew the idle speed adjustment screw until you can just about see a gap between the accelerator lever end-stop (1) and the idle speed adjustment screw (2).
Now check the gap with a thin piece of paper, it should just about fit into that gap. Now turn the adjustment screw ½ turn clockwise (inwards). The accelerator lever should now be correctly adjusted.
Now check to see if the throttle butterfly valve (shown in fig. 2) is completely closed.
Fig. 2 Air Intake Unit viewed from above
Key to fig. 2:-
1 = Accelerator Lever End-stop
2 = Idle Speed Adjustment Screw
7 = Throttle Butterfly Valve
8 = Air Intake Temperature Sensor
9 = Accelerator Potentiometer
The value of the accelerator potentiometer must now be checked. This can be checked by using any of the following diagnostic tools:-
- VAG 1551/1552
- VAS 5051/5052/5053
- or VAG-COM + PC interface cable
To do this enter the following commands (in this case using a VAG 1552):-
01 – Engine Electronics (followed by the Q key)
08 – Read Measuring Block (followed by the Q key)
002 – Measuring Block 2 (followed by the Q key)
You should now look at the angle of the potentiometer (shown in the second column). It must read 0.00% when the throttle is fully closed (eg. at idle). This value should then increase as the throttle is gradually opened.
This adjustment procedure is particularly important. The following symptoms will be present if it is not adjusted correctly:-
Symptom Cause
Increased fuel consumption, erratic idling, Accelerator end-stop screw
ECU does not recognise the idle position turned in too far !!
Engine cuts out or splutters on acceleration Accelerator end-stop screw
from idle speed. turned out too far !!
After you have adjusted the idle speed adjustment screw correctly, you should now use locktite or paint to prevent the thread from becoming loose.
The accelerator cable adjustment should now be checked which will require two people. You will need to watch the accelerator cam (shown in fig. 3) whilst your assistant sits inside the car and pushes the accelerator pedal down fully.
The gap between the accelerator cam (3) and it’s full throttle end-stop (4) should be between 2mm to 3mm when the accelerator pedal is pushed down fully.
If this gap is incorrect, then it should be adjusted. Release the accelerator pedal and carry out the accelerator cable adjustment.
Fig.3 Adjustment at full throttle
Key to fig. 3:-
3 = Accelerator Cam
4 = Full Throttle End-Stop
The accelerator cable can be adjusted by undoing the 8mm bolt on the accelerator lever. You should now be able to move the accelerator cable to tighten it up. Pull it outwards to decrease the gap between the accelerator cam and the air intake’s full throttle end-stop and do the opposite to increase that gap.
Once the accelerator cable has been adjusted, tighten up the 8mm bolt on the accelerator lever and repeat this adjustment procedure if necessary.
After you have adjusted the air intake unit correctly, the basic setting procedure must now be carried out. To do this make sure that the following conditions are satisfied:-
- No faults reported by the ECU
- Engine oil temperature at least 80°C
To carry out the basic setting procedure do the following (in this case with a VAG 1551/2):-
01 – Engine Electronics (followed by the Q key)
04 – Initiate Basic Setting (followed by the Q key)
001 – Block 1 (followed by the Q key)
Now wait for about 60 seconds for the ECU to learn the current setup (eg. throttle potentiometer position) and press the C or the -> key to exit the basic setting mode.
The car should now run properly. |
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HastaAlaska
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Joined: November 22, 2012
Posts: 1420
Location: Off Grid
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| Posted: Sun Apr 20, 2014 1:05 pm Post subject: |
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Thanks guys,
Yeah the problem is getting worse. I had to do a lot of pushing yesterday in the Mexican mountains - damn!
Seems to only happen once I've been going for a while, and now it's taking much longer to start working again after it stutters to a stall.
I confirmed that no gas (only air) was arriving at the injectors. The pump sounded like it was spinning free (i.e not pushing gas).
I disconnected the intake line from the tank to the pump (after the filter) and the gas rushed through immediately...I also heard a gurgling in the tank 
Once I reconnected the fuel line the engine started up straight away.
I will still change the filter because it sounds like it is about time anyways, but what do you make of this vacuum lock? The pump is directly below the gas tank. Removing the gas tank lid didn't seem to help the problem so what is going on?
...I also posted this question over in the vanagon forum in case it was a computer fault or something they might know about, but it seems to be simple physics? I say simple, but....
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avus
Samba Member
Joined: November 11, 2005
Posts: 268
Location: Drain, Oregon
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| Posted: Sun Apr 20, 2014 1:15 pm Post subject: |
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| HastaAlaska wrote: |
Thanks guys,
Yeah the problem is getting worse. I had to do a lot of pushing yesterday in the Mexican mountains - damn!
Seems to only happen once I've been going for a while, and now it's taking much longer to start working again after it stutters to a stall.
I confirmed that no gas (only air) was arriving at the injectors. The pump sounded like it was spinning free (i.e not pushing gas).
I disconnected the intake line from the tank to the pump (after the filter) and the gas rushed through immediately...I also heard a gurgling in the tank
Once I reconnected the fuel line the engine started up straight away.
I will still change the filter because it sounds like it is about time anyways, but what do you make of this vacuum lock? The pump is directly below the gas tank. Removing the gas tank lid didn't seem to help the problem so what is going on?
...I also posted this question over in the vanagon forum in case it was a computer fault or something they might know about, but it seems to be simple physics? I say simple, but.... |
I've had floating debris in the tank become sucked down and plug the outlet when fuel is flowing, then float away when flow stops. Might try gravity flowing fuel into a large container, and see if flow slows or stops after a while. Removing the tank for cleaning would be the only remedy I can think of at the moment.  |
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Wildthings
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Joined: March 13, 2005
Posts: 50337
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| Posted: Sun Apr 20, 2014 1:45 pm Post subject: |
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Maybe your pump has some kind of inlet screen that has gotten clogged, many pumps do. Remove the pump so you can get a good look at the inlet and see if there is anything in there. Is there a way to disassemble the pump and check for restrictions inside?
Maybe a new pump would be in order, or maybe you could get someone to loan you one off of their car for a test.
I know your pump has several additional connections besides just an inlet and an outlet. What do the others connect to? |
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HastaAlaska
Samba Member
Joined: November 22, 2012
Posts: 1420
Location: Off Grid
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| Posted: Sun Apr 20, 2014 4:07 pm Post subject: |
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| Wildthings wrote: |
| I know your pump has several additional connections besides just an inlet and an outlet. What do the others connect to? |
well there is
inlet from tank
breather to some pipe that looks like it connects to the tank fill neck
output to injectors
return from fuel pressure regulator
I would really like to not take the tank out, damn man!
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busdaddy
Samba Member
Joined: February 12, 2004
Posts: 51125
Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Sun Apr 20, 2014 4:35 pm Post subject: |
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And we already discussed the gas cap and it's venting, didn't we?
Didn't you have a hose Tee'd into te filler neck somehow?, I wonder if we can use that as a return line and run the pump as a constant flow/recirculating system?
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avus
Samba Member
Joined: November 11, 2005
Posts: 268
Location: Drain, Oregon
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| Posted: Sun Apr 20, 2014 6:26 pm Post subject: |
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| HastaAlaska wrote: |
| Wildthings wrote: |
| I know your pump has several additional connections besides just an inlet and an outlet. What do the others connect to? |
well there is
inlet from tank
breather to some pipe that looks like it connects to the tank fill neck
output to injectors
return from fuel pressure regulator
I would really like to not take the tank out, damn man! |
After thinking some more, I believe that the fact that you heard gurgling as the gas (gravity) flowed out of the tank after the starvation event indicates that air flowing UP INTO the tank through the fuel line is what cleared the blockage. I'm betting on a restriction in the tank outlet is the problem.
Here's a thought: Drain the tank into a container through the outlet. Remove the filler cap and apply air pressure (as much, as quickly as possible) back into the tank through the outlet. This may clear the screen, if partially clogged, or blast any friable debris into particles small enough to pass through the screen into the filter. Beetle fuel tank outlet screens are removable from outside, I'm ignorant about bus tanks. |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50337
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| Posted: Sun Apr 20, 2014 7:52 pm Post subject: |
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| HastaAlaska wrote: |
| Wildthings wrote: |
| I know your pump has several additional connections besides just an inlet and an outlet. What do the others connect to? |
well there is
inlet from tank
breather to some pipe that looks like it connects to the tank fill neck
output to injectors
return from fuel pressure regulator
I would really like to not take the tank out, damn man! |
Okay I am going to take a guess here. It sounds like your fuel return does not circulate the fuel through the tank like a late FI bus does. This means that the fuel in the rail is getting hotter and hotter as it is recirculated. You need a way to either keep the fuel from getting too hot or to somehow cool it down. I think it is worth a try to put an 1.5 - 2.0 ohm resister in line with the power supply to the pump to see if that will slow the pump enough to make a difference.
You could also try running the fuel return through some form of a cooler.
.
. |
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Danwvw
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Joined: July 31, 2012
Posts: 8892
Location: Oregon Coast
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| Posted: Sun Apr 20, 2014 8:48 pm Post subject: |
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If it is vapor lock again then throwing some Ice Water on the rails or lines from the fuel pump or both or even the fuel pump if it is too hot will Instantly let you start it up again.
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HastaAlaska
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Joined: November 22, 2012
Posts: 1420
Location: Off Grid
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| Posted: Tue Apr 22, 2014 9:53 am Post subject: |
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| avus wrote: |
After thinking some more, I believe that the fact that you heard gurgling as the gas (gravity) flowed out of the tank after the starvation event indicates that air flowing UP INTO the tank through the fuel line is what cleared the blockage. I'm betting on a restriction in the tank outlet is the problem.
Here's a thought: Drain the tank into a container through the outlet. Remove the filler cap and apply air pressure (as much, as quickly as possible) back into the tank through the outlet. This may clear the screen, if partially clogged, or blast any friable debris into particles small enough to pass through the screen into the filter. Beetle fuel tank outlet screens are removable from outside, I'm ignorant about bus tanks. |
Hmm I like this thinking, I did drain the tank completely around Christmas time. I noticed there there is NO SCREEN over the exit pipe from the tank. i.e behind the screen it was just open to the tank.
I tried to buy one here in San Cristobal but they didn't sell it. Home made job?
Thanks guys keep the ideas coming please. I'll be changing the fuel filter today.
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HastaAlaska
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Joined: November 22, 2012
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Location: Off Grid
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| Posted: Wed Apr 23, 2014 8:45 pm Post subject: |
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Tried new gas filter and got a few hundred miles down the road, but today it crapped out again. Backfired twice then spluttered to a halt! 20 mins before it would start again...
Still thinking gas tank? I tested for spark at todays breakdown and it was good, also there seemed to be fuel as I purged the injector rail. Without the gauge to measure the psi I can't tell if it is producing the required 35psi.
To me this only happens when I have been on the road for some time... and when it last happened the engine was HOT!
The gas sure does seem hot in the injector rail, but I am not sure if there is a vapor lock or if the injectors aren't firing due to a relay problem or something.
Any ideas?
Ben
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77VWBusDude
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Joined: April 09, 2008
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Location: Seattle
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| Posted: Thu Apr 24, 2014 4:15 am Post subject: |
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I would get a pressure gauge on there. That's how I figured out I had a clogged tank. I even put a long enough hose on it so I could monitor it while I was driving lol.
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