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Landsverk
Samba Member
Joined: March 23, 2015
Posts: 10
Location: Sweden
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 Posted: Thu May 14, 2015 6:59 am Post subject: MV engine will not start |
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I have a MV engine that is transplanted in a new vehicle and it will not start. Absolutely nothing happens when cranking the engine. So I have started to search for faults bot no success so far. I have tried to sum up what has been done so far. Hopefully someone can make something out of it that leads to a solution.
When turning the ignition on I can hear the fuel pump relay switch and the pump buzz for a couple of second. That’s correct as I understand it; the engine must crank to allow the pump to continue.
There is voltage from the ignition (15) to the relays and the power relay has voltage at 87.
When cranking the engine no power is going out from the relay to the fuel pump. No ground from the ECU or no voltage from the idle stable control?
I switched the ignition on/off some times until fuel came to the breather in the T-junction. So the pump is functional as I see it.
Connecting the fuel pump direct to the battery voltage makes the idle stabilizing valve vibrating.
Checking for spark was a disappointment. Nothing to be found. I made sure the distributer and cables were correct mounted.
I then put a steel wire in the middle terminal in the hall sensor connector on the distributor and touched it against ground. A proper nice spark appeared between the cable from the ignition coil and ground. The coil should be OK.
There is voltage between the two outer terminals at the hall sensor connector. When cranking the engine there is a pulsating voltage at the middle terminal. He hall sensor should be OK.
I started to check the input for the ECU.
1. No voltage. I have not connected anything to the solenoid at the starter. Which cable/terminal is that? Must go through the schematic.
2. The pump runs when bridging. OK
3. Voltage at 14 but not 13.
Two wires I did not find anything to connect with. Behind the alternator.
Another wire that puzzle me. Red and black.
1. Starts at the idle stabilizer
2. Enters the fuse box
3. Leaving the fuse box
4. Merge with another wire and leaves the connector
5. Enters the coupling box
6. Leaves the coupling box in the harness that goes to the dashboard in the front of the vehicle.
How should it be connected there? 30, fuel enrichmnet when starting?
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61Scout
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Joined: November 06, 2011
Posts: 1297
Location: Shoreline/Yakima WA
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MarkWard
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Joined: February 09, 2005
Posts: 17154
Location: Retired South Florida
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| Posted: Thu May 14, 2015 1:17 pm Post subject: |
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Wow, your post should get an award. Anyhow in this chart.
Step 3 I am pretty sure you are checking for voltage and ground by metering between 13 and 14.
Step 1 also suggests you meter between 1 and 13. I don't have the diagrams, but since 13 is in all three steps, that is probably the ground.
I am not sure if this test is valid on the 2.1, but with the key in the run position you should be able with a 12 volt test light grounded operate the coil by tapping the outer pin, then the middle pin and then the opposite outer pin of the distributor harness with the testlight harness unplugged. If the coil fires with this test, I would be suspect of the Hall effect or the wiring of the hall. If you look closely inside, I have seen the shutter wheel accidentally damage the wire in the case. Excellent documentation.
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Landsverk
Samba Member
Joined: March 23, 2015
Posts: 10
Location: Sweden
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| Posted: Tue May 19, 2015 3:52 am Post subject: |
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I have now done some more testing on the connector to the ECU.
Terminal 13 seems to be ground when tested to battery power. Ignition on.
No voltage between 1 and 13. Ignition on. Cranking engine.
Voltage between 13 and 14. Ignition on.
Checking voltage at the connector for the third cylinders injector. No voltage when cranking engine.
I see that I have one yellow connector with nothing connected in the connection box. Black cable. A component missing signal for ignition on? Must be investigated.
To answer my own question; the red/black cable at the idle stabilization control unit must be for terminal 50. At the ignition switch or starter.
The fuel pump does not work when cranking engine. I thought it should be signal from the Hall sensor that the engine is cranking. Perhaps it is from this cable connected to terminal 50? Not only fuel enrichment for the for starting. Will be tested next.
Still not explaining no spark or signal to the injectors, or….
Workshop booked on Thursday if no success before! If they can do something nowadays for this old equipment? |
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djkeev
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Joined: September 30, 2007
Posts: 32625
Location: Reading Pennsylvania
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proofpudding
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Joined: March 02, 2012
Posts: 83
Location: Nanoose Bay, BC
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| Posted: Tue May 19, 2015 11:51 am Post subject: |
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Pretty sure your two mystery wires go to the back of the power steering pump.
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1988 Vanagon GL Wolfsburg |
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djkeev
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Joined: September 30, 2007
Posts: 32625
Location: Reading Pennsylvania
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Landsverk
Samba Member
Joined: March 23, 2015
Posts: 10
Location: Sweden
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| Posted: Wed May 20, 2015 1:42 am Post subject: |
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Yes of course, it must be the two cables to the steering pump. I don’t have a pump so I can leave them out I assume.
I connected the red/black cable to the starter (terminal 50) but that did not help at all.
The black cable in the connection box was in fact black/blue which must be for the backup light. Can be left out in my case.
At least I now have all the cables identified and connected as it should now, I think……..
It can be an easy fault sometimes but yes the distributor is rotating. At least when I timed it to the correct position with cylinder one in top. I assume it rotates with the cap on also.
I will buy two diodes today. |
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MarkWard
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Joined: February 09, 2005
Posts: 17154
Location: Retired South Florida
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| Posted: Wed May 20, 2015 1:57 pm Post subject: |
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Do you have a wire on the wrong spade connecter on the starter solenoid? One spade gets power when cranking from the ignition switch. The other spade has power when the solenoid is engaged. At a glance you can't tell the difference. Not all starters have the same spade configuration. Worth a look.
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Landsverk
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Joined: March 23, 2015
Posts: 10
Location: Sweden
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| Posted: Fri May 22, 2015 1:21 am Post subject: |
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The diagnosis cabling is done and tried. The fuel pump works constant as it should. No engine start. I get an impression of the smell of gasoline from the exhaust. I suspect no spark since nothing more happens.
Not able to check the connection at the solenoid now, the vehicle is at the workshop. |
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61Scout
Samba Member
Joined: November 06, 2011
Posts: 1297
Location: Shoreline/Yakima WA
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| Posted: Fri May 22, 2015 12:54 pm Post subject: |
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What's the story behind the engine? Was it running before? Is this a rebuild? Could the problem be a static/mechanical issue? Valve issue?
And the vehicle... Was there a running engine in it prior to this work? In other words... is the harness known to be good? Are the ECU and MAF known good parts?
OP, you verified that fuel is coming out at the tee-fitting, but what was the pressure?
If you're satisfied the individual components work and the wiring is good, and that you have fuel and compression, I might try swapping in a known good ECU and/or entire distributor (one at a time). Also recheck the simple stuff... all the grounds and connections. Speaking of which, be careful jamming in wires for testing. Those connections can be delicate, and being too rough or forcing a paper clip or other type wire into them can spread that connection apart... now you've just created a loose or bad connection because of your testing.
-Kevin
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1986 Westfalia Weekender Wolfsburg, RJE 2.3
1985 Tin Top, Subie 2.2 + 5MT
Floppy Mirrors no more: http://www.thesamba.com/vw/forum/viewtopic.php?t=653018&highlight=
Remove the front spindle nut with ease: https://www.thesamba.com/vw/forum/viewtopic.php?t=679567&highlight=
Remove the rear wheel bearing housing without messing with the big 46mm nut: https://www.thesamba.com/vw/forum/viewtopic.php?t=679507&highlight=
-Nec Spe, Nec Metu |
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Landsverk
Samba Member
Joined: March 23, 2015
Posts: 10
Location: Sweden
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| Posted: Sun Sep 06, 2015 7:03 am Post subject: |
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Finally there is some result. It really took some time both waiting for ordered material and the workshop had holiday in the middle of my project!
First the workshop made the same conclusions that I had but there was a problem with the hall sensor now. It was not functional. A new distributor was bought from the scrap yard but it did not last long and the engine did not start. Then I ordered from a firm abroad specializing at VW-busses. It was stated in their web shop; “it fits all petrol VW T25s from 1979 to 1992” . Even so it did not fit. They sent another one which they double checked to be for a 2,1 liter MV engine. It was the same as the first one. They have promised me a refund. Hope it works out good. It wasted a lot of time though. Amazing that after the communication between us they have not changed their statement on the web site for which vehicles their hall sensors fit! Some problem with their quality work.
The MV-hall sensor has the attachment screws straight down, not from the side.
Now the work shop was hiring an electrical guru and after some wait he turned up and after a short while found out that there was one cable not correct connected. After disconnecting this one and another distributor from the scrap yard the hall sensor worked and gave signal! So bloody easy!
I bought the engine and cabling already dismounted. An easy job to connect all connectors marked with same colours , some different shape and located appropriate when mounting engine and harness. Also this two connectors; male and female, with wire length to reach each other, both yellow and with green wires on both sides. But they shall apparently not be connected!
Now there was so fuel to the injectors! It was before and luckily it was soon found out that a cable to the fuel pump had broke right where it came out of the harness. It must have been due to all the bending while searching for the fault.
So now the bus is back in the garage and there is a lot of other stuff to do before it is finished but the engines runs and sound good. |
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