Anyone had a VDO oil pressure sender fault?

kubicixfactor

Anyone out there had a problem with a VDO OP sender? I have one with a Dakota OP gauge. I have a T with the idiot light connected. I was getting concerned over OP generally and was advised to check the OP sender - put a mechanical one on and when the DD gauge is reading 4 PSI (!) the mechanical one is reading 12PSI. Note that when the DD gauge reads 4 psi the idiot light doesn't come on.....

Note sure whether these senders do go bad, or whether they're affected by temperature? I've checked resistance and my multimeter shows 11 ohms with the engine off, 21 ohms when the DD gauge reads 4 psi.
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1973 LHD Westy 2.0l Type IV, Twin Solex PDSIT, 123 Ignition Vac Distributor, CB2201 Cam

Randy in Maine · Posted: Wed Aug 05, 2009 12:23 pm Post subject:

The VDO di-pole sender sender reads a little bit low usually.

kubicixfactor · Posted: Wed Aug 05, 2009 12:29 pm Post subject:

Hi, is it as much as 6-8 psi? This is a bit random - sometimes the gauge reads 0psi, other times it's 7psi - no faults with the wiring at all.
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1973 LHD Westy 2.0l Type IV, Twin Solex PDSIT, 123 Ignition Vac Distributor, CB2201 Cam

Randy in Maine · Posted: Wed Aug 05, 2009 12:31 pm Post subject:

Do this....

Put a manual gauge on one side of the T and the di-pole sender on the other side and see what you get at about 3500 RPMs.

germansupplyscott · Posted: Wed Aug 05, 2009 2:14 pm Post subject:

are you using a 150psi sender?
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SL

kubicixfactor · Posted: Wed Aug 05, 2009 3:04 pm Post subject:

Yes, it's a 150 psi sender - DD supplied both sender and gauge.........is there a problem with that sender?
_________________
1973 LHD Westy 2.0l Type IV, Twin Solex PDSIT, 123 Ignition Vac Distributor, CB2201 Cam

whip618 · Posted: Wed Aug 05, 2009 4:11 pm Post subject:

I had a problem with my VDO 150psi OP sender from DD, it was reading low compared to a mechanical gauge so I called DD and explained the problem and was told there was no problems that they were aware of with that sender but they sent me a new sender anyway at no charge. The new sender took care of the problem. The original sender was about four years old.

Phil
_________________
Life is simple....either you're qualified or you're not.
USSVI.......Pride Runs Deep
USSVI Life member and Holland Club member

Samba Member No. 3307

kubicixfactor · Posted: Thu Aug 06, 2009 10:14 am Post subject:

Just measured this alongside a mechanical gauge across the rev range - 8 psi low dropping to 10 psi low when idling. I was surprised by the tolerence here as well +- 4psi which is high for such an expensive gauge.
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1973 LHD Westy 2.0l Type IV, Twin Solex PDSIT, 123 Ignition Vac Distributor, CB2201 Cam

Randy in Maine · Posted: Thu Aug 06, 2009 11:02 am Post subject:

Nice gauge, poor sending unit.

kubicixfactor · Posted: Thu Aug 06, 2009 11:09 am Post subject:

agreed - surprised that they associate it with such a poor sender, you'd think that they'd go for something with a little more reliability. VDO can't be the only manufacturer.
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1973 LHD Westy 2.0l Type IV, Twin Solex PDSIT, 123 Ignition Vac Distributor, CB2201 Cam

kubicixfactor · Posted: Thu Aug 06, 2009 11:31 am Post subject:

Here's a reading taken tonight against a mechanical gauge.

Image may have been reduced in size. Click image to view fullscreen.

[/img]
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1973 LHD Westy 2.0l Type IV, Twin Solex PDSIT, 123 Ignition Vac Distributor, CB2201 Cam

whip618 · Posted: Fri Aug 07, 2009 8:53 pm Post subject:

I thought that since I'm going to try and sell my Bay that I might do another OP test just to make sure that the new engine is running fine.

So with the engine fully warmed up and sounding good I tried three different mechanical gauges comparing them to the DD 150 psi sender and gauge.

All three were tested the same way by removing the op sender for the dash light that is hooked to a tee with the DD sender.

At idle the DD gauge was showing 14psi and the each of the gauges confirmed this reading.

At 3500 rpm the DD gauge showed 48 psi while each of the mechanical showed 57. 58 and 59 psi a full 10 psi average difference on the high end. A surprising difference considering the gauge.

Phil
_________________
Life is simple....either you're qualified or you're not.
USSVI.......Pride Runs Deep
USSVI Life member and Holland Club member

Samba Member No. 3307

CatfishCalhoun · Posted: Fri Aug 07, 2009 11:58 pm Post subject:

I just installed the dual pole VDO. One pole marked "WK" the other marked "G". I sent the "WK" to the dash OP warning light and the "G" post to the VDO 80PSI gauge, along with hooking up the + & -, the gauge goes directly to 80+ when I turn the ignition. Ground is good on the sender. Question

Edit:
When the gauge pegs right it is a sign that the sender data is not making the trip. d'oh!

_________________
". . . In beer there is freedom,
in water there is bacteria." -Ben Franklin

whip618 · Posted: Sat Aug 08, 2009 7:55 am Post subject:

My newest VDO sender from DD is a dual pole model, the rep. I spoke to at DD said to connect one pole to the gauge and the other pole to gound and it did not matter which pole went to ground and that is the way I hooked it up and it performs great. The op sender for the dash light comes off of the same tee and still uses the original wire but they operate as two independant systems.

Phil
_________________
Life is simple....either you're qualified or you're not.
USSVI.......Pride Runs Deep
USSVI Life member and Holland Club member

Samba Member No. 3307

kubicixfactor · Posted: Sat Aug 08, 2009 11:44 am Post subject:

Well, here's the solution.

Dakota Digital asked me to measure (with engine running) DC voltage between the sender case and the engine block. My measurement was 0.16 volts. Apparently anything above 0.01v will cause innacuracy with the gauge. Running an earth wire from the sender case directly to the battery ground terminal reduced this to 0.08 - still not low enough. However isolating the sender completely (possible in this case because it is connected to a flexible hose on a T) gave me 0.0v and the gauge now reads correctly.
_________________
1973 LHD Westy 2.0l Type IV, Twin Solex PDSIT, 123 Ignition Vac Distributor, CB2201 Cam

guanella74 · Posted: Sun Jul 10, 2011 7:03 pm Post subject:

This thread is a couple years old, but thought I'd add to it as I've been having trouble with my OP gauge readings.

At oil temp of 195-205, my Stratomaster AND an aux VDO 80psi gauge were approximately reading the following:

2000 rpm, 15psi
3000 prm, 20psi
4000 rpm, 25psi

At idle gauge was showing 6-10psi, and idiot light was on. Talk about freaking out - visions of main bearing replacements were swirling in my head...

I hooked up a mechanical gauge, and voila, the temps showed as they should at various rpms - about 10psi per 1000 rpm. So, since I had already tested the gauge theory, it must be the sender. Just ordered a new one today, however wish I'd have read this post and tinkered with the electrics (maybe isolating the gauge as above?). I'll let you know if the new one gives me problems...
_________________
- Travis

1974 Westy CampMobile - the OG!
1979 Transporter
1979 Transporter
1977 Transporter
1974 Transporter
1973 Transporter
1971 Westy


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