BBA-Reman Forums



Land-Rover 200 TDi 90 - Fuel gauge puzzle ***FIXED***

Posted By Angus Monday, February 21, 2011 5:59:17 PM
Add to Favorites0
Author Message
Angus
 Posted Monday, February 21, 2011 5:59:17 PM
Forum Master Technician

Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)

Group: Advanced Members
Last Active: Monday, December 29, 2014 2:26:39 PM
Posts: 9,673, Visits: 33,033
Land-Rover 90 Hardtop.  Factory-built 2.5ltr 200TDi.  93-94 vintage [but on an F-plate??]

This thing is driving me nuts and I must be overlooking something - but I can't see what.

This vehicle has just been rebuilt on to a new galvanized chassis.  When the wiring loom was refitted; several things were amiss, including the fuel gauge, that had - apparently - worked normally before.

Fairly simple factory VDO gauge system.  12 volt feed to gauge; wire from gauge to sender; wire from sender to earth.

The gauge reads 3/4 full even with the sender at the bottom of its travel.  Raise the arm even a little and the gauge reads max.  Disconnect the sender and the gauge drops to zero.

Feed voltage at gauge 12.2v.

Resistance of sender [measured at gauge end - wire disconnected]   9.0 ohms tank full - 330.0 ohms empty.

Voltage on sender earth [all connected] 2 millivolts.

A new sender was tried even though I could find nothing wrong with the old one; exactly the same.  I clipped a substitute cable between gauge and sender - exactly the same.

Even though I'd never seen one go faulty; it just had to be the PRC7313 gauge, as everything else checked out.....

Except it wasn't....  Exactly the same.

So what am I missing here?  There's no voltage stabilizer and the similarly-fed ECT gauge reads correctly.

There is - allegedly - a "Low Fuel Warning Light Control Unit" connected to the link between gauge and sender - but that can't have any effect when I've got a direct link wired in.  Although the low fuel light is wired to something; [not the spare terminal on the sender - which is a low tank level switch?] there's no sign of this mysterious unit.

Is it the wrong gauge?  Where is this "Low-fuel Light" device hidden?  Does anyone have the calibration resistance for the gauge?

 

 

.

Thursday, February 24, 2011 5:18:02 PM by Angus
miketribe
 Posted Tuesday, February 22, 2011 3:18:57 AM
Forum Technician

Forum Technician - (845 reputation)Forum Technician - (845 reputation)Forum Technician - (845 reputation)Forum Technician - (845 reputation)Forum Technician - (845 reputation)Forum Technician - (845 reputation)Forum Technician - (845 reputation)Forum Technician - (845 reputation)Forum Technician - (845 reputation)

Group: Awaiting Activation
Last Active: 2 days ago @ 10:49:02 AM
Posts: 562, Visits: 8,735
845
Angus, if you p.m me with your contact details, I will send you the name and contact details of a colleague of mine who is, probably the most knowledgable Land Rover partsman in the country.

I know he will confirm whether the correct parts are fitted or not

regards

Mike

Being in business would be fine, if we didn't need customers.

Angus
 Posted Tuesday, February 22, 2011 12:03:59 PM
Forum Master Technician

Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)

Group: Advanced Members
Last Active: Monday, December 29, 2014 2:26:39 PM
Posts: 9,673, Visits: 33,033
Mike

Thanks for the contact - nice guy.  I've spoken to him and he's confirmed that there is only the one gauge fitted on these.

He's baffled too - but there has to be some sort of answer?

Anyone got a factory wiring diagram - could there be an in-line resistor twixt gauge and tank-unit?  Nothing shown on the Haynes; but....

.

Mad-Eric
 Posted Tuesday, February 22, 2011 1:20:17 PM
Forum Technician

Forum Technician - (573 reputation)Forum Technician - (573 reputation)Forum Technician - (573 reputation)Forum Technician - (573 reputation)Forum Technician - (573 reputation)Forum Technician - (573 reputation)Forum Technician - (573 reputation)Forum Technician - (573 reputation)Forum Technician - (573 reputation)

Group: Advanced Members
Last Active: Monday, December 02, 2019 5:16:56 AM
Posts: 477, Visits: 9,912
573
Angus,

 I will try to get on the Landrover site tomorrow, can you PM me the chassis number less the last 4 and any other info that may be relevant.

Cheers

Mad-Eric

Tuesday, February 22, 2011 1:20:59 PM by Mad-Eric
wor-mate
 Posted Tuesday, February 22, 2011 1:36:42 PM
Forum Technician

Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)

Group: Forum Members
Last Active: Saturday, November 30, 2019 10:24:20 AM
Posts: 753, Visits: 2,665
827
i have a rave disc but its for a 300tdi, think it will be similar.

it shows the gauge to be fed from a ign switched green that also feeds the temp g , both gauges are earthed as well as a 2nd earth for the panel illum,  two red and whites feed the panel bulbs, finaly a single wire the goes to the senders dark green /black fuel g, light green temp g.

 no sender earths are shown so i assume that a earth goes from sender to tank then tank to chassis and chass to bat neg. 

no low fuel warning is shown at all but would think it goes live to light thats earthed by terminal on sender when float arms low.

Angus
 Posted Tuesday, February 22, 2011 2:07:37 PM
Forum Master Technician

Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)

Group: Advanced Members
Last Active: Monday, December 29, 2014 2:26:39 PM
Posts: 9,673, Visits: 33,033
Eric

Thanks; but this is an e-bay special of very dubious provenance.  The chassis number on the V5 and the rivetted-on VIN plate relates to a 2.5 petrol of '89 vintage; so won't be much help...

If they can ID a diagram for a 93-94 build 200 TDi 90" that would be magic - I'm reliably informed that the same fuel-gauge system was used from '83 until '98.

w-m

Thanks; the set-up is exactly as you describe.

Twin green feeds to the gauges; green/black to the tank sender.  The sender has an earth wire that runs all the way back to the bulkhead earth point by the fuel filter.

The low-fuel light gizmo's sensing wire is tapped into the green/black - but I have direct-wired the gauge to sender to eliminate any effects from that - wherever it is.

No resistor shown in the green/black wire then?

.

wor-mate
 Posted Tuesday, February 22, 2011 2:33:41 PM
Forum Technician

Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)Forum Technician - (827 reputation)

Group: Forum Members
Last Active: Saturday, November 30, 2019 10:24:20 AM
Posts: 753, Visits: 2,665
827
no sign of anything in the green/black

i am puzzled with the earths on the gauges, the wires have a 1amp marking next to them,it ends where they meet a header, i assume it means a light duty cable is used.

have you tried a earth from fuel filter to bat neg

Angus
 Posted Tuesday, February 22, 2011 3:20:22 PM
Forum Master Technician

Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)

Group: Advanced Members
Last Active: Monday, December 29, 2014 2:26:39 PM
Posts: 9,673, Visits: 33,033
w-m

Now THAT is very interesting.  The gauge earth is a ring terminal on a 0.7mm 6 amp cable - so there must be something particular about that earth's rating.  I hadn't given it much thought as the illumination works fine.

Thanks; that gives me something to investigate when I go back to it on Thursday.  I can run a direct earth to batt neg and see what happens.

.

Dcspringlane
 Posted Tuesday, February 22, 2011 3:27:37 PM
Forum Technician

Forum Technician - (862 reputation)Forum Technician - (862 reputation)Forum Technician - (862 reputation)Forum Technician - (862 reputation)Forum Technician - (862 reputation)Forum Technician - (862 reputation)Forum Technician - (862 reputation)Forum Technician - (862 reputation)Forum Technician - (862 reputation)

Group: Forum Members
Last Active: Thursday, October 20, 2016 11:10:41 AM
Posts: 789, Visits: 11,202
862
Wern,t these early ones fed by a voltage stabilizer on back of clocks stabilizing voltage to guage at 10 volts
Angus
 Posted Tuesday, February 22, 2011 4:29:19 PM
Forum Master Technician

Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)Forum Master Technician - (10,638 reputation)

Group: Advanced Members
Last Active: Monday, December 29, 2014 2:26:39 PM
Posts: 9,673, Visits: 33,033
DCS

Yes; the Series IIIs were indeed - but these gauges have direct 12v [NBV] feeds.

.


Reading This Topic

Expand / Collapse

Back To Top