Classic Audi Technical Mech/Tech Engine » Ur quattro will not turn over with key

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Old 01-01-18, 05:33 PM   #1
Colin Aitchison
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Default Ur quattro will not turn over with key

Trying to get the red Ur (WR) to start, after some investigation, getting 12.5 volts at starter large wire, only getting 6-7 volts from the small wire from ign. switch at the starter with key in start mode, I have introduced an earth from the battery directly to engine block as well, also swapped out the ign. switch, don't want to remove the starter to replace it because I don't think it is the starter, there is a brass jumper in the fuse box in relay position 8 the fuse box lid says its for automatic transmission lock out but I presume with the car being a manual the relay is not fitted and the wires are connected straight through via the brass jumper, any thoughts would be most helpful, thanks in advance.
Car has been dry stored for 4 years but was running back then.
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Old 01-01-18, 05:42 PM   #2
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Try bridging the main feed to the small connector on solenoid .
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Old 01-01-18, 07:01 PM   #3
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Hi John, that is the normal way to do things, but not happy doing that with the digital dash, on normal starting the dash turns off when the engine is in start mode, but if I try that with the ign. on and dash on I might take out the dash, the digital dash dose not like low voltage and sometimes takes out the voltage regulator in them.
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Old 01-01-18, 08:19 PM   #4
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In the 25years of messing around, and dealing with dead batteries, I've not once had a problem with the dash. Over-voltage I thought was the big consideration. The dash along with most other devices are simply load-shed via the old x-relay function. To simulate the load shedding, you could simply pull the appropriate fuses/relay while running the test.

I'm with John. If you can activate the solenoid directly, you've at least started to isolate the problem. Which sounds likely to be a bad connection, resulting in a large volt drop in the circuit to the solenoid.

...meanwhile, I'll take a quick look at the schematics, and maybe come up something more elegant.

Ps. I've had similar issues occasionally, which I believe are actually a problem in the solenoid. Ie. The voltage is there, (and may well be in your case if the circuit was open at the solenoid) but the solenoid is not moving, resulting in a non-start.
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Old 01-01-18, 10:27 PM   #5
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Colin,
Can you bump start it? Or alternatively rock it in gear and try again with the ignition and key. Has worked for me in the past.
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Old 01-01-18, 10:39 PM   #6
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Quote:
Originally Posted by Colin Aitchison View Post
Hi John, that is the normal way to do things, but not happy doing that with the digital dash, on normal starting the dash turns off when the engine is in start mode, but if I try that with the ign. on and dash on I might take out the dash, the digital dash dose not like low voltage and sometimes takes out the voltage regulator in them.
If this was the case then a failing battery could cause digi-dash-mayhem?.....surely not?

As a precaution I would have the solenoid wire disconnected while supplying the solenoid with battery voltage.

Why not supply the solenoid with the ignition off just to see if the starter will turn the engine?
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Old 01-01-18, 11:20 PM   #7
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Hanuman, Whilst I agree with you and John this would have already been done by my self to eliminate the starter from from the list of suspects in the non-starting car, I can not find the post that talks about low voltage being one of the problems with the digital dashes, but Peter Knight name was mentioned in the post as always, as for the wire that controls the starter solenoid it only has 6 to 7 volts when the ign. switch is in start mode, the starter solenoid dose no even click, but with only 6 to 7 volts I am not surprised, looking through the wiring diagram from a 1980/81 quattro the output wire from the back of the ign. switch is 4.0mm red with black stripe, runs to fuse box, tee of in fuse box 1.0mm red and black stripe to J95 timing relay for cold start valve and F26 thermotime switch and N17 cold start valve, then out of fuse box in 2.5mm red and gray stripe to connector T9a (nine pole, engine compartment left) then to connector T1a ( single pole, engine compartment right) now black wire and terminates in female spade end on starter, now with my limited knowledge of wiring and this car connector T1a will be my first port of call, from memory there are three single pole connectors down behind the drivers side head light clipped to the inside of the chassis leg, I think they are red, yellow and blue, can you confirm any of this or if you can send me the correct wiring diagram for a 1984/85 WR Ur quattro.
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Old 02-01-18, 12:21 AM   #8
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Yes John, see where you are coming from with the ign. switch off and a temporary wire to energize the starter solenoid, that is a fine test with the dash off, I have two batteries on this car, one was out of the coupe and the other was my spare fully charged but still not convinced it is the starter as yet due to the solenoid control wire voltage, many more problems to come I fear, fuel pump not buzzing in start mode but again that could be down to the low voltage in the starter solenoid wire not triggering the fuel injection pump relay, if that is how it works, anyway onward and upward in 2018.
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Old 02-01-18, 01:13 AM   #9
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I have got the big red Bentley book, with earlier '84ish and later '85/'86 diagrams.

I'll try and scan them tomorrow, if you'll pm me an email address. However, I think they're also around on the net.

As for fuel injection relay- it's driven by a signal from the ECU. An old friend in Glasgow had pump issues, which were actually down to bad connections to the relay at the relay position in the fuse box.

Laid up for long periods, some of my cars insist on randomly weird electrical issues- simply pulling relays and fuses an reinserting is a common fix. Similar issues used to plague many of the systems I used to support in my old career. It's amazing how many problems can be fixed by unplugging and reinstalling connections. Even good old Boeings play up after a few days laid up unpowered, and re-racking bits often sorts it.

And yes, the connections behind the right headlight are a good call.
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Last edited by Hanuman; 02-01-18 at 01:16 AM.
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Old 02-01-18, 09:48 AM   #10
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Quote:
Originally Posted by Hanuman View Post
It's amazing how many problems can be fixed by unplugging and reinstalling connections. Even good old Boeings play up after a few days laid up unpowered, and re-racking bits often sorts it.
That's reassuring...
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