S3 STARTER CLICK AND NO CLUNK! new stream

Phillip, I am not familiar with the S3, but from what I read, some models with the seat belt warning system will prevent the engine from starting. Can anyone confirm this? Hopefully some one else will jump in, but usually the ballast resistor is near the ignition coil. Unless something is wired very wrong, the ballast resistor should not prevent cranking, only running/firing issues.

You don’t mention trying the other link I suggested - namely directly from starter relay C2 to the battery, and then try the ignition key. You might try temporarily disconnecting the C1 terminal on the relay (which should connect to the ballast relay, wherever that is on a S3). I suppose it’s possible that the load of the ballast relay is dragging down the voltage on the Cx terminals when the starter relay is activated if something isn’t quite right. As Tom suggested, you could also measure the voltage at the C2/C4 terminals and S solenoid terminal when the relay is activated to make sure it isn’t dropping too low to operate the solenoid.

-David

Was that the heavy duty cable to the bulkhead? Maybe 3/8" diameter in my S1½ car.

It is a thick braided connection direct to the negative terminal

Next task is to try the direct link to the relay C2 as you suggest David, then the voltage drop at C2/4

As you can tell…I am more mechanical than electrical in experience!

Update David…
I tried a direct link to battery from C2…no change
I volt tested C2 and 4 when cranking…no voltage drop below 12 v. In fact…the voltag went up slightly from 11 to 12 when ignition turned to start position.

I notice that the rev counter needle ‘kicks’ very slightly when I turn to start position on ignition key

Just tried the voltage at S when starting and showing no volts…could be a breakthrough! Voltage at C4 but not at S …so cable?

Getting no volts out of C4 or S now. I may have accidentally shorted relay during testing (before I got the no volts at S) Groan…

Philip,

Frustrating isn’t it? :grin: Don’t give up…you’re getting there. The fact that a direct connection between the Solenoid S and the battery causes the starter to run means the tricky (read expensive) bits are OK. All we need to do is find out why the S connection on the Solenoid doesn’t get 12V with enough current to drive the solenoid when you turn the ignition key. If the relay clicks when you turn the key, the ignition switch and wiring as far as the W1/2 connection on the relay appear to be innocent. So, we’re left with the relay itself, and the connections to the three C (C1, C2, and C4) terminals on the relay. The fact that you now get nothing on the C4 terminal when you turn the key is actually probably positive progress. Temporarily shorting out the relay during testing isn’t going to damage it. So, my guess is that the previously poor connection somewhere, has become no connection. No connection should be easier to find than a poor connection. If it were me doing this, I’d start by confirming which wires (by colour) are connected to which terminals on the relay, and write them down. Then remove each of them from the relay. Inspect the connectors on the end of each wire and flex the connector slightly. Do they seem to be firmly connected to the wire? Could the wire have fractured at the point it goes into the connector? Make sure the relay terminal and connector on each cable are clean and shiny. Assuming all seems good, proceed. With all C wires removed, does the relay click when you turn the ignition key to the start position? It should. Use your voltmeter to measure the voltage on the wire that is unplugged from C2 without turning the key. The other lead of the voltmeter should be connected to the battery ground, or another good ground point such as the engine. Do you get 12V+? Flex the wire around while you are doing this. The voltage should be steady. If it fluctuates, then the wire is suspect. Now, put the C2 wire back on the correct relay terminal. Turn the key to the start position while measuring the voltage on the C4 terminal of the relay. Do you get 12V+? If not, your relay (even though it’s new) is suspect. Assuming all is good so far, connect the C4 terminal of the relay to the correct wire, which goes to the S Solenoid connection. NOTE: we have left the C1 wire off all this time. Now try turning the ignition key to the start position. Does the starter run? If all these tests pass except for the final one, we’ll proceed from there. Hope this helps…

-David

Thanks David…I really appreciate your time and patience.
I will proceed as you suggest.

I have noticed that the click isn’t obvious now when I turn the key. I will listen out as the fuel pump was noise and may have covered the noise.

I have some diagrams that show how to rewire standard Bosch sealed relays to emulate any Jag configuration. (for test purposes)

You may have a failing relay, if it is an original silver box type, when I dismantled a 5pin version, it was so full of corrosion I almost fainted it had not failed years earlier…it was almost completely full of rust flakes

just something else to worry about…

Tony,

Philip stated in his original post that he replaced the relay. Though this doesn’t mean it’s not faulty (as we all know from bitter experience!), it will hopefully not be full of corrosion. If, as he says, it may not be clicking any more, it needs to be checked out again, and re-verified that it is the correct relay - suppliers have been known to ship the wrong parts too…! The longer this goes on, the more I feel that those of us sitting behind a keyboard are making some basic assumption which is not in fact true…

-David

my bad, had it on my mind, as I have a suspect horn relay situation to diagnose later

has the OP tried a wired in 30amp MOM from battery to solenoid?
that eliminates every suspect except battery, solenoid,SM

MOM? What’s the acronym?

Mother of mine? Sorry couldn’t resist
I would guess a momentary on switch?

Tony,

I’m afraid that “MOM” has me stumped too. However, I think you’ll find that if you read through the entire thread, the original poster (OP) has described in detail what tests he has carried out, and what the results were. If you are asking has he tried connecting the “signal” terminal of the solenoid directly to the battery, the answer is yes, and the starter motor spins fine. Hence, we have eliminated the solenoid, battery and starter motor itself as being sources of the problem. I thought we were on the cusp of identifying exactly where the issue was, but the most recent post from the OP suggests that the behaviour (in particular that of the replacement starter relay clicking or not) may have changed, so we need him to revisit some tests to move forwards. Hope this helps…

-David

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lol,I think its an abbreviation for momentary…that is just what I have always known them as.

same as the pushbutton Start button various Jags (which can go faulty)

available in autoparts stores ~$10, can be fitted in cabin or engine bay

(also bypasses any neutral safety system in autos)

there is a big benefit to this apart from diagnostics, which is that you can reliably test, or even drive your car, mine is a permanent fixture now anyway

I have thought seriously about the switch option as I prefer that system on the earlier e types

However…I will endeavour to understand the actual problem.

UPDATE. I am sending the replacement relay back so will be buying a replacement to eliminate that as a possibility.
I need an assistant to go through Davids latest checks, so I will be delayed

for sure you will get there following Davids excellently detailed fault finding

my “spare” start button is fitted in the engine bay

a few things that help me when lone fault finding;

test light
multimeter with Continuity setting that goes beep
couple of jumper wires with insulated alligator clips

I think that is a good idea. It also seems to me you already replaced this relay once. Yes, it easily may have been damaged and does need replaced again. However, before replacing it again, I would suggest troubleshooting the problem to determine if it needs replacing. No use putting a new one on if indeed there is still a problem that will burn out the newest relay. Since you have a voltmeter, this should not take much time to determine your problem. If you do not understand the procedures David and others have provided, ask.
Tom

Just to refresh this trail…I am back now, and hope to continue the investigation this week. I am waiting for MOM switch to get me by (so i can at least start the car) but will get to the bottom of the original problem.
I think the MOM switch will be a good back up; as Tony suggests