Another starter motor click idea?
Discussion
...sort of.
Well, I fitted the new starter this morning and the bloody thing still clicks! Am I right in thinking activation of the starter is effectively controlled by only two things: a single relay in the MFRU and the solenoid?
Well, the rather resonant click from the solenoid remains with the brand new starter (not surprisingly) and I can definitely hear a relay clicking in the MFRU if I take it out from under the ECU and stick my ear to the casing. Also did a continuity check on the lead to the MFRU and the earth. So what else is there?
I did have one thought: One of the belts makes a horrendous screeching noise for 10 seconds or so after start up and the alternator seems to be the looser of the two (so I assume that's the culprit). Could it just be low battery voltage, either due to a faulty alternator (say it's partially ceased inside and that's causing the belt to slip) or even because of the slipping belt?
The battery is reading 12.59 volts off-load, which doesn't strike me as obviously low, but it would be a nice simple solution! Got to head out now, but I might try tensioning the belt (gotta be done anyway) and then giving it a good run from a jump start.
Well, I fitted the new starter this morning and the bloody thing still clicks! Am I right in thinking activation of the starter is effectively controlled by only two things: a single relay in the MFRU and the solenoid?
Well, the rather resonant click from the solenoid remains with the brand new starter (not surprisingly) and I can definitely hear a relay clicking in the MFRU if I take it out from under the ECU and stick my ear to the casing. Also did a continuity check on the lead to the MFRU and the earth. So what else is there?
I did have one thought: One of the belts makes a horrendous screeching noise for 10 seconds or so after start up and the alternator seems to be the looser of the two (so I assume that's the culprit). Could it just be low battery voltage, either due to a faulty alternator (say it's partially ceased inside and that's causing the belt to slip) or even because of the slipping belt?
The battery is reading 12.59 volts off-load, which doesn't strike me as obviously low, but it would be a nice simple solution! Got to head out now, but I might try tensioning the belt (gotta be done anyway) and then giving it a good run from a jump start.
Edited by Chris71 on Saturday 15th August 14:11
Run a fly lead direct from the + of the bty to the solenoid (where the small red cable connects) if the car starts, then its not the bty.
I started to suffer from the dreaded K click and fitted the 30 amp relay mod, well documented on blatchat, haven't had the click since. But haven't tried it after being on the track, but it is looking hopeful.
I started to suffer from the dreaded K click and fitted the 30 amp relay mod, well documented on blatchat, haven't had the click since. But haven't tried it after being on the track, but it is looking hopeful.
The path of the cables supplying MFU is not the most direct, and goes through a couple of connectors. The current demand of the starter solenoid is quite high, and there can be a significant voltage drop across the cables, connectors, and relay contacts.
This volt drop can prevent the solenoid pulling in sufficiently.
If you fit an additional relay that is engergised by the cable that would have gone to the starter solenoid, and then use the relay to switch a new cable direct from the battery to the starter solenoid, then the volt drop will be minimised.
I used to suffer "K Click" but fitted a relay a few years ago, and have not suffered with it since.
This volt drop can prevent the solenoid pulling in sufficiently.
If you fit an additional relay that is engergised by the cable that would have gone to the starter solenoid, and then use the relay to switch a new cable direct from the battery to the starter solenoid, then the volt drop will be minimised.
I used to suffer "K Click" but fitted a relay a few years ago, and have not suffered with it since.
Oh. I didn't answer your question.
If you have 12.5V at the battery, then it is not likely to be the alternator.
If the voltage at the battery drops to less that say 10V when the click occurs, then it could be a duff cell in the battery.
It's also possible that you have a duff earth from the engine to the chassis, or from the chassis to the battery. (you can prove a bad earth by measuring the voltage between the engine and the -ve battery terminal when you get the click)
If you have 12.5V at the battery, then it is not likely to be the alternator.
If the voltage at the battery drops to less that say 10V when the click occurs, then it could be a duff cell in the battery.
It's also possible that you have a duff earth from the engine to the chassis, or from the chassis to the battery. (you can prove a bad earth by measuring the voltage between the engine and the -ve battery terminal when you get the click)
Will give the fly lead another go, but I tried that with the old (and possibly totally functional) starter motor without sucess. What I was getting at is the fact I can hear two clicks, so it appears that the relay in the MFRU and the solenoid are both activating even when it doesn't start. The odd thing is it appears to be a little bit intermittent - you always get the clicks (audible when it fails to crank) but sometimes it cranks (and starts) perfectly first time.
ETA: Stranger and strangerer! The flylead now appears to do the trick (didn't connect the existing wire, just went straight to +ve and it cranks fine - it does also weld the end of the wire to the battery terminal, so possibly not a long term solution!) Anyway, after a couple of starts with the flylead I swapped it for the usual wire from the MFRU and the car now starts perfectly. As stated, it has always been intermittent, but it seems very strange that it suddenly started working afterwards - as if something had been freed up in the process. It's a brand new starter from the works though, so can't believe it's mechanical.
The only thing I did notice, was that the back of the relay unit's PCB has some big smudges on:
I suppose they could be creating a resistance or shorting something out? But I can hear the relay clicking...
I'm confused!
ETA: Stranger and strangerer! The flylead now appears to do the trick (didn't connect the existing wire, just went straight to +ve and it cranks fine - it does also weld the end of the wire to the battery terminal, so possibly not a long term solution!) Anyway, after a couple of starts with the flylead I swapped it for the usual wire from the MFRU and the car now starts perfectly. As stated, it has always been intermittent, but it seems very strange that it suddenly started working afterwards - as if something had been freed up in the process. It's a brand new starter from the works though, so can't believe it's mechanical.
The only thing I did notice, was that the back of the relay unit's PCB has some big smudges on:
I suppose they could be creating a resistance or shorting something out? But I can hear the relay clicking...
I'm confused!
Edited by Chris71 on Sunday 16th August 14:00
You need to measure the voltage actually being delivered to the solenoid to see where the problem is.
With everything off you should see at least 12.5V at the battery. As you turn the key you should see at least 12V at the solenoid. If you get less, either the battery is low or there's resistance in the wiring. You can measure the voltage drop through the wiring to find where the resistance is. Solenoids typically draw 30A+ as they close and the cables, connections and relays all need to be rated to cope with that.
If you are seeing 12V+ at the solenoid and it isn't closing then the problem is probably a fault in the solenoid itself, for example it may be corroded, heat damaged or worn. Occasionally you may get a situation where the starter motor pinion fouls a tooth on the ring gear and rocking the car in gear to turn the engine over slightly will usually clear that.
With everything off you should see at least 12.5V at the battery. As you turn the key you should see at least 12V at the solenoid. If you get less, either the battery is low or there's resistance in the wiring. You can measure the voltage drop through the wiring to find where the resistance is. Solenoids typically draw 30A+ as they close and the cables, connections and relays all need to be rated to cope with that.
If you are seeing 12V+ at the solenoid and it isn't closing then the problem is probably a fault in the solenoid itself, for example it may be corroded, heat damaged or worn. Occasionally you may get a situation where the starter motor pinion fouls a tooth on the ring gear and rocking the car in gear to turn the engine over slightly will usually clear that.
I don't get where the problem is thought to occur with the click. Ignoring my particular predicament for a second, is the idea that the relay still opperates, but the voltage it supplies is no longer addequate? Surely that'd be a problem with the wiring incurring a resistance somewhere, not the relay itself? Maybe the wire to the starter motor breaks down under the heat from the exhaust or something?
The other thing is this click is supposed to be hot start only, is that right? Mine occurs from cold.
That said, it doesn't occur at all at the moment, because ever since that 'jump start' from the fly lead it's been starting on the key - hot, cold, whatver.
The other thing is this click is supposed to be hot start only, is that right? Mine occurs from cold.
That said, it doesn't occur at all at the moment, because ever since that 'jump start' from the fly lead it's been starting on the key - hot, cold, whatver.
One problem seems to be the cable from the MFRU to the solenoid gets toasted and then loses its ability to supply enough juice to kick the solenoid into action (the solenoid maybe sticky because of gunk, but on a new motor that won't be the case)
By fitting the relay (as I have), the voltage from the MFRU only switches the relay to allow the 12 volts from the bty to go direct to the solenoid (same as a fly lead). Its a very simpy mod and is working on my car at the momemnt.
Normally click is when the starter is hot, but can happen when cold, as the resistance in the wire will be the same hot or cold, it just normally starts when engine is hot, but progresses to cold starts as well.
Not sure why after the fly lead start, yours now works, but it still looks like either not enough voltage from the MFRU or possibly a bad earth.
By fitting the relay (as I have), the voltage from the MFRU only switches the relay to allow the 12 volts from the bty to go direct to the solenoid (same as a fly lead). Its a very simpy mod and is working on my car at the momemnt.
Normally click is when the starter is hot, but can happen when cold, as the resistance in the wire will be the same hot or cold, it just normally starts when engine is hot, but progresses to cold starts as well.
Not sure why after the fly lead start, yours now works, but it still looks like either not enough voltage from the MFRU or possibly a bad earth.
I had a brief chat with my dad last night night (who unlike me knows about all things electrical) and he did raise an interesting point: does this click tend to happen on cars with MSA cut offs? If there's miles of high-current wiring to the battery isolator and back, this might make them more marginal?
Chris
You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
Just got back from hols keen to see how things are progressing...
Chris, I was suggesting that you leave the fly lead in-situ so you can use it on the occasions you get the click (I think it'll be back). That's what I did with mine and eventually did the relay mod which I am sure will cure your problems.
fergus said:
Chris
You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
I don't understand what you are suggesting Fergus. Are you proposing to feed the starter motor itself through a relay?You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
Bert
BertBert said:
Just got back from hols keen to see how things are progressing...
Chris, I was suggesting that you leave the fly lead in-situ so you can use it on the occasions you get the click (I think it'll be back). That's what I did with mine and eventually did the relay mod which I am sure will cure your problems.
Bert
yup!Chris, I was suggesting that you leave the fly lead in-situ so you can use it on the occasions you get the click (I think it'll be back). That's what I did with mine and eventually did the relay mod which I am sure will cure your problems.
fergus said:
Chris
You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
I don't understand what you are suggesting Fergus. Are you proposing to feed the starter motor itself through a relay?You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
Bert
fergus said:
BertBert said:
Just got back from hols keen to see how things are progressing...
Chris, I was suggesting that you leave the fly lead in-situ so you can use it on the occasions you get the click (I think it'll be back). That's what I did with mine and eventually did the relay mod which I am sure will cure your problems.
Bert
yup!Chris, I was suggesting that you leave the fly lead in-situ so you can use it on the occasions you get the click (I think it'll be back). That's what I did with mine and eventually did the relay mod which I am sure will cure your problems.
fergus said:
Chris
You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
I don't understand what you are suggesting Fergus. Are you proposing to feed the starter motor itself through a relay?You can bypass all the extra master switch wiring if you use a high amp relay direct from the battery to the relay, then the relay to the starter 12v feed. The switch from the relay can be the cable currently used for switching the MFRU. This will give you about 18" max of high amp battery cable to pass the current through. You can get some pretty chunky stuff from vehicle wiring products. I'm going to do this mod to mine! This then ignores all other existing wiring in the car. A high current (60A) relay will give you more load protection on the relay than just using a std (30A) unit.
Give me a bell if you want help fitting it. The battery cables are difficult to attach to the relay!
Bert
Bert
BertBert said:
Isn't the solenoid on the starter actually the high current switch anyway?
Bert
Isn't the idea just to provide an alternative feed? As I understand it the relay mod does the same job, just without the high resistance that occurs in the original start motor supply? May have misunderstood...Bert
Bert, I don't think there was enough clearance on mine to get the fly-lead on with the original connector piggy-backed on. I didn't notice any problem before, but with the new starter I can't get the spade on unless I take the original connector off. Dunno if that makes sense, but I think basically the failure to start on the fly-lead before was a red herring - I don't think it was making contact properly, had it done so I suspect it would have started. Think I'm just going to stick the relay mod on and see how I go.
I think Fergus is suggesting a relay in the actual starter feed wiring (the fat one that delivers 100-200A of starting current). That's a different and possibly quite novel relay mod 
Chris is it that you don't have enough room to put the fly lead on and then put the original connection onto the fly lead piggy-back spade? What gets in the way?
Bert
Chris is it that you don't have enough room to put the fly lead on and then put the original connection onto the fly lead piggy-back spade? What gets in the way?
Bert
BertBert said:
Chris is it that you don't have enough room to put the fly lead on and then put the original connection onto the fly lead piggy-back spade? What gets in the way?
Bert
It seems to be clearance - the 'new' connector plus the old one piggyback'd on seems to be too wide to fit in the gap surrounding the spade. It appeared to go on before and didn't work, this time it doesn't seem to want to fit (despite the starters being apparently identical) and yet just the fly-lead on its own will turn the starter.Bert
I guess there is another solution. If it's not a red herring and in fact the fly-lead did fail to work despite being in contact, then maybe it's the earth to the starter motor? Don't think I thought to check that.
davidball said:
When I suffered the dreaded click I was advised to fit a heavy duty battery cable from the negative battery terminal direct to the chassis. That solved the problem for me.
Ah, that sounds interesting. Certainly fits with the 'jump start' solution.Is there a suitable place to anchor it to the chassis already?
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