KEITH G Posted March 10, 2003 Share Posted March 10, 2003 I have an intermittant fault on my SLR starter motor.When hot it just clicks.I have replaced the red button and the wire to the starter motor.Anyone know how you can undo the rear 17mm nut to remove .No spanner i have will fit.Any help welcome.Keith Gale Link to comment Share on other sites More sharing options...
Sheds Moderator Posted March 10, 2003 Share Posted March 10, 2003 I am mystified that the spanner won't fit. Is there no access? If you need a slimmer spanner then cone spanners for adjusting bike wheel bearings are very slim. Slimline sockets exist also for snug fitments. Other than that it's down to checking connections are clean and firm and correct solenoid operation, but this last does mean taking the thing off first. Link to comment Share on other sites More sharing options...
Big Brother Posted March 10, 2003 Share Posted March 10, 2003 Keith, Try doing a search for K series starter motors. There was quite a lot discussed recently including details of a "stock" fault and its remedy. Symptoms were similar to those you describe. Steve Se7en-Up! Less is more! Link to comment Share on other sites More sharing options...
F355GTS Posted March 10, 2003 Share Posted March 10, 2003 Keith is the larger race type starter? if so the back bolt should be an Allen socket bolt? if it's a 17mm bolt I can't see how you'd get to it other than reomove exhaust primaries (maybe) remove alternator remove lhs engine mount use a thinwall socket and long extension bar Mark ps Keith if you drop me a mail to my profile e-mail address I'll send you some procedures to try on your starter, once it's out! Edited by - F355GTS on 10 Mar 2003 21:02:29 Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted March 10, 2003 Leadership Team Share Posted March 10, 2003 Keith - I've mailed you a wiring fix for it, you'll need a 30amp relay. Stu. BTW, radiator going great 😬 Link to comment Share on other sites More sharing options...
Mrs Kipper Posted March 11, 2003 Share Posted March 11, 2003 Stu I have been plagued with starter problems in my 1600K, particularly in the summer and the hot(?) weather. I remember a fix that someone posted last year which involved a power feed directly to the solenoid as the suggestion was that the problem was caused by a power drop. Is your fix the same? Would very much appreciate a copy. Kipper Fun is not a straight line. Link to comment Share on other sites More sharing options...
AlShack Posted March 11, 2003 Share Posted March 11, 2003 I have a similar problem - could someone post the link to the resolution thread? Cheers Al Link to comment Share on other sites More sharing options...
John Howe Posted March 11, 2003 Share Posted March 11, 2003 Try doing a search for "K series starter motors" JH Deliveries by Saffron, the yellow 222bhp Sausage delivery machine Link to comment Share on other sites More sharing options...
KEITH G Posted March 11, 2003 Author Share Posted March 11, 2003 Thanks everyone for your help.I will try the wiring fix.Keith Link to comment Share on other sites More sharing options...
Paul Richards. Posted March 11, 2003 Share Posted March 11, 2003 All If you use the search facility, the heading of the post I put on last year for fitting a relay was "K Series Starter - The Cure??" It has worked a treat and has never failed since that time. Previously I had regular problems on any good run where car gets hot. If anybody needs help or advice, please drop me an e-mail and I am only too pleased to assist. If you're close enough to Bury, I am even prepared to fit for a small donation to Nuke the Luke. Paul R. C7PPR K series that starts when hot!! Link to comment Share on other sites More sharing options...
Chris W Posted March 11, 2003 Share Posted March 11, 2003 Paul While I don't dispute your starter problems went away after you fitted the relay, I suspect that what actually happened is you unknowingly cured a dicky connection somewhere in the starter circuit at the same time and that was the real fault. I fully understand what the relay is doing, and the circuit details, but don't understand why putting in the relay would cure the "hot start" problem. The wire which normally carries the solenoid current to start the car will carry it just as well whether the engine is hot or not and IMHO is of sufficient diameter that a relay should not actually be necessary. In fact, adding the relay probably increases the chances of problems at some time in the future as it's one more mechanical item that could fail. Further, if the "hot start" problem is a function of the actual starter motor or solenoid getting hot and causing a problem then again the relay won't cure that. I'm not knocking your belief in this mod, just want to understand what mechanism you believe is at work here. rgds Chris 1.8K SV 140hp see it here Link to comment Share on other sites More sharing options...
F355GTS Posted March 11, 2003 Share Posted March 11, 2003 Chris I've worked on a number of different starters to track the problem and depending on type they each had different problems from dry joints to warped solenoid bores and another with a snapped connection inside. I was due to do a test on the circuits to try and trace the specific hot starting problem but the engine blew up! so I never got round to it. I was given to believe that heat in the cable can cause a greater resistance reducing the current to the starter. It's a shame that i didn't get a chance to try what would have been a basic test using a jump lead directly from the battery to see if it turned, perhaps somebody else with a dicky starter could try this next time Mark Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted March 11, 2003 Leadership Team Share Posted March 11, 2003 Cheers Paul, that saves me a task of e-mailing everybody - if anybody else does need a coy of the instructions though, e-mail me then i can attach Pauls info and send it back. Chris - this fix seriously works. I've been dogged with the hot starting (and occasionally cold) problem for 4 years - fitted Pauls mod and the starter hasn't missed a beat since. Definately not a loose connection - my starter had been off more times than a whores drawers, with little effect, but now it's staying right where it is, doing the job it's supposed to. Caterham quoted me £183 for a new starter 3 years ago - Paul's mod can be done for less than a fiver. Stu. Link to comment Share on other sites More sharing options...
Tony C Posted March 11, 2003 Share Posted March 11, 2003 "Don't knock it if it fixes the problem". But along with Chris W, I too would be interested in the reason why this mod. works. A relay on a relay just doesn't make much sense. I too consider this relay 'fix' to be perhaps masking the "real" problem. Link to comment Share on other sites More sharing options...
Mick Day Posted March 11, 2003 Share Posted March 11, 2003 I now have a K which starts hot or cold since doing the relay mod last year. The problem is probably a combination of 1. heat increasing the resistance in the solenoid exciter wire; 2. increased resistance in the ignition switch &/or 3. increased resistance in the imobiliser (in my case a 9 year old Vecta). Good luck & many thanks to all who push started my car before I fixed it. Mick PS: I'm reliably informed there is no relay in the "standard" starter circuit. Edited by - Mick Day on 11 Mar 2003 21:08:39 Link to comment Share on other sites More sharing options...
Tony C Posted March 11, 2003 Share Posted March 11, 2003 😬 Just to make absolutely sure there can be no understanding of my previous posting 😬. I consider that if a "fix" works, why argue about it. BUT, I'd really like to know why putting "another" relay in the start circuit cures the hot starting problem. I'm saying "another" relay because I consider the starter solenoid to be a relay - I thought that's what it did - allow a small current circuit to "make" a large current circuit. BTW, I notice that new starter/solenoid assemblies from Caterham have a postage stamp sized piece of heat shield try-wrapped around the solenoid. My humble belief is that the solenoid "mechanicals" or interior wiring/contacts might prove to be the hidden culprit, which the "extra" relay is masking - just my thoughts, you understand. Heat, vibration and corrosion are the "enemies" of electrical components. Sure, heating the exterior solenoid wiring and starter wiring won't help, but hmmmm, seems to be a bit odd to me. Link to comment Share on other sites More sharing options...
Mick Day Posted March 12, 2003 Share Posted March 12, 2003 Tony The starter solenoid needs a fairly hefty whack of current to throw in the 1st place. Consider this: maybe the extra heat etc increases friction within the solenoid bore to the point when it just wont throw? To excite the solenoid the current has to flow from the battery to the ignition switch, through the immobiliser, & then down to the starter. Quite some distance really. Putting a relay in the circuit shortens this pathway by ?? 80%. I admit it still doesn't explain why only K's experience this problem. Mick Link to comment Share on other sites More sharing options...
Paul Richards. Posted March 12, 2003 Share Posted March 12, 2003 Tony/Chris W I obtained the cure to this starting problem from a local auto electrical engineering company (recommended by my good friend John E.) who have come across similar problems on other cars - Peugeot diesels amongst others. My original problem occurred about 4 or 5 months after the car was new and I had 2 new starter motors fitted (supplied under warranty by Caterham with one fitted by their agent who also carried out some investigation, but found no problems). Each time the problem went away for a couple of months and before long car was out of warranty. The problem returned and got worse. It became even worse when I fitted a battery cut out switch. Like most intermittent problems it was difficult to investigate and the fact that it got worse actually helped me to find the solution. I discovered that when the problem occurred it was possible to start the car by connecting a temporary wire to the solenoid and touching it to the positive terminal of the battery. This never failed. The auto electrician came up with the fitting of a relay as a cure. What Mick suggests is correct. I am not an expert on electrics, but my understanding is that as the car gets warm, resistance is built up in the wiring. The K series starter motor appears to have a solenoid which is marginal (Mick - I suspect this is the reason why only K series have the problem, or it could even be the wiring of a K series is slightly different i.e. to accomodate the Rover immobiliser or similar) and needs full power to activate it. The small drop in power caused by the resistance build up is apparently enough to prevent it working. Facts which seem to make sense:- New starter motors gave a temporary cure only as they were new with no dirt in mechanicals, new connections, no corrosion etc. and therefore able to work with a small drop in current (It is so marginal). The inclusion of additional wiring for a cut out switch had an adverse effect because this increases the length of wiring and my understanding is that this increases resistance. Suggestions that the internals of the starter or solenoid are a problem can be dismissed. I had 3 new starters in all and I can’t imagine that they were all faulty. I also swapped starter motors with someone and my starter worked on his car and my problem still persisted. This definitely points to a problem outside the starter. There is no doubt that this fix works. My problem got worse and worse. I came back from Le Mans last year and travelling on motorways, the car got “hot”. At each fuel stop had to push start the car. I then found the problem manifested itself on even short journeys - every time the car got fully warmed up (as opposed to hot). Since the modification I have had not even a hint of a problem. You cannot believe how embarrassing/inconvenient it was to have to push start the car. It got to the point where I was so fed up that I considered selling. If anyone has a similar problem, I urge you to try this mod. As Stu says it will cost less than a fiver and take about 20 minutes to fit. A number of people have had success (I am not aware of any failures). What have you to lose? It’s certainly cheaper than buying a new starter!!! Paul R. C7PPR K series that starts when hot!! Edited by - Paul Richards. on 12 Mar 2003 12:51:57 Link to comment Share on other sites More sharing options...
Tony C Posted March 12, 2003 Share Posted March 12, 2003 Thanks Paul/Mick, 😬 Can't argue with success Where can I get a wiring diagram, so many people have had similar problems, it must be worth a fiver for the fix. Thanks muchly Waiting for my BRG SV kit. 😬 DELIVERY BROUGHT FORWARD, only three weeks to go now - WHOOPEE Link to comment Share on other sites More sharing options...
Chris W Posted March 12, 2003 Share Posted March 12, 2003 OK guys - I believe I know what the real problem is and why the additional relay indeed solves the problem - I just didn't buy the high resistance wire theory so investigated further.......... .........are you sitting comfortably..................... I opened up the MFRU unit (I've been like that since I was 5 years old - always taking things to pieces) and inside are 4 relays, whose wiring I traced. The relays are open types, ie: not enclosed in a casing, so you can see the mechanics of them clearly. The 4 relays function as follows: 1. Controlled by ECU 2. Puts 12v on fuel pump if ignition and ECU are active 3. not used 4. Puts 12v on starter solenoid if starter button pushed and ECU active So the red/white wire from the starter button applies 12v to the coil of relay no. 4 in the MFRU which closes and switches 12v on to the starter solenoid via the thickish brown/red wire coming out of the MFRU. The point is that this relay will be switching about 10 amps and when it opens after you release the starter button there will be a nice juicy spark which will corrode the terminals. There is no spark suppression circuitry in the MFRU. The other relays (ECU and fuel pump)are handling much smaller currents and so will be far less affected compared to this one. My belief is that this relay is probably not man-enough for the job of switching 10 Amps and the contacts inside are getting burnt causing a high resistance. My SV is only about 7 weeks old but there is already evidence of some corrosion on the contacts of this relay and not the others. Hence starting problems. So by introducing the additional relay (30 amp type) the 10 Amp current for the solenoid is now handled by the new relay and the relay in the MFRU is only handling the current required to switch the 30 Amp relay (probably about 150milliamps). Therefore, no more sparking inside the MFRU and the additional relay's contacts are running well under maximum current, so no problem there either as the contacts are built to take up to 30 amps. I'm not sure yet why it should be worse when hot but it's possible that the resistance of the solenoid decreases when hot and so it draws even more current making matters worse. I'll think about that a bit more. However, I can now understand why the new relay solves the problem and will be fitting one myself!!!! Hope this helps Chris 1.8K SV 140hp see it here Edited by - Chris W on 13 Mar 2003 01:54:23 Link to comment Share on other sites More sharing options...
Mick Day Posted March 12, 2003 Share Posted March 12, 2003 *thumbup* Good one Chris: I always wondered what the MFRU did & now I know. Your explanation makes good sense & certainly eliminates some of the witchcraft associated with this mod. Mick Link to comment Share on other sites More sharing options...
Chris W Posted March 13, 2003 Share Posted March 13, 2003 For those interested, I have put a photo of the inside of the MFRU on my photo webpage - just click below Chris 1.8K SV 140hp see it here Link to comment Share on other sites More sharing options...
Colin Heseltine Posted March 13, 2003 Share Posted March 13, 2003 Was interested to see the various solutions to the hot starting problems on K series starters. I suffered from this problem for 12 months. In the end I removed the starter and had a look at the threaded pillar that the starter cable is attached to. On close examination using bright light and magnifying glass it became apparent that there was a hairline crack in the solder wher the pillar is attached to the solenoid internals. Solution: Using jewellers welding torch and desolder gun I removed as much solder from the joint as possible. Then resoldered the joint using old fashioned spirits of salts to clean the joint followed by old fashioned stick of solder and soldering flux. Never had a problem for the last 18 months, whether track day, sprint or road use. Hope this helps someone. Regards, Colin R 7 CJH Yellow Supersport Link to comment Share on other sites More sharing options...
Miles Taylor Posted March 13, 2003 Share Posted March 13, 2003 When my 1400 Roadsport gets particularly hot the starter appears to stick. If I rock the car in 6th gear (only slightly is enough, by rocking my weight in the seat) it starts immediately. Someone suggested to me that being near the exhaust made the parts expand due to the heat and thus stick ? I had a new starter from caterham but it still does it. Milo Link to comment Share on other sites More sharing options...
philwaters Posted March 13, 2003 Share Posted March 13, 2003 hmm Raceline also suggest fitting a Relay to Zetec owners who have problems. I am one... but a requested wiring diagram did't arrive so it got forgotten - until Stu kindly mailed me a copy . The Zetec installation doesn't have an MFRU though, so I wonder if it isn't just a combination of all the factors discussed. Unless my contact wear is occuring in the starter button? Phil Waters You mean you can drive these? I thought it was just there to polish 😬 Link to comment Share on other sites More sharing options...
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