myothercarsa2cv Posted September 17, 2012 Share Posted September 17, 2012 Argh still got to do this! The pressure is on... Link to comment Share on other sites More sharing options...
Myles Posted September 17, 2012 Share Posted September 17, 2012 Arnie surely that is just what the relay mod does switches a direct feed from battery to starter cutting out everything else? Umm - but if you leave the MFRU in the equation, that gives you a relay switching another relay - and that's where I found my final problem. My k-click only truly went away when I bypassed the MFRU entirely and hooked the Big Red Button direct to the (replacement) relay. Still can't start the b***** reliably as the Brise seems to be on its last legs - but at least it turns over every time with no click... 😬 Link to comment Share on other sites More sharing options...
Frying Pan Posted September 17, 2012 Share Posted September 17, 2012 I just don't fancy the idea of having the starter circuit permanently live - too easy for someone to sit in the car and make 'brrmmm brrmmm' noises and start pressing buttons, particularly the shiny red one... Link to comment Share on other sites More sharing options...
Bricol Posted September 17, 2012 Share Posted September 17, 2012 Yep - same here. I didn't wait too long when mine started to click 5 yrs of so ago. Clicked twice on me, so modified the circuit. New relay, new live supply to the relay. New cable from relay to starter. Original power cable left on starter. New wire from from start switched live on ignition switch to new relay coil. New earth wire from new relay to chassis. Original Caterham starter and power cables. Powerspeed exhaust for around a year longer than the click. 2001 car, well used. Works every time Bri Link to comment Share on other sites More sharing options...
charlie_pank Posted September 17, 2012 Share Posted September 17, 2012 I know I've explained this before, but here goes again: The click is caused by the current being insufficient to throw the solenoid of the starter, this can happen for a couple of reasons OR A COMBINATION OF SOME OR ALL OF THEM: 1. The current at the solenoid is lower than it should be 2. The solenoid is stickier than it should be 1. The current at the solenoid is lower than it should be - causes: - There are one or more 'dry joints' in the main circuit - The relay contacts on the low-current side are corroded - One or more of the wires involved have a high resistance because they get too hot - One or more of the wires involved have been through lots of heat cycles and now their resistance is higher than it should be - The wire(s) carrying the current from the battery to the solenoid are too long (causes higher resistance) - The FIA switch's terminals are corroded 2. The solenoid is stickier than it should be - causes: - There is dirt in the solenoid - The piston is corroded - The solenoid has expanded because it's getting too hot You can test a number of these issues - eg. If you short the terminals on the starter (make sure the car is out of gear first), does it start the car? If 'yes' then there's nothing wrong with your starter motor; if the starter motor doesn't spin, but does if you short the terminals on the MFRU, then your relay is to blame etc... HOWEVER, any number of these problems can occur simultaneously, and each component might work fine on its own, or if you swap any one of them out, but put a slightly dirty solenoid together with a slightly corroded piston and run a (old, slightly higher resistance) long line from the battery via the (old, slightly corroded terminals) FIA switch to the starter, and they lower the current enough that the solenoid won't throw. You also might get a situation where replacing any one of the components in a system where all the items are 'tired' will fix the symptoms because they push the current back up over the 'throwing' threshold, or decrease the stickiness of the solenoid; yet when the symptoms return, replacing the same component that you did last time won't fix it! Many many people on this forum have posted that getting a different kind of starter motor/solenoid fixes it, or cleaning the piston, or getting a new FIA switch, or the relay mod, or rewiring etc... but if you really want to get to the bottom of it, I think you need to understand what's going on in YOUR car, and think about how you can test the components together and in isolation to determine the actual root cause of YOUR problem. Edited by - charlie_pank on 17 Sep 2012 14:12:22 Link to comment Share on other sites More sharing options...
john milner Posted September 17, 2012 Share Posted September 17, 2012 I did the relay mod a couple of weeks ago after looking a wally for twenty minutes on a very large supermarkets filling station forecourt on a Friday evening. I found it fairly easy to do and used the recommended 30A relay (Halfords £5.68). I did have the option of 40A for the same money which might be better as the contacts should be stronger. I pulled the MFRU apart and could see a slight blackening of the contacts. No problems since but the relay needs some weatherproofing. I'm going to get a 40A as a spare. A few months ago I did the solenoid service detailed on the Alcester website. For me this was a waste of time as the innards were clean (30k+ miles. I also applied a limited amount of exhaust wrapping on each of the primaries in the region of the starter & alternator. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted September 18, 2012 Share Posted September 18, 2012 As Bricol says this worked perfectly for me too using the OE Skoda starter on a well tweaked 1.8K. If you've detaped the loom it's worth checking for poor connections / soldered joints you won't have to go far to find some that need attention! Link to comment Share on other sites More sharing options...
Myles Posted September 19, 2012 Share Posted September 19, 2012 I just don't fancy the idea of having the starter circuit permanently live - too easy for someone to sit in the car and make 'brrmmm brrmmm' noises and start pressing buttons, particularly the shiny red one... It ain't on my car. The power for the relay is switched (certainly through the FIA and (I'd have to check as it was a long time ago) also through the aircraft-ignition switch). It's as secure as it was with the original MFRU wiring - but with rather higher ratings for all of the components. No problems since but the relay needs some weatherproofing. Top-tip (from experience!) I mounted my original bypass relay with the contacts uppermost (for convenience). Unfortunately (really didn't think this through at the time 😬) this makes the relay cover into a lovely 'bucket' for rain etc - and it didn't take too long for the relay internals to be submerged Current installation has the relay with the contacts facing straight down - so at least the darned thing can drain if it needs to. The other (other) advantage of the relay mod is that you can test some of Charlies suggestions quite easily - i.e. if the engine is turning over slowly or just clicking, you can easily whip the feed off the bypass relay and touch it to battery-positive. This proved to me at one point that it was time to stop worrying about the starter and to work back up the wiring-tree - the engine would burst into life when all of the MFRU/FIA/BRB/etc. was taken out of the equation. Sadly, for me, the slow turnover does appear to be starter related. Link to comment Share on other sites More sharing options...
Bricol Posted September 19, 2012 Share Posted September 19, 2012 Mounted my new relay on the scuttle bulkhead inside the car - alongside the Emerald ECU - have to be pretty hard rain to get wet Bri Link to comment Share on other sites More sharing options...
Myles Posted September 20, 2012 Share Posted September 20, 2012 Mine was originally mounted on the bulkhead at the end of the footwells - on the passenger side, at the top - that certainly managed to get wet! Link to comment Share on other sites More sharing options...
TomB Posted October 8, 2012 Share Posted October 8, 2012 Picked this thread to talk about my K click, as its the most recent! I have just replaced all the heavy battery cables and earth lead from starter bolt to battery; cleaned/greased the starter solenoid & emery papered all the contacts; replaced the last few inches of the brown solenoid exciter wire from were the brown and brown& red cable join (soldered on); Ive added the relay mod a few months ago; recently installed a Odyssey 545 battery (2nd hand, could be a getting on a bit). Ive found the battery needs keeping on a conditioner to allow starting (Ive got a list of voltage readings at home which Ill update later if helps). While out yesterday, I stopped for a break and it wouldnt restart. At all. Before the above, it consistently started on a 2nd push of the button, but its much worse now. Unaware at the time, I ended up blowing the ECU fuse, so after trying push starting with no start, I called the RAC. While waiting, I tried again and with no fuel pump priming noise , checked the fuse, replaced and it started. Back home, on the drive, hot start was fine, tried it a few times, one after the other and it started each time. What next? As I see it options are 1) Put the old Banner back on to rule out battery, or replace Odyssey with a new one? 2) wait till winter and unwrap loom and replace all brown/brown red wiring 3) FIA key 4) Rewire relay 5) Replace MRFU 6) Replace Solenoid or whole starter (original, 15yr old Magnetti Mareli, solenoid on top) Milage this year is woeful after one problem after another ☹️ Now Im worried about going anywhere incase I need a pee or fuel! Edited by - TomB on 8 Oct 2012 11:47:36 Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted October 8, 2012 Leadership Team Share Posted October 8, 2012 Tom, there's a couple of ways of wiring the new relay - is the MFRU still in the circuit or have you by-passed it completely? Stu. Link to comment Share on other sites More sharing options...
TomB Posted October 8, 2012 Share Posted October 8, 2012 I cant remember, will check tonight! Link to comment Share on other sites More sharing options...
TomB Posted October 8, 2012 Share Posted October 8, 2012 Some voltages - I think I know the answer Static 12.78V staight after run and turned off Engine running 13.56V, so its charging. 12.62V @1300hrs Sunday 12.61V @1700hrs Monday 12.60 @2000hrs Monday Internal resistance 9.15mOhms 5.6 - 6.3V cranking = ☹️ I think I have a poorly battery. As if further proof was required, I jumped it off the old Banner equivalent Yuasa, at it started. It wouldnt start on Sunday when hot because there was too much voltage drop on start. I wonder if thats part of the answer. Link to comment Share on other sites More sharing options...
Myles Posted October 10, 2012 Share Posted October 10, 2012 I changed the Powervamp in my seven at MOT time this year to see if it would help with the slow turnover problem. It didn't really - battery is probably four or more years old though. My ropey Focus completely flatted its batter whilst standing for probably 3ish months at my flat - needed to dig it out for a bicycle event last weekend. Jump-started fine from another vehicle but wouldn't retain a charge - at all! Even after just an hours rest following a long drive, the central-locking, boot release etc. couldn't operate - it was that dead! Arranged for a replacement battery to be ready at the local Halfords - but had to get the car started from the office carpark mid-morning to get there... Popped the old Powervamp in the boot - it has been sitting in the garage for months - hooked it up with jump-leads on the off-chance - and the Focus burst into life 😬 Conclusions: Even an elderly Powervamp can be worth saving from the scrapyard... ...and I still reckon it's the Brise that is preventing the Caterham from turning over quick enough ☹️ Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted October 10, 2012 Share Posted October 10, 2012 Bypass the tiny relay in the MFRU - just cut the inlet and outlet wires to it and use them on an external 30A relay. Tom - did you upgrade your ECU fuse from 20A to 30A as per long-standing recommendation. Link to comment Share on other sites More sharing options...
TomB Posted October 10, 2012 Share Posted October 10, 2012 Im not sure I ever did the fuse upgrade. Ill try and dig out a 30A fuse tonight! I need to recheck the bypass wiring and probably hard wire it in. When I did it, I think I wired it in parallel to the MRFY relay - I remember using scotch clips to avoid cutting wires and making permanent changes to the wiring. Does no one ever replace the MFRU and have a new relay that way? Neater, but more expensive? Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted October 10, 2012 Leadership Team Share Posted October 10, 2012 Tom, I used the starter output from the MFRU (IIRC it's a brown/red wire) and interupted it to fit the new relay, ie. I still have the MFRU in circuit. I cut the wire, fitted a male and female spade connector to each new end and then added new wires to loop via a second 30A relay ... this enables me to remove the second relay from the circuit if I should so wish. My new relay is added to the relay block under the dash so pretty long cabling all now wrapped in with the loom. It's proven to be perfectly reliable - if not I'd have also broken into the starter input wire into the MFRU and linked this to the brown/red wire to the starter solenoid to effectively bypass the MFRU also. This second method may be what you need to do. Stu. Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted October 10, 2012 Share Posted October 10, 2012 The MFRU relay contacts are pretty tiny ! Much better to use a £5 30A external relay Link to comment Share on other sites More sharing options...
TomB Posted March 5, 2013 Share Posted March 5, 2013 Aghhhh!!! F&&Cking blo&&Dy car!!! It wont start after winter hibernation. When the battery (inc a borrowed good one) is fully charged, it will crank and turn the engine over reasonably well. But the next time, all I get is a loud click which I think is the starter solenoid. After that it wont turn over at all. Following my earlier post Back home, on the drive, hot start was fine, tried it a few times, one after the other and it started each time. What next? As I see it options are 1) Put the old Banner back on to rule out battery, or replace Odyssey with a new one? 2) wait till winter and unwrap loom and replace all brown/brown red wiring 3) FIA key 4) Rewire relay 5) Replace MRFU 6) Replace Solenoid or whole starter (original, 15yr old Magnetti Mareli, solenoid on top) 1) I did this after my earlier non start breakdown and it was a bit better. Should I buy a new battery? 2) not done yet 3) New key on order 4 & 5) to do 6) Starter has been replaced with an eBay sourced reconditioned one. So I think there is enough umph to throw the solenoid but not enough to turn the motor over. My relay mod (I think) is in parallel, as I have scotch clipped the relay mod wires into the main MRFU feed wires to avoid permantly cutting the wires. Is there a plonkers guide to wiring it to completely bypass the MRFU which could be completely knackered? If the MRFU is goosed, presumably there isn't enough power getting through to the external relay and causing a non start. The method I wired my relay in is that of Chris W/ AR7E page here Ive a rolling road session booked a week on Friday and have yet to road test the car after winter work and need to fix the car ASAP otherwise Im going to have to cancell it. Im fed up of spending time working on the car and SHMBO is getting grumpy as Im always in the garage. Edited by - TomB on 5 Mar 2013 11:45:18 Link to comment Share on other sites More sharing options...
Mankee Posted March 5, 2013 Share Posted March 5, 2013 Sorry to hear of your troubles, Tom. I've been planning the re-wire of my car late and night recently and one of the jobs is to junk the MFRU completely, and just have three external relays for the fuel pump, main power and starter (I don't run a lambda sensor). On my internet travels, I saw this handy link from a club overseas I think. Click on MFRU and it shows the schematics of the innards of the MFRU: http://www.tom-seven.stillgame.ch/Navigation2/Map.htm# If you need an MFRU to try or just to have as a backup for Friday, let me know and I can stick my spare one in the post to you ASAP. Does your fuel pump still prime when you turn the ignition on? Good luck! Link to comment Share on other sites More sharing options...
TomB Posted March 5, 2013 Share Posted March 5, 2013 Thanks Mankee. That link looks useful, I just need a nice simple set of intructions as my electrical knowledge is limited. I hate electrics, they are the worst part of woring on the car. I like spannering and fitting, but electrics leave me baffled most of the time! Fuel pump primes, all I get when I press the red button is a loud click which I think is the starter solenoid. It sounds heavy, rather than a quieter relay click. Tonight Ill crawl under the dash to check switch connections. Should hopefully have a new FIA key arrive tomorrow which will eliminate that as a problem. Link to comment Share on other sites More sharing options...
Mankee Posted March 5, 2013 Share Posted March 5, 2013 I could post up some wiring instructions that work by logic in my head, but seeing as I've not actually put it into practice yet (apart from annoying the missus at random hours of the morning by scribbling down wiring diagrams), I shall leave that down to someone else! I had an FIA key problem whereby the switch/key was getting worn and bottomed out, not making a good connection to the main power feed to the starter, fan fuel pump etc. Ignition and dash still worked, but no "heavy" stuff that needs a strong +ve feed. New key didn't fix the issue, but a very small self-tapper screwed into the end of the key to stop it from bottoming out did. Bodge-tastic! Link to comment Share on other sites More sharing options...
TomB Posted March 5, 2013 Share Posted March 5, 2013 The link Mankee provided, particularly the MRFU page here, looks useful. Am I right in thinking that I need to completely remove the starter relay in the MRFU from the system, and I can do this by removing the scotch clips piggy backing onto the input wiring, unclip them from the plug and directly connect to the new relay? Link to comment Share on other sites More sharing options...
TomB Posted March 6, 2013 Share Posted March 6, 2013 Ive rewired the relay in a more robust manner, and got rid of one of the scotch clips by feeding +ve directly from the battery to the relay rather than via a scotch clip on the MRFU live feed. I think Ive narrowed part of the problem to high resistance across the FIA switch - when 'on' the resitance through the switch is 5ohms. Im no electrician, but that sounds high on 12V system. The resistance on the cable from the battery to the switch is 0.03ohms, so its several orders higher. Further, when the input cable is attached to the output of the switch, and thus bypassing the higher resistance, the starter cranks the engine quickly enough for the Emerald ECU green LED to light. Hopefully the new witll arrive today and I can confirm a dodgy FIA switch. Link to comment Share on other sites More sharing options...
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