exint2 Posted April 21, 2016 Report Share Posted April 21, 2016 Well it's not the relay! Following my previous thread I have replaced the Relay and the issue still exists - also I can feel the relay "latching" when I flick the column switch. My feeling is that the solenoid is not getting enough voltage to fire - reason being that when driving home in the dark last night and seeing negative amps it was even more recalcitrant than normal - also the indicator relay was suffering (I am fitting an alternator soon so these charging issues should be a thing of the past). However I'm not sure that explains why it is unreliable in daylight when ancillary current draw is very low. From the experience of the forum will the impending upgrade to my electrical system cure this issue or is it a "lazy" solenoid that needs replacing? Any simple tests I can do to establish either theory - or a different one! Thanks Nick Quote Link to post Share on other sites
RogerH Posted April 21, 2016 Report Share Posted April 21, 2016 Hi Nick, It is difficult to solve/understand one problem if there is another problem causing chaos. you can eliminate the electrics whilst driving by investigating the solenoid from only the battery whilst standing still - engine not running but ignition on. When the OD switch is operated and you here a click from the relay - have you tested the volts to the solenoid. If you have battery volts at the solenoid and the solenoid has not operated then either the solenoid is burnt out or it is not being earth correctly. The OD earths through its body - check the engine earth strap. There is also a cable connector to the solenoid from the relay. This may be corroded/dodgy. If all works OK from the battery then you have a dynamo problem that is reducing volts and current. Roger Quote Link to post Share on other sites
ChrisR-4A Posted April 21, 2016 Report Share Posted April 21, 2016 (edited) Hi Nick, its a 4A? and all the power goes through the ammeter. I had a similar problem where the overdrive disengaged when the electric fan came on taking an additional 5 amps. I found the nuts on the back of the ammeter were all rusty, a good clean up fixed it. You may have 12 volts but not enough current. Always worth having a spare soleonoid, why not try a new one and that will either fix it or you will have a spare. Edited April 21, 2016 by potts4a Quote Link to post Share on other sites
RogerH Posted April 21, 2016 Report Share Posted April 21, 2016 Hi Chris, Only the charging current should go through the ammeter. However I would agree that more than one 4A has the lot going through it. http://www.advanceautowire.com/tr24a.pdf Roger Quote Link to post Share on other sites
exint2 Posted April 21, 2016 Author Report Share Posted April 21, 2016 Hi Guys I can get a click from the solenoid most of the time (certainly more than when she is running) when the car has ignition on and in 4th gear but not running. Looks like it is an amp's issue I will look at the ammeter to check - thanks Chris though I think that Rogers "dodgy earth" might be the answer (as I've had a couple of others on the car) Nick Quote Link to post Share on other sites
LGFromage Posted April 21, 2016 Report Share Posted April 21, 2016 My money is on the gearbox switches. Sometimes they work and sometimes they don'tl Tim Quote Link to post Share on other sites
Paul Down Posted April 21, 2016 Report Share Posted April 21, 2016 (edited) Are you sure that your problem is electrical? With wear the normal ( as technical manual) instructions for setting up the solenoid gap can sometimes cause intermittent operation. I had this problem and a bit of over adjustment cured the problem. Edited April 21, 2016 by Paul Down Quote Link to post Share on other sites
littlejim Posted April 21, 2016 Report Share Posted April 21, 2016 With mine the lever positioning 'by the book' didn't get the overdrive to engage. I had to put it up on jack stands adjust the lever past the 'spot' by hand and then run it to see if it worked. Finally got good engagement with the lever about 2/3cm (memory, haven't been under to check) above the dimple in the gearbox casing. Quote Link to post Share on other sites
peter clarke Posted April 22, 2016 Report Share Posted April 22, 2016 I agree that the switch on the top of the box could be the cause if it has spade connectors. The connectors are riveted to the contacts in the switch and they can work loose and give intermittent continuity. With care it is easy enough to open the crimps on the switch body to release the top plate of the switch, punch the connector tight and replace. Quote Link to post Share on other sites
PhilipB Posted April 22, 2016 Report Share Posted April 22, 2016 You may have this already, apologies if you do Link to the Type A overdrive Manual http://www.tonydrews.com/Overdrive/A-type%20OD%20manual.pdf There is a detailed section on fault finding including the electrical circuit Phil Quote Link to post Share on other sites
Steve Priest Posted April 22, 2016 Report Share Posted April 22, 2016 The gearbox switches earth the relay coil, so if the relay is clicking but the solenoid isn't then I don't think it can be the switches - a dodgy switch would stop both the relay and solenoid from working. Sounds like a dodgy connection on the solenoid circuit or the solenoid itself to me. Could perhaps be a problem with the contacts in the solenoid that switch the more powerful 'pull-in' coil on and off. Cheers, Steve Quote Link to post Share on other sites
RogerH Posted April 22, 2016 Report Share Posted April 22, 2016 Hi Steve, generally if it is the internal solenoid switch then you would be getting a vibrating racket as it breaks and then tries to make. Roger Quote Link to post Share on other sites
exint2 Posted April 22, 2016 Author Report Share Posted April 22, 2016 Thanks for all the advice Chaps. Seems to definitely be a dodgy connection on the solenoid wire that "comes out of the transmission tunnel" - I have replaced the push connector with a new one and soldered the connections rather than using a crimp fit only (I race RC electric cars so crimp fitting is an anathema to me!) - This does seem to have fixed it - however I am aware that I have "waggled" the wire at the solenoid end so that may have temporarily improved that contact which might be the real problem...... time will tell :-) Nick Quote Link to post Share on other sites
John Morrison Posted April 22, 2016 Report Share Posted April 22, 2016 Loose inhibitor switches can bounce in running. They are not just screwed tight but have a setting as described in the workshop manual. John. Quote Link to post Share on other sites
TR 2100 Posted April 22, 2016 Report Share Posted April 22, 2016 Not to say that my intermittent operation was caused by the same fault as yours But Mine was dodgy switches in the gearbox cover. These switches provide the earth that is required but only when the gearbox selectors are in 2nd, 3rd or 4th. I cheated a bit to identify this fault - I took the overdrive switch wiring direct to earth. Although this can either identify or eliminate the earth as the cause, it means that you can select overdrive in ANY gear, including reverse. If you forget you are in overdrive and try to reverse, you will knacker your overdrive as they are NOT designed to go in reverse. AlanR Quote Link to post Share on other sites
LGFromage Posted April 22, 2016 Report Share Posted April 22, 2016 When they are old the gearbox switches are less likely to operate properly and do not allow the full voltage to be passed on to the solenoid. In turn the solenoid tries to work but has insufficient power to select the internal switch for normal operation. This leads to the vibrating racket to which Roger refers and could lead to solenoid failure. If the switches are removed their performance can be restored by using WD40 and actuating the plunger a number of times at the same time as testing the electrical resistance/continuity. This worked for my car and I cannot imagine that this method is any more unreliable than buying new replacement switches Tim. Quote Link to post Share on other sites
tthomson Posted April 22, 2016 Report Share Posted April 22, 2016 Check that the solenoid plunger is not being prevented from moving freely by build up of rust or dirt inside the solenoid, but in my view it is more likely the adjustment of the lever not being sufficient to engage the O/D TT Quote Link to post Share on other sites
exint2 Posted April 24, 2016 Author Report Share Posted April 24, 2016 Almost fixed ...... or less intermittent (if that is possible!) Longish run yesterday 60 miles worked all but twice, but on both those occasions switching it off and then on again a few seconds later got it to fire ..... Thoughts? Quote Link to post Share on other sites
ChrisR-4A Posted April 24, 2016 Report Share Posted April 24, 2016 Could be the main column switch, some can be dismantled and cleaned. Quote Link to post Share on other sites
TR 2100 Posted April 25, 2016 Report Share Posted April 25, 2016 Almost fixed ...... or less intermittent (if that is possible!) Longish run yesterday 60 miles worked all but twice, but on both those occasions switching it off and then on again afew seconds later got it to fire ..... Thoughts? Thoughts ?? Rather depends on what you have done since you last checked. AlanR Quote Link to post Share on other sites
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