Carina Starter Motor Constantly Engaging And Starter Relay Burnt

[dave48703]

Model: carina e 1.6 gli auto

My starter motor was turning on and off even with the ignition off and the key out, and also with the car in "park" (in an auto this should cut off the starter ciruit too CORRECTION: I got this mixed up here, but did try it the right way with no effect when I actually had the problem: in autos it is when the car is in "drive" that the starter circuit should be cut off, you can normally only start it in "park" and "neutral") (in fact the starter had started engaging, and I smelt a burning smell, while actually driving, and then I pulled in). It was not on all the time, but was as if it was switching on and off constantly.

I left it like this for about half an hour until the aa man came. This was a mistake, I should have disconnected the negative terminal of the Battery immediately. I did not do this actually because I didn't then know what the problem was and I had just recently been reading about how it is bad to disconnect the Battery when the car was running and intially (when the Battery had enough power) the engine was being started although not continuing because the ignition was off. Also. I didn't have a spanner (note to self: should always carry the means to disconnect the battery).

Anywya, the aa man did just disconnect the battery and said he was more or less sure the problem was caused by the starter motor only. When I pulled the starter motor it was indeed damaged (magnet cracked on armature I think) and has been repaired by an autoelectrician. He said the fault could have caused the symptoms I had.

However, on opening the fusbox I noticed that the starter realy is burnt (that is where most of the buring smell was coming from actually, a horrible plastic burning smell), and not only that but it had burnt its way though part of the fusebox, with some of the metal tracks (thick on this fusebox, not pcb-like tracks) even being melted. The side of the relay that was most burnt was the side with the connector labelled "1", and on the fusebox the track and connection spade had melted away completely for this connector (in fact the other connectors on the fusebox and realy didn't really look to have been heating up themsleves, just maybe scorched from what was going on at terminal 1). According to the wiring diagram in Haynes the connector "1" leads to the automatic inhibitor switch and then the ignition switch.

Now, although puzzled at first as to how the starter motor could have been running with both the ignition switch and auto switch open, after looking at the wiring diagram I could sort of understand how current could flow through the starter motor because of a short of somekind on the starter or solenoid. What I cannot understand is how this could have caused the starter relay to be burned, especially the part of the starter relay that is not the part where the current for the solenoid flows through. Surely (even though it was happening for quite a long time as I didn't disconnect the battery) the current would have just taken the easier route through the thick wires direct between the starter motor and battery?

So I am kind of thinking now that the initial problem was with the relay or the wiring to the relay on the "switch side" as opposed to the solenoid side. It is hard to belive that both the ignition switch and the auto switch failed at the same time, so probably a short somewhere in the wire that comes into the relay at connector 1, after it has gone past the ignition and auto switches? I also can't understand how no fuses blew throughout all this (would it be worth contacting Toyota as it potentially dangerous - does anyone know the best Toyota contact for things like this in the UK - the general contact on their website doesn't look very promising and they don't even have email?)

(Oh, I tested the relay with an ohmmeter - it is a bit distorted from buring but even terminal 1 survived - it must be stronger than the fusebox connector. Terminals 3 and 5 (the "solenoid" side terminals) are open, and there is resistance of about 1 ohm between terminals 1 and 2 (the "switch" side). There is no unexpected continuity between 3 and 1, 5 and 1 etc. But the ohmmeter only uses low voltage/current so maybe this is of limited use ..)

Anyway, if anyone has any ideas/experience of this kind of thing please ...

(Side note, just in case anyone is interested in how I removed the starter motor: on this particular model it is quite possible to remove the starter motor without raising the car on axle stands as it say to do in Haynes. Iin fact the most dificult nut was the upper nut, and access to this is not really improved by the Haynes suggestion of removing the air cleaner assembly - the biggest impediment are some other pipes running off the engine block and also a big electircal wire bundle and clip positioned just where you would need to put a socket - so had to use a flat spanner; still haven't figured out how I am going to tighten the bolt on refiting to the specified torque if I can't get a socket in there. Even with a flat spanner the upper bolt is really hard as you only have a few degrees of turn without hitting pipes and things (very tough when the bolts are seized on), again the Haynes suggestion of removing the air cleaner assembtly makes absolutely no difference. As for the lower nut, I would not have liked to have tried to loosen it when the car was on axle stands anyway, and you can slide under the car unless you've got a really big chest, or alternatively reach round and down from the top - I found initially I had to go from below just so I could get the force to loosen the seized bolt (note: there is another bolt very near to the lower starter mounting bolt that I think is an engine/transmission bolt, well whatever it is it is important not to loosen that instead!). With the lower bolt you do also have to be careful not to drop a spanner and be careful where you are levering from as the lambda sensor is in that region - I dropped a spanner and it did hit the sensor - not head on but brushed it, so I hope it is OK. Anywyay once the bolts are removed, it is possible to take the starter motor out from the top and rear of the engine by carefully manouvering it round obstructions (as opposed to lowering it as Haynes suggests), of course being very careful not to drop it (it is difficult to both support the starter motor and remove the bolts but I used a strap secured on the front crossmember for security - it could be secured anywhere probably the front crossmember was not the best place as it had to come over the engine). Generally, although Haynes is a good general guide, it never contains enough info and you have to work 50 % or more out yourself. I usually end up making notes - I think it would be useful if there could be somewhere on the net a Haynes addendum where people could put in their own experiences for particular models - mayeb Haynes is the wrong starting point I don't know - for one thing motor manufacturers could follow the expample of IBM, HP etc and have full service manuals available for free download - we pay enough for the hardware!).

P.S. I have been looking even more at the wiring digarams in Haynes and unfortunately for my car they are wrong. Certainly the colours of the wires can not all be right, and it is hard to work out which terminal is wich on the relay as the numbers given are different in Haynes and even when they are the same as for the starter motor relay I'm not sure they really correxpond (e.g. I think 1 and 2 may be swapped round, in terms of what is written in Haynes and what is written on the top of the relay). The wires for example - either terminal 1 terminal 2 (according to the starter relay cover it is terminal 2) out of the starter relay connects to a black/red wire (I took the fusebox apart so I know - the wire connectors are not just where the relays are but may follow tracks on the fusebox to get to them) and Haynes says it is a either a white/black wire or a black wire (i.e. the colour Haynes says for terminal 1 or 2). The other problem is that Haynes says terminal 2 connects to earth 3 (via white/black wire), but whichever is Haynes terminal 2 it doesn't matter as some other terminals on other relays are also supposed to connect to earth 3 and they all seem to be joined to a track that does not in fact go to a big wire, but in fact two small wires and although one is white/black the other is white. My main problem in the fusebox now is figuring out which track (then wire) terminal 1 (or maybe it is 2 accorgin to Haynes) connects to, as that is the part where the track is melted. I suppose the most likely explanation if there is some truth to the Haynes diags is that Hyanes terminal 2 is in fact termnial 1 as shown on the top of the starter relay and vice versa, and that somehow earth 3 is via those thin wires (at least one of them is the right colour but they really don't look thick enough to be earths.) Sorry probably this last para will be meaningless unless you have opened up a carina fusebox and tried to understand how everything fits together - if anyone has by the way a photo of the tracks near the starter realy corner would be very much appreciated ..

It is all so difficult to see where the wires go with them all in the bundle as well. Does anyone know how if you can do damage with a multimeter in OHM measuring mode to car wiring components if you used it to figure out which wires went where.

[dave48703]

Does anyone have any recommendations on where to buy starter relays. I tried searching for my toyota one with no luck for buying it although it was listed on a Chinese site. I could try toyota but hte realays look expensive too. I suppose any starter relay should work as the principal of the ignition switch providing a low current to switch a slightly higher current to the solenoid is the same? But my relay has a100 written on the side which I hope doesn't mean 100 A which would make it more difficult to find a replacement. Frankly with all of these relays in the fusebox half of the wires (even connecting to the higher current part), don#'t seem thick enough to do supply the relay with what it is rated at (e.g. 30a for most of the realays, which seems alot).

I did some tests with an ohmmeter (Battery completely removed) and am even more confused now. The engine compartment fusebox was removed also, so testing the circuits leading into it really.

When I tested between the relay/fusebox end of the fairly thick black wire that I guessed goes to the solenoid, and the solenoid end of the wire that does in fact connect to the solenoid, this was indeed OK with zero resistance (think I checked for no leak to earth but didn't write down result), so at least I know that this is the wire for terminal 3 of the starter relay, and this tallys with both Haynes and the relay cover.

Then I tested between the end of the wire that comes from the ignition switch and goes into what Haynes calls F32 (with the fuse removed of course so jsut testing this wire - the wire is identifiable and tallys with Haynes as regard colour, as it is a white/blue wire, with a thick positvie white/red wire on the other side of the fuse), and the relay/fusebox end of the thin red/black wire that must come from the igntion switch (via the auto box and maybe alarm/immobiliser that I am not sure what I have) to starter relay terminal 2 (which Haynes calls terminal 1) (I say must because this is the only logical explanation of how the wires can connect after taking the fusebox apart and looking at all the connections, but if Haynes is radicallly different to my car it could come from somewhere else). This will only really make sense probably if you have Haynes and can look at the diagram. Between these two ends is the circuit which is supposed to trigger the relay.

So (with autobox in "Park") I got infinite resistance with the ignition off, and on "acc", and about 50 ot 70 ohm resistance with the igniton held in start position (a bit high but kind of looking good at this point). Howver, with the ignition switch in the ignition position, I got 4.86 kilo ohms. I would have thought there should have been no contiinuity. I tried removing fuse F6 (which is in the way of the part of the circuit I thought I was testing, and still got the same result with the ignition in the ignition position).

With the auto selector in D, and the ignition turned to start, the resistance was the same as with the ignition in ignition with auto selector in P (4.86 kilo ohms), so at least the auto switch is having some effect, but how current is still flowing between the ends of these two wires baffles me.

Between the end of the wire that goes into fuse 32 and earth there was 0.588 kilo ohm, with the ignition on (I think with it in "off" as well). And between the end of the wire that goes to starter relay terminal 2 (haynes terminal 1) and earth, no matter what position the ignition was in, there was 4.86 kilo ohms.

Just totally confused, for it to be 4.86 k between the end of the two wires when they should be isolated, I guess with the results to earth the conclusion is that they are both leaking to earth, at separate points either side of the ignition, F6 and auto selector, but if so why do they not leak to earth when the igntion is in the off position?