tacho eratic movment

Post by **pcman** » Wed Oct 20, 2004 9:27 am

hiya all as of yesterday my fj40 with a stocker 2f engine the taco has been jumping i didnt really notice it but it was running like crap i thought it was about to run outta gas but it wouldnt run any better on petrol when i started it last night then i noticed the tacho jumping from 2000-3000 rpm
now ive never seen this before so i dunno where to start im guessing its something to do with the points like there not opening and closing properly but ive never liked dealing with them

anyone got any tips

cheers
pcman

Post by **dumbdunce** » Wed Oct 20, 2004 10:08 pm

your diagnosis is probably correct. points ignitions are pretty crappy, you really need to clean and adjust the points every few thousand and replace them every 10,000km, more frequently if you do a lot of offroad/low range. the alternative is to convert to an electronic ignition - Dickies and Jaycar have a kit that will run off the points without converting to a hall effect or optical pickup, but with a very small current through the points so they never burn and almost never need adjusting.

other things that could cause the behaviour you describe are a bad distributor capacitor or flakey wiring betweeen the coil and distributor, or a coil on the way out.

ignition systems suck to troubleshoot. good luck!

Brian

Post by **pcman** » Wed Oct 20, 2004 10:12 pm

everything has been replaced less than 1000km ago and ive only just firtted a new gt40 coil last weekend
i think ill check the points ive been reading up on the gm hei conversion that looks interesting but seems to have its fair share of problems

the dse/jaycar kit looks interesting might have to see if i cant get it going might be w worthwile mod

Post by **dumbdunce** » Wed Oct 20, 2004 10:21 pm

pcman wrote:everything has been replaced less than 1000km ago and ive only just firtted a new gt40 coil last weekend
i think ill check the points ive been reading up on the gm hei conversion that looks interesting but seems to have its fair share of problems

the dse/jaycar kit looks interesting might have to see if i cant get it going might be w worthwile mod

didi you fit the right type of coil (resistor/non resistor?) if you've fitted a resisitor type coil without a resistor the primary winding might be breaking down with the excess voltage. on the other hand if you've fitted a non-resistor type WITH a resistor, the voltage will probably not be sufficient to drive the coil especially at higher rpm and at starting. (this setup might not even run at all and would be really hard to start).

could also be a flakey resistor. try bypassing it for a SHORT drive to see if the problem goes away?

but I still think you're on the right track with the points.

Post by **pcman** » Wed Oct 20, 2004 10:47 pm

umm no idea about a resistor i just brought it and bolted it up lol ill check it out tomorrow with my multimeter and see what voltages its getting but it was running fine till yesterday so hopefully its just the points

cheers for the tips

Post by **dumbdunce** » Wed Oct 20, 2004 11:55 pm

pcman wrote:umm no idea about a resistor i just brought it and bolted it up lol ill check it out tomorrow with my multimeter and see what voltages its getting but it was running fine till yesterday so hopefully its just the points

cheers for the tips

resistor is a white ceramic box about the size of your thumb, on the side of the coil. My FJ had one I think, it was an 81 model. Old ones might not have one.

it will be more enjoyable that the 22R 4 runner I am working on at the moment, anyway.

Post by **pcman** » Thu Oct 21, 2004 9:16 am

well i took a look at it this morning the points are screwed so ill go get a new set and a new set of feeler guages mine i cant read any mesurment on them
also the coil says 12v system use with resistor and its currently getting 14v so im gonna find a ballast resistor if supercheap dont have one im sure ill find one at the wreckers i looked at my bros gemini and its got a big white resistor thing attatched to the coil so i know what im looking for

Post by **dumbdunce** » Thu Oct 21, 2004 12:10 pm

pcman wrote:well i took a look at it this morning the points are screwed so ill go get a new set and a new set of feeler guages mine i cant read any mesurment on them
also the coil says 12v system use with resistor and its currently getting 14v so im gonna find a ballast resistor if supercheap dont have one im sure ill find one at the wreckers i looked at my bros gemini and its got a big white resistor thing attatched to the coil so i know what im looking for

you can't really just slap a resistor into a non-resistor system, there is a second circuit in resistor systems that shor circuits the resistor on starting. if you don't have this extra circuit it will be very hard to cold start. best thing to do is get a 12v non-resistor coil. if you are dead keen on a resistor system (it does make the points last longer and) then you have to run a wire from the starter solenoid trigger, to the coil + side, and ensure that circuit is capable of supplying an additional 5 - 10 amps, or you'll need to stick a relay in, or run the wire from the starter motor + terminal.

cheers

Brian

Post by **pcman** » Thu Oct 21, 2004 12:55 pm

well i just wacked a resistor in and it has fixed the problems 100% runs perfect but yes its hard to start but it always has been but not its a bit harder ill wack a power wire from the starter to the coil and see if that helps

Post by **the_smoo** » Thu Oct 21, 2004 2:29 pm

i whacked in a jaycar ignition kit to the 308 a coupla months ago.. helps more so with idle, and overall it is generally smoother..

not a bad investment for 5itty odd bucks..

Post by **pcman** » Thu Oct 21, 2004 2:39 pm

sounds good might have to invest in one of them im ok with electronics built a few circuits and crap so i should be cool doing it but if i stuff it up ill be contacting you to fix it for me lol

Post by **the_smoo** » Thu Oct 21, 2004 3:31 pm

no problemo

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