1984 xjs HE ign amplifier modual
#1
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ok I have possably a faulty modual in my ign amplifier.its ohming out acros terminals at 12,000 but its also ohming to amplifier case.on a 20,000 ohm setting.when i disconnect it from casing its doesnt gound out.so is it bad? I see this is GM can I replace it.and if so anyone know what is part nunber modual i need? i also herd you can replace it with an echlin?
#2
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jagernut (05-23-2014)
#3
#4
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Well I'm no expert (far from it) but since I have just gone through some of the same stuff and have had my amplifier box off like 50 times in the last week I can hopefully offer some assistance. The white rubber triangle has 2 resistors in it. One is 10 ohms and the other is 6.8 I think? The condenser is held in with a small bolt and is right next to the rubber triangle. The ground wire you speak of comes out of the harness coming from the distributor and may be connected to your manifold. It should have a round terminal end on it. There should be 2 other wires from this same harness plugged into your amplifier box. One is green and the other is red I think and they are in a 2 pin connector. Hope this helps!
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jagernut (05-23-2014)
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Yes, with emphasis on 'usually'
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Lots of recent postings (see Capriceguy's remarks) and threads on the subject. Somebody (can't keep it all straight in my brain) recently had the diode fail. Unusual, but not not unheard of
Cheers
DD
#6
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ok thanks for all the good knowledge.guys
ok i just took of amp and backing plate.looks clean inside no burt marks or burnt wires.I disconnected wire from cond to modual it does not ohm to ground.so think its good.there is another item in there just oposite of the cond in far corner.a round disc shaped object looks like huge watch battery but thicker it protrudes through amp casing it has one wire in the middle of it (white with black tracer)goes into triangle rubber thingie ill take pics and put them on my garage albums.for some reason i cant dowload them on posts go figure.anyways.I disconnected all wires from modual and tested it with ohm meter.it is grounded to amp casing.but only on a scale of 20k or higher.so think its bad.ill check harness from distributor pick up and see if there is a ground strap going anywhere.
ok i just took of amp and backing plate.looks clean inside no burt marks or burnt wires.I disconnected wire from cond to modual it does not ohm to ground.so think its good.there is another item in there just oposite of the cond in far corner.a round disc shaped object looks like huge watch battery but thicker it protrudes through amp casing it has one wire in the middle of it (white with black tracer)goes into triangle rubber thingie ill take pics and put them on my garage albums.for some reason i cant dowload them on posts go figure.anyways.I disconnected all wires from modual and tested it with ohm meter.it is grounded to amp casing.but only on a scale of 20k or higher.so think its bad.ill check harness from distributor pick up and see if there is a ground strap going anywhere.
Last edited by jagernut; 05-23-2014 at 03:57 PM.
#7
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The round disk that looks like a watch battery is the zener diode. It was shorted in my amplifier but as I understand this is not a common occurrence. The steel mesh ground strap should be connected up by the amplifier box somewhere but not connected to anything down at the distributor. This serves as a shielding wire for the 2 signal wires in this harness. I don't know of any definitive way to test the module with a multi meter, I just bought a new one.
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jagernut (05-23-2014)
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#8
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ok when you say mesh you mean the whit coax looking wire that i spliced into the inner wire of that goes to the right side female bullit connector on the four bunch of wire two middle ones that go to main coil.I was told to just peal the mesh back and insulate it from any grounds or other wires I pealed it back about half an inch and taped it good.I did however take modular out of amplifier and took it in to have it tested it was good.so i put some dielectric grease on back plate of modular that contacs amp housing and reinstalled it.also the leads conming out of dist up to amp box are red and blue like i said i ohmd them they are spec 3.75 ohms.but i have no ground wire comming up with them or comming out of dist my dist only has the two wires.the wires are factory and no broken wires in or around dist.I was told the modular in amp box has metal plate on bottom (one side) that grounds to amp casing and amp casing grounds to intake.eliminating the ground wire to dist.does that make sense? anyways im going to hook all wires back up and do the test light test.hook test light to neg side main coil and crank eng see if test light pulses.ill repost after.I posted two pics on my garage so you can see the two wires only i have from dist.
Last edited by jagernut; 05-23-2014 at 04:08 PM.
#9
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update.i tried the test light test.. connected test light to neg side of main coil.turn ign on test light lighted up brightly,turned over eng.test light pulsed brightly very fast.so i dont think i have an amplifier problem it must be somewhere in dist cap rotor or secondary wire from coil to dist.should i try cleaning all plug wires inside of cap rotor.by the way i disconnected seconday coil from main coil.dont know if that helped.Your thoughts??
#10
#11
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Did you by chance see if it would try to run with starting fluid?
Also, did you verify a good connection on the coolant temp sender?
Car will not run without signal from this sender. It's on the left side of the engine up top and has a 2 pin plug with a spring clip on it. Check resistance and if there is none then the sender is bad. Good luck!
Also, did you verify a good connection on the coolant temp sender?
Car will not run without signal from this sender. It's on the left side of the engine up top and has a 2 pin plug with a spring clip on it. Check resistance and if there is none then the sender is bad. Good luck!
#12
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yes,I tried to start but no start.Doug told me to check timming.so I did.looks like timming is 180 degrees out..when my finger blew out of 1A spark plug hole,while cranking eng, rotor was pointing to 1A on dist cap.but when I checked under car at timming mark on crank pully,it was 180 off.Somebody must had had dist out at one point.Just wondering,when I put my thumb over #1A spark plug hole it blew it out even though rotor was 180 degrees out.on dist.Is that normal? since its not technically.on comp.stroke?
as far as the coolant temp sensor.I did ohm sensor,it is around 1.6 K Now my Question is if there is no coolant water in eng and radiator,will it still start?
as far as the coolant temp sensor.I did ohm sensor,it is around 1.6 K Now my Question is if there is no coolant water in eng and radiator,will it still start?
Last edited by jagernut; 05-23-2014 at 11:27 PM.
#13
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[QUOTE=jagernut;981748]yes,I tried to start but no start.Doug told me to check timming.so I did.looks like timming is 180 degrees out..when my finger blew out of 1A spark plug hole,while cranking eng, rotor was pointing to 1A on dist cap.but when I checked under car at timming mark on crank pully,it was 180 off.Somebody must had had dist out at one point.Just wondering,when I put my thumb over #1A spark plug hole it blew it out even though rotor was 180 degrees out.on dist.Is that normal? since its not technically.on comp.stroke?/QUOTE]
Be very careful. First be 100% SURE that IA is on the compression stroke TDC. If it DEFINTELY is, then the rotor arm on the DIZZY, IF CORRECT, should be pointing at the minute 1 cast into the cap. If the cap is off, then looking down at the top of the dizzy, head pointing forward in the direction of the front of the car, the ROTOR should be pointing at roughly the 11 o clock direction.
If it is instead pointing at 5 o clock, the timing is 180 off, if it is pointing at roughly 11 o clock the timing is ROUGHLY ok. Remember that the HT leads go on in the firing order ANTIclockwise, looking down at the cap.
Greg.
Be very careful. First be 100% SURE that IA is on the compression stroke TDC. If it DEFINTELY is, then the rotor arm on the DIZZY, IF CORRECT, should be pointing at the minute 1 cast into the cap. If the cap is off, then looking down at the top of the dizzy, head pointing forward in the direction of the front of the car, the ROTOR should be pointing at roughly the 11 o clock direction.
If it is instead pointing at 5 o clock, the timing is 180 off, if it is pointing at roughly 11 o clock the timing is ROUGHLY ok. Remember that the HT leads go on in the firing order ANTIclockwise, looking down at the cap.
Greg.
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jagernut (05-24-2014)
#14
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In my experience (with other engines not this v12 madness) even if you are 180 out the engine will run, just badly. I would say that if you are sure that you have spark then you should move on to fuel. As far as blowing your finger out of the spark plug hole, yes, the piston will push air up no matter which stroke you are on. These are high compression motors and cylinder pressures are higher so even if you are on the exhaust stroke you will still have pressure, just not as much since the exhaust valve is open.
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jagernut (05-24-2014)
#15
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Thank you guys for great infoThis is what I know,I took out The 1A plug,right side front spark plug (passenger side).I put my thumb over spark plug hole.I had someone just bumping starter with key.When piston blew out of hole.I checked rotor position.looking from above,using the a/c comp as 12 o clock,I noticed rotor was pointing at aprox 1 o clock.I went under car and checked crank pully mark,stamped 1A on pully dampner to scale.I could not find mark.when I had eng cranked again I finally saw mark comming around on dampner it rested right exactly on the O degrees, tdc mark on scale.I looked in spark plug hole.looks like piston is up all the way the rotor is pointing at aprox the 7:30 on distributor.
Last edited by jagernut; 05-24-2014 at 09:43 AM.
#16
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ok, Greg in france.Im going by your description.I just put cap back on dist.(dizzy), with timming mark on dampner still set at TDC 0° on timming scale at crank pully. 1 minute mark on cap is sitting at 11:00,but rotor is at the 3A mark on cap,aprox 7:30.Now they did start leads, (plug wires) where rotor is pointing on cap and correctly placed them counter clock wise in correct order.It does look like, they started plug wire 1A off on cap by one,going counter clock wise. So do i need to remove dist and reinstall it, so rotor is pointing at 11:00 on cap,(1 mark).Then place leads,plug wires on cap in order, counter clock wise,starting at the 1 mark on cap?
Last edited by jagernut; 05-24-2014 at 11:34 AM.
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OK, if I understand correctly, you have the 1A piston at TDC compression and the timing mark on the balancer at 'zero'... but the rotor is pointing to 3A on the dist cap. So, yes, you need to lift the distributor and reinstall it to that the rotor points to 1A on the distributor cap.
If you can't 100% line up the rotor to the 1A position on the cap just get as close as you can and then turn the dist slightly to get the last couples degrees you need to line it up
After that arrange your wires on the cap, anti-clockwise, starting with 1A, so they follow the firing order.
Cheers
DD
If you can't 100% line up the rotor to the 1A position on the cap just get as close as you can and then turn the dist slightly to get the last couples degrees you need to line it up
After that arrange your wires on the cap, anti-clockwise, starting with 1A, so they follow the firing order.
Cheers
DD
#18
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Ok thanks Doug,Looks like the distributor was out and one point.Now once I do all that,my book says to release the adjuster screw locknut,on distributor and turn the screw until the timming mark on the electronic timming rotor is exactly opposite the center of the pick up modual housing.Then tighten the vernier adjuster screw lock nut.Does that tune in distributor timming?
#19
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ok,just took distributor out.With timming mark still at 0° TDC on mark.Dist turns fine.The timming rotor, the round meatal disc over shaft of distributor wiith splines on it,is pretty rusty looking.should I clean up the facial part of the spliens,with some fine emery cloth?I know these rotate around and pass pick up modual for timming on each cylinder.On that same disc.(electronic timming rotor),towards the center in deap grove that goes all the way around,on timming rotor,there are to perpendicular slashes casted in about 1/8" apart is this the mark that is to line up with middle of pick up modual?
Last edited by jagernut; 05-24-2014 at 02:30 PM.
#20
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What book are you in?
The terminology you are using sounds like it would apply to the older 'Lucas Opus' ignition, used mid-1981 and earlier.
Your car should have the 'Lucas CEI' igntion....which doesn't have an 'electronic timing rotor'
Cheers
DD
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jagernut (05-25-2014)