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The next direction would be disconnecting the white wire (tach) at the Hei and start /run the engine and look at the tach. On visuals, is the white wire next to any plug wires? If so reroute it clear of them.
Thank you..
fascinating
ok..removed white wire..or yellow/white condenser wire
observations
ignition on not running..needle at 100 rpm and noticed slowly settles to 0.
start car dives down and up like before then stays at or below 0..
while running it pulsed , ticked off zero..grab phone to video and only catch it once..engine speed did not matter.
also noted that it is below zero..which is probably why it reads off at 400 when idling..
thoughts?
Last edited by interpon; Jun 17, 2020 at 05:43 PM.
Make sure the capacitor is unplugged from the engine harness and retest. If the tack still acts erractic the tach is most likely defective. At this point I would have the tach exposed and verify power and ground right at it. Then condem it.
Make sure the capacitor is unplugged from the engine harness and retest. If the tack still acts erractic the tach is most likely defective. At this point I would have the tach exposed and verify power and ground right at it. Then condem it.
thanks.
unplugged both sides..at cranking same drop and flutter then fine after starting.
so this is interesting, no clue how or why this happens..
key on is at about 100 rpm..as i leave ignition on it drops...slowly.when oit starts it starts keeps going past zero but if i increase rpm andi hear alternator whir and charge more it accelerates the dropping of the needle below zero...assuming it stops somewhere and makes sense when first idling tach is accurate at 900 rpm then drops to 400 andlevels out...its done thissince i got it working with first board
so what could make the tach slowly drop as it heats or is powered ? Alternator again high?
could
not get it to flicker when running this time..and 99.9% doesn’t flicker when running justcranking drop below zero and up til it starts..
3rd board willcox triple checked...i have measured studs each time for groung and voltage..sent entire tachometer to willcox too for calibration and board
Last edited by interpon; Jun 17, 2020 at 08:44 PM.
Issues like this are frustrating for sure. For most its not practical, but having a laptop based oscope will set you free on identifying "why". For example I helped out a guy with a 582ci 70' Charger and his issue was with the fuel gauge. After the engine started the gauge would drop to empty. Key on engine off the gauge read normal. After the basic tests and found nothing I put a Pico scope on it . I found his MSD Black 7AL-2 Ignition Control was sending a square wave back feed into to the car when started influencing the dash voltage limiter. The owner had replaced it previously 3 times. He purchaced the car with the 7AL 2 aready in it and wanted it out for some reason after he learned the issue. Anyway I called MSD for info for sending the unit in for repair and the tech line thought I was nuts and had never come across an issue like that. He installed an all in one MSD distibutor. Problem solved
Issues like this are frustrating for sure. For most its not practical, but having a laptop based oscope will set you free on identifying "why". For example I helped out a guy with a 582ci 70' Charger and his issue was with the fuel gauge. After the engine started the gauge would drop to empty. Key on engine off the gauge read normal. After the basic tests and found nothing I put a Pico scope on it . I found his MSD Black 7AL-2 Ignition Control was sending a square wave back feed into to the car when started influencing the dash voltage limiter. The owner had replaced it previously 3 times. He purchaced the car with the 7AL 2 aready in it and wanted it out for some reason after he learned the issue. Anyway I called MSD for info for sending the unit in for repair and the tech line thought I was nuts and had never come across an issue like that. He installed an all in one MSD distibutor. Problem solved
thank you..
i did change coil cap plugs wires..i did not change module or distributor.. any link to a laptob oscope? i remember my dad building a heath kit one when i was a kid..thought i was really someone playing with it..
I found his MSD Black 7AL-2 Ignition Control was sending a square wave back feed into to the car when started influencing the dash voltage limiter. The owner had replaced it previously 3 times. He purchaced the car with the 7AL 2 aready in it and wanted it out for some reason after he learned the issue. Anyway I called MSD for info for sending the unit in for repair and the tech line thought I was nuts and had never come across an issue like that. He installed an all in one MSD distibutor. Problem solved
I have no idea if this means anything or not but I just replaced my interior dome light with an LED when I put it in it didn’t work so I turned it around for a different polarity, works fine.
Without starting the car if I turn the ignition on the tachometer goes to about 200 RPM and slowly drops down towards zero as it ‘heats up’ kind of but the interesting thing is is that when I click the ignition off my new LED light flashes for just a quick second. Like a flash..
I have no idea if this means anything or not but I just replaced my interior dome light with an LED when I put it in it didn’t work so I turned it around for a different polarity, works fine.
Without starting the car if I turn the ignition on the tachometer goes to about 200 RPM and slowly drops down towards zero as it ‘heats up’ kind of but the interesting thing is is that when I click the ignition off my new LED light flashes for just a quick second. Like a flash..
Oh boy.
Well, something is making a transient spike for sure.
Still looking..i was wondering about the positive cable to starter..is it supposed to be so close to the heat shield? I remember changing plugs i tried to index further away but there is a locking tab on cable end and only fits one way..i dont see any arcing? Does it look right?
Last edited by interpon; Jun 23, 2020 at 08:34 PM.
I really appreciate everyone’s help..i am learning how to do you tube..so if anyone can help me resolve this tachometer thing it’s driving me nuts.
so tachometer was dropping about five hundred RPM so I reset the needle to zero for some reason it seems to when it gets warm or runs for a while and tachometer slowly drops five 600 RPM so I’m resetting it to zero I noticed it was jumping again and in one video after I started it a second time I can turn the heater on high and move it from off through max back-and-forth and make it job a couple thousand RPM still looking so any help appreciated
once in a while i thought i could move window and make it jump not this time..just blower now and only high on and off (well off to low fan)
This video was after zeroing, then jumping doing nothing just idling
At around the 1:15 mark of the 3rd video I can hear you cycle one of the windows and the needle fluctuates a little but then you do something else and the needle moves erratic, are you selecting the fan speed switch to High only, NO A/C NORM or MAX?
At around the 1:15 mark of the 3rd video I can hear you cycle one of the windows and the needle fluctuates a little but then you do something else and the needle moves erratic, are you selecting the fan speed switch to High only, NO A/C NORM or MAX?
correct.. window does almost nothing (it did in past sometimes) and yes I was trying everything..and switch in HIGH, from off to max and off again...(and between max and normal it pauses and does same thing)..do it in low or mid points nothing
Reading and re-reading post #42 to present it does sound like you are getting a spike.
I know you are focusing on the Tachometer needle fluctuating, but do you see any odd twitching of the volt meter needle and does your GEN light work as it should?
Circuit #39 is your Gauges circuit that includes your Tachometer.
The GEN light includes both Circuit #39 & Circuit #25 (Circuit #25 is your Brown Wire at the 2 wire connector) at your alternator.
I know you have had the R12 side open for another problem but when you can, unplug that Brown & Red 2 wire connector and cycle your ignition switch and watch your tach needle movement.
Reading and re-reading post #42 to present it does sound like you are getting a spike.
I know you are focusing on the Tachometer needle fluctuating, but do you see any odd twitching of the volt meter needle and does your GEN light work as it should?
Circuit #39 is your Gauges circuit that includes your Tachometer.
The GEN light includes both Circuit #39 & Circuit #25 (Circuit #25 is your Brown Wire at the 2 wire connector) at your alternator.
I know you have had the R12 side open for another problem but when you can, unplug that Brown & Red 2 wire connector and cycle your ignition switch and watch your tach needle movement.
thank you..
volt meter moves/ jumps but only loads no spikes or twitches like tach.
edit: tach jumps ignition on move high relay blower off and on..volt meter fairly steady..UNPLUGGED alternator repeat test.. same..
no gen light all working OK
i shall unplug wire from alternator and repeat test ignition on ..start too i assume unplugged?
hope to button up AC if seals come today and vacuum only, then will proceed as above..(do i need analog meter? i have digital)
while screwing with my AC and blower..
i noted that when AC on and ignition on with blower in HIGH..when you turn off ignition the fan has a delay for about 5 seconds..
when ignition on and shown in video.. i can make tach jump on and off by the switch in high..
When it shuts off WHEN ON THE DELAY ignition off.. there is NO JUMP at all.. hmmm
edit.. and remembering early on testing that even tach not connected to distributor will still jump..
Let me get on the same page...
You slide your selector to MAX A/C energizing the High Speed Fan Relay coil, fan speed will be on High no matter the position of fan speed switch.
You turn the ignition switch off and the fan continues to run for about 5 seconds?
It is still unclear to me what you are doing with other switching that makes your tachometer needle wig out.
If you pull the 2 wire connector (Orange & Black wires) from the high speed fan relay and slide your selector to NORM A/C and move your fan speed switch through all positions does your tachometer needle do the same twitching?
Also when in the NORM A/C position and fan speed switch in ANY position and you turn ignition switch OFF does your fan continue to run for the same 5 seconds?
Now connect the 2 wire connector of the High Speed Fan Relay leaving the slide selector in NORM A/C and run the fan speed switch through all of its positions and watch tachometer needle for twitching.
When you turn your ignition switch off in the NORM A/C position does your fan still run for the same 5 seconds?
Trying to isolate is twitching only happening under certain conditions.
Let me get on the same page...
You slide your selector to MAX A/C energizing the High Speed Fan Relay coil, fan speed will be on High no matter the position of fan speed switch. fan speed switch works..only jumps in high
You turn the ignition switch off and the fan continues to run for about 5 seconds? Correct ONLY in AC mode
It is still unclear to me what you are doing with other switching that makes your tachometer needle wig out. Only moving the switch from off to max normal..fan in high position. it also blips between max and norm as it slightly shuts off between the two..normal to defrost does not blip as it does not shut off fan..
If you pull the 2 wire connector (Orange & Black wires) from the high speed fan relay and slide your selector to NORM A/C and move your fan speed switch through all positions does your tachometer needle do the same twitching? NO and no high speed fan obviously..with connector pulled.
Also when in the NORM A/C position and fan speed switch in ANY position and you turn ignition switch OFF does your fan continue to run for the same 5 seconds? NO with it unplugged
Now connect the 2 wire connector of the High Speed Fan Relay leaving the slide selector in NORM A/C and run the fan speed switch through all of its positions and watch tachometer needle for twitching. IN AC MAX OR NORM it will delay (stay) on in HIGH only.. any other speed blower shuts off when ignition off
When you turn your ignition switch off in the NORM A/C position does your fan still run for the same 5 seconds? ONLY IF IN HIGH
Trying to isolate is twitching only happening under certain conditions.
thank you!
Note this is the third relay for blower..original i sanded contact but eventually gave up..second rock auto..worked but third more like original so kept it..(ebay)..audible click in and out of high in relay ..
and only high on and off (well off to low fan)
