is it nessesary for the ivr to produce "pulsating" 5v instead of steady 5v out to the gauges?
meaning, is the bimetal ivr constantly heating / cooling thus opening and closing its internal wire wound contact?
speaking of gauges, is the eVTm accurate with the 5.0L diagram vs the 2.3L?
5.0 diagrams show the ivr powers the fuel and temp gauges
2.3 diagrams show the ivr powers the fuel, temp and oil gauges
My ignition switch melted and i lost power only to the gas and temp on my 86.
IVR powers water temp, oil pressure and fuel level gauge. And no, it isn't necessary to feed them with pulsating voltage. I have IVR mod (78T05) in both my birds and it works like charm.
PS: 5.0 refers probably to base cluster, which doesn't have oil pressure gauge.
we worked on a temp high issue but conclude the temp is not high.
the resistance from the ign sw to cluster is 8.2ohms
we were able to dial counter clockwise the IVR calibration screw but my son decided he wanted to swap another IVR on.
if he had kept the one we tweeked, it would have yielded a lower temp reading.
we placed another ivr on and the same results
temp is up to the red when the radiator cap temp gauge reads 200
the gauge is reading 12.2ohms
the sender is new,
the wiring fromt he sender to the cluster has not been checked yet but if it were high resistance, then i would think the gauge would read low temps.
so,,
do you have a diagram on the ivr? you modified?
i wonder if this symptom is normal, read carefully
-with the car running
-with the cluster pulled out enogh to get ot the rear
-wth my meter on the IVR ouput
i get dc volts pulsating between 8 and 12vdc
for some reason i thought the resistance wire made the 5v then the ivr fed the gauges... seems i have hit backwards.
with the cluster connector disconnected , i read battery voltage on the resistance wire, i was expecting a lower voltage.
the resistance on this wire was well within specs of 8.2ohms. the guage itself read 12.5ohms.
odly enoiugh, when we turn on the headlamps, the temp needle goes up about a little as well.
Remember that the resistance wire doesn't limit Volts, it limits Amps. The IVR should be steady, not pulsating. If I ever end up with an IVR problem, I'm going to build a solid state IVR. So far, though...
I wonder if you have a charging problem.
a high resistance to ground will artificially inflate voltage as well as.get worse as things heat up electronically.
another thing to consider maybe.
i considered the resitance wire as to also include a voltage drop,, since it does act as a resistor., and in series there should be a proportional voltage drop.
the evtm / shop manuals state the ivr provides pulsating 5v
i also considered the ivr to be a somewhat additional resistive load and this coupled with the series resistance wire aided in getting the amps / volts conditioned for the gauges.
I've never seen one pulse. For me they've always measured around 5v while fluctuating about .5v in either direction. So up and down a bit, but not something I would describe as pulsing.
although this does not actually fix the "potential problem"
i am considering twisting 4 100ohm resistors in parallel then place this in series with the sender wire.
100ohm because thats what i have for some various clr items in my parts bin.
this should get me to a min resitivity of 25ohms signal to the gauge max.. not sure if that would reflect a pure "over heating" indication yet.
i would really like to figure out what the actual issue is.
double post..oopps
to solve this issue> "when i turn on the headlamps, the temp needle climbs up slightly"
i am considering using a product ive used in the past ~ http://www.rofu.com
There is a product #9148 which is a voltage converter.
it takes 12 to 60v AC or DC input and converts it to steady 12vdc out.
If i place this upstream of the resitance wire in series, the ROFU 9148 will then feed the ivr with stable 12v, thus what i suspect being the alternator increasing ouput when i turn on the headlamps will be nullified with this product... it will buffer out the influence of the alternator.
basically its going to end up being 12v dc input,, then 12vdc output.
now, if someone understands this circuit better than me,, here is what i am thinking if i want to iliminate the ivr........
since the guages are 12.5ohms.. in parallel being for the 5.0 only the temp and fuel are fed off the fuel guages........
then thats about 6 ohms resistance resulting in both gauges being in parallel,(excluding the downstream fuel fload variable resistor and the downstream temp sender.
should i put a 6ohm resistor on the oput put the ROFU so 50% source is dropped, and then each guage will then have the remaining battery voltage which is about 5 or 6 volts?
or,, would i place the rofu upstream of the resistance wire?,, this seems more logical to me, it would have to be wired driectly off the ignition switch where the gray/yel wire is and its output tied to the resistance wire,, thus everything upstream including the resistance wire would remain the same.
I think if you eliminate the irv completely, your going to have to try a few different resistors to give you the exact correct value.
for example, the gas guage sender can be off by a good bit and still be within.spec. if you change the input voltage to make the dash input read correctly, you might alter the displayed voltage of the guage itself.
it makes sense to me to do away with the resistive wire all together, then use the output of your 12v regulator, and then ad the resistor as the new output for the irv.
running a voltage regulator off of a resistive wire just seems sort of silly to me.
If you want to elliminate IVR completely, then you need constant voltage source, not just resistors. Why? Because Ohm's law. If your temperature, oil and fuel gauge reads high, there is some current flow and corresponding voltage drop on that resistor. When all the needels reads low, the current is way lower and voltage drop too.
I really don't know, why nobody listens to my advices with modifying IVR with 78T05 linear voltage regulator. You need just two more capacitors and everything fits perfectly inside the IVR case.
(http://obrazky.trinom.org/obrazky/g9z3_P6170061.JPG)
BTW, standard IVR will always produce pulsating voltage because of its internal design with bimetal switch.
im listening,, i did mention the exact same delta you described on the resistors and thier application.. i get it.
my son may actually have a simi-bad battery so the alt might be loaded down more than normal, the arriving voltage at the IVR may be a tad too high.
are those two 10uF caps there?
Jay you can not eliminate the CVR. Cluster Voltage Regulator. reason being the impedance is variable as the gauges change readings. An electronic unit as posted is the best bet. Other than individual feeds with the resistor and constant 5 volts. The resistor limits voltage and current. I think the resistor is in the circuit in case the CVR goes bad and remains contact closed. It will save the gauges from burning up. I thought about it last night after posting i did not understand it's use. I am certain it is used as protection for the gauges by design if the CVR shorts out and supplies 12 Volts to the gauges. remember resistors limit current and voltage as well with it's load, OHMS LAW applies here. So last night at 3 AM i woke up in a cold sweat and i am certain the low OHM resistor is a protector for the coils in the gauges if the CVR shorts out and supplies full 12 Volts to the gauges. I dont believe a charging issue will effect the gauges enough to make a difference. But i will tell you that at 12 Volts engine not running and at 14 Volts engine running there is a slight difference. I tested it last night on my Ramcharger and it does move the needles all of them a bit higher when under charge voltage. My Ramcharger is 100% stock and you can actually see the gauge needles pulse a tiny bit weather under charge or not. It follows the pulsing of the CVR. I use the electronic chip and capacitors as posted above several times with good results as well. Have a good night guys.
i wasnt considering eliminating it.
your agreeing, the resistance wire coupled with the internal resistivity of the CVR/IVR, coupled with the far end termination resistance all offer voltage drops.
that was my earlier point.
There is a 1u/100V at the input and 10u/35V at the output, if my memory serves. Data sheet says at least 330n at the input, I've just used what lied around. 10u and 10u should work fine as well.
BTW, it's necessarry to use 78[COLOR="#FF0000"]
T[/COLOR]05, which is designed for 3A current draw. Standard 7805 is designed for just 1A, which isn't enough when all needles show high values.
in your layout, i assume the caps serve as over current protection to the regulator and instrument cluster gauges?
Nope, they are just smoothing the volatge. The output one should be at least 100n, if I am right, but they are necessary.
It's DC circuit, so capacitors can't work as a current limiter. They can work that way only in AC circuits.
as time allows and as i mentioned earlier in this IVR dedicated post, my son finally was able to do a test.
he removed the neg battery cable while the car was running and the car died. He did take it to a parts store which they did a charge system test but the fella there just did the test and handed him a slip with the information. I find it odd they didnt try to sell him something. the slip says things that point to a failing charge system.
I told my son to get another 3g, when we did his engine build , all we did was put on a new regulator. I suspect the alternator itself may be partially bad,, the battey does not last him very long either if he leaves a door open or the radio on just to do something simple like an oil change.
He is convinced that taking off the battey cable will make the car die,, ill get through to him but in the meantime... we are not mod'ing anything until this charge issue is solved by a battery, alternator or both. I told him i would prefer he do both at the same time.
his original call to me today was to tell me that putting the 4) 100ohm resistors in parallel at the sender worked great and the needle went to just a hair above half way. I told him to yank it out though so we can get it confirmed that new charge parts will lower the needle.
im suspecting the alternator is ramping up the voltage a tad too high. I wish i had remember to ask him to put his meter to AC and see if there was any ripple.
oh well.. stay tuned.
Check your engine ground to chassi and also the fender ground by the battery. if either of these are bad they will do the same thing.
JAY with all due respect disconnecting a cable from a running engine is not only extreamly dangerous. But is not an approved test by any means. I do not know where this nonsense started but i would advise you to tell your son not to do it again. Not only can the battery explode you can fry every electronic component in the car. it is something i would suggest not doing. We have had only 3 battery explosions in my career and one is to many. They can inflict serious injuries. Removing the battery from the charging system while running puts AC spikes in every component. The AC voltage spikes over 130Volts without a battery load. The battery smooths out all the AC ripples in the charging system. Many a car has be ruined doing this. Especially newer cars loaded with electronics. Never ever do that. Have a good evening folks
Tom, I remember the FIRST time I witnessed a battery exploding. I was surprised at how violent it was. Poor fella who's bay it happened in.......ouch.
Matt we all take battery's for granted and do stupid things around them myself included. But as you point out when they go it is horrific. Acid spray in your face ETC. We have a charging station that is OSHA approved for charging batterys and they check it. In the vehicle one must be extreamly careful around battery's and how we charge them and jump them. have a great day guys> Be careful around battery's!
in a last cast / worse case situation where you've looked at everything,, and managing the risk, i see no issue in confirming a fault this way.
many miles separate us from each other and so to that end, what would you say is the issue if the car fails to continue running after the battery is removed from the circuit? I have mentioned this before but your saying you dont know where this nonsense came from. *it came from my comments early on that you didnt tie in. my guess is you dont have reasonable understanding of this threads objective.
here is your situation supporting the end user....
-he's in a parking lot at his appartment
-he has just got off work
-he has 2 hrs to get to his next job
im a subject matter expert on batteries,, ill stop there.
yeah did
oddly enough the 3.8L ground is different from the samy year 5.0 variety.
the 3.8 L does the battery ground in a logical manner to me.
the 3.8 neg cable transitions down to the frame, which a partial section of the insulation is removed and a crimped on side tap lug is there to bolt the copper to frame ground. The wire coninues on and over to the engine block.
on the 5.0, the neg batt cable is a home run to the engine block.
yes we check the smaller parallel gnds as well.
Ok
Ok
http://www.headsuphobby.com/3-Amp-Universal-Battery-Elimination-Circuit-UBEC-G-150.htm
i was thinking about this while playing with my model airplanes tonight.
Up to 30v's input and a continuous 5.00v output. i mesured mine with a multi meter and a load of about 5 amps and it never got above or below more than .01v's. might be a bit more expensive, but its cheap and easy to wire in.
this week update
R&R'd the alternator and battery as a matched set.
Results- no change- temp gauge still hangs out a tad higher than the actual real engine temp being shown on the radiator cap.
Having the radiator fill cap with built in temp guage from advance helps us understand the temp reading on the dash is actually too high.
Testing we did
(meter turned on set to ohms, R x 200, connecting red lead to black lead, meter reads .1 to .2 ohms.. so that's our calibration)
-measured the resistance of the red wire from the cluster connector (unplugged) going out to the temp gauge sender= 1.2ohms (both ends isolated , easy test since it a home run)
-wiggle test at the 90deg boot yielded a fluxuating resistance but not very much so........
-at the 90deg boot connector in the engine bay, we penetrated the insulation about 2'' upstream of the connector and the ohms was about .2
***I cant see 1 additional ohm being a concern unless my math is off.
-with IP cluster unplugged and ign sw unplugged, the tiny resistance (gray) wire in parallel with the large Gray / yellow reads 8.5ohms
-with a hot motor, with the 90deg red wire unplugged, the temp sender reads 78ohms to the brass housing and the lower intake. (this is the resistivity I need to get higher to simulate lower guage reading).
-with all things plugged back in, KOER, input to the ivr is approx. source voltage, the output is a pulsing 8 to 11vdc.
*****the gas guage is very correct, son ran it out of fuel (well near) and the visual display matched the end result),,, fuel gauge operates off the accuracy of the IVR output which complicates matters since the IVR also drives the temp gauge needle display.
-resistance of the temp gauge matches the resistance of the fuel gauge , both are about 12.8ohms
son says he is adding 3 and then 2 100 ohm resistors in parallel at the 90 deg slip on connector in series with the sender to calibrate and put about 33 to 50 additional ohms on the circuit. he needs to let me know how this goes.. yet I cant still seem to find the root of this problem.
guage seems fine
wiring seems fine
sender (that's the third one we've swapped in)
cant use my 20th to compare notes with since I don't have the same sender as he does
and for the life of me,, I totally forgot to double check the chassis to engine ground bonding..... its all connected from what was provided by ford,, I totally forgot to jumper cable an additional temporary ground in during our testing.
I am stumped.
sent my son the Trinom layout / link, he may end up building this and seeing if the results change. a part of me tells me there wont be because of the fuel guage isn't acting up. when the guage gets up at 80 and 90% needle swing on warm days,,, there has to be an issue.
We assumed ate first it was the TC nose swap but in body and appearance section here, we modified and added a front scoop to solve that.
additionally we even modified the bumper cover by cutting the openings of the slots along the bottom to introduce more air.
How high does it read, when the car is idling and the radiator fan just turned on? My needle is in N (the top letter of the word NORM) when the fan start blowing and when it stops the needle fall down somewhere to the middle of the range.