'88 --3.8 TBird Cooling

Topic: '88 --3.8 TBird Cooling (Read 7798 times) previous topic - next topic

'88 --3.8 TBird Cooling

Reply #15 – August 31, 2012, 11:16:28 PM

OK Tom---when you say "pull the dash," I take it you mean the cluster panel only?

'88 --3.8 TBird Cooling

Reply #16 – September 01, 2012, 06:26:24 AM

Yes!!!

'88 --3.8 TBird Cooling

Reply #17 – September 01, 2012, 09:54:39 PM

Thanks Tom---I will look at it this weekend or so. The link on Ebay was nice, but it appears that those regulators wont fit this TBird---per their check "fit." First things first--I'll see what condition this voltage regulator is in and see if I can repair it.

'88 --3.8 TBird Cooling

Reply #18 – September 02, 2012, 11:16:41 AM

listen,,,pls
as you get the connector off the rear of your instrument cluster, locate the gray wire on your connector.
locate the same gray wire down on you ignition switch.
unplug the ignition switch.

use an ohm meter and read from the cluster connector to the ign sw connector.

It is "more likely" the resistance wire is needing attention at the ign switch than the regulator going bad.
I just now a few days ago had intermittant guages on my sons bird and his little gray wire at the ign switch was highly discolored and when i read its resistance, i personally was reading over a meg..no go.

i cut off about 2'' down at the ign switch and soldered it , remeasured and came up with 8.4ohms.

the little gray wire is a solid strand of "something" metal not really sure what its made of but it doesnt matter, its designed to act as a resistor and reduce the input voltage to the regulator.

if you are taking some time to tinker with the regulator itself, pry up on the flex print connector gently and very precise under the brass looking snaps. The comment tom made about the IVR ground is good advice, you will see a small copper looking foil where they pinched the cover over it achieving a ground. this foil transitions to a "hair" sized wire inside the ivr.

I dont know you you feel comfortable opening it up or not, i found it to be easy but its a jewlers screwdriver and tiny needle nose pliar job.

I am just saying to test the wire that makes the voltage input to the IVR first so you dont have to dig in toooooooo deep.

if your piddling around on this over the weekend, you can buzz me for help at 304 772 3411.

on consideration also that is not mentioned and frankly is very possible.............
It makes no sense why the needle reacts this way when you first start the car,, awsome problem to troubleshoot and i dont think we will see it again EVER.

My second thoughts were that the needle as poped out of one of its holders in the guage.
If you use your thumb and pointer finger and hold a coin standing up, thats how the needle is mounted. it is not attached though, its axle that it pivits on is about 1/8'' long ,(axil diameter is about 1/64'')and machined to a fine point on each end and these two points sit in a hole that is lets tne neele stand up so to speak.,,verrrrrrrrrrrrry tiny hole.
what i am getting at is that you may have a needle that is cantered or has poped out of one if its holes but is still holding on,, this would cause it to read odly or react to the magnetic lines of flux generated in gauge coil odly. Either way, first steps in all troubleshooting are visual inspections.. your almost done with this part.
Root cause for a needle poping out could be anythign from a hard bump in the road, cluster was dropped, or someone got so pissed off or agitated that hard force on the dash by hand could cause this...dono.

'88 --3.8 TBird Cooling

Reply #19 – September 02, 2012, 11:44:47 AM

Foe
other people know stuff to, dont worry about other advise, yours is valid and stable and i personally see this on many of your posts. this is a very unique problem and im sure it will be one of those things you could caulk up to experince.
it takes YEARS to experince issues like this and thats where you really separate "experince in the job" from "qualified to do the job"

in short, when your actual "fualt" is not on the list of shop manual probable fautls, and you pointed to it first, your finally experinced.

example,, neck Va naval base-
radar screens were all glowing a slight limish green,, no body could figure out what was causing this.
Tech Reps called in and none of them could either,,except one older guy...who said....

"didnt we just have a hurricain?" I closed my mouth and opened my ears......

Salc00cher intrusion into the ground ring around the building was hosing up our reference grounds throughout the facility just enough that the only system effected were the array's. (salt being a conductor and all)

i'll likely never see that problem ever again,, but I did once.

things dried up and all went back to normal in a few days slowly.

'88 --3.8 TBird Cooling

Reply #20 – September 02, 2012, 04:47:46 PM

Hey guys I have now read the posts since last night. Here's what I got into today...and mind you...I did what I did because it was the most logical and seemingly easy thing to do on this problem (Tom Renzo's comments). Unfortunately, I had to reassemble the dash stuff to take the Tbird for a spin an hour ago. I took the cluster off and examined the voltage regulator. I opened the regulator casing--the contacts did not look bad but I polished them up anyway. The results are two fold. The problem appears to be the regulator because both gauges are now pegged out completely! This occurred less then 3 minutes into the test drive--and I know the engine was still stone cold. SO.....I know it's the gauges and not the engine--what a relief after some years of trying to get to the bottom of this. Now I know I can drive the car without concern for the mechanical side of the matter. So now that I banged up the regulator and presumably sent it to the max output, I presume I will have to get a replacement? Or should I also be concerned with the wiring as mentioned in posts above? The regulator has a built in headache--it is mechanically fastened to the plastic circuit board and therefore will have issues with means of replacement. Pics attached.

I also replaced two bulbs of the nineteen I counted on this cluster. There were bulbs installed for 1) low fuel 2) washer fluid 3) lamped burned out , and even 4) check oil. We have never seen these in action and I guess that some were probably optional stuff which isnt part of this TBird--but not sure. ?

'88 --3.8 TBird Cooling

Reply #21 – September 02, 2012, 05:22:38 PM

PS---I note that it appears this regulator is just snapped onto its electrical partner (the plastic printed circuit board), making it easy to remove? I also looked this part up and find that it costs about $50 if you wish to buy it from parts stores--and is a special order too!

'88 --3.8 TBird Cooling

Reply #22 – September 02, 2012, 09:44:06 PM

did you notice the calibration set screw?
if we had an extention cable such that you could plug up the harness and have room to fiddle with it easier out of the dash but still in the car.

if your wires are not broken then it may need fine tuning.

i did not controdict polishing contacts because i have not done it but.... the bi-metal separation is calibrated to complement the spring loading effect of opening and closing during the heat generated while in use.

take it back out and turn out the adjustment screw , you threw off the calibration by separating the contacts.
better yet,, just ping someone here for another,, there really isnt a way to get it right without a spare to compare to. in my book this would be a very tedious task to recalibrate yours.

'88 --3.8 TBird Cooling

Reply #23 – September 02, 2012, 10:10:06 PM

Jcassity--yeah, my picture clearly shows it- the screw. I know I'll have to remove the cluster again. Maybe I can rig up a connection with alligator clips (2 wire and a ground)--at least for the IVR. Of course, this would have to be done with the cluster electrically attached and the engine off--relying on the Fuel gauge for accuracy (key on). At least that's all I can think of. Otherwise, I'll have to spend $50 for something I'm not sure about, and fixing the existing equipment, if possible, is definitely preferred. I could also check the resistance in wires mentioned. Thanks--I still have some time this weekend to fool with this.

'88 --3.8 TBird Cooling

Reply #24 – September 02, 2012, 10:32:04 PM

You have to check the pulses. The regulator pulses a 5V output. So remove the wire from the temp sender place a test light between the wire and ground and look for the pulses. The test light will blink. If it does not blink the regulator is shot. Personally i have never seen a defective wiring issue with a high reading gauge. The regulator controls the voltage because the gauges are not a constant. Another words the fuel gauge can be either full or near empty. That would load down the circuit of the other gauge or gauges and cause false readings. Years ago with 6 Volt systems regulators were not used. I personally never had an issue cleaning the contacts of the regulator. The heater element may be defective. That is why i use the electronic replacements. And yes i remote mount them as well for serviceability!!

'88 --3.8 TBird Cooling

Reply #25 – September 02, 2012, 10:37:37 PM

testing procedure from the ford service manual

Disconnect wiring harness connector at sending unit. Connect a test lamp or voltmeter between terminal in wiring harness connector and ground.
With ignition switch in ON position, light should pulse or meter reading should fluctuate.
If lamp lights but does not pulse, or if meter reading remains steady, check ground to IVR. If ground is satisfactory, IVR is defective.
If lamp fails to light, or if meter reads 0 volts, check for open circuit across IVR terminals, indicator gauge terminals, or open circuit in wiring harness and printed circuit between components.
Connect test lamp or voltmeter ground lead to ground terminal in sending unit wiring harness connector. Light should pulse or meter reading should fluctuate as in step 2. If not, locate open in ground circuit. Do not apply battery voltage to system or ground output terminals of IVR, as damage to system components or wiring circuits may result.

'88 --3.8 TBird Cooling

Reply #26 – September 02, 2012, 10:53:56 PM

Jay the fine tuning can be dun with a lamp in series with the 8.5 OHM wire. If in fact the resistor wire is shot (i have never seen this but anything is possible) A 194 lamp can be used to see if the resistance wire is bad. Put it in series with the IVR and if the gauges even out the resistor is shorted. Once again i have never seen this happen. He has to check for the pulses. If the IVR pulses it is basically good. Actually the voltage does not matter to much just the pulse rate. All dash gauges use the 5V regulator with buttstuffog gauges. And if i am not mistaken all the IVR'S are the same other than MOUNTING. My DODGE had the same exact regulator

One other thing??? Is your alternator putting out to high a voltage??? Have you checked for overcharging??? Just something DUMB i just thought about. Because you now have a regulator that pins the gauges further. So in theory the regulator was working to some capacity. Strange. I have changed several regulators to fix this issue as well as burnished contacts on the units. Well both gauges are effected so the regulator is most likely the ISSUE???

'88 --3.8 TBird Cooling

Reply #27 – September 02, 2012, 11:11:59 PM

Tom and Jay---I am sitting here trying to digest all this info. First, if anything, I have had problems in the past with alternators. The current one---if I don't drive the car for a week, the battery is shy of full crank. I haven't checked it, but have not had any issues otherwise. Also, Tom --you gave me a link on regulators (Ebay), but those shown (the cheapest $20) appear not to fit this car per the compatibility check? The $50 one from the parts stores are simply way overpriced. Just wonder if the "Compatibility Check" Ebay shows is wrong. $20 just makes it more feasible to trash the existing and replace it...and where do you find an electronic one? I re-thought the idea of testing the IVR straight from the battery, but with a resistor wire set into the input voltage, sounds like that is suicidal for the device and/or other components. Actually, you guys are much more advanced than I and I am faltering on where to go from here. Spending $50 might sound easy, but that's alot of bread for this deal.

'88 --3.8 TBird Cooling

Reply #28 – September 03, 2012, 11:17:50 AM

the resistor wire is one continuous wire from the ignition switch up to the cluster connector and its appearance leads you to think its approx 16ga or 18ga wire.
when the insulation is skinned back you find a single approx 24 or so awg wire inside the insulation. its about 2 or so feet long so its length is probably a factor as well. It kinda reminds you of a fuse link with one conductor.

I found the tests tom mentions in my shop manuals, they do a good job of explaining it like already written up.

in the spirit of completeness, and since these cars are getting older, maybe you make a good point that a bench test proceedure might be needed, more advanced than the shop manual but simple also.

Quickly thinking through this,, this is what i would do....

-remove cluster to work bench
-find a wall power adaptor that puts out about 5vac like you find on old chordless phones ect and use this for a power source (5vdc may work also, not sure)
-verify adaptor is putting out approx 5vAC, i would let 6vAC go as well because after the circuit is loaded, the voltage should drop.
-cut the end off the adaptor chord that would normally plug into the device it powers
-split the two conductors
-find the positive and negative wires with a meter, (typically positive wire has all the writing on it)
-put a fuse in line with the pos wire going to the pos input side of the ivr
-aligator clip the ground side of the guage to the metal can of the ivr
-aligator clip from the ground side of the guage to one side of a 10ohm resistor
-aligator clip from the other side of the 10ohm resistor to the neg power adaptor wire.
-plug up wall adaptor to ac outlet and your fuel guage should peg

if you use your fuel guage as a point of calibration, the temp guage should follow suit,

I suppose you could do this same test and place your temp sensor in water on a camp stove with a thermometer in the water then calibrate the ivr that way as well.

see quick etch and sketch below..

'88 --3.8 TBird Cooling

Reply #29 – September 03, 2012, 01:44:13 PM

Currently came back here to recheck all instructions--my intention now is to check the resistance on the gray ignition wire= should be 8.5 ohms? I also will use a train transformer I have to output a 5vac into the IVR and see what it ouputs on a tester lamp....