North American Turbocoupe Organization



Dash gauges quit working
MN88TurboCoupe Offline
Member
#1
This is really strange.  My dash guages quit working but the RPM and speedometer work just fine.  This happened about a week ago for no reason and went and started it up two days later and they worked.  Took the car to work 2 days later everything works.  Come home it's working, stop at the stoplight a few blocks from home and they just stop.

Along with that my idle has gone crazy this spring.  I'll be driving and stop at a stoplight and it goes up to about 2k.
Publicity, fame and accolades can make a theory popular. They can't make it true.
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Rob H Offline
Member
#2
This comment won't be helpful in any way, but I can relate to strange things with the gauges.
I have had my gauges out a couple times. And when I put them back there's one thing I now know for myself. If I tighten the upper right screw my gauges will stop working. Back it off a bit and they're fine.
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Kuch Offline
Senior Member
#3
Your high idle may be an issue with your IAC valve. they should be removed and given a good cleaning with carb cleaner and a small acid brush. I let mine soak overnight with cleaner in it and gave it a good rinse after. A sticky IAC will cause a high idle like that.
1988 Turbo Coupe, Black/Black, 5 Speed, Moonroof,  T3/T4 50 trim, ported E6, 255LPH, BBK AFPR, 3" DP dual 2.5" w Hooker Maxflows, MGW shifter, K&N, Gillis valve, RR cam, Koni's
1964 Ford Galaxie 500XL, 390 6V, 4 Speed, Vast and fast
1960 Ford Starliner, 292 Y Block, 3 Speed, slow and low
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Jeff K Offline
Administrator
#4
Assuming you mean the oil pressure, fuel and temp gauges all stop working at the same time? If so, the issue is either the archaic mechanical / thermal IVR Ford has used since the 1960s failing or a poor connection in one of the gauge cluster connectors. If it is the POS IVR, you can still get new ones of the same antiquated design or replace it with a solid state unit from Ebay, or build your own using a 5 V 1 A regulator if you are comfortable with building electronics. There is a tech article I wrote many years ago about how to build a solid state IVR in the tech articles section.

Try pulling the cluster and disconnecting / reconnecting the cluster connectors that plug into the cluster several times if you have a bad connection at the connectors. Also possible there is an issue with the light gray / yellow resistance wire that runs from the ignition switch to the IVR or the ignition swith itself. Ford ignition switches from the 80s are a known issue, but are cheap and easy to replace.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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MN88TurboCoupe Offline
Member
#5
(05-10-2020, 02:29 PM)Jeff K Wrote: Assuming you mean the oil pressure, fuel and temp gauges all stop working at the same time? If so, the issue is either the archaic mechanical / thermal IVR Ford has used since the 1960s failing or a poor connection in one of the gauge cluster connectors.  If it is the POS IVR, you can still get new ones of the same antiquated design or replace it with a solid state unit from Ebay, or build your own using a 5 V 1 A regulator if you are comfortable with building electronics.  There is a tech article I wrote many years ago about how to build a solid state IVR in the tech articles section.

Try pulling the cluster and disconnecting / reconnecting the cluster connectors that plug into the cluster several times if you have a bad connection at the connectors.  Also possible there is an issue with the light gray / yellow resistance wire that runs from the ignition switch to the IVR or the ignition swith itself.  Ford ignition switches from the 80s are a known issue, but are cheap and easy to replace.

Yes. to the temp, oil, fuel gauges.  And that light grey wire from the ignition switch I believe was replaced by the previous owner so that gives me pause to think that may be the culprit.
Publicity, fame and accolades can make a theory popular. They can't make it true.
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MN88TurboCoupe Offline
Member
#6
(05-10-2020, 10:53 AM)Kuch Wrote: Your high idle may be an issue with your IAC valve. they should be removed and given a good cleaning with carb cleaner and a small acid brush. I let mine soak overnight with cleaner in it and gave it a good rinse after. A sticky IAC will cause a high idle like that.

Any issue taking it apart?

Thanks
Publicity, fame and accolades can make a theory popular. They can't make it true.
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Jeff K Offline
Administrator
#7
You dont really take the IAC apart...... you just remove it (2 8mm / 5/16" bolts) and clean it. I always put a drop of oil on the shaft where it enters the solenoid body.

Common cause of hanging high idle is TPS closed throttle voltage over 1.0 V. If 1.0 V or more, reset it to .94 V or so.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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anasazi4st Offline
Senior Member
#8
(05-10-2020, 02:29 PM)Jeff K Wrote: Assuming you mean the oil pressure, fuel and temp gauges all stop working at the same time? If so, the issue is either the archaic mechanical / thermal IVR Ford has used since the 1960s failing or a poor connection in one of the gauge cluster connectors.  If it is the POS IVR, you can still get new ones of the same antiquated design or replace it with a solid state unit from Ebay, or build your own using a 5 V 1 A regulator if you are comfortable with building electronics.  There is a tech article I wrote many years ago about how to build a solid state IVR in the tech articles section.

Try pulling the cluster and disconnecting / reconnecting the cluster connectors that plug into the cluster several times if you have a bad connection at the connectors.  Also possible there is an issue with the light gray / yellow resistance wire that runs from the ignition switch to the IVR or the ignition swith itself.  Ford ignition switches from the 80s are a known issue, but are cheap and easy to replace.

Funny how things work.

I have had my IP cluster out many times over the course of 29 years of ownership. The other day I saw something I had honestly never seen before in there, as least I don’t recall it.

As part of my Spring Renovation project—which has included new headliner and matching visors that I carefully crafted by hand, a new IVR (old one was causing the gauges to be all over the place)—there was also the 140 mph speedometer conversion. Obviously to get at that I had to pull the IP cluster. After doing the mods required for the conversion I reinstalled the speedo and put the IP back. Now, I have always had problems getting it to fit back in there properly, and this time was no exception. During my test drive I noticed the Temp Gauge was inoperative, and the other gauges were acting kind of weird. I knew the IVR was new, so I discounted that possibility.

I pulled the IP cluster out again and saw that some of the little clips that hold the wiring into the harness had broken off, causing several of the wires to come loose and not make contact. After verifying that the temp gauge did work, I traced the circuit and sure enough, that loose wire went to that gauge. There were several others loose as well, which I think accounted for the other wonky readings.

I laid the flashlight on the top of the dash so the folding LED panel was at a 90 degree angle pointing in, and I’m embarrassed to say that I noticed something I had never seen before. It was the light hitting the inside of the IP dash cavity that caused me to even see it, this time.

There is a channel—groove or trough, if you will—that runs along the top of that cavity. I held up the wiring harness and it fit perfectly in there.

That’s where that harness is supposed to go. In a flash I realized that was why I was having trouble getting the IP to fit properly in there, why I have always had trouble, and why the little plastic “catches” broke off the harness. For years, I have been just mashing the harness in there without putting it in the correct spot, in that channel.

Rob, I would bet that is why when you tighten that screw you have problems. Yours is not in the correct location either.

Again, I am embarrassed to admit I never noticed that before. You are never too old to learn.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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MN88TurboCoupe Offline
Member
#9
Stupid question. Which side is the grey wire and which is the other? I took apart the old one knowing I had a photo of it but the photo doesn't show the wires. Sad
Publicity, fame and accolades can make a theory popular. They can't make it true.
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Jeff K Offline
Administrator
#10
Not sure I understand your question. Are you referring to the light gray / yellow stripe resistance wire? What exactly do you mean by "Which side is the grey wire and which is the other?"
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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