Istrument cluster help?

sluggo42

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Aug 9, 2007
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Hi,
My oil pressure gauge quit, so I'm assuming I have to pull the cluster? I have changed the sensor already, and have determined that wiring is sound.
I have searched for about an hour now, and found very little. I was hoping somebody could enlighten me on how to proceed with replacing the oil pressure gauge on my 91 turbo???

thanks a ton in advance,

Doug
 

sluggo42

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jetjock;1811349 said:
Again, it's all in the book. No offense dude but you're starting to come across as helpless.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BO&P=52

I would not be removing the cluster unless there's 12 volts on the wire *and* the gage doesn't move when the wire is grounded...

lol, hey mate, I had no idea all of this is in this "book", but I sure am glad you're helping me with it. I do have 12v at the sensor and I will do the grounding thing tomorrow. I'm a retired old fart, and I'm not quite as savvy as guys like you, but, with your help I'm able to do these things by myself.

So with that thought, please know that your help and guidence and most of all patience, is saving me from hours of frustration. All my old fart friends wonder why I keep driving this old car, but when the turbo kicks in it gives me a speck of fun that's difficult to describe.
Thanks for bearing with me, and I will turn to the "book" from now on, thanks for sharing!!!!

Helpless...
 

sluggo42

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Greetings again,

One more stupid question. I searched the "book" and found out how to test the sending unit, but it requires the car to be running with a test bulb in line from the sender to the + side of the battery. When not running, the bulb should NOT be lit, when running, the bulb should flash on and off, in relation to RPM.

My question is: will the car run with out all of the turbo air hoses connected? I'm guessing not, but it's kind of a pain to have to reassemble everything for the test, then take it all apart again.

I did find that the gauge moved when I grounded the wire, so I'm assuming that the gauge is alrite after all?

thanks,
helpless
 

jetjock

creepy-ass cracka
Jul 11, 2005
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Yes, the gage and wiring are fine. See, this is why stuff needs to be tested by the book or using another method that definitively verifies it. Your changing the sender meant nothing. It was just swapping of parts and it appears you swapped one bad part for another.

The engine should run with the hoses disconnected and the AFM unplugged but if yours is out of whack it may not. If it were me I'd just take the sender back off because everything points to it being bad. Once off it can be tested with air pressure and a meter.

Supply pressure to the sender. Anything from 10 to 100 psi will do. A meter set to ohms connected between the sender's body and terminal should display pulsed continuity. Put simply, when working correctly the sender shorts its terminal to its body with a pressure dependent duty cycle.
 
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zby67

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the sensor is on the passenger side of the engine near the oil filter and bellow the dis/CPS. mine stopped work as well oddly after power sliding the car in the snow it fixed it lol. (not oddly prob cleaned out build up.)
 

sluggo42

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The car did run without the turbo hoses. I did nothing but idle, but it did the trick. The test bulb did NOT light, indicating a faulty switch. I pressured it up as you described with air pressure, and got a consistent ohm reading of 48. My electrician friend told me a general rule of anything over 23 ohms is too much interferance for the switch, so he told me that this ohm reading indicated a bad sensor. I repeated the test with the other sensor I bought from someone in here, and it was faulty as well. I ordered a new sensor, and should be installing it in about an hour.

Again Jet, thanks for the help, as well as directing me to the "BOOK"

Side note,
I tested the gauge according to the "book", and while I was able to make the gauge "move", it didn't move as the book indicated it would. So, after I install the new sensor, we'll see if all restores to goodness.

***sigh***

helpless in California
 

jetjock

creepy-ass cracka
Jul 11, 2005
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I'm afraid it's not that simple. Expect to see 20 to 50 ohms because of the heater and calibration resistor internal to the sending unit. By "shorted" (shouldn't have used that term) I didn't mean zero resistance. Nor will the sender cycle without power on it.
 
Oct 11, 2005
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Your electrician friend has never seen a sender like this one, its pretty unique, so his advice will not be useful.

42 ohms is what you should read from the gauge wire to ground , as described here http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BE&P=43

Then follow this exactly (no shortcuts) http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BE&P=42
Basically put a 3.4W bulb in place of the sender and the gauge should read high.

Since the sender is now brand new, no need to measure it, bit if all else fails you might want to measure the oil pressure with a mechanical gauge in place of the sender. Maybe you have no oil pressure!
 

destrux

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May 19, 2010
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The gauge has a heat sensitive plate and a coil of wire that heats it to move the needle. It was never designed to be completely grounded (hence the 3.4V bulb test) and doing that for more than a second or two will heat the gauge internals up so much that the pin that slides in a little plastic channel inside the gauge to move the needle will melt right out of the end of the channel and end up out of place. You might be able to pop the pin back into the channel, or you might need to replace the gauge. I should also mention that if this happens the gauge will still pass the 42ohm test, but the needle will not move where it should move (but it might still move, mine was actually moving down below zero a little under high oil pressure)


I was able to pop the pin back in on my gauge, but I had a spare oil gauge from the N/A cluster I was swapping a volt gauge in from so I used that one anyway. The pin shouldn't be able to pop back out during normal operation anyway, since the oil pressure can't get high enough because of the relief valve.

If you take the cluster apart and look at how the gauge works then what I'm talking about there will be obvious. All you need to get the cluster apart is a #2 phillips screwdriver, a small pick or flathead screwdriver, and some patience. The only things to watch out for are the two hidden screws behind the air vents (they have to come off, they each have two screws and some clips) and the security and TEMS wires have to be unscrewed. Don't force anything, it all comes apart easy when it's completely unfastened.
 

sluggo42

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3p141592654;1811868 said:
Your electrician friend has never seen a sender like this one, its pretty unique, so his advice will not be useful.

42 ohms is what you should read from the gauge wire to ground , as described here http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BE&P=43

Then follow this exactly (no shortcuts) http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BE&P=42
Basically put a 3.4W bulb in place of the sender and the gauge should read high.

Since the sender is now brand new, no need to measure it, bit if all else fails you might want to measure the oil pressure with a mechanical gauge in place of the sender. Maybe you have no oil pressure!

Hi, and thanks so much for jumping into my mess, I live in Camarillo.
I am reading about 61 ohms at the best. So I'm not quite sure what that means, besides the obvious guess of it being a bad gauge...I am trying to find a 3.4 test bulb, but the rocket scientists at O'Reily's have no idea what that is, so this is proving to be a little hard for me to find. At this point, I'm guessing it's one of those screwdriver type things with an alligator clip on a lead, with a pointy tip, and the little bulb inside. I'll be tracking that one down today...
I guess the worst thing that can happen is that I have to get a new gauge. I wonder if I can get a new one through Toyota for $8K, or if I would be better off getting a used one from the classifieds in here...
 

sluggo42

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destrux;1811914 said:
The gauge has a heat sensitive plate and a coil of wire that heats it to move the needle. It was never designed to be completely grounded (hence the 3.4V bulb test) and doing that for more than a second or two will heat the gauge internals up so much that the pin that slides in a little plastic channel inside the gauge to move the needle will melt right out of the end of the channel and end up out of place. You might be able to pop the pin back into the channel, or you might need to replace the gauge. I should also mention that if this happens the gauge will still pass the 42ohm test, but the needle will not move where it should move (but it might still move, mine was actually moving down below zero a little under high oil pressure)



I was able to pop the pin back in on my gauge, but I had a spare oil gauge from the N/A cluster I was swapping a volt gauge in from so I used that one anyway. The pin shouldn't be able to pop back out during normal operation anyway, since the oil pressure can't get high enough because of the relief valve.

If you take the cluster apart and look at how the gauge works then what I'm talking about there will be obvious. All you need to get the cluster apart is a #2 phillips screwdriver, a small pick or flathead screwdriver, and some patience. The only things to watch out for are the two hidden screws behind the air vents (they have to come off, they each have two screws and some clips) and the security and TEMS wires have to be unscrewed. Don't force anything, it all comes apart easy when it's completely unfastened.

hmmmm great. previous poster gave me guidence to ground the wire, without the warning of melting the gauge... But, I believe the auto shop that did my head gasket is the guilty party that smoked the gauge. It worked fine when it went in, but didn't work when I got it back. He then challenged me to prove that it worked before I brought it in.... **sigh** I would advise that nobody goes to "Camarillo Independant" auto care.
Anyways, I will again test once I find the real 3.4 test bulb. It's looking more and more like I will be pulling the cluster...

THANK YOU! I appreciate your very real help and clear explanation without belittling me for my lack of expertise.
 

jetjock

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Jul 11, 2005
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jetjock;1810935 said:
...Or you can briefly touch the wire to ground and see if the gage moves...

I don't explain everything because it'd take too long. I do expect instructions to be followed.

You're still making this way too complicated. There's no need for a bulb. All you have to do is use any sender that shows resistance when pressurized.

And I wasn't belittling you for lacking expertise. Laziness on the other hand...
 

sluggo42

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jetjock;1811963 said:
I don't explain everything because it'd take too long. I do expect instructions to be followed.

You're still making this way too complicated. There's no need for a bulb. All you have to do is use any sender that shows resistance when pressurized.

And I wasn't belittling you for lacking expertise. Laziness on the other hand...

Jet,
I had no idea the "book" was so complete. I'm not a regular Supra electrical/mechanical tech, that spends a lot of time on working on these cars. How would I know? I am a driver/owner, not a tech guy. But I'm trying to learn a bit about the car now. Now that I have spent a lot of time reading and exploring the "book", I see that it offers up a lot of important information.

But you decided that I was pretty helpless pretty darn early in the process, and now you have labled me as lazy as well. I just received a couple of reponses that were much more complete and helpful than what you have offered up, without telling me off in the process.

Thank you for responding in the first place to help, but I think I can do without your insults from here out..., now that I have the "book".
 

IBoughtASupra

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He called you lazy/helpless based on the reason that you created a second thread to only hear what was told to you in the first thread.

When I was a noob, Jetjock was one of the most helpful people even though he didn't spoon feed, he gave hints which made you work to learn on your own.

Saying goes, "Give a man a fish, he eats for a day, teach him to fish, he eats for a lifetime."
 

Supracentral

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Mar 30, 2005
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Jetjock is a very effective teacher. His style may be a little "rough around the edges", but his students tend to learn how to help themselves and to discover answers on their own. That is the absolute best skillset you could walk away from here with.

Now with that said:

threaddirection.jpg


Let's get back on topic folks.
 

suprarx7nut

YotaMD.com author
Nov 10, 2006
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Lol.

While I understand its annoying when these guys rag on you, you need to understand you are receiving high value advice here.

You couldn't find any mechanic that could help you or tell you 1/3 of the useful info you've received here in this thread alone.

You have to understand its a common theme that new people come in and don't appreciate any honest, thorough advice given by the dozens of experienced people on here.

You may not be a tech guy when it comes to supras, but there are plenty here who want to help.

Sent from my ADR6400L using Tapatalk
 

sluggo42

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Perhaps I over- reacted, and Jet, I apologize for that. It's just been a very frustrating problem that is not only difficult mentally, but getting those stupid sensors out of that mega- tight spot was starting to pile up on me. My sincere apologies to anyone if I offended, and especially to the Jet, who actually was the first to step in to help me. Cars are not my forte, bass fishing and classic rock are my skillsets. If anyone wants to know anything about fishing or playing in a rock and roll band, fire away...