93 and 94 CS fake oil gauge resolution, on how to convert..

[Crazy K]

This will be the thread where we will determine how to fix this once and for all.

I have NOT got the gauge to work, but I think I understand how it works.

 

My only(no... rather most important) question is, have any of you tried installing a sender in place of the switch?

 

I need someone to try swapping a sender for their switch... the switch is loacted above the starter with plenty of clearance. I would test myself but can't afford the switch right now, if it should be useless, and am not willing to disable my only winter car.

 

The goal is to see how the check guages light performs, and how the guage actually moves, pre-cutout of the resistor

 

On the CS cluster, 93 and 94 have a fake oil guage, it simply holds steady if there is any oil pressure above 4 psi(the switches cutoff point). It utilizes a switch(on-off) and not a sender.

word has come to me that the 92 has a real guage. (and otherwise all have the same gauge set, although all three years have slight differences, making them incompatable?)

I have request a pic of the gaage for the purpose of this project.

 

quote from the 94 CS factory manual:

"[fuel pump/oil pressure switch] opens above 4psi, sending curent through the In-Line Resistor to ground. This moves the pointer to the middle of the range, indiacating normal oil pressure. A 68 ohm In-Line resistor keeps the indicator from going full scale with normal oil pressure."

 

Based on probe tests on the rear of the cluster... the resistor is one of two inline resistors on the rear of the guage itself. I'm trying to determine which one it is, but if i snip, there will be no going back if it doesn't work (I've already shredded a parts cluster just for the wiring info of the coil windings.)

 

The guage max reading is regulated by resistor on the rear of the guage inself. These are attached to the coils or the guage. There are two resistors, they each measure 75 ohms. I've experimented with bypassing them, but no solid result yet.

 

This conversion has been done by someone on a caprice:

the excerpt from

http://captainpackrat.com/Misc/ratmobile2.htm

 

"I've modified the oil pressure gauge so it displays accurately. (The stock Caprice/Impala oil gauge doesn't actually display oil pressure; if the oil pressure is above 4 PSI, the needle will always point to 75%, regardless of the actual pressure. By replacing the oil pressure sensor with the police version and removing a resistor from an electrical harness, the gauge will read the correct oil pressure) Unfortunately, the calibration markings on the non-police Caprice and Impala are designed for the fake sensor, so the oil pressure frequently reads into the "low" range, even though the oil pressure is just fine. (The instrument panel on the police version has the correct markings) "

 

btw, anyone know of a how-to tech info to convert the caprice gauge?????

 

THE MOST IMPORTANT THING I NEED IS FOR SOMEONE TO TRY THE SENDER UNIT, AND POST THE RESULTS.

And answer:

Does the check guage light work normally, and does the guage act nomally (within the compressed range it has?)

 

also please do not clutter this post as it may be added to FAQ if this works!

[94CutlassSLCoupe]

the 92 guage cluster has the real gauge and sending unit...it does move, i test drove a 92 with that.

[ToroToro]

I was under the impression that the faux oil pressure gauge was a 94 thing only. At least that's what I hear.

[digitaloutsider]

I'm not sure if this would help or anything, but I helped a buddy install a pressure sensor in place of the switch on his '97 GP SE. That worked fine. The PCM didn't complain and he spliced in wires for his gauge on the pillar.

[Rocketman]

I can almost guarantee it will work providing you remove that 68 ohm resistor.

[GutlessSupreme]

the 92 guage cluster has the real gauge and sending unit...it does move, i test drove a 92 with that.

 

I was under the impression that the faux oil pressure gauge was a 94 thing only. At least that's what I hear.

 

'92 was the last year they worked completely (I also know for sure '92s have real gauges.. I do own one..). If simply replacing the switch for a sender doesn't do anything, picking up a '92 cluster would be the next easiest step I'd imagine.

[ToroToro]

A 92 cluster will have numbers on the oil pressure gauge as well. '94s, and probobly '93s just have an L and a H.

[Crazy K]

can someone post a pic of said 92?

i have done some verification, and it seems 92 has a sender, and not a switch.

I'd take a pic, but i can't find my camera (uh-oh)

[ToroToro]

[Crazy K]

thank you for the pic, this confirms that the 'pin markings' are the same.

btw 323,000 miles! (not to be discussed in this thread! look for highest mileage thread!)

[ToroToro]

That's Taylor's car. He added the indicator to the cluster because his Aurora shifter didn't allow the use of the stock console indicator. Edit: Sorry Crazy K...

[Crazy K]

damn. I missed that. I thought i had the only CS's with both (yeah two I've done that to) Who is taylor? I guess in the end, i will submit a summary with a link to this thread, so keep it clean. thanks.

here is a pic of the coil windings on the rear of the gauge.

I summarize that the resistor in question is the one on the left.

I did probe the gauge rear and it confirms that the limitation of the guage movement is internal of the coil that is pictured.

 

I expect no other resistors to be found.

 

So another question:

 

ToroToro, has the gauge swap to a UB3 you speak of worked yet? How has the oil gauge responded?

[ToroToro]

damn. I missed that. I thought i had the only CS's with both (yeah two I've done that to) Who is taylor?

 

Taylor's an admin on modernolds with me. He hasn't been a member here in many years.

 

Back on topic. If the weather is good, I'll go get a sender for my car Tuesday or Wednesday, and see what happens I put it in. I'm betting everything will work just fine.

 

DAMN YOU EDITED YOUR POST!!!

 

Everything on my UB3 works fine, with the exception of the oil pressure gauge that always reads full. Obviously because the UB3 lacks the resistor to make it read anything else except high and low. Like I said, if the weather is decent, I will see if I can get a sender in, in which case it should then work good. I misread your first post and thought that you only found one of the two resistors that make the oil gauge stay still. I see now that the only resistor is in the cluster.

[GutlessSupreme]

My '92 dash does not have the number markings.

 

 

 

http://www.3100mpfi.com/images/Cutlass/steeringwheel1.JPG

 

what's that turn signal switch out of?

[Crazy K]

[

Back on topic. If the weather is good, I'll go get a sender for my car Tuesday or Wednesday, and see what happens I put it in. I'm betting everything will work just fine.

please do, make sure you get theo long one and not the short one, and report back.

 

ToroToro

one further test, (It discovered the flaw in the lumina gauge swap)

if you have a switch and not a variable sender, the oil guage will remain low when the key is on, engine off. The guage will sit at full range with the engine on, otherwise.

 

Does your UB3 indicate low presure with the key on, engine off?

or pegged when key is on at all times?

[Crazy K]

My '92 dash does not have the number markings.

 

 

 

http://www.3100mpfi.com/images/Cutlass/steeringwheel1.JPG

 

what's that turn signal switch out of?

can I confirm if you 92 dash has a real pressure guage? (or could it be a 93 cluster installed by a previous owner? (does it ever pass 5/8 on the scale?)

[ToroToro]

The turn signal lever on his car is a 94+ one.

 

Ken, I will check on that for you later tonight.

[ToroToro]

My '92 has a pressure gauge and sender Ken.

 

Does it have the numbers? Taylor's is a DOHC cluster. Maybe only they got the numbers. :?

[ToroToro]

K, well the only thing that I can say is that maybe only the TDC cars got the numbers, until I see otherwise.

[ns87]

If you guys get really desperate, I will be installing Torotoro's 94 Gauge in my 90 Cutlass Supreme with an oil pressure sensor (not switch) in April. If this is completely irrelavent..well hey what can you do

[GutlessSupreme]

can I confirm if you 92 dash has a real pressure guage? (or could it be a 93 cluster installed by a previous owner? (does it ever pass 5/8 on the scale?)

 

By my grandfather? yea...

 

 

it's been showing 3/4s on the gauge lately. I'm not making it up.

[ToroToro]

Ken- I have confirmation that my gauge shows empty and flashes "low" with the key in run and the engine off. So it all comes down to swapping in the sender. Hopefully.

 

And if you want/need a sender for your car, I can get you one from the JY. I have pockets. I'll even test it in my car for ya before I send it.

[Crazy K]

Ken- I have confirmation that my gauge shows empty and flashes "low" with the key in run and the engine off. So it all comes down to swapping in the sender. Hopefully.

 

And if you want/need a sender for your car, I can get you one from the JY. I have pockets. I'll even test it in my car for ya before I send it.

Good confirmation, thanks.

I have no need for anyone to pocket a sender, I just have trouble snatching one while I'm shivering. (and thats is soooo the real reason )

 

ok, so.... get that sender changed, I'm tempted to take a spare cluster from another car and temporarily hook up (just the oil guage wires.) to see if i get true scale or not.

 

TEST: it is easy to unplug/disconnect the oil pressure sensor's connector. And doing so WILL reveal the upper limit of your oil gaage.

If it goes full scale(Key on, engine on or off does not matter), you should have a real gauge

If it goes about 5/8 scale(Key on, engine on or off does not matter), you should have a fake gauge.

 

btw, the 94 CS 3.4 or 3.1 seems to have

 

I hope some of you with a 92 CS could do this(both engines), and report back.

I already have the info on 94 and it's dummy H-L gauge period, either engine.

 

remember the sensor is above the oil filter and slightly to the right on the 3.1, and in the center front of the block on the 3100

[Crazy K]

Ken, I know mine has a sender, I changed the oil the other day and it has the long one as opposed to the short switch.

oh, I should refraise the question:

 

If you know whether you oil gauge is fake of not, let me know, and how high it goes on the range(usually maxes at a complete chilly cold start). Also let me know if you have a long sender or short. thanks.

 

If you don't...

TEST: it is easy to unplug/disconnect the oil pressure sensor's connector. And doing so WILL reveal the upper limit of your oil gaage.

If it goes full scale(Key on, engine on or off does not matter), you should have a real gauge

If it goes about 5/8 scale(Key on, engine on or off does not matter), you should have a fake gauge.

[Crazy K]

thanks!