93-97 Coolant Temperature Gauge Modification

[tarbe]

I like it right where the 100/150 puts it. Leaves plenty of room for movement prior to red zone/high temps.

In 15 miles of sand running at 90+degrees ambient Saturday (and with a total load of about 800 lbs), the gauge never went past horizontal. In fact, when I ran in low-range, the gauge never got within a needle's width of horizontal (probably never above 195). When in high range and experimenting, I did get to horizontal once or twice in some really soft, deep sand. Maybe 200 degrees? A/C was on, too.

Looks like my cooling system is working well.

[RavenTai]

Originally Posted by Rookie2

I've got the original RT version. I can't remember the resistor values.. 50 and 100 maybe..??



Thanks B. I wasn't really concerned about it and thought it was somewhat to be expected. If I was one of those that's got a vehicle that's running hot (AC cutoff hot that is), I'd be worried about it. That extra spike at shutdown can't be good if you're already at 225 to 230.


Rookie2

the spike is in water temperature only, CHT (Cylinder Head Temperature) gets no hotter after shutdown

I am still experiencing pop ups in temperature with low speeds, I do want to do the fan clutch mod, Going to adjust it and top off the oil, but I only have one day off a week right now and very little money not a good combo for working on the 80,

[Rookie2]

Originally Posted by RavenTai

Derek I was going to PM you but aparetly I have lost that ability

FWIW, I got a message that your PM box is full.

[LandCrusher'70]

Originally Posted by tarbe

I like it right where the 100/150 puts it. Leaves plenty of room for movement prior to red zone/high temps.

In 15 miles of sand running at 90+degrees ambient Saturday (and with a total load of about 800 lbs), the gauge never went past horizontal. In fact, when I ran in low-range, the gauge never got within a needle's width of horizontal (probably never above 195). When in high range and experimenting, I did get to horizontal once or twice in some really soft, deep sand. Maybe 200 degrees? A/C was on, too.

Looks like my cooling system is working well.

Mine climbs often just driving around. I got to within 4 or 5 needle widths climbing a fairly steep hill near home.

Looks like my cooling system isn't working well.

[extremetoy1]

Originally Posted by extremetoy1

has anyone sent in a 91 gauge or pics yet? i am patiently waiting!!

well has anyone sent him a temp gauge from a 91 or has anyone done this mod for a 91 yet ? or do i need to send my gauge to him to be the guinea pig?!

[semlin]

extremetoy, noone has done this for a 91. The 93-94 and 95-97 turned out vritually identical despite different part #s so if you pull the gauge and photograph it we can likely tell you if the same mod will likely work. right now raventai does not have time for any more bench testing so that is likely as good as we can offer.

[Tool Pusher]

Originally Posted by Darwood

The 100 ohm resistor replaces the 75 ohm resistor and the 150 ohm resistor replaces the diode. These are the same type and brand that Raven sourced.

Mouser Part #: 71-RS2B-100
Manufacturer Part #: RS02B100R0FB12
Manufacturer: Vishay/Dale
Description: 3watts 100ohms 1%


Mouser Part #: 71-RS2B-150
Manufacturer Part #: RS02B150R0FB12
Manufacturer: Vishay/Dale
Description: 3watts 150ohms 1%


Here is the 180 ohm reisistor is anyone feels so inclined to use that. Note however that I haven't tried out this value.

Mouser Part #: 71-RS2B-180
Manufacturer Part #: RS02B180R0FB12
Manufacturer: Vishay/Dale
Description: 3watts 180ohms 1%


(I'm having issues with posting functioning links)

I found some resistors locally that are 2 watts and 2%. Do those of you who would know think that these would work? Was the 3watt and 1% rating speced off the OEM resistors?

Thanks, David Sword

[RavenTai]

IIRC the OEM 75 ohm resistor was 2w, it got very hot (fingetip burn hot) when reading higher temperatures where the current through that resistor was high, with the move to 3w resistors they are better able to handle the current and run cooler witch helps them retain accuracy,

the mod resistors are of a higher resistance this somewhat lowers the current,

so the 2w would probably work but are borderline and will get hot maybe not quite as hot as OEM resistors, IMO the 3watt wire wound resistors are preferable

% of the OEM resistor is unknown, the lower the better but accuracy %, but really no diffrence between %2 and %1

[semlin]

raventai, while i've got your attention on this thread, a quick question about my 93 gauge. Is there any chance it could electrically have a dead spot just below the bottom of the red line? I towed a 4500lb boat over a bunch of mountain passes a couple of weeks back and it never exceeded the top of the needle just about touching the bottom of the red, although it regularly went to near that point and stayed there for a long period on long climbs without climbing higher. i am pretty sure that's just where my modified fan clutch kicks in to do its job but I'm just curious if there might be another reason.

[RavenTai]

nope no flat spot, I have a full set of temp pics for that particular gauge if you want them.

I would agree that it is probably something that kicks in at that temperature, fan clutch sounds like a good suspect,

[semlin]

i think you have posted them before as ftp but i have no clue how to grab an ftp. if you are able to email them to me I'll pm you my email address.

[RavenTai]

Originally Posted by semlin

i think you have posted them before as ftp but i have no clue how to grab an ftp. if you are able to email them to me I'll pm you my email address.

probelm is the pics are 134MB, I think my e-mail tops out at 10MB

[RavenTai]

Ok let’s try this

click here

FTP

You should get log in box of some kind,

user name = ih8
password = mud

browse to /Pictures/93-94/110050, copy all the .jpg's to your computer, you should be able to just select copy and then paste and they will start downloading,

That is the "after mod" pics for your particular gauge, you can copy the stuff from all the other folders also, it is the full documentation of the project,

If anybody else want them grab them be my guest but do not expect great speed, I will leave it up and running for the rest of the weekend or until my IP cheanges witchever comes first,

If it is not working for anybody let me know and I will try to fix

[semlin]

thanks rt but i get a username or password error when i try it in lowercase or caps.

is there not a program that will do a mass resizing in windows, so they could all be reduced to 150kb or something? if i can grab yours I will resize them using my mac and post them up.

[RavenTai]

I've got a PM it no one else can connect either, I may not be able seve an FTP,

i have photoshop but dont know how to mass resize, I am sure photoshop can I'll have to look into how.

[RavenTai]

Semlin I uploaded the set to Kodac galeries, Kinda stupid way to do it but I think it will work

Pm me a disposable spamable E-mail address and I'll send you the silly invite Kodak makes you use,

[Darwood]

Originally Posted by tarbe

I like it right where the 100/150 puts it. Leaves plenty of room for movement prior to red zone/high temps.

In 15 miles of sand running at 90+degrees ambient Saturday (and with a total load of about 800 lbs), the gauge never went past horizontal. In fact, when I ran in low-range, the gauge never got within a needle's width of horizontal (probably never above 195). When in high range and experimenting, I did get to horizontal once or twice in some really soft, deep sand. Maybe 200 degrees? A/C was on, too.

Looks like my cooling system is working well.

Bit of an update... and I still haven't found time to post what Raven wants me to

I replaced my radiator (and other cooling bits) in late August (or was it September?) and with the the 100/150 mod my gauge has never gone above horizontal which according to the ODBII scanner is about 200 degrees. Once warmed up the gauge regularly goes from about 2 needle widths below horizontal (185ish) to almost horizontal (195ish) during normal driving (on/off freeway, around town, etc.) All in all I'm very pleased with where these resistors put the gauge with a (now) health system.

Tarbe, are you observing behavior similar to mine now?

I can tell you that before I did my cooling system overhaul the AC would cut off when the gauge was about 1.5 needle widths from the bottom of the red line which according to the ODBII scanner was 222 to 224.

[RavenTai]

Originally Posted by Darwood

I still haven't found time to post what Raven wants me to

Its Ok, on the original mod I would pick it up for a day and then not mess with it for a month, took about a year with a heavy push at the end.

[Darwood]

Originally Posted by RavenTai

Its Ok, on the original mod I would pick it up for a day and then not mess with it for a month, took about a year with a heavy push at the end.

To top it off I'm even less motivated now since I'm happy with the mod and I recently moved half way across the country. Come to think of it I'm not sure where my notes are now... probably in storage with just about everything else I own.

[Beowulf]

Without going back through everything, do you think a modded '94 gauge would work in a '97?
-B-

[tarbe]

Originally Posted by Darwood

Tarbe, are you observing behavior similar to mine now?

Yup. I have never been above horizontal, even crawling long hills at low speed. Usually 1 to 2 needles below.

[semlin]

Originally Posted by Beowulf

Without going back through everything, do you think a modded '94 gauge would work in a '97?
-B-

it would work mechanically but iirc there is a screw mounting hole out of place.

[RavenTai]

Originally Posted by semlin

it would work mechanically but iirc there is a screw mounting hole out of place.

What Semlin said,

See pic below, stock 93 on the left, modified 97 on the right, like a lot of other year changes 93 and 94 are the same, and 95 through 97 are the same.

Notice the placement of the bottom standoff and screw, The screws are also the electrical connection, (In this case ignition switched 12v + supply) it would not be to bad to move it on the gauge PCB, it is already pre-drilled you woudl just have to make contact, but the circuit board of the cluster is a different story, it could probably be done by a good tech, possibly deleting that screw and making a wired connection but I think it would be a lot easier to just modify your 97 gauge.

Please ignore the poorly executed bends on the resistor it was the first run on the test bed gauge,

[wearsabrowncoat]

Anyone have any extra resistors? I'd be willing to pay for parts and shipping. I'll order from the source if I have to but I hate paying inflated shipping costs.

[LandCrusher'70]

Originally Posted by wearsabrowncoat

Anyone have any extra resistors? I'd be willing to pay for parts and shipping. I'll order from the source if I have to but I hate paying inflated shipping costs.

Where are you?

[Rookie2]

Originally Posted by wearsabrowncoat

Anyone have any extra resistors? I'd be willing to pay for parts and shipping. I'll order from the source if I have to but I hate paying inflated shipping costs.

Yeh, they kind of get you of stick it to you on the shipping. I sold my extras to Mr. Bryan. It cost about a dollar to ship them to someone. If you can get a couple of people to buy with you, you can dilute that shipping charge some.


Rookie2