93-97 Coolant Temperature Gauge Modification (1 Viewer)

[RavenTai]

mod #7

hmm I have not had much rise at highway speeds, will be interesting to see what maintenance gets actual returns, now at least you can get real feedback.

 

[Arya Ebrahimi]

Raven/Semlin, any update on the '93-94 gauge? Would be very interested in doing this should it prove to be doable.

Ary

 

[RavenTai]

I am sorry I have been slacking and doing other things, the 93 gauge is sitting right next to me, I promise to get to it before the warm weather gets here.

 

[loquito]

I am parroting Ary
I have the electric parts and hoping to see You say it will work on a 94.

 

[semlin]

loquito I thionk there is a 95% chance you could just throw it in there and find that it works fine, and then have raven calibrate it later when he gets time. as i have discovered recently, there is no time like the present to pick up a responsive temp gauge even if all it does is show you that the truck is heating up more than usual. I managed to boil my rad dry from a small hose leak and never got a temp gauge problem until it was too late.

I would like to have the mod done in time to test drive my new h/g

 

[tiorio]

Mod #8

Thanks for all the leg work! Only time for a quick 5-min test to see if at least it moves. All seems well! Almost ready for wheelin' season...

Cheers!

 

[lxed]

Help!!

If anyone can start a new thread, I need to tow my fj80 w/rental equipment
u-haul say their stuff is too small.

Blew head gask 300mls south of LA going to AZ. Truck is still in
El Centro...

I'll get it fixed there if anyone knows a good mech.

lxed

 

[semlin]

in the top right hand corner of the 80 forum there is a spot that says "new thread". click on that and post up your questions. if you do a search on "towing" you should get some ideas. I recommend against using dollies for a long tow.

 

[lxed]

thanks

Thanks ....I just put in a new thread after I had that brain cramp
lxed

 

[Darwood]

I've been running this mod for almost 2 months and yesterday I got to drive 70 miles or so with a my OBDII scanner connected (which happens to be my Palm pilot). I compared the ECU read temperature with the gauge.

First of all since the ECU and the gauge use different senders I did notice that thier measurements relative to each other were a little off. The gauge seemed to register temperature rises sooner than the ECU. The ECU would eventually match (as well as I could tell) the gauge (if the gauge was steady enough).

According to the ECU my truck liked to run at around 187 to 208 degree Fahrenheit. These temps seemed to be speed and load sensitive. For instance going 80 mph brought about the 208 temp and slowly driving in stop and go traffic around 5 mph resulted in temps of 187-190. The ambient air temperature was probably the low 60's.

So here are some generalizations with speed versus ECU temp vs gauge:

60 mph : 190-195 degrees : middle of the gauge to a needle width above the middle

70 mph : 198-200 degrees : about 2 needle widths from the red line

80 mph : 205-208 degrees : about a needle width from the red line to a half a needle width from the red line

My truck seems to be running a little hot, but the temps are still below the old moving point of the gauge before the mod. Also the temps seem to be a little higher than before I installed my Hella 4000's on the front. From what the needle was showing before the lights it seems like they are adding about 2-4 degrees more to the coolant temp in the high speed freeway driving.

I haven't hit the bottom of the redline yet, but I think it might be around 212. I'm still not sure if I like the red line this low. To me hitting the redline means I need to shut off the truck. I'm not sure if 212 means this. In the old gauge it didn't.

 

[tiorio]

I've been waiting for a chance to do this same thing with my laptop. After mod, my truck seems to be running a lot cooler than I thought it was, the needle hasn't hit the middle of the gauge yet, although trips have been kinda short.

I'm wondering how consistent the temp readings are between gauges. I'd assume they're pretty darn consistent but what do I know? (Answer: not much apart from how to order some resistors and work a soldering iron).

 

[Darwood]

I'm curious to see what you read from the ECU as well. I think we might find a lot of variation on temperatures between trucks depending on cooling system health. My gauge seems to be fairly consistent with RavenTai's experiments and observations.

Todd, what kind of ambient temperatures have you been driving in?

 

[tiorio]

Mid 60s to mid 70s. I haven't done more than a few freeway miles, mostly LA surface street traffic. I also did a full back- forward- and sideways flush on the cooling system not 6 months (and less than 5000 miles) ago so my cooling system should be in pretty good health.

Nothing like having slighty divergent results to make one quesiton one's soldering skills!

 

[Darwood]

Mid 60s to mid 70s. I haven't done more than a few freeway miles, mostly LA surface street traffic. I also did a full back- forward- and sideways flush on the cooling system not 6 months (and less than 5000 miles) ago so my cooling system should be in pretty good health.

Nothing like having slighty divergent results to make one quesiton one's soldering skills!

It looks like your ambient temperatures are the same or slightly higher than mine. The more I think about it the more I'd love to see what temperatures your ECU is reading.

 

[RavenTai]

This is good stuff, thanks for the ECM comparison

The bottom of the red mark is suppose to be 217, I would be bummed if it did wind up being 212. I tried to be as accurate as possible in designing the test bed, I could accept a degree or two variation from the test bed to the real engine but not 5. Do you think it could make that 5 degrees in the space left? When I called bottom of red @ 217 that was the line forming bottom of the red at the center of the needle. See attached,

Also due to the height of the needle off the face of the gauge there is some parallax error, reading vary with viewing angle. Nothing can be done about this, in the test bed the camera was set to perpendicular to the face of the gauge. The other variable is gauge to gauge variation, I would hope that they are consistent being a near Wheatstone bridge it has the potential to be accurate and consistent, time and what they are exposed to could effect things also.

My main goal in this mod was for us to have an inexpensive reasonably accurate troubleshooting and monitoring tool, we may be getting to some early results here.

I am hesitant to make the mod less sensitive. If we are seeing actual problems even if they are minor, fix the problem not the symptom, 217 is 32F above thermostat opening temp, but if we are seeing consistent hits into high needle positions on many vehicles that are otherwise good then maybe I should look into it but not any time soon. Have other things that need to come first, Will have to see what happens as summer approaches.

In general my needle stays at or near the middle at highway speeds. long acceleration can get it to pop up a bit (200 or so) but not near the red mark, I ran a early version of the mod near the end of summer on a trip to FL, it was hot and never got that close to the red mark even with a more sensitive early version of the mod. Mine seams more to rise up at low speeds where airflow is less,

Could I talk you into pulling the lights and retesting? Could they be restricting flow airflow to much? Possibly combined with some other minor cooling efficiency problems?

Tiorio at the other end of the scale, have you done any non short trips at all yet? The last bit of warming up is slow, takes over 10 miles or more to finally hit the middle.

 

[tiorio]

I'm doing a couple hours freeway tonight. Depending on the hour when I leave I'll try to hook up the laptop for a portion of the trip and get some data from the ECU as well.

 

[Darwood]

This is good stuff, thanks for the ECM comparison

My pleasure. This mod is starting to suck me in. I wish I had found the thread about it while the testing was going on.

The bottom of the red mark is suppose to be 217, I would be bummed if it did wind up being 212. I tried to be as accurate as possible in designing the test bed, I could accept a degree or two variation from the test bed to the real engine but not 5. Do you think it could make that 5 degrees in the space left? When I called bottom of red @ 217 that was the line forming bottom of the red at the center of the needle. See attached,

If that is what you meant by bottom of red then I think that yes, it should make the 5 degrees with the space left. I think 212 will be just when the top of the needle touches the red line. From my limited experience it's about 5 degrees a needle width (give or take).

Could I talk you into pulling the lights and retesting? Could they be restricting flow airflow to much? Possibly combined with some other minor cooling efficiency problems?

This is a good idea. I'll probably try it this weekend. I'm starting to think I have some cooling issues (big surprise there). My truck definitely gets hotter with higher mphs. Slow speed (35-40) driving seems to be fine with the gauge in the center.

 

[Mr.Bryan]

I know this might be a bit off topic, but anyone have any resistors layin around? I'd much rather give you guys 5$ for 2 little resistors, then some company who wants like 8$ to ship a gram worth of parts...

 

[tiorio]

I'm doing a couple hours freeway tonight. Depending on the hour when I leave I'll try to hook up the laptop for a portion of the trip and get some data from the ECU as well.

Well, I ended up hitting the road shortly before midnight, with wife and half-alseep/half-screaming 2-yr old so me plugging the laptop in was not a priority nor well-advised distraction.

Will try to get ECU temps this week and post 'em up!

 

[Rookie2]

I know this might be a bit off topic, but anyone have any resistors layin around? I'd much rather give you guys 5$ for 2 little resistors, then some company who wants like 8$ to ship a gram worth of parts...

Yep, I bought two extras. I'll PM you if you still want them.


Rookie2