Engine/Transmission (1994 - 1998) New EGT gauge trouble!

[CStansbury]

New EGT gauge trouble! FIXED!!!

Hey guys,

My new Di-Pricol Optix EGT gauge is acting weird. At first it was working great, but then all of a sudden the readings started getting funky.



Sometimes I will go out first thing in the morning when it is about 35 degrees out and the gauge will be reading 210*. The when I run the truck it seems to be reading high. Then, when I park it, and let it idle, the gauge won't drop back to 300 even after letting it idle for 5-10 min. It hovers around 400.



I disconnected everything and hooked it all back up and the gauge dropped back down to normal levels. It worked fine for a couple of drives and then last night, it was reading high again. I pulled the fuse from the (+) wire and rehooked it and it was back to normal.



Does this sound like a gauge problem or a wiring problem? I wired it just like my old truck which worked great. Any clues here?



Thanks,

Chris

 

[Matthug]

Get isspro gauges LOL.

 

[CStansbury]

Thanks Matt The truck came out of PA, maybe that's the problem :-laf

 

[Matthug]

Good one.



Sounds like wiring but you never really know. Pyrometers are very finicky.

 

[Smokn Bio]

I have a di procal doing the same thing sometimes i see it at 125* but usually it says2-400 on a 35* morning??? I have no idea i just think its dispicable for all new setup. all i hooked up was the wires to the probe no light.

 

[BHuebner]

I installed the same gauges in my truck last week. the lowest it will go is 250, even with the truck turned off. it doesn't fluctuate like you described, but i figured it should at least read zero with the truck shut off. is your egt gauge as bright as your boost gauge?

 

[CStansbury]

I wired the LED power wire to the headlight switch. The LED ground and stepper motor ground go together to chassis, and the stepper motor positive goes to the underhood fuse box on the cab side of the 120 amp fuse. I have a 10 amp inline fuse on the stepper motor positive. If I go out in the morning and the gauge is reading about 200-250, I will disconnect/reconnect the stepper positive and it will then show outside air temp. The gauge will continue to work fine if I just drive around town. If I get out of town and get the EGTs up to 1000 or so, then it seems to get screwed up and won't drop back down to ambient air temp overnight. I disconnected everything again this morning and made double sure the connections were clean.



This really chaps my a**. I need to tow about 8000lbs next weekend and I don't know if I can trust my readings.



BHuebner, my gauges are the same brightness. Maybe you have a bad LED from the factory.

 

[BHuebner]

Yeah Chris i remember now telling you about the lighting problem in another thread. LED looks good, when i turn on the ignition it glows. the bulb in the back of the gauge is bright when i turn on my marker lights, but when i plug it into the gauge itself you cant see the 8* mark at night (maybe its the gauge). sucks having 2 bright gauges and 1 dim.



as far as the needle mine wont drop past 250 no matter what, came out of the box that way. probably should call TST. see how good their customer svc is.

brian

 

[CStansbury]

Bummer Brian. Me and the Mrs. drove the truck out to dinner tonight. It was working fine when we left the house (I had pulled the fuse and put it back earlier today). We had about a 30 min. ride down the highway. After dinner, I noticed that the gauge was still at 600* On the way home it was about 600* off. I was cruising at 65mph with 2. 5 lbs of boost and 1200* on the EGT. What a joke!



I have trouble-shooted all I can. Time to send it back.

 

[BHuebner]

sorry to hear that Chris! yeah mine is not even that bad. mine should be accurate( 600* at 65 w/5lbs boost) like you said with yours that could get dangerous if you tow 8000#'s. wonder why it zeros out when you remove the fuse?? i would think you could send that back for a new one.

 

[Howard Durand]

Is the Di Prical gauge a mechanical gauge or is it electronic? Mechanical gauges are only affected by the voltage output of the thermocouple.

If the gauge has to have external voltage applied to function, then there must be a problem in the gauge itself.

 

[CStansbury]

The original DP EGT gauge I had in my '04. 5 was mechanical so the only power wire was the lights. This new Optix EGT gauge has a stepper motor to make it smoother, quicker and more accurate supposedly. At least that is what the www.danininc.com website says. But actually the description is a little confusing on their website because it says "no external power" required, speaking of the thermocouple I guess. I pulled it out again this morning and looked over all the wiring. It felt almost hot to the touch, not good...

 

[Mark Craig]

CStansbury,



The ground is very very important on any stepper motor gauge like the Optix is! At DPPI we try our best to get folks to use the DiPricol factory made installation harness too as it has built in dimmers for each individual gauge that also eliminates the LED connection thru the trucks dimmer circuit. The dash lights are incandescent bulbs the Optix are LED, LED's use next to 0 current as compared to the normal bulbs. When you tie the two of them together you end up more often than not with some weird lighting results.



I have had a few pyros operate as you have described and so far the ground for 12V + has been the cause of the problem. I reccomend that you use a OHM meter at the ground you have and see how good it really is. Or just change it to a really heavy part of the chassis. Most likely you'll be OK. If you didn't use the optional harness and used the short pigtails that came ont he gauge be SURE you have a good plug in connection. I have also seen folks make their own harness so short that it actually partially comes undone and the ground is weak then too!



Mark @ DPPI

 

[CStansbury]

Hey Mark,

Thanks for the reply. My problem is I ordered off of the website instead of calling you guys. I didn't see that there was an additional harness listed. I just got off the phone with your co-worker at DPPI and he is going to get me a 2 gauge harness out pronto. Thanks!



The problem with erratic temps turned out to be a wiring issue. Di-Pricol sent a wiring diagram that showed the stepper motor (+) hooked up to the Battery (+). The guys at DPPI tell me that it should be hooked to a switched (+) power source instead. I'll try that and see what happens.



I soldered all my connections so they should be secure. I will move the ground to the frame and the (+) to a switched fuse inside and let y'all know how it goes.

Thanks,

Chris

 

[HookMeUp]

By any chance did you extend the leads of the thermocouple wire? And if so did you solder the connects? The connections must have ring terminals and bolted together.

 

[CStansbury]

No, the thermocouple leads were long enough to reach without extending them. I bolted them together and covered with the supplied heatshrink.



I think it must be the stepper motor power wire. I thought it was weird that every time I disconnected and reconnected the inline fuse that the gauge dropped back to normal. Danin needs to redo their wiring diagram to show a switched (+).

 

[CStansbury]

Got it working now!

Turns out it was the the thing was wired. The simple diagram that comes with the gauges makes it look like you wire the stepper motor direct to batt (+).



I received my DP wiring kit from DPPI yesterday and man that thing is nice. DP supplies a detailed instruction sheet with that and it spec'd that the stepper should be wired to a switched (+). I changed that and it is working normally now.



As soon as I get a chance, I'll rewire with the new harness. It is sweet and well worth the $50 as it comes with dimmers for the LEDs to match the dash lights, color coded wiring with DP connectors on one end, color matched heat shrink, grommets, and everything is loomed together. The dimmers alone are worth the coin.



I'll post up when I get that changed out. Thanks to Mark and the rest of the gang at DPPI for the great tech support.



Chris