Engine/Transmission (1994 - 1998) Isspro gauge/bulb problems/zero?

[pwerwagn]

Has anyone else had problems with the isspro EGT guages (R-607g is what I have) sticking? Mine is fine w/o the bulb, but with the bulb in, the needle sticks at 800* and you have to tap on it to get it back down.

also, i noticed the isspro gauge is "zeroable", you can stick you finger in the bulb hole and zero it, or move where it starts at. is this true on all gauges?



--Jeff

 

[Andy Redmond]

Sounds like the heat from the bulb is jacking with the calibration you discuss. Perhaps the bulb is too long or large in diameter? (perhaps manf. mis-matched bulb to your application). When the bulb socket screws in is it grounding the circuit? Maybe a bad ground is your problem? A bad thermocouple or lead wire could possibly cause this (inaccurate, no or stuck reading).



If you've just installed it (yellow is + on a pyro and the red lead attaches to the opposite gauge head post). Match the wire colors on the thermocouple to lead wire connection near the exhaust manifold.



I would adjust the head only with a pyrometer testing to assure accuracy.



Call Isspro or your vendor to discuss its malfunction, perhaps it is new enough to be in warranty.



I've spoken at Don at Isspro tech on several occassions and found him to be knowledgable and helpful on such questions.

 

[pwerwagn]

I thought about the heat also, but I think the problem is the length of the bulb. Is it normal for the pointer to be able to be moved, and it will stay there? I can move my pointer from 0-300 degrees easily, and the reading will start from there. I usually set it to ambient temp. The gauge has been in the truck for a while, but it only started acting up when I replaced the bulb. The gauges is innacurate, because when it hits 800 and sticks, it makes the needle in the wrong place, and then when it drops, it is off by a few hundred degrees.

I'll try calling Don for some suggestions.

thanks,

Jeff

 

[Andy Redmond]

Jeff:



Most "analog" pyro's like yours will show 50-100 deg. when engine is cold. Don't calibrate it for ambient air temps. . It doesn't follow a mercury thermometer. The pryo head accuracy can be tested by a pryo tester to see if 300, 500 1000 1700 deg. etc. are truly accurate.



I think the bulb was the start of your problems, then the adjustments made may have it calibrated.



If you'll send me the head I'll recalibrate it with the pryo tester if you like. I'd like the lead wire and thermocouple too just in case. A 1/4" or 1/8" pipe plug would likely plug the manifold or downpipe when removed from the truck.



Redmond Ent.

6921 Marigold Ct.

Plano, TX 75074 or if you like the PO. .



Box 261605

Plano, TX 75026-1605



Let me know if its on its way and pls. insure in case the common carrier loses or damages your parcel.





Maybe you need a "6 volt" bulb or illumination lamp?



Good luck

Andy

 

[pwerwagn]

So, should i never mess with the needle adjustment?



thank you very much Andy.

I will mess around with it a little more, and if I cant get it right, I will send it to you.

thanks for the offer,

Jeff