So i unplugged it and now I have temp gauge again now I need to clear the codes. I think there is something wrong with the switch.

Could it be that the coolant is 140 degrees?

 

Ed

He said the scangauge is reading 190, so that would mean something is wrong with the wiring to the gauge in the dash, or the gauge in the dash is bad. 

Gauge in the dash does not move after using high idle and turning switch off. Works just fine if I don't use the high idle. I did the cluster test everything was fine. My concern is does it affect the running of the truck like gpm. Like I said the scan gauge temp goes back to normal. I haven't tried going from high idle to gpms to see what it does . On gpm mode is the ect temp messed with or is it left open to normal?

Sorry yankneck696 I need to pm or call you like you asked.

ECT is just used for extending the 6 cylinder high idle & allowing it to stay on until it is turned off. It fools the engine into thinking it's still cold.

I think that if the Scangauge is reading correctly, there is a different issue.

Ed

If the scangauge is reading 190 then that is what the ecm is seeing so I wouldn't think you will have any "running issues"

 

It's almost like the gauge cluster is ignoring the temp from the ecm until a time period passes or the ecm isn't sending the temp? 

 

Is the gauge actually reading 140ish or is it just on bottom as if it isn't getting a signal?

OFF - Both sensors are seen as normal.

 

MPG - The IAT sensor is fooled. ScanGauge II should report  IA 143*F

 

6 CYL - The IAT and ECT are both fooled. The ECT fooler makes for the extended hold feature of the high idle. ScanGauge II should report  IA 26*F and WT 123*F

 

3 CYL - The IAT is fooled. ScanGauge II should report IA 13*F

So i figured out if I turn on 6 cylinder then start and warm up then turn switch to off before driving I have no temp guage. But if I turn on 6 cylinder start truck then immediately switch it off then I have a temp gauge even after it high idles. Then before driving i switch to mpg or should I go straight to mpg after starting? when switching to off while running it actually makes the truck Rev up a sec as your turning the nob and sometimes I get 3 cylinder high and I don't think it's that cold out I always have truck plugged in. also sometimes I get the p1291 code but my grid heaters are working. Aim I doing this right when aim I supposed to be turning the switch and what order?

It just suggested to switch to the high idle mode BEFORE you start. Then after the mode is set you can select either OFF or MPG. The 6 CYL selection is working normally and fooling the coolant temp to 123*F so it would hold high idle indefinitely for you. Soon as you switched away from the 6 CYL it should cancel if the coolant is over 170*F. 

 

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/64-mopar1973man-com-high-idle-kit/455-mopar1973man-com-high-idle-operation-manual

Recently I have had a problem with the high idle kicking in even with the switch in MPG mode. If it is telling the computer that the IAT is 143* then why would the fast idle kick in? This is before the truck gets up to the 170* coolant temp. I haven't checked into it at all yet. It just acts like there isn't an MPG mode at all.

 

I will check resistances maybe this next weekend when it gets nice out.

Recently I have had a problem with the high idle kicking in even with the switch in MPG mode. If it is telling the computer that the IAT is 143* then why would the fast idle kick in? This is before the truck gets up to the 170* coolant temp. I haven't checked into it at all yet. It just acts like there isn't an MPG mode at all.

 

I will check resistances maybe this next weekend when it gets nice out.

 

Diagnostic...

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/64-mopar1973man-com-high-idle-kit/53-high-idle-mod-diagnostic

Ok. The IAT fooler checked out fine. It read 39k and 56k ohms on the 3/6 cylinder fast idle settings. It read about 22k on the MPG mode. Is that where it should be reading on the MPG mode?

 

As for the ECT fooler, it reads 0 ohms with the fooler off but on the 3 and 6 cylinder fast idle it was open. Seems like this is a problem. It read 0 phms on the MPG mode.

 

What should I do next?

MPG should be 2.2K ohm I think. Have to look. As for checking the resistance of the ECT, the way it is wired, it gets the "Common" from the IAT. You need to measure from the signal wire of the ECT plug & common of the IAT plug.

 

Ed