72fj here, 2000 2500/my engine temp has suddenly started to go up? new thermostat,water pump,radiator,fan clutch,temp sender,intake temp sender,trans not sliping engine also changed idle from 800rpm to 850rpm about 2 months ago.no fault codes reman v44 pump about 1 year ago,engine always runs 180-185 even on hot days maybe 190 even on 100+ days w a/c running.temp going up and down per acceleration up/down like a yoyo??? drive w/scaner and temp correct w/gauge.could i have a over fuel problem starting? have not changed the injectors still factory units engine has 148k and is in exelant running condition any hints would help. thanks 72fj

 

all three of the 24vs in our family of trucks run between 180-200, they dont fluctuate very much. are we talking big fluctuation or just 5-10 degrees? Are you saying when you push the pedal down, temp instantly goes up and when you release, it jumps back down instantly?

 

my truck never runs above 185/190 yes tump goes up fairly fast and back down to 190
just seems to fluctuate more than normal..

 

it may fluctuate 5-10 degrees after the t-stat opens and closes. Which T-stat did you go with, 160 or 180?

 

i used the cummins 180 deg thermo/installed new test thermo and same problem, could the intake air temp sender be going bad and sending the wrong info to ecm?

 

doubt it, thats a seperate system, granted it helps govern the fuel rate but I dont see this being a fuel related issues, seems to me its in the water temp sender, i know you said you replaced it but it could be faulty

 

i have a new temp sender in the box,ill throw it in and retest drive truck,and let you know tomarrow!thank you for the feed back!!!!

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dukeboy,installed new temp sender last nite and test drove.same thing? hey do you have pn# for the 160.thermo?

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dukeboy,installed new temp sender and test drove,same results?hey do you have the pn# for 160deg thermo??? thanks 72fj

 

ill try to find it but im thinking its gauge issue, talked to a buddy of mine at cummins today, hes thinking the same thing, guage issue

 

dukeboy, i will throw in a mecanical temp gauge and test drive. when driving with scanner hooked up shoes same as gauge??? if i could just make an adapter for my cummins insite program i could really see whats going on!!! and i would be rich i could sell a ton of them!!!
i run a heavy diesel shop in so cal. any way i will let you know. thank you for the feed back.

 

hey dukeboy 318, gauge is the problem,thank for you feed back!!!!!