View Full Version : Engine temp sensor resistance values new/old

Mark rsa2au
06-29-2013, 04:10 AM
Hi Guys

I am still chasing a very frustrating issue. Sometimes the engine will not rev above approx 2000 rpm no matter how far the throttle is pushed. Stop, shut down, start and go again and it runs fine.
We suspected the ECU sensed an over heat issue from a possable faulty Engine Coolant Sensor. Below are the Measurements taken from the old unit, the new unit and the factory specs. Can some one shed some light on these and if the new unit (Std chev engine temp sensor) is wrong and needs an Indmar part to be closer to the factory specifications. Both units seem to over read.

Deg F Ohms/factory Ohms/Old Ohms/New
122 973 730 807
140 667 480 550
158 467 320 380
176 332 234 263
194 241 186 198
212 177 - -

PS, just in case it is a fuel issue I am pulling the pump from the fuel tank and will replace the fuel filter and clean any intake mesh etc. Will also replace Impeller and strip /check raw water system again as precaution.

06-29-2013, 06:44 AM
Do you have access to a diag,computer or dealer? .....the diagnostics can excercise the sensors for you ..... Which engine and year?

Mark rsa2au
06-29-2013, 07:03 AM
Do you have access to a diag,computer or dealer? .....the diagnostics can excercise the sensors for you ..... Which engine and year?

Finally found a dealer but need to find lots of cash first ..... 2001 X5, Engine is 310 hp, TBI, predator

Mark rsa2au
06-30-2013, 01:41 AM
Replaced temp sensor today with Newer unit as above. Noticed the previous unit was not screwed all the way into the hole. Was ony about half way down and the ammount of build up in and arround the hole was surprising. I suspect the coolent temp sensor was not getting enough water flow over it to give an accurate read because of all the muck.

Had to use a screwdriver and small wire brush attachment on the dremmel to get all the muck out, used Old unit to "Cut" a path down and managed to get it about another quater of the way deeper. New unit inserted and it is almost all the way in.

Need to test still but should be much better!!

07-01-2013, 01:11 PM
I just replaced this sensor on my boat too after it seemed to be running rich. Test 32, 100, and 200 degrees and it was somewhat off at each point. Only have taken it out once since but fingers crossed the exhaust didn't smell as rich!

Mark rsa2au
07-01-2013, 06:27 PM
Mine is the opposite with the sender telling the ECM the engine is overheating and then reducing revs. ... I think? Problem is the new sender is only marginally better and still not to Indmar Factory specs.
Will try to test next weekend!! Hoping it will be better!