I have a '93 XJ with a '98 4.0 in it. It didn't have the hole tapped on the head, and it was just the plug, no sender. I want to get the temp gauge working, so, I got a 3/8" T, and put it in the the t-stat housing so I could put both the temp sender for gauge and the temp sender for the ECU in the t-stat housing hole. I bought a new temp gauge sender from Advance, and plugged it in. Now, this was done on a cold engine. When I turned on the Jeep, the temp gauge went to the halfway point right away. AS the engine warmed up, the temp gauge went up until it pegged out. Now, what would cause this? Everything that I can diagnose leads to the sender either being the wrong one, or it's a bad sender. What else can I check? Thanks!!
More likely the sending unit you bought isn't calibrated with your gauge... wrong part. You'll either have to get an OEM sending unit (dealer or jy) or get an aftermarket gauge that comes with its sender.
I did come across an old thread that stated the aftermarket senders that are supposed to work with the OEM gauge were off quite a bit. They said that the OEM sender from the dealer is the only way to go to get a correct reading on the OEM gauge. I was wondering if something had come up since that thread that would work. Not sure how hard it would be to get a temp sender for a 20 yr old Cherokee from the dealer. Thanks!
Aftermarket is going to be hit and miss (way more misses than hits...). Dealer would be the safest bet, but it's gona cost you $$. You could pull one at the junk yard for pennies on the dollar. Year moldels older than '96 would probably work, later models won't because the gauge gets its reading from the coolant temp sensor on those (via PCM); this is why your '98 engine did not have a spot for the sender unit.
The correct sender should read these values for given temperatures.
Application & Test Temperature Ohms
100 F (38 C) ...................................... 1365.0
220 F (104 C) ....................................... 93.5
260 F (127 C) ....................................... 55.1
Thanks, I appreciate those readings! I know they are in the FSM, just haven't found them yet. The problem I've been having with JY senders is they seem to fall apart very easy, if you're not VERY careful, the plug terminal comes right out of the brass base! I've only got one off successfully, and later found out it was open, D'Oh!
I'm willing to get a new one, I found a thread on swapping XJ gauge clusters, and it has part numbers for the temp and oil senders. I will try those first, then go from there. Thanks again!