Just changed the coolant temp sensor on my 97 Expy, 5.4. It's the coolant sensor on the top of the intake manifold right behind the alternator. Problem is the engine started running a little rough since the change. I noticed the temp gauge wasn't registering anything and I found the plug configuration on the new sensor is slightly different than the old one so I have the wrong one. I've tried to find the correct sender and have come across 2 different ones but neither is right. Would this being unplugged cause the engine to run rough and does anyone have the right PN for this thing? I also put a new DPFE sensor on. No codes.

 

davet,

The 97 expy uses the cylinder head temperature sensor for engine control, not the coolant temp. I would suspect the DPFE install. Make sure that the hoses are routed correctly. The sampling hoses are two different sizes. Make sure the connector is seated properly. Did you remove anything to get at the DPFE? Make sure it is pluged back in if you did. Is the Iac hose and is the Breather hose from the driver side cam cover connected and not leaking?

Regards

Jean Marc Chartier

 

Found the right sender today at the dealership for $8.00. I'll check the DPFE connections again but I changed the hoses one at a time to make sure I didn't mess it up. After I initially started the truck I hadn't hooked up the intake hose or the additional 2 rubber hoses leading to it near the throttle body. The engine ran for a few seconds then died before I put the hoses back on. Maybe I'll reset the computer too. Thanks JMC.

 

I just came back from a 120 mile trip with my 97 Expy, 5.4, factory tow towing my Jeep on a trailer (5,600 lbs). No problems towing and tranny temp never went over 150-160. I did have a bad alternator on that trip and made it running on the battery. I came home and put in a new alternator and coolant temp sensor. They gave me the wrong one and the engine ran rough for 2 days before I got the right one. I put the right one in and the engine runs smooth but tranny temp hit 220 and had some odd shifts in town then the tranny started making a whining noise. It started slipping then eventually would slip 100% and not go into gear. I'd wait a few seconds then it would whine again and engage then a few blocks later would disengage. I'd wait a few minutes and it would whine then engage. This continued until I got the few blocks to my home and it whines but wont engage. The tranny fluid shows way over full but was at the full line when I left on the trip this last weekend. I smell burnt tranny fluid outside the truck now that I parked it but see no leaks. I have a Banks Trans-Command on it and have had it for 2 years with no problems. Seems since I washed the engine prior to changing the alt. and changed the temp sensor I'v got problems. I covered all the electrical before washing the engine.
.........UPDATE......
I have a friend at a large, well known scrap yard who could install a used tranny with 88,000 miles including flushing all lines and a new filter along with a 2 yr parts and labor warranty for $1,501.00. Just as I was going to give him the go-ahead I received a call from an acquaintance that owns a tranny shop. He said he would rebuild the entire tranny with anything it needed including hard parts for $1,700.00 and extend the normal 1 yr/12,000 mile warranty out to 2 yrs to match the scrap yard deal. I went the rebuild route. That way I get to keep the same tranny and find out what happened to this one. They pulled the pan today and it was full of metal. I'll let you know next week what they find when they tear it down. They had information there describing how the different, common sensors affect the engine and tranny. On the sheet was listed the Engine Coolant Temperature Sender and described how it is used to assist in the operation of the tranny. I'm convinced that the $18.00 engine coolant temperature sendor I replaced because of the high mileage on the truck and because it was easily accessible with the alternator off is the culprit. NAPA gave me the wrong sender. The plug fit on it but the prongs inside didn't match up. When I replaced it the plug fit fine but I didn't check the actual prongs with the old one. Even worse is that the right sender from Ford was only $8.00. I had a prefectly good tranny and ruined it with a stupid mistake. Thanks for the advice.