ECM Coolant Temp Sensor (Page 2/2) Gene1000 AUG 19, 11:47 AM LOL….thanks, Vintage. Like everyone else, you’re entitled to your opinions, as I am to mine. Even if one disagrees, differing views should be respected. While I may not agree with yours, I certainly respect your right to express it. Thanks again for your comments. Mickey_Moose AUG 19, 03:13 PM quote Originally posted by Gene1000: The engine runs poorly on a cold startup. After it gets warm, it runs better. As you know, the coolant temperature sensor, CTS, lets the ECM know and when the engine is cold, the ECM will adjust fuel mixture and timing accordingly so it runs properly. So I want to replace it as a possible cause. Steve, I scanned the codes and nothing came up. So I replaced the MAP sensor and TPS sensor anyway. Next comes the CTS and spark plugs. Haven’t checked vacuum yet. I’m familiar with the bushing and I’ll see what happens. Vintage, thanks for your suggestion on the fitting. I’ll try removing the sensor again tomorrow. If I can somehow use an impact driver, I’ll do so. But it’s very tight down there. Thanks again, guys. Gene You say you checked for codes, but did you actually monitor the sensor via the scanner (or di you just do the paper clip thing)? The scanner will tell you the temp that the ECM it is reading - this way you know for sure if it is the CTS that is the actual problem or something else. But if you just want to replace the CTS that is your call, but you should actually diagnose if it is actually the problem. Gene1000 AUG 19, 06:40 PM Good question, Mickey and well worded. I appreciate the considerate way you put the question. I don’t have a scanner so I used both the paper clip method as a “scanner” as well as performing tests on each individual sensor. The paper clip method didn’t reveal any issues. So I tested the sensors. The voltage on the TPS was way off. I adjusted it to 5 Volts in and 0.6 v out of the sensor. I finally got the coolant temp sensor out with an impact wrench. I applied heat to it and confirmed it was working with a meter. I didn’t bother testing the IAC and MAP sensors. I simply replaced them. Patrick told me about a decent testing software package which I’m going to purchase. Thanks again for the question. Patrick AUG 20, 02:11 AM quote Originally posted by Gene1000: But I think I’m going to take you up on the ALDL monitoring tool. Wise decision, you won't regret it. When you're able to see sensor readings (and more) appear in real time while the engine is running, you'll wonder how the heck you could've ever tried to diagnose engine issues without it. fierofool AUG 20, 09:48 AM If you break the CTS, don't worry about it. Just get a bigger socket and remove the reducer that screws directly into the lower intake. As Steve308 said, you can easily get another at most any hardware store. I have occasionally found that the reducer would come out with the sensor and then be impossible to separate and reuse. Ace Hardware was my friend for a new reducer, lavishly slathered with antiseize before installing. Gene1000 AUG 20, 01:14 PM “I have occasionally found that the reducer would come out with the sensor and then be impossible to separate and reuse. Ace Hardware was my friend for a new reducer, lavishly slathered with antiseize before installing”. Fierofool, Thanks. Well, I’m on my second reducer-bushing. I tried screwing the sensor on the first one but it was so tight that even with a large torque bar it was impossible. I even removed the leak prevention coating on the new sensor and still couldn’t. The vise I had the bushing in wrecked it. So now I have a new bushing. And the sensor no longer has the sealant coating. My attack plan, cleared with the admiral, is to use permanent thread locker with teflon tape on the sensor threads. Then use a large torque bar to screw on the bushing. Hopefully if I ever need to remove the sensor, the reducer will come out with it. Ain’t this fun……. fierofool AUG 20, 03:09 PM Don't use thread locker (LokTite) You can wrap reducer and the sensor threads with teflon tape to seal it. It doesn't need to ground through its base like the fan switch or gauge switch. It's a two-wire circuit that has a ground. A regular socket and ratchet should be sufficient to tighten either both reducer and sensor. Gene1000 AUG 20, 05:32 PM Firefool, My concern is if I don’t use a thread locker between the bushing and sensor, if I need to remove the sensor in the future, the bushing may not come out with it. I’m looking to use antiseeze on the new bushing because I had a helluva time getting the old one out of the engine. Eventually had to use an impact wrench. Very difficult getting the wrench in that tight space. Thoughts? fierofool AUG 21, 02:24 PM I think I've only once had the reducer come out with the sensor. I would personally prefer that it stayed in the manifold because of the two different metals. Removing and installing the bushing might be more prone to damaging the threads of the aluminum manifold. I believe I used pipe compound on one because I didn't have any teflon tape, but the tape would be ideal for both the sensor and reducer installation. I don't believe the coating on the sensor threads is a locking compound. More like a sealing compound. Vintage-Nut AUG 21, 03:10 PM I use high-temperature RTV...