Is teflon tape a bad thing?
Thread Starter
Intermediate
Joined: Dec 2006
Posts: 48
Likes: 0
From: Prairieville LA
Is teflon tape a bad thing?
Fighting problems with rough, low idle on my '82. The wiring going to the coolant temperature sensor is in really bad shape so I'm going to replace the sensor and the connector/wiring. Does the sensor need to ground to the manifold? I plan to use teflon tape to seal the threads but didn't want to cause a problem doing so. My schematic shows both the yellow and black wires going back to the ECM so I wasn't sure if a ground was needed.
Former Vendor
Joined: Aug 2006
Posts: 76,656
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
You will be fine on this one, but always remember: Teflon tape is only used as a lubricant on the threads. Excess will not allow the threads to seat as they were meant too! Put one or two wraps on the first three threads and install. 
Willcox Inc.
Willcox Inc.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
use the PASTE.....not the tape....apply to the middle of the sender that way the lower threads will give a ground if needed.....the tape is bad news in a lot of automotive applications....good luck
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Teflon is a lubricant and an insulator. Do not use it if the part requires connection for electrical grounding. If you use it to seal a leak on a pipe thread, be very careful with the amount of torque you apply to the installed part; since it is a tapered thread, excessive torque and the slippery teflon can allow the mating part to split and crack. You would be better to use a non-hardening thread sealant like Permatex pipe thread sealant, which will seal up any leakage but still allow metal-to-metal contact for electrical continuity.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
I guess most of you didn't read or didn't understand the original post. Perhaps you should before you give out generic info for a specific question. The sensor in question does not need a ground so tape will work fine. Many senders do need to be grounded, but not the one in question.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
We read and understood the post..but sometimes owners are mistaken on how their system is set up. More information than you may need is not necessarily a bad thing. It helps to give the owner a better context of how [and why] things should be applied. 
But, thanks for caring...
But, thanks for caring...
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Thread Starter
Intermediate
Joined: Dec 2006
Posts: 48
Likes: 0
From: Prairieville LA
Thanks for the input guys. I replaced the sensor but the idle speed is still low at times. Idles ok (700-750 rpm) in park or neutral, but ~ 500-600 rpm in drive, which makes the car idle rough. A while back MN-Brent suggested in addition to checking the CTS and TPS setting that I disconnect the MAP sensor to see if the idle speed changes. After the engine warmed up I disconnected the MAP and the idle speed did not change at all.
Is this an indication the MAP sensor could be malfunctioning? Is there a way to check continuity? Looks like they cost $50-60 bucks so I would like to be sure this is a problem before I swap it out.
Is this an indication the MAP sensor could be malfunctioning? Is there a way to check continuity? Looks like they cost $50-60 bucks so I would like to be sure this is a problem before I swap it out.
