tach sensor wire strain relief?

[pybyr]

As I mentioned in another thread, my tachometer sporadically goes dead and then the E4OD automatic enters the 'fallback mode.'

Some of you have confirmed for me that this is almost certainly the tach sensor- which makes total sense

I pulled the tach sensor from the timing gear cover over the weekend, and it's plainly visible that the wires have ended up doing a lot of vibration and flexing right where they come out of the sensor body. The wires just directly exit the plastic center 'core' of the sensor which has a flat face- which is a recipe for wire strain at that spot.

Do the replacement tach sensors hopefully have a better design incorporating some kind of strain relief like you see on some power cords, so that a new sensor won't merely die of the same fate? (my truck rides hard and I travel a lot of absurdly beat-up roads, so lots of vibration is unavoidable)

Or, if the new sensors are built just like the OE one in my '89, have any of you come up with a "mini-mod" to add strain relief to the wires, or somehow secure the wire leads so that they don't flop and twist?

Thanks

Trevor

 

[Brianedwardss]

I got a good one from a junk yard and put a nice gob of rtv on the wires on the flat sensor face, mine has worked like a charm. I also zip-tied my chord to the pump to help with vibrations.

 

[Agnem]

New ones are same as the old ones. After all, they enjoy selling you those $70 sensors don't they? Securing the wires is the best way to protect them.

 

[BioFarmer93]

Like Brian Edwards said with the RTV, but I'll take it a little further...Taper the blob so that it comes to a point about an inch above the face of the sensor, and do it so that the wires come out at the "point". This lets the wires flex gradually, moving away from the face, with complete immobility at the face. Just a homemade takeoff of what electrical appliance manuf's. do to protect AC cords where they exit a tool handle...

 

[LCAM-01XA]

I don't think it's vibrations that cause the wires to go bare there, but more of the insulation shrinking from years of heat and no proper retention inside the sensor - seen it on many older gassers too. If you look down the hole where the wire fist you see no insulation in there, cause the darn thing shrunk and pulled itself out. Agreed with Mel tho, zip-tie them wires to whatever other fat and fairly stiff harness you got running in the vicinity.

 

[Brianedwardss]

Like Brian Edwards said with the RTV, but I'll take it a little further...Taper the blob so that it comes to a point about an inch above the face of the sensor, and do it so that the wires come out at the "point". This lets the wires flex gradually, moving away from the face, with complete immobility at the face. Just a homemade takeoff of what electrical appliance manuf's. do to protect AC cords where they exit a tool handle...

That's exactly what I ended up doing. I shaped the rtv glob to a point in the direction the wire is coming in to the sensor.

 

[BioFarmer93]

Great minds...

 

[THECACKLER]

I used "Liquid Electrical Tape", a Dorman branded product, to build up the junction, tapering it out as a strain relief as I went. About 5 or 6 coats as I recall. Degrease the wires and sensor top first. Let each coat dry for 30 mins. or so between applications. I then used 1/4" split loom over that and secured it at 6" intervals to whatever was available with Zip Ties.
The liquid tape is nice stuff. It's available in the electrical section at the local Auto Parts for about $10 for a small can that will last quite a while. Also good for battery cables and the like.

 

[Pino2234]

What is the thread size of that sensor?

 

[OLDBULL8]

IIRC 3/4"-10 But you can take yours out and measure it.