85' MR-260 Ignition Senser failure WHY?

[Ron-P]

My 85' MR-260 Ignition Sensor has failed twice within 20hrs runtime.<br />I don't understand why this happens.<br />I have checked Shift Cutout Switch is not shorted, I have checked the Coil and they are working properly. I don't know how to check the Amplifier <thunderbolt IV Black Box> is the only component left in the loop. I ask why it fails at dealerships and I get a AHHHH, They just do. <br />Any Suggestions?,<br />Thank you,<br />Ron-P

 

[vinney]

Re: 85' MR-260 Ignition Senser failure WHY?

Is the ground wire hooked up on the distributor? There are two sensor coils new one and old one. You have the old one. The new style one is half the cost of the old one and its been redesigned. You will have to change the ends but they hold up better and are half the cost. Look up a sensor coil for a 1996 5.7. The color codes on the sensor red/white and green/white make sure there in the correct location. The preamp doent fail very often. My experience one in 20 plus years.

 

[vinney]

Re: 85' MR-260 Ignition Senser failure WHY?

Make sure the trigger plate on the rotor is not rubbing the sensor coil. The aftermarket trigger plates are suspect (bent ears).

 

[Ron-P]

Re: 85' MR-260 Ignition Senser failure WHY?

Vinney, I did notice rev # on the newer ones that i have purchased and asked any differance from my original? He replied, No just that it's a newer ver. Thanks for a new direction to look into. You sure have given me hope!<br />Ron

 

[Ron-P]

Re: 85' MR-260 Ignition Senser failure WHY?

And I will follow up with results as well.. Ron

 

[vinney]

Re: 85' MR-260 Ignition Senser failure WHY?

The old sensor coil has studs on the back. The new one has wires sticking(white/green and white/red)out with connectors. I would get the new style one.

 

[vinney]

Re: 85' MR-260 Ignition Senser failure WHY?

More info the new style sensor coil had a problem in about 1999 they changed the color of the epoxy on them I think the new one has gray epoxy. If that thing sat on the shelf awhile you may have got a bad one. I would make sure you get the newest one you can there is a service bulletin on the sensor coil failure.

 

[Trent]

Re: 85' MR-260 Ignition Senser failure WHY?

Is this the one Vinney??<br /><br /> Service Bulletin

 

[vinney]

Re: 85' MR-260 Ignition Senser failure WHY?

Good job Thats the one I didnt remember what color the epoxy was. I ran into a few of this bad sensor coils. Thanks for the help.

 

[Ron-P]

Re: 85' MR-260 Ignition Senser failure WHY?

Vinney, My buddy is on his way over now, he's helping me out too.I have printed all pages,<br /> including the Service Bulletin for sensor failure Thank you SO MUCH.<br />And Hello Trent, thanks for the SB.PDF file That was a score for me! I'm Excited!<br />We are going to take a quick stab at it - for he has limited time today. I'll be in the hatches for a few.<br />We now know a TON more than yesterday!

 

[Trent]

Re: 85' MR-260 Ignition Senser failure WHY?

This may or may not be of help.. Troubleshooting

 

[vinney]

Re: 85' MR-260 Ignition Senser failure WHY?

Trent your good with that stuff. good job.

 

[Trent]

Re: 85' MR-260 Ignition Senser failure WHY?

Wish my Wife would say that!!

 

[r_bremmer]

Re: 85' MR-260 Ignition Senser failure WHY?

Ron-P,<br />When your ignition sensor failed was it immediate or gradual. I'm having heat related problems in my ignition and I'm trying to figure out what is the likely item. It dies when warm, but when I get it home everything runs again.