98 expedition security transponder bypass

i just reciently installed a compustar4200 for a client of mine on his 98 expedition... everything works well except the security bypass... i originally tried one of the dei power'd capsule style bypass's and it worked about 40% of the time, so per the recomandation of a senior installer i swapped it out for a 556u and it seems to work better but if the vehicle has been sitting at the customers house for more then about 2 hours strait, it fails to start with a blinking theft light.... the antenna ring is positioned between the steering colum plastic and the front of the key cylender (right where the transponder antenna is)... can anybody shead any light on this... other things to check?... i do have it hooked to constant power and status.... any and all recomendations will be greatly appreciated. - geeky907

I have had issues with 556u on some of Ford Vehicles.....U have to make sure Key is secured inside, with the Transponder being almost center....Also I place the Ring overlapping the Ford antenna, running the wire away from any RF interference in the Harness & mounting Box close to the same area.Have you verified that the Transponder is the cause?  Like having the key in Ignition when it fails to start?MO

Don't Learn from Others Mistakes

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The key is not positioned right on in the module. There's a sweet spot that the key has to sit in order for the signal to be transmitted properly.Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

mo12v wrote: I have had issues with 556u on some of Ford Vehicles..... U have to make sure Key is secured inside, with the Transponder being almost center.... Also I place the Ring overlapping the Ford antenna, running the wire away from any RF interference in the Harness & mounting Box close to the same area. Have you verified that the Transponder is the cause? Like having the key in Ignition when it fails to start?

well... unfortunatelly this is one of those 'it works great for me' kinda things.... every time im working on the clients ride, it never fails for me... but upwards of 50% of the time it fails for the cleint, he says that the theft light is blinking every time it fails... ... when i remote start it the theft light goes out long before starter-crank... i will check positioning of the key in the box... however i have had the client try remote-starting it with the key in the ignition, and it starts everey time... so im pretty sure its totaly a transponder issue... what are ya supposed to do if the antenna ring is too large for the ignition swith? - geeky907

Zip it down with zip tiesMO

Don't Learn from Others Mistakes

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