rf transponder rings sensitivity issues

experienced installers.   

i have been gradually finding more sensative and inconsistant problems w/ transponder boxes and rings.  i prefer to use them do to cost and speed.  i deal primarily w/ bypasskit boxes or build my own w/ a relay.    

the main thing is that i see more and more cars that work fine right away come back,,,,,,but not right away.    ex.   i had 2 honda odyssy vans come back this week(and we are super busy so it sucks)  that i have done months ago on one and 2 yrs ago on the other.   one i wrapped my own key and used a relay and the other i used a box w/ one of the new "sticky ring" loops w/ the exposes windings.   

why are they all of the sudden deciding to be picky..    neither of them moved a mm from inital install.        obiviously if you do a ford when its 70 degrees and the next morning its 10 degrees it will show up quickly if your not in the correct placement.    but when that same car comes back 2 yrs and nothing has changed makes for an irritating day.   especially when the customer is wized and of course you cant get it to not start in the shop and it has to be w/ in 3 inches and  starts every time.   

any tricks ...i am pretty experienced, own a shop and do alot of cars so please no "basic" comments like try to move the ring.

ahh yes very irritating especially on some cars *cough* chrysler *cough*. it's hard to say that it hasnt moved if you havnt seen it in 2 years but i know what your saying. the problem is the ring (depending on the sensitivity of the transponder system) for the most part needs to be as close as possible to the front of the cylinder.  it only needs to move like an 1/8 of an inch back sometimes to lose connection. as for the tricks part, i put like 4 little pieces of dum dum(sticky tac or whatever you want to call it) around the cylinder to help hold the ring in place. then wrap it as tight as possible and use a wire tie to keep it tight. usually works for me with no problems. i find those "stick on" ones not very useful, i never use them but i seen cars come from other shops before and i guess in the cold, they lose their stickiness and just move.

oh yea...if that doesnt work try moving the ring haha 

when i use a raw wire or non sticky ring,  i usually even hot glue the damn thing in place..    i swear they become more sensitve or the chips get alittle less strength in sending or something, and CONVIENENTLY the problems get worse in the cold.    i like the sticky rings alot for fords.. seem to have good luck w/ cars that came back transponder issues,  i chop the wires up there and add my sticky ring and its usually much improved.    also have had one chrysler and multiple vw's that the only thing reliable was a ring on the outside of the shroud....VISIBLE to customer..  i just  made them black w/ tape and the customers never noticed..  sounds ghetto i realize but no probs.

what brand of boxes do you use ?    the funny thing is that i have had a few cars that wont catch the signal if i am using a transponder box  but will work w/ a 95cent relay and an 6 cent piece of wire..   the $15 box is no good,  but my rig job does the trick.  

this is the first time i have done this... just yesterday i did an 03 audi A8.    its my car and i have 2 switchblade keys.   i can get them to work w/ a relay and wire but often sucks for reliabiltiy... as per a previous post i used a 556u?   which i have in the bypasskit  version..i think the tbkv off the top of my head.. the one w/ the big rubber ring style coil and 3 black wires in the plug goin to the ring side.    anyways thanks to the post that let me know that would work by integrating into only one side of the transponder  wires.   everything was cool w/ the exception that my key wouldnt fit in the box.   i didn't really want to hack it apart and i didn't want to pay for/wait for a new smaller basic key.   i took a piece of wire and wrapped the hell out of the portion of the key w/ rf,  then picked a jumper setting on the key winding selector and soldered the ends or my homemade wrap to the circuit board..  works good.   the key was to bulky allow the box to fit back together correctly.  i did some creative hacking on it and then taped it together as close as it would get.. not the prettiest, but effective..

i wasn't aware the you just had to interupt one wire on german cars.    i.e introducing your new wrap wires in line w/ only one of the two factory wires. 

in bmws i have removed the factory rf ring, relocated, taped a key in the middle.. and then this is critical!  use a relay to open one of the wires when the car is not on.. the ignition triggers the relay to close the loop and sense the key.   if you dont break it w/ key off, doors might not lock, dinger is funny, ect. 

thanks for the intelligent replys guys

OK I don't know if it will help but let see;

Solid telephone wires we find in walls are the cheapest one strand almost pure copper wires. Youpull one wire out to cut the envelope and you have now 4 wires to create your own best ever transponder loop.

A 1.5K resistor squeezed between the transponder and your loop will generate enough heat to avoid a transponder failure even at -55c. Make sure the resistor is powered OFF when ignition is ON (one end of the resistor to 12vdc, the other to 12ACC) to avoid amplifying the noise generated by the current flowing in the resistor when the transponder challenge is engaged by the immobilizer module.

Another way to make a transponder when you are desperate;

Wrap a very thight coil to cover the entire key head

The loops around the key will not permit proper RF field dissipation to the transponder unless they are all at one end of the key.