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Discussion Starter · #1 ·
Hello everyone, i need help :)
Lately i am facing a very annoying issue about OBDII on my 2004 Exige, it stopped to send consistent data, i can see no IAT's, RPMs going randomly from 0 to thousands more times per seconds and so on. Sometimes something works, like IAT's but like after 5 or 6 minutes of running, sometimes not even so.
What i can say is that once during a track day the car started misfiring and turned out it was probably the IAT cable exposed grounding or shortciruiting somewhere during driving, maybe fried something at the ecu level?
The car is a 2004 throttle cable with Komotec SC kit and BOE IAT-MAF mods, Federal ECU, data in the cluster is fine, rpm, clt... I use Torque, tried but different adapters and apps.. not different mobiles i have to say.

Thanks!
 

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Did your obd reader work in the past? I've read where after some ECU updates others reported problems communicating with it. Also read where many readers won't work properly with Lotus.
 

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Discussion Starter · #3 · (Edited)
Yes it worked, i tried ordering 2 different new units but same behavior. I have to say that i just found a pattern.. if i have IAT i don't have baro data and rpms, and when i have those two (very slow data refresh) i don't have IAT, or better i have IAT at 0°c.
IF when i have IAT i disconnect the IAT sensor i get a -40°c, so the 0° in the other case is kind of weird.
More weird is that i can switch between these two modes by randomly restart car, or disconnect obd or reboot mobile.. still looking for a pattern there lol.
I think it could be something in the area where i splitted harness for BOE mods that produce unconventional data to the K-line.
 

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Beyond my PD but there are several guys on here that might be able to shed some light. I dug this up may be pertinent not sure if you had seen it. ECU stopped working with ODBII readers
 

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Discussion Starter · #5 ·
Very interesting read.. had no idea that this issue existed, i hope is not my case since it is workishing (is that even a word lol?), badly, but not dead.
I was reading the service manual that says :
Potential failure modes:
• Signal short circuit (IAT = –40°C (–104°F) < 0.049 V)
• Signal open circuit (IAT > 140°C (284°F) > 4.932 V)

But, i get -40° IF i disconnect it WHEN is working, that should be an open circuit instead, not short circuit, and show me 140° instead of -40°..
Am i overthinking?
 
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