I don't think so, maybe, but I wouldn't rush to it. How have the sensors been tested? I am a big proponent of testing sensors before replacing.
As for the ign module, without PCM
control the timing is fixed, like around 10 degrees or so, when the PCM
comes into play, it then can delay or adv as needed. So knowing that, IF it is working now in open loop, I personally would not be rushing to think it is bad just yet.
If the CTS and IAT are good (did you ohm them out or read on datalogger?) and very close in temp at cold start, then look at the O2. The important thing on the O2 is disconnecting it will trigger only open loop mode, and if the ign module is good, will run perfectly fine, lower on power and mpg, but run fine, maybe some issues if you get on it.
You can ohm out the coils too, the Magnavox coils can fail (they are generally pretty reliable) and when the PCM
is in open loop it runs rich, and when in closed loop it will lean out to 14.7. So if the coils are weak or at least one is, then you have 2 cyls that will be having a weak spark, and the PCM
could be reacting badly to it (reading the O2 and messing up fuel mixture due to lots of raw fuel coming out the pipe).
Is the thermostat good? Up to 140F or higher?
Originally Posted by hoppercarmaker
n0dih Thank you for the reply. Both of the sensors are in the proper range.
It has been sugested to me that this could be a problem with the module under the coil pack.Any further help would be great thanks.... Dave