Well i completed the mass air conversion today, but i am getting a code 212 loss of diagostic monitor signal/spout fault. I am also having a drivablity problem if i try to gain speed with a slight load it has a miss, and chug, until it kicks down. Im not sure what to test on this code 212. I pulled the spout plug and it did have an effect on the engien rpm so i think its controling the timing. The miss might have been something i did during the swap maybe.

 

did you do anything with the timing? im assuming. ok ASSUMING that you have to do some sort of rewiring on the distributor to change how it fires. if you did then you likely messed with the timing.

as far as the code. ive been told that comes on anytime the timing has been reset. but im not sure.

 

the change to mass air doesnt require any swaps of the pins involving the ignition, unless i inadvertanly mess something up. I have been looking into the possibility that i need to change to a black TFI module, but not sure if the black one is OBDII only or it made it onto the late EECIV.
No it have not adjusted any timing, i pulled the Spout plug.

 

are you driving with the spout pulled? thats what may be causing your code. the spout allows the timing to advance when the engine is underload.

 

Yeah that's a good possibility because the the IDM signal is on a different pin on grey module versus the black.

 

No i just pulled it to see if the timing was being controled by the ECM and then put it back in.

 

My truck is a 93 and the mass air computer i put in is a WAY1 5.0 computer w/E4OD. i also think the signal is different if it doesn tak the black module

One type is referred to as the "Push Start" type, while the other is called the "CCD" (Computer Controlled Dwell) type. The "Push Start" module gets its name from the 4th pin on the module connector, which is a start signal inputfrom the starting system. When the module receives this 12 volt input, it increases or "Pushes" he ignition coil dwell for maximum coil output for easier starting. The "CCD" module does not use a start signal input, but does rely upon the ECM Spout input to control ignition coil primary dwell. By the way, ECM Spout controls ignition timing on both module systems.

Under normal running conditions, the "Push Start" module starts the ignition coil primary dwell time about 3.5 milliseconds before then next anticipated coil firing. At this point the module is waiting to see the Spout signal voltage change from low to high. When this happens, current flow to the coil is stopped, which will result in the coil firing. If the time is longer than 3.5 milliseconds, the module will reduce the primary current to prevent the coil from overheating, since it cannot anticipate the next coil firing. The "CCD" module relies solely on the ECM Spout input to change ignition coil primary dwell time. On this system, the trailing edge of the Spout wave will start the primary cycle, while the leading edge of the next wave will end it, resulting in the coil firing. The time in between signals is the dwell.

Both modules are used in systems where they may be mounted on the distributor, or, they may be remotely mounted away from the distributor (commonly called "Closed Bowl" versions). Usually, the "Push Start" modules are gray in color, while the "CCD" modules are black.

IDM is a feedback signal generated by the ignition system and is monitored at pin #4 of the ECM. Its purpose is to diagnose missed ignition primary pulses at the time the ECM commands the Spout signal to fire the coil. Since it is used solely for diagnostic purposes, if this circuit is not operating properly, it will not affect vehicle driveability.

Both "Push Start" and "CCD" systems produce an "IDM" signal, however, they do it in different ways. The "Push Start" system uses an external 22K ohm resistor (22,000 ohms) that is usually taped to the wiring harness that is connected to the negative terminal of the ignition coil. [On our trucks, it is usually located in the harness between the engine and the driver's side fender] This resistor is used to lower the voltage of the Tach signal being supplied to pin #4 of the ECM.

This external resistor is not used on the CCD system since it is part of the internal circuitry of the module, which produces the IDM signal. So, the IDM signal travels from pin #4 of the module directly to pin #4 of the ECM.

i havent quite got my head wrapped around this , but if its not the worst case is i have a toasted computer.