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Discussion Starter #1
I have a 94 Deville 4.9 starting problem. Driving home one day and it just died. waited about 30 min and it finaly fired back up. then the next day it wouldnt start again, pulled a plug and found that im getting no spark. checked cap, rotor, coil tested good, module tested good 5 out of 7 times at the auto parts store so i replaced it...still NO START (spark) crankes but no start. i dont know where to go from here...someone told me to check the pickup coil in the distributor. could anyone here give me any advice on where to go from here or what to check(replace) if it is the pickup coil how would i replace it?? oh yeah ...i was getting i code of P012 when it wasnt starting. i think i cleared it, codes not there now but it still wont start.
thanx for any advice !!
 

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i hope this helps...it's for a 91....but it should be pretty much the same...the connectors on the HEI and the ignition module is the same as my '79 chevy...so i doubt there is a difference between the '91 and '94 4.9L

on another note...i just had the same problem sans the code...the module tested bad so i replaced it and i was up and running...till i got to work...lol...it ended up being a bad terminal...i had to replace the connector...whopping 3 bucks:D
 

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DESCRIPTION:

Possible causes of "no distributor reference" are:



  1. The grounding screw is located on the metal tab that is attached to the plastic fitting on the five wire harness.
  2. HEI module unable to process pick up coil signals to produce distributor reference pulses.
  3. Open or shorts on CKT 430 from distributor module to PCM/ECM.
  4. Defective pick up coil.
TEST CONDITIONS :



  1. Code E41 not set.
  2. Code E12 is tested any time the cam sensor signals are being received.
FAILURE CONDITIONS :

If the PCM/ECM does not see distributor reference pulses for 4.0 seconds with cam reference pulses being received, current code E12 will be set.

ACTION TAKEN :



  1. The PCM/ECM turns on "SERVICE ENGINE SOON" telltale.
NOTES ON FAULT TREE :



  1. Checking for proper voltage output of the HEI system. If the voltmeter shows .5 to 2.8 volts, then HEI is producing reference pulses.
  2. Checking for proper ground connection between the PCM/ECM and the HEI module.
  3. Checking for proper voltage through CKT 43O from HEI to the PCM/ECM. If PCM/ECM terminal D8 sees .5 to 2.8 volts, then the PCM/ECM is receiving reference pulses.
  4. Checking for HEI module operation. If the HEI system will produce a spark then fault is not at the pick up coil or module.
NOTE ON INTERMITTENTS :

If code E012 is stored as a history code, start engine and allow to idle while manipulating CKT's 430 and 453. An intermittent open will cause the engine to stumble or quit when the PCM/ECM loses distributor reference.

If wiring and PCM/ECM connectors are OK, check the HEI pick up coil leads for an intermittent open circuit.
 

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The magnetic pick-up assembly located inside the distributor consists of a permanent magnet, a pole piece with internal teeth, and a pick-up coil. When the teeth of the timer core, rotating inside the pole piece, line up with the teeth of the pole piece, an induced voltage in the pick-up coil signals the electronic module to trigger the coil primary circuit. The primary current decreases and a high voltage is induced in the ignition coil secondary winding which is directed through the rotor and secondary leads to fire the spark plugs. The capacitor in the distributor is for radio noise suppression.
 

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Discussion Starter #9
PROBLEM SOLVED! hey thanks for the replies!! much appreciated. I pulled the distributor and replaced the pick-up coil it wasnt to hard, just had to make sure i put it all back in correctly. 42$ later the cadi's floatin again:D
 

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wait, this might be my problem too, how do you get the plate off on the top to get to the sensor under it? on mine there seems to be stuff under the plate on which the distributor rotor mounts on, and it's not removable as i can tell...

Is there some hidden way to get to the pickup coil?

PS: i'm guessing the pickup coil is right under that plate and it's where those two wires are coming from which plug in to the inner pins on the HEI module

Thanks
Eugene
 
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