S30Turbo Posted August 13, 2012 Share Posted August 13, 2012 I have a 81 turbo engine that swapped into my 75 last week we started it for the first time. We finished all the intercooler piping today and tried to start it again but I didn't. We checked for sparked but it didn't have any. My question is why would the ecu all of sudden stop sending signal ? Im running the GM HEI. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13, 2012 Share Posted August 13, 2012 Might be the HEI module, not the ECU. I killed one by leaving two plug wires off and running the engine for a few seconds. Or the CAS if you're using one. Or anything on the path. Or anything feeding the path like power wires to the coil and ECU. CAS > ECU > HEI module > coil > coil wire > distributor > spark plug wires > spark plugs > ground to block > ... Quote Link to comment Share on other sites More sharing options...
S30Turbo Posted August 14, 2012 Author Share Posted August 14, 2012 Ecu has power I checked that. So the CAS sends the signal to the ecu? Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 14, 2012 Share Posted August 14, 2012 (edited) It's all described in the 1981 FSM (except the GM HEI modification). You really can't get far fast without opening it and at least browsing. Edit - actually it's described in the Turbo Supplement, Engine Fuel section - www.xenons130.com/reference That's all I got. There are descriptions, wiring diagrams,and diagnostic procedures. You can't go wrong by downloading and reading at least that one chapter. Edit 2 - Reading the 82 and 83 chapters would probably help also, since 81 is focused on using the ECCS Analyzer. Edited August 14, 2012 by NewZed Quote Link to comment Share on other sites More sharing options...
S30Turbo Posted August 14, 2012 Author Share Posted August 14, 2012 Ok thank you I will take a look at that Quote Link to comment Share on other sites More sharing options...
S30Turbo Posted August 14, 2012 Author Share Posted August 14, 2012 I checked the ecu and there was no signal so I think the CAS isn't sending the signal to the ecu to send it to the HEI module. I still can't believe it doesn't want to start after starting right away the first time . Quote Link to comment Share on other sites More sharing options...
S30Turbo Posted August 14, 2012 Author Share Posted August 14, 2012 I there a way to test the CAS? Quote Link to comment Share on other sites More sharing options...
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