aiiadict Posted March 30, 2007 Share Posted March 30, 2007 how to set timing timing light EA81 timing specification (hopefully that will help someone in a future search) I have EA81. It has EA82 SPFI on it. What are the specs for timing this thing? RPM at idle, and timing at idle? and then... just to test and make sure it's ok for the SPFI setup (IE the computer controlled advance/retard), what RPM should I bring it up to, and what should the timing advance to? what would be considered unsafe? IE predetonation, or crackin the connecting rods in half. While I'm on the subject: Why does it spark BEFORE TOP DEAD CENTER? If it sparks before dead center, the compression stroke hasn't completed yet. Spark, ignite... compression stroke is trying to push piston up, combustion is trying to push piston down... metal under stress breaks. Rich Link to comment Share on other sites More sharing options...
Zebisko Posted March 30, 2007 Share Posted March 30, 2007 Well, as for the spark being before TDC, it takes time for the ignited flame to get to the piston, so it isn't actually pushing on the piston until the end of its stroke. Also, with the faster the engine going, it takes less and less time for the piston to go through a stroke, thus the timing changes, as the flame still takes just as long to burn. I hope that made some sense. Link to comment Share on other sites More sharing options...
aiiadict Posted March 30, 2007 Author Share Posted March 30, 2007 I have EA81. It has EA82 SPFI on it. What are the specs for timing this thing? RPM at idle, and timing at idle? I read tiny bits of information about "freezing" the advance on an SPFI ECU, IE like removing vacuum lines from vacuum advance. Does anyone know which pin on ECU goes to ?gnd? or ?+12v?. This isn't the stock harness, and doesn't have the "test" connectors. RPM of idle and idle timing would be very appreciated. Rich Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 30, 2007 Share Posted March 30, 2007 Once you put the ECU in test mode the timing is locked. Timing is set to 20 degrees for the SPFI system regardless of RPM (test mode locks it to 20 even if the engine isn't at idle), but the idle RPM should be 700 to 800. As for the pin - well shame on you for cutting the test connectors out of the harness. I guess you'll just have to figure it out. This will help some (from my write up): http://home.comcast.net/~trilinear/EA81_SPFI/ECU_pinout.jpg You don't need a timing light either - just set the flywheel to 20, and point the rotor at the #1 plug wire. There's not enough predetonation in all the land to break an EA rod in half. Their burst speed is well up into the 11,000+ RPM range. Short, stubby, and very thick. You would collapse the ring lands on the piston first or blow holes in it. But none of this ever happens with N/A engines. Only forced induction. As for your "concern" about BTDC - that's basic engine theory. The desire is for the flame front of the burning intake charge (which starts at the top of the cylinder) to reach the top of the piston just as the piston reaches TDC. In order for this to happen the fuel must be ignited BEFORE the piston reaches that point so the two can meet in the middle. The faster the piston travels, the more advance is required for them to meet at the right point. The piston's speed is variable, but the intake charge burn rate is not. Therefore the ignition must be set off at different times to accomidate varying engine speeds. "predetonation" occurs when either the ignition is advanced too far ("ping"), or when the fuel spontaneously ignites due to high compression (diesel engine for example) or from excess heat. GD Link to comment Share on other sites More sharing options...
aiiadict Posted March 30, 2007 Author Share Posted March 30, 2007 Once you put the ECU in test mode I think this is one of the places I'm having troubles in the manual. The procedure to go to dcheck, memory check, etc is worded in a way that is very difficult for me to understand. I left the test wires hanging off the back of the ECU, I need to figure out which one does WHAT. on ECU: pin 3 = Red, Test4 pin 10 = Yellow, Line end cord output pin 11 = L, line end cord output pin 12 = RL, line end cord output pin 37, LgR, Test mode connector (used at line end only) pin 32 BR, Test mode connector (used at line end only) pin 31, Br, Test mode connector (used at line end only) Link to comment Share on other sites More sharing options...
aiiadict Posted March 30, 2007 Author Share Posted March 30, 2007 I think this is one of the places I'm having troubles in the manual. section 2-7, page 22 test modes: Ucheck - "user mode", tests items related to start and drive Dcheck - "dealer mode", tests all items read Memory clear memory relationships between modes and connectors: d=disconnected, c = connected ------------------------------------------------ User = ign on, read connector d, test connector d Read = ign on, read connector c, test connector d Dealer = ign on,read connector d, test connector c Clear = ign on, read connector c, test connector c What does "connected" and "disconnected" refer to? (connection to Ground? connection to +12v?) Anyone have the proper wire colors to disconnect/disconnect? Link to comment Share on other sites More sharing options...
aiiadict Posted March 30, 2007 Author Share Posted March 30, 2007 section 2-7, page 22What does "connected" and "disconnected" refer to? (connection to Ground? connection to +12v?) Anyone have the proper wire colors to disconnect/disconnect? OK with ~trilinear SPFI conversion page, I see that there are 2 connectors for READ and two connectors for TEST. Connected means the two connectors are connected :-P Now I need to figure out which wires on the ECU go to the 4 connectors. Rich Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 30, 2007 Share Posted March 30, 2007 The connectors consist of a single wire from the ECU, and a ground wire. So the proper terminal (there's two) on the ECU gets grounded and that tells the ECU it should be in Ucheck, Dchech, Readmem, or Clearmem. All you need is Dcheck for setting the timing, but it's very important to have all the modes availible when you need them. They are insturmental in being able to diagnose problems effeciently, and in some cases there really isn't any other way since some codes can come only from driving with it in Dcheck. Sometimes a fault will only set a code while in Dcheck so that without it you will just have a strange operating condition but no code at all. The very first step in troubleshooting much of the system is to put it in Dcheck and run it though the diagnostic procedure. I don't recall which wires go to the connectors however. I may get a chance to look at one of my harnesses later tonight, but I'm not sure. GD Link to comment Share on other sites More sharing options...
daeron Posted March 30, 2007 Share Posted March 30, 2007 it sounds like you are finding the right path.... General Disorder's advice on "needing" the connectors is spot on. One of the beautiful parts involved in using the EA82 SPFI is the test modes, and the fact that you don't need a code scanner to get your ECU codes. Seriously, how many vehicles come with a stand alone on board diagnostic system? HOW MANY VOLKSWAGENS come with that? Link to comment Share on other sites More sharing options...
aiiadict Posted April 3, 2007 Author Share Posted April 3, 2007 The connectors consist of a single wire from the ECU, and a ground wire. So the proper terminal (there's two) on the ECU gets grounded and that tells the ECU it should be in Ucheck, Dchech, Readmem, or Clearmem. I don't recall which wires go to the connectors however. I may get a chance to look at one of my harnesses later tonight, but I'm not sure. GD Looking at the pinout of the ECU, the proper terminal for U(ser) or D(ealer) check aren't obvious. The FSM doesn't include pinouts for the test connectors either. Thanks for the information about them being grounded to indicate which mode. If you could put a meter on your test connectors and see which connector goes to which pin, I would appreciate it very much! Rich Link to comment Share on other sites More sharing options...
aiiadict Posted May 5, 2010 Author Share Posted May 5, 2010 Looking at the pinout of the ECU, the proper terminal for U(ser) or D(ealer) check aren't obvious. The FSM doesn't include pinouts for the test connectors either. Thanks for the information about them being grounded to indicate which mode. If you could put a meter on your test connectors and see which connector goes to which pin, I would appreciate it very much! Rich anybody ever get a chance to do this? Link to comment Share on other sites More sharing options...
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