Kbsubie Posted December 23, 2015 Share Posted December 23, 2015 Hello everyone and seasons greetings! We are trying to get our sons 1986 mpfi ea82 running again. He had it running "well" a few weeks ago after reviving it as a school project car. Currently there seems to be no spark coming from the coil to the distributor. The only spark we see is turning the key off. The last time it started it ran for a few minutes sitting still idling very fast then dying. Prior to this current issue it would start intermittently. When it would run it would idle fast and then idle down to normal, but would only keep running if you kept the Rpms up. He has replaced fuel injectors, repaired the distributor, rewired the coil and cleaned grounds. Since the most recent problem we have replaced questionable spark plug wires and the alternator, all fuses seem ok but have not tested them yet. Testing the coil shows plenty of juice getting there, but doesn't seem to go thru to distributor. Since the only spark is when the key gets turned off, is the ignition switch going bad? Would that cause it to simply quit after it's running? Could it be a bad key? Thanks in advance to anyone able to help, and Merry Christmas! Quote Link to comment Share on other sites More sharing options...
john in KY Posted December 24, 2015 Share Posted December 24, 2015 Check the rotor. May be loose and also check while cranking the engine. May be a broken timing belt. Quote Link to comment Share on other sites More sharing options...
Kbsubie Posted December 24, 2015 Author Share Posted December 24, 2015 Yes rotor turns with cranking engine. Doesn't feel loose, no screw just slips on. Could still be passenger side timing belt? Forgot to disconnect distributor cap while checking the rotor and had a great blue spark once, but then only get spark when turning the key off again. Did notice that the wire to the starter from inside was/is horribly frayed; starter always turns over fine tho. What should the voltage read at the coil? Still thinking ignition switch or related or is there anything else we might be missing? Thanks again for your help! Quote Link to comment Share on other sites More sharing options...
john in KY Posted December 24, 2015 Share Posted December 24, 2015 Other timing belt has nothing to do with this problem. There is a small "cannister" attached to the coil bracket. Forget what it is called but the entire coil bracket needs to be grounded to complete the circuit. No ground=no spark. Coil should see 12volts. Check all the fusible links near the battery. Quote Link to comment Share on other sites More sharing options...
naru Posted December 24, 2015 Share Posted December 24, 2015 No ignition amp or "cannister" on an 86 MPFI. Coil should have 12 volts on coil negative. If a test light lights up on coil -,but does not pulse w/engine cranking,the ignition module is bad. Quote Link to comment Share on other sites More sharing options...
scoobiedubie Posted December 24, 2015 Share Posted December 24, 2015 (edited) "Repaired the distributor" ? What does that mean? The 85 & 86 distributors are particularly problematic because the black plastic encased electronics in the top of the distributor, that has several connector tabs pointing up for wire attachment, go out frequently. You can't repair this. You replace it, and/or replace the entire distributor with another used one because new ones cost a small fortune. The inside swing weight mechanisms can also get worn and can require replacement. Get yourself a couple of used distributors that both work, and then use the best parts off of both of them to put together your primary distributor. Use the remainder parts, and parts off of your now presently bad distributor, to put together a working back up that you carry with you in the car. I keep a half dozen spares because this is such a big issue. You also did not report the mileage on the vehicle. For vehicles over 250,000 miles, two wires require replacement of the sections that have gone brittle and have lost their conductivity. The first wire is the engine ground wire that connects to the chassis just in front of the battery. That connector at the chassis, will get hot when the engine is running, if it requires immediate replacement. A low mileage wire replacement will do wonders like you won't believe. The second wire is the black wire that connects the positive battery cable end to the bottom of the fusible link box. The connector at the cable end, goes bad. By attempting to flex the wire at that end, you will see whether it is stiff, which means that it is brittle and has lost it's conductivity. Since you cannot replace this entire wire, you have to just replace the end at the cable. This requires splaying out the wires at your new splice joint, overlapping them and twisting. A stock auto parts store butt end connector, WILL NOT TRANSFER ENOUGH ELECTRICITY to allow the engine to run smoothly. Edited December 24, 2015 by scoobiedubie Quote Link to comment Share on other sites More sharing options...
Kbsubie Posted December 24, 2015 Author Share Posted December 24, 2015 Thanks everyone for the input Was looking over the fusible links area, top wire (closest to the engine) looks homemade. All pass current well, but are stiff... Did the ground check again, easy enough to replace those Distributor work was rotor Had the battery on the charger just to make sure. The dash meter drops pretty low when cranking, are these fairly accurate? There is a resistor/can next to the coil, is it not supposed to have one? Thanks again , probably not going to post for a day or to due to the holiday Merry Christmas everyone! Quote Link to comment Share on other sites More sharing options...
Kbsubie Posted December 24, 2015 Author Share Posted December 24, 2015 Sorry, reply incomplete. Trying to do too many things at once! 120,xxx miles Distributor needed rotor and pickup(?), everything else tested "ok" according to class technician Saw a swap for the fusible links, not sure if I can attach picture but they had converted to plugs instead of wires Quote Link to comment Share on other sites More sharing options...
Dee2 Posted December 25, 2015 Share Posted December 25, 2015 You've listed several symptoms: -- had it running "well" a few weeks ago ... -- Currently ... no spark coming from the coil to the distributor. -- The only spark we see is turning the key off. ( not sure what this means) -- last time it started it ran for a few minutes sitting still idling very fast then dying. -- Prior to this current issue it would start intermittently. -- When it would run it would idle fast and then idle down to normal, but would only keep running if you kept the Rpms up. Sounds to me like a bunch of possible concurrent timing issues. Since the car was revived as a class project check to make sure : -- the plug wires are connected properly and in the right order. -- the plugs are the right type and gapped correctly -- the setting of the engine timing is correct. -- the timing belts are installed correctly and -- the distributor is positioned correctly. -- all electrical connectors are secure Quote Link to comment Share on other sites More sharing options...
DaveT Posted December 25, 2015 Share Posted December 25, 2015 The only spark happens when key is shut off thing.... sounds like what would happen if the breaker points (or thier electronic equivalent ) were failed shorted. The high voltage pulse that makes the spark happens when current through the primary of the ignition coil is interrupted. Quote Link to comment Share on other sites More sharing options...
Kbsubie Posted December 25, 2015 Author Share Posted December 25, 2015 Is it possible that they checked the control module and it went bad ? We'll have a few days to get a new part. Is it worth testing the module? It shouldn't be to difficult to test, use a voltmeter to check for power at the control module with the ignition on. If there is power, crank the engine and check for a pulsating ground at the module. If there is no signal, the problem is with the computer or a sensor. However, if there is a signal, the ignition control module is bad. Does this actually work for this application ? Does the module have to be in the distributor to test it ? Quote Link to comment Share on other sites More sharing options...
naru Posted December 25, 2015 Share Posted December 25, 2015 If there is no pulsating ground at coil -(use a test light),then the MODULE is bad ,not the computer or anything else. Module is best tested in situ. Quote Link to comment Share on other sites More sharing options...
jono Posted December 25, 2015 Share Posted December 25, 2015 hi, just following this now .... 85 and 86 models as far as EA82T are different from the later models. Does yours use a flapper style air flow meter that bolts direct to air filter housing or the smaller, petite hot wire cylindrical AFM ? vac control module cannister on side of disty or not ? These babies also have an ECU with flashing LED visible have you followed this line of enquiry yet ? Quote Link to comment Share on other sites More sharing options...
Kbsubie Posted December 31, 2015 Author Share Posted December 31, 2015 Replaced the module, but had to pull the distributor to get at the bolts due to stripped grooves Was difficult to tell with the test light if the module was bad. had pulsing light not flashing on/off as we were anticipating and was different if we wired the test light directly or took the wire to the module off the coil Have not had time to readjust the timing and check for spark. Will also redo grounds again Thanks again Happy New Year!! Quote Link to comment Share on other sites More sharing options...
Kbsubie Posted January 6, 2016 Author Share Posted January 6, 2016 well could this be THE problem or is it a separate bad problem while replacing the ignition control module we noticed some metal shavings stuck to the pickup coil the distributor shaft corners are gouged/filed off!!! was the pickup coil the wrong part or did the distributor shaft wobble?? Quote Link to comment Share on other sites More sharing options...
Kbsubie Posted January 6, 2016 Author Share Posted January 6, 2016 Even wth the gouges off the distributor we were able to set the gap appropriately adjust the timing and .... It runs!!! Hopefully it will keep goin. At some point the pickup coil was making contact causing some significant metal work. Is it ok to even the edges off and re adjust the gap should this run only temporarily? Thanks everyone for the help! Quote Link to comment Share on other sites More sharing options...
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