no ignitor signal

[novatc]

HELP!! just replaced head gasket on a '86 4age. ran great b4 teardown. now, after reassembly, not getting a signal to my igniter. tried a different one, replaced that noise suppresion thing that sits under the coil, nothing. checked all fuses. fyi, there is 12volts going to that noise thing, found out the hard way. this car is on the verge of going bye-bye if it doesnt start soon. got over $650 tied up in this project. taking requests 4 parts now.
P.S.- need to pull head back off, head bolts didnt torque down just right. out of time, money and patience with this rusted pos.

[muffinman]

where are you located?

[novatc]

i am on the east side of columbus OH. i have a truck that can tow this thing. the headlight retractors, power windows, all the electrical still works. car has recent struts also. was thinking about parting out on ebay. the head got a valve job w/new seals installed. new wp, t-belt, and t-belt pulley. body not in greatest condition, bad rust on underside, front. if u want this car, parts or whole, please let me know asap.

[Jackstand Queen]

O.K. this might help you . . . the engine rocks forward and backward in its motor mounts . . . a lot. The wiring going off the head to the ignitor harness flexes a lot.

Wiring fatique and finally failure occurs.

Check for wiring continuity. An ohmmeter works for this. Or add power (careful not to route power the wrong way back into the ECU or Ignitor) and use a ciruit test lamp.

[novatc]

thanx 4 that tip. really had to stretch harness when i pulled head off. intake manifold came off with it, 2 of the 12mm bolts on the underside decided to round off. didnt even think about that. does the igniter get a signal from the ecu? thats the part of the harness that got stretched.

[Jackstand Queen]

The ignitor sends a signal to the ECU for certain. The ECU could in turn modify the Ignitor's switching function to the coil. . . . not sure about that.

Bolts shouldn't round off. You may be using 12 point sockets. The six point sockets (hexagonal) with six sides inside them don't round off bolts at all. Also, another good practice is to use an "anti-seize" lubricant paste on all bolts that go into aluminum engine parts.

Your wiring harness could have been just hanging on by a few strands of wire. The wire could be broken off inside an intact sheath of insulation plastic.

[Luni]

ECU gets signal to fire Igniter based off the distributor triggers. IGT is the wire that pulsed the igniter that the igniter uses to in turn pulse to the coil. IGF is the return wire from the igniter telling the ECU a successful spark event occurred.

To test it, first test for presence of 12v at the igniter harness with the key on, and grounding to E2 on the igniter harness. If you have 12v on that wire, then using a 12v resistor type LED from Radio Shack, positive to 12v signal, negative to IGT, have a buddy crank it and see if it pulses. If you get pulse there, then test continunity of IGF back to the ECU through the harness.

[novatc]

this is for both, jackstand queen and luni. that little black noise suppresion thing that sits under the coil, attached with one of the coil bracket bolts. Is it very important? The wires to mine broke off, both @ the 'thing' itself, and from the plug connector. I didnt know that there was 12v going thru this. i tried to bypass this and nearly fried the harness. got a new 'thing' and still no spark. i did what the service(hayes) manual said to do, on checking for voltage @ the ignitor, got only .1v where i am suppose to have 12. its called line source voltage, positive lead on positive wire, igniter to coil, negative on right side of igniter. thats all i could check @ time. will this info help? the service book is almost useless at this point. luni, i will try to do those tests u mentioned. i was trying to rush thru this project and got sloppy. this was my daily driver, 80mi a day! got an '05 car to take over driving duties for now, still unsure of to keep or part this(MR2) out. got part adds in a diff forum.

[Jackstand Queen]

The ignitor is extremely easy to burn out by mis-wiring the coil power and ground leads. Don't ask me how I know this. Doh!

The black rectangular chip with the two wires is a noise suppression rectifier or condensor. It reduces static transmitted to the stereo system. It should have continuity when tested by an ohmmeter. I think the car will run without it though.

If you got the coil power leads wrong for just a second or two, its probably enough to wipe out the ignitor. Ebay usually has ignitors for sale very reasonably priced. I have a spare ignitor for the Pre-88 N.A. 4ages if you don't have the Ebay hookup.

[novatc]

thanx jackstand. I still have one from a corolla sr5-gts swap. that motor ended up with a cracked head. what do u expect for $400, incl tranny. got rid of that car a long time ago, but saved the ignitor/coil assembly. also, it was the 2 bolts on the underside of the intake that gave me problems. couldnt get a good hold of them. do u know of a way to test these? this car needs a lot of other parts after it fires up. time, money and patience are running out on this car, its up for grabs, for the rite price. if i keep the car and have to replace the igniter, i may go with an MSD box, and really build this thing up since its not a daily driver anymore(ie, rebuild the WHOLE motor).