Topic: Hesitation and missfire problem

[Jeff F]

I am having a strange problem with a misfire at light throttle between 2000-3000 rpms.  It only happens when holding speed in any gear in the 2000-3000 rpm range, but immediately clears up when the engine is put under load.  I have replaced plugs, wires, cap, and rotor.  The coil tests within spec and the air gap is also within spec.  The tach also moves around when it is misfiring, and if I let off the throttle suddenly, the tach dives to 0 rpm and the engine back fires when I come back on the gas.  The check enging light sometimes blinks once if the misfire gets really bad, and it threw a code 3 when I checked the ecu.  Is there a way I can check the igniter?  Could it be something I am overlooking?  I even cleaned all the connections at the coil and grounds in that area.  Any help will be appreciated.  Thanks

[Jeff F [OP]]

Forgot to mention this is a stock 87 Runner with 22RE.

[BigMike]

I was going to suggest a bad ignitor. Do you have any other 84(celica)/85--95 22R-Es who could lend you an ignitor?

The tach is controlled directly from the ignitor (black wire) so it seems like the trouble is there. You can open the ignitor up and see if there is any moisture inside, wouldn't hurt.

BigMike

[reklund5]

I had the EXACT same problem after my EFI conversion on my truck...

The fix?  I had the timing WAY too advanced for my TRD cam- at like 12degrees.  I backed it down to 5 degrees, and all was well.  My tach even moved around all goofy like yours.

I'd say double check the timing- like remove the valve cover and make sure the chain guides are in place and the chain hasn't jumped a tooth.  One tooth is around 13 degrees, and could be what is causing your trouble.  Even if you time it properly via the distributor, if the chain is off a tooth, you'll have these issues. 

Just a suggestion...
Ryan

[Jeff F [OP]]

What should the timing be with the service connector jumped?  I am showing 8deg with the timing light at idle.

[Uncle Jesse]

my book says 5 degrees for 87 22re

[79coyotefrg]

back it to 3 or 4 degrees then hit the throttle ,  i always bring it in to spec with my timing light then fine tune by ear then recheck with the light,
and always recheck your settings after getting to operating  temp

[Jeff F [OP]]

I got the timing backed up, and the problem stays.  The tach does not jump up as much, but still falls to zero when I release the throttle.  The tach thing might be the problem progessing.  Also, I have noticed my temp gauge jumping.  When it is below operating temp, it will jump up to normal temp for a given time, then fall back to its original position.  This does not always happen, but will continue until the engine reaches normal temp.  I guess the only thing I can do now is get my hands on another igniter and see if that fixes the problem. 

Could I just replace my igniter with an MSD?  I know that one of the MSD6's would have all the same output signals that the igniter sends, and will run off the magnetic pickup.  Any suggestions?  Thanks for the help.

[BigMike]

Check around for grounds and make sure you have all three engine grounds on. One direct to the battery, one behind the cylinder head, and one direct to the P/S bracket.

BTW, was your timing off quite a bit?

[79coyotefrg]

 do you have your engine to frame and body to engine  ground straps hooked up

[79coyotefrg]

hey mikey you read my mind

[BigMike]

hey mikey you read my mind

[yotaboy79]

have you torn into any of the valve train it sounds like it could be cam timing of a tooth is it down on power at all sense this started? the temp gage bouncing around sounds like a ground problem mine used to do the same think. is it putting out black smoke when it misses another thaught could be the fuel pressure regulater but again it could be as simple as the ignitor if you want i might have another ignitor you can try get the part # off of you igintor and ill see if the one that i have lying around is the right one. good luck

[Jeff F [OP]]

The timing was at 8 degrees after replacing the cap, rotor, plugs, and wires.  I backed it down to 5 degrees.  I pulled all the ground cables, scuffed up the mounting locations, and reinstalled them.  I even added another heavy gauge ground from the block to the battery.  Problem is still there.  It is just not throwing spark when holding speed in the 2000-3000 RPM range.  If I bring the engine to 2500 just sitting still, the engine misses.  Using a timing light, I verified that it is not getting spark.  The weird thing is, that this only happens when the engine is under very little load.  If I am going up hill, there is no problem.  The check engine light does not come on, but I get a code 3 when I jump the service connector.  I am pretty sure it is the igniter.  Does anyone know what the three wires going from the igniter to the ECU transmit.  I am sure one is an RPM reading for the ECU, but not sure what the others might be.  Maybe I can throw an MSD on there and put something together that will simulate those three wires to the ECU.  I know the engine will not run without them.  Anyone got that info?

[gonzo]

Check and clean the grounds from the ECU or at the ECU.

[brainlessfool]

this is kinda odd-ball butt check that there is nothing hitting the dist. pick-up when the vac. advance moves. try unhooking the vac advance and repeat the 2500 rmp check you did. if it's still there, never mind! butt if it's gone, your on to some thing.

[FATB0Y]

I'd say double check the timing- like remove the valve cover and make sure the chain guides are in place and the chain hasn't jumped a tooth. One tooth is around 13 degrees, and could be what is causing your trouble. Even if you time it properly via the distributor, if the chain is off a tooth, you'll have these issues.

Just a suggestion...
Ryan

That is what I was gonna say

[Jeff F [OP]]

Well, got a new igniter in there and the problem is gone.  Thanks for all the help.