Jump to content
Ultimate Subaru Message Board

Ignition timing adjustment issues


Recommended Posts

So im trying to adjust the ignition on my ea82 89 mpfi engine.

The sticker on the hood says 20° before TDC but i could only turn the distributor so it was about 0 , so i grind of some metal on the dissy so i could turn it more.

But when setting it to 20° before tdc the engine start to stumble.

Now its about 10-15 Before tdc and runs pretty good.

 

When setting ignition timing you are supposed to make sure the Idle switch is of if i remember correct and the green cables under the steeringwheel is connected.

 

When checking the Idle swits (TPS sensor) i could not get any reading on my multimeter.

And noticed today when i hold the rpm at 2500 the rpm goes up and down.

Might be a bad Tps sensor. so the question is where do i get a new one with 3 pins.

Or do any of you have the original number?

Found one that might fit but the price goes from 300-400 dollars?

Link to comment
Share on other sites

The timing marks, are you using the ones on the flywheel or the front pulley?  I think the balancer has marks. Could be wrong about that.  Anyways, if using the timing marks on the balancer, the balancer could have slipped on its hub.  

 

As far as I know, the TPS sort of controls the injector pulse lengths and the automatic transmission shift points. I don't think it has anything to do with ignition timing. 

Link to comment
Share on other sites

Timing marks are on the flywheel. Could the timing belt be off 1 tooth? Are the bearings in the distributor good?

 

A bad connection or ground could be interfering with something. The fsm has pretty detailed checks for all of the sensors. You also should check them from the ecu connector end, not just the sensor alone.

Link to comment
Share on other sites

Do you have the green connectors hooked up? 

 

If not the ECU will keep adjusting while you are adjusting and  you never get it set.

 

If it's that far off of 20, you may need to reset the dirty one notch. then do the timing again.

  • Like 1
Link to comment
Share on other sites

Timing marks are on the flywheel. Could the timing belt be off 1 tooth? Are the bearings in the distributor good?

 

A bad connection or ground could be interfering with something. The fsm has pretty detailed checks for all of the sensors. You also should check them from the ecu connector end, not just the sensor alone.

I dont think the belt is 1 tooth off i have checked that and the bearings in the dissy seem to be ok.

 

Do you have the green connectors hooked up? 

 

If not the ECU will keep adjusting while you are adjusting and  you never get it set.

 

If it's that far off of 20, you may need to reset the dirty one notch. then do the timing again.

Yes the green connectors is connected, but when connected the Check engine light should come on according to subaru manual? mine does not.

What do you mean with reset the dirty one notch?

 

I have actually had an engine stumble when trying to set the timing. It lost the ground connection as I was turning it. I had to put a jumper between the engine and the distributor to set the timing because at one point during the turn.

Do you mean a ground cable from the engine to the distributor?

Link to comment
Share on other sites

The contributor above was referring to "one tooth off" on the gear inside of the back of the camtower that you cannot see, where the distributor inserts in a hole.  Not one tooth off on the timing belt gear at the front of the camtower.  I concur.  When setting the timing, the timing belt gear hole mark must be exactly up or exactly down.  Opposite on each side, in other words.  The flywheel triple marks should have the fixed pointer mark, point to the middle mark of the triple marks.  Then, in order to fix your problem, you will be loosening the distributor and partially lifting is up until you can swing the rotor one notch one way or the opposite way.

  • Like 1
Link to comment
Share on other sites

The contributor above was referring to "one tooth off" on the gear inside of the back of the camtower that you cannot see, where the distributor inserts in a hole.  Not one tooth off on the timing belt gear at the front of the camtower.  I concur.  When setting the timing, the timing belt gear hole mark must be exactly up or exactly down.  Opposite on each side, in other words.  The flywheel triple marks should have the fixed pointer mark, point to the middle mark of the triple marks.  Then, in order to fix your problem, you will be loosening the distributor and partially lifting is up until you can swing the rotor one notch one way or the opposite way.

I see ..well i have set the belts according to Miles fox on youtube.

And i have tryed to swing the rotor one notch at both ways but then the engine fail to start.

As now the rotor points at the hillholder when cylinder one is at tdc exactly the same as mile fox shows in his video.

Link to comment
Share on other sites

The idle switch needs to be working.<br />They tell you to MAKE SURE it is CLOSED for a reason.<br /><br />TPS part number is 22633 AA051 for an 89 MPI.<br /><br />I disassembled mine to clean the idle switch.

Edited by naru
Link to comment
Share on other sites

Yes, just a small removable jumper wire from the block to the distributor to maintain the ground when you loosen the bolts.

 

Distributor body does not require a ground.  Not a thing that would ever need done on this type of disty.

Link to comment
Share on other sites

The distributor does need to be grounded to the engine to work. It normally is done just by contact to the head but on one of the Subaru's I worked on it lost the ground when loosened the hold down bolt. That was when I used a temporary ground jumper to set the timing. I still have the car and it still does it every time I check the timing.

Link to comment
Share on other sites

The distributor does need to be grounded to the engine to work. It normally is done just by contact to the head but on one of the Subaru's I worked on it lost the ground when loosened the hold down bolt. That was when I used a temporary ground jumper to set the timing. I still have the car and it still does it every time I check the timing.

 

BS

 

On optical disty  used in FI subarus, The entire disty's electrical system is insulated from the body of the disty.

 

I've bench tested them and watched the pulses on an oscilloscope.

 

That's why there are 4 wires.  Ground for the optical system is one of them.

 

12v+

Ground

Reference volts (5v+)

Signal pulse

 

The disty body does not need to be grounded.

 

Wanna test it?  Remove the disty from the block but leave the cap, rotor and coil wire hooked up.  Run one of the plug wires to a spark plug grounded against engine.  Turn key on, Now spin the disty drive gear and watch the spark.

 

Perhaps you are confusing it with the Older magnetic pickup coil distributors used with carbs? 

Edited by Gloyale
Link to comment
Share on other sites

That particular car must have a break in the ground system because I have checked others off car and they do pulse. This car would die as soon as I loosen the hold down bolt. I tried 3 different distributors with the same results thinking I had a bad one. It still runs great ( for a 3at ) but still died without a temporary jumper.

Edited by silverhelme
Link to comment
Share on other sites

That particular car must have a break in the ground system because I have checked others off car and they do pulse. This car would die as soon 8as I loosen the hold down bolt. I tried 3 different distributors with the same results thinking I had a bad one. It still runs great ( for a 3at ) but still died without a temporary jumper.

And this was a mpfi?

Link to comment
Share on other sites

I may have the exact same issue as you. If I find anything I'll let you know. I've been logging all my findings on my build thread. Right now I've got the timing set at 24 degrees and premium fuel. It has tons of power, had a wierd miss that doesn't affect the power at all. But if the rpms stay steady (idle or if I hold the pedal at a certain rpm) there is a stutter

Edited by TheGageinator
Link to comment
Share on other sites

I see ..well i have set the belts according to Miles fox on youtube.

And i have tryed to swing the rotor one notch at both ways but then the engine fail to start.

As now the rotor points at the hillholder when cylinder one is at tdc exactly the same as mile fox shows in his video.

The firing is "before top dead center".  For instance, my turbo gl10 is something like 24 degrees before top dead center.  The rotor should be pointing towards the back of the battery, when the triple notch alignment is used.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...