distributor all the way advanced on '87 GL

I am by no means a Suby expert, having just bought my first one (an '89 GL), but I had something similar happen to an 88 Supra after changing plugs/wires.

Try disconnecting the fuse to the ECU. This will force the ECU to 'relearn' the engine parameters and may reset the advance.

It worked on an '88 Supra and an '89 Mazda...it may work for you.

Can't adjust/check the distributor timing without first connecting that green test connector located by the wiper motor.

Well, I'm doing the rough-cut no-timing-light version of a timing adjustment. I'm traveling for the summer and my timing light is far far away.

So, I'm advancing the distributor until it starts to misfire. Except it's not - the engine runs faster and faster until I hit the limits of the adjustment track. That seems weird - shouldn't the correct spot be somewhere you *can* go too far past? it doesn't seem to be on this one right now. It was set to the upper limit when I got to the car.

So my question is - what would cause this distributor to have a "correct" timing point that's off the adjustment area? What can I do to try to "pull" the timing back a bit?

thanks!

It is completely normal for the engine rpm at idle to increase when the timing is advanced. Any engine can tolerate too much ignition timing at low rpm/no engine load conditions. Problem with this is when the rpms increase and the engine is under a load, too much timing will eventually melt a hole in one or more pistons.

Really need to find that green test connector. This test connector is only used to set the ignition timing and should be unplugged all other times. If it is currently connected this means the timing is "locked". In other words the ECU cannot advance/retard the timing.

You can get the timing within a few degees + or - without using a timing light. Just turn the distributor housing one way or another until the hold down bolt is centered in the adjustment slot.

What happens when you fully turn the distributor in the other direction? Engine should stall or at the least, just barely run.

Don't pull the distributor thinking it may be a tooth off. It can be a real bear to reinstall.

Another possibility is the timing belt that powers the distributor could be a tooth or two off. Did anyone recently replace the timing belts?

ah, now we're talking. Ok, I'm not taking into account how the ECU is adjusting the situation as I rotate the distributor. So the best approach is - attach the green connector and center the distributor, and wait 'til I can get my hands on a light to do the fine tweaking...

Just what is the ECU doing? when I first got to it I centered the dist (without connecting the green connector) and the car was very bogged down under 3000 rpm, so I switched it back. Without connecting the green connector, what does the ECU do to adjust to make the car run better so fully advanced?

yes, the engine rpms drop as I retard the timing.

thanks, I won't...

not that I know of but this is an oooold car that came from a little old woman (literally) and my dad has only put 500 miles on or so.

thanks for the feedback, this is interesting! I'll play with it today.

elijah

Don't know exactly how the ECU regulates the timing but since this distributor has no vacuum can, however it is done it isn't mechanically. Do know the ECU sends a signal to the coil that allows it to fire. My guess is there is some sort of time delay function hardwired inside the ECU.

Since you don't have a timing light, there is no need to connect the green test connector. Just center the distributor and maybe just a tad on the advance side and you'll be in the ballpark.

When you do have your hands on the timing light, do connect the test connector. Timing marks are on the flywheel or flexplate.

Since you are aware of the green test connector, plug it togather and turn the ignition key to the RUN position. The ECU is located behind that panel under the steering coluum. It has a little green window that will flash trouble codes if any are stored.

Trouble codes can be determined by counting the flashes. All long flashes equal ten and the faster flashes are one. Example: 4 long flashes followed by 3 short flashes is trouble code 43.

Good chance you may have one or more stored. Find any just post and I'll check a list that tells what they are.

Another possibility here is a small vacuum leak somewhere. Engines don't like them at low rpms. Also has the fuel filter been recently replaced?

ok - this was my first move, way back when. The car drove like the engine was mired in molasses up until about 3000 rpm. so I moved the advance up to almost-all-the-way - still muddy... so I moved it to fully advanced (where it was originally) and it runs alright now.

I think finding a borrowable timing light is my next move.

just to make sure - the green test connector is in the engine compartment , right in front of the driver. Two green connectors that fit together. Right near it, there are two smaller white connectors that aren't connected. any idea what those are or if they're important?

When I connect them and turn the car to the ON position, some sorta motor or something starts cycling in the engine compartment - it sounds like my cell phone on vibrate. I tore off the under-steering- column panel and found the SPFI controller. With the test connector connected - the red LED blinks 5 times, rapidly, over and over... this code wasn't in my Chilton's. Any idea?

speaking of Chiltons -- the Set Timing section refers to setting the "Idle Switch" to "on" (as well as connecting the green connector) but doesn't give details. What's that about?

hmm, that's a good idea, I'll get under there with some starting fluid and check that too.

thanks for the help, it's really nice to be able to talk to people that know what's going on in there...

elijah

oh - and one other thing - the "Check Engine" light *never* comes on - not before starting the car, even...

The 5 flashes means there are no stored trouble codes.

The location of the green test connector is correct.

I think, fairly sure, the unplugged white connector is used for a more indepth trouble code retrevial. I never used it in any of my old GLs.

Leave both unconnected.

You have a problem but I don't think whatever it is has anything to do with the distributor timing.

Hi,

It's been a while since mine blew up, so this is off the top of my head: IIRC the white connectors are used to effect something like a "warm boot" and erase at least some of the codes the ECU has stored. Seems the check engine light flashed when I connected mine, too. If you have no CEL under any circumstances, the bulb could be dead. The whole dash has to come out to replace a bulb if it's like mine, so might as well get a whole bunch of bulbs and replace 'em all while you're in there. Seems Subaru used a proprietary bulb back then, too, so you'll probably end up at the dealer.

Best to double check everything I've said here, though. As I said, off the top of my head...

Rick