Toyota Nation Forum banner

Iridium Plug after about 12k miles

2K views 26 replies 6 participants last post by  GHT 
#1 ·
Looking pretty Lean to me. Any ideas?


282780
 
See less See more
1
#4 ·
The picture doesn't do much justice, but if you look at them IRL the arc electrode is much more white than grey.
 
#5 ·
282793
Heres the new version of the Iridium one. You can definitely tell the tip was worn down a lot.
 
#8 ·
So, what's the problem? Was it misfiring or running rough? Iridiums are supposed to wear out that fast I thought. Why do you think the gap increased that much in 12k miles?
 
#9 ·
It's been running rough for awhile. Iridium plugs are generally a weaker spark than copper, but last well over 50k miles in most vehicles. I think running lean for this period caused it to get a little hot and eventually just wore itself down. Iridium plugs as a whole tend to get hotter than any other plug, but not in the way that would actually be useful. It's got a better spark than platinum, but not as good as copper does.
 
#10 ·
So far it seems like Copper makes the old dirty a little happier. I also changed the Coolant Temp Sensor today too. wish i had a picture to show you how nasty that thing was.
 
#11 ·
All spark plugs have a copper core. It's just the tip that is platinum or iridium, so it's ability to generate a spark really shouldn't be any different than a copper tip plug. I mean the electrical resistance should be the same. The iridium or platinum tip won't wear away as fast as a copper tip.
 
  • Like
Reactions: Apples555
#13 ·
I'm reviving this thread, I think its time i need to get a new ignition coil. It's been raining a lot lately and i just can't deal with the bogging it's been doing once it's fully warmed up. As soon as that thermostat opens up it feels like i lose half my power. I have to avoid a road i take home to work every day because of the fact that the incline of it is very steep and i have to keep the car locked in 2nd Gear and Throttle just under the first gear shift point to maintain 30mph up the hill. I don't know what the problem is at this point.

I've got 3 ideas.

Distributor is dying.
Fuel Pump is not able to provide enough pressure, and going bad.
or my Ignition Coil/Cap is shot.

Seems like the power loss mainly occurs during very wet or hot days. It's been persisting like this for quite a few years, but it seems like after i had to leave it on jackstands for a few months it just got worse than what it was before. If i have a passenger in the car, it really really struggles unless I'm kicking it at about 60% throttle to get off the line to keep up with people behind me.

During all gears, it will take off pretty slowly, but as soon as i hit the higher range of RPM, i get an almost VTEC kind of feeling from it after about 4000RPM and all of a sudden it has a massive amount of torque compared to what it did before.

Engine is a 2nd Gen 4AFE paired with an A131L 3 Speed Automatic. 151K

I've replaced:

Rotor
Wireset
Spark Plugs (NGK V Power Coppers gapped at .032 ~)
Air Filter(I even took out a section of the snorkel to see if it would help, and because the fastener split in half)
Coolant Temp Sensor (seems like after this it was worse to be honest, but may have been a coincidence and probably was)
Fuel Filter



Things I don't know are bad or not
Oxygen Sensor
Catalytic Converter (leaks anyway, waiting for it to just fall off so i can get rid of the cat)
Fuel Pump (can't hear it make noise when i start it, but to be fair i never really could, i got it at 90k miles)



I seriously doubt it's a lack of back pressure related issue, because I had a cracked manifold for awhile and the flange going to the flex pipe was barely held on, along with a disconnected muffler and it still ran better then than it does now.

I've heard you can test the Oxygen Sensor on OBD1 systems using the diagnostic port under the hood, but i have no idea what pins to jump to check values.

No CEL,I've pulled the Oxygen Sensor plug and let it idle and it seemed like it ran worse, I've also pulled the plugs on various sensors to see how they run without them to see if i'm having an issue at all

pulled the Plugs to each fuel injector One by One to see if they don't affect the idle or not, they all do, so i know they're good. I also did this with each spark plug wire to verify that as well, all changed idle.

My only lead i think i can have at this point are the Ignition Coil, Oxygen Sensor, or Fuel Pump causing the problem.

If anybody has any advice on what to do at this point, i'm open for ideas. I've adjusted the timing back to it's default 10 Degrees, but honestly it felt like it ran so much better at the 17 Degrees i had it at for a week just to see what kind of gas mileage i'd get.
 
#14 ·
I'd pull a used Denso distributor from the junkyard and try that if possible. You'd have to get the pre-OBDII version from a 93-95. If you can't find the whole distributor, the same coil was used on other models, and you could swap just that.

The cam sensor and crank sensor are built into the distributor and those pickup coils could be bad or the air gap clearance is wrong. This is why sometimes a whole new used distributor solves the problem where just replacing the coil doesn't

The aftermarket coils and distributors can give you all the same problems like hesitation, poor acceleration, hard starting, rough idle. You don't always have all those symptoms. That's why we suggest getting a used Denso over a new aftermarket. Do you have an original Denso distributor and coil now? You can check the specs on the coil (resistance), but sometimes those pass the test and the coil doesn't work when actually being used.

And have you ever checked your compression?
 
#16 ·
All original Baby! :D (besides the rotor.)
Here's some interesting information i found. A '94 T100 Cap is practically identical in terms of pictures to a 4AFE's distributor cap. The only real difference i can see between them is the length of the electrode ports for the wires seems like they're maybe an Inch or so longer than the ones on the 4AFE. They're different part numbers but I can definitely see it fitting and working at least. It's half the price of a cap for an AE101 too.

Compression Check has never been done on the car, but if i had low compression wouldn't I end up having more issues and a higher rate of oil burning? I don't seem to use all that much oil. Seems most of it comes from the valve cover leaking. I tighten it up every once in awhile and the leaking slows. I see it all over the Alternator's top mount bracket and on most of the outer corners, but once i tighten it up again i stop losing oil for a little while. It doesn't misfire, the only thing i hear out of it is a touch of clatter every once in awhile during the first start in over 8 hours when the oil pump has to build pressure. (this honestly sounds like its just from the valves though, not the oil pump or rods.)

I'm always scared to buy a used Distributor because every one I see has play at the very end of it where it goes inside the block. Is it supposed to have a tiny bit of play or does that not matter? I've never seen what a brand new distributor looks like on these because Denso doesn't make them anymore.

Another thing i don't really wanna touch is the Distributor cap itself, I can't find the seal that mates to the base of the Distributor for it anywhere besides Toyota. I've even reached out to the manufacturers I have connections through at a certain auto parts store that shall remain nameless to find a gasket and the Toyota Numbers come up with nothing. Do I even need to use this?
 
#17 ·
I'm always scared to buy a used Distributor because every one I see has play at the very end of it where it goes inside the block. Is it supposed to have a tiny bit of play or does that not matter? I've never seen what a brand new distributor looks like on these because Denso doesn't make them anymore.
I'm not sure what you mean. There is a little piece that fits into the slot on the camshaft, and I think this has some looseness in it by design. There may be some play built in also to account for the camshaft meeting the distributor shaft. If everyone you find is similar then it's probably supposed to be that way.
 
#15 ·
...and if you have a weak spark, then advancing the timing might help because it gives the fuel a little bit longer to fully ignite before TDC which compensates for the weak spark. Of course, it's better to make sure the spark is strong, then set timing to proper spec rather than advance timing to compensate.
 
#18 ·
Might just bite the bullet and grab the best looking one i can find from my local pick and pull. My uncle is friends with the owner and he said he'd charge me 50 flat, 40 if i pull it myself.
 
  • Like
Reactions: DrZ
#21 ·
wellp. I pulled off the cap today.
Took a wire brush to the Distributor Points. Chunks of them fell off immediately. So there's pitting on every point.
 
  • Like
Reactions: DrZ
#22 ·
Cleaned up what was left of it, along with cleaning up the rotor. It already runs better, but my test will be drive time. There is no Oil at all internally inside the cap or the internal distributor components, and it looks like if anything its too dry in there rather than wet.
 
#23 ·
If you continue to have the issues that you've described, I had a weak fuel pump that I eventually figured out was my problem. It fooled me for some time as it would flow on the bench to look like it was pumping fine but apparently couldn't generate enough pressure. Perhaps try and test your FP for pressure reading.
 
#26 ·
There is another really cool thing you can do if your car is Pre OBDII. You can get a crystal chip from a pager with a faster frequency and swap it out for the one that's in your ECU to increase your redline. But there is one thing you'll have to remember. You will run into fuel leaning out in the higher RPM.
 
  • Like
Reactions: Pete Suhman
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top