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And maybe useless info, but some PIDs from OBD reader while driving at 40mph. Ambient temp was around 68F, but intake temp was reporting much higher - is that normal? That reading comes from the MAF correct?
I'm starting to think this is a mechanical / valve / cylinder issue. Not something I can really fix and might have to drive until it blows.
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Congratulations, just shows you have to have patience and just can't give up. Hope you have solved your problem for good, sounds like it. Now go and enjoy your SC, You have earned it.
looks like cylinder 5 has a bad valve stem seal or injector issue. how many miles ont he motor? all of these engines have bad valve stem seals between 100k and 250k miles, some sooner, some later.
the oil will burn on the top of the piston and increase compression over time. the oil will cause misfires and it will get worse as it builds up. the clean plugs didn't tell the story cause they are relatively new but the picture down the hole does.
you should be able to see the metal piston tops. first figure out if it is valve stem seals, you will need to do those and then a top end clean if not removing the head. if removing the head you can just clean the tops of the pistons easily.
Unknown on block, it was from an imported Aristo front chop. The head was purchased used on eBay from a 1997 Supra with 76K miles (supposedly). I've put about 20k on both since they were changed, so safe to assume 100k on head and 200k on block.
I am assuming someone cleaned the pistons before they put the supra head on. If they didn't do the valve stem seals on that head then they are probably going bad now and is pretty common.
Especially if the head has been sitting for a while you want to go ahead and put new viton seals in just to be safe.
Every time I have a cylinder head off I do the valve seals unless I know I did them recently, it isn't the most fun job to do but its much easier when the head is off versus doing it later.
It could be a ring issue but the compression readings look good and consistent. look for puffs of oil smoke on the first start in the morning. if it is valve seals it will get worse and misfire/smoke more and more then all the time.
If that is what is going on it looks like you caught it early cause there aren't a crazy amount of carbon deposits yet, so it should clean out pretty easy once you do the seals.
I knew this was still happening just not enough to trigger CEL.
I installed a better code reader update and can see the following. This was after a light acceleration from one light to the next - not WOT or anything like that.
Unfortunately I do not have the resources to tear anything else apart from the top basics. Can't do valve seals or rebuild anything big like the block.
Misfire count went to 2 on cyl #1 then at a stop it reset and when I stopped driving (about 5 mins total) it showed the total of 10? or something - not sure how to read this.
Does the fuel up VSV mean high pressure mode? end total
Pulled #1 plug just to randomly check it since I see that misfire and the tip of these new plugs (<100 miles on them) it's like a greenish-yellow color.
I googled around and it could be anything from seafoam to a compression problem so I have no idea.
That's unsusal build up on the plugs. I've never seen green before. What brand and octane gasoline do you run?
Did you ever replace the wires? Because 7 years is past their lifespan. They're supposed to be changed every 60k. Plugs every 30k (these cars were before iridiums).
As for the oil residue by your Tbelt - that could mean that cam seal is leaking OR your front main seal is leaking slightly. IF your front main seal is leaking, it's possible it could be interfering with your crankshaft sensor, and that could be what is causing your intermittent misfire
Ignore the green/yellow tip for a second (which is a sign of unusually high combustion temp) and look a little lower and you'll see a black ring at the end of the threads which sticks down into the cylinder.
That is fresh carbon deposits forming on the new plug which is a sign of excess oil and/or gas in the combustion chamber, which you can also see is baked on top of the actual cylinder (the rusty carbon color).
This usually happens from either super rich gas mixture, or from oil entering the system, and also both of these.
The cam seals at the front should have also been done with the head swap, should not be leaking at 20k already so I would question if the head was refreshed when it was installed (and the valve stem seals which could be related to the carbon buildup).
1997soarer, the front crank sensor on the crank is a 36-2 setup for detecting misfires as it is more accurate, but the engine runs off the 12 tooth sensor in the distributor.
So while the front crank sensor is used to detect misfires, it would not be the cause of the misfire as the engine runs off the other crank sensor.
So full circle back to the green spark plug tip, my guess why you would have such high combustion temps to cause it to turn that color is you are experiencing pre-ignition and detonation which show up as misfires.
Believe it or not, carbon deposits can actually get so hot during normal driving that they can ignite the air fuel mix before the spark plug does... causing preignition which causes detonation and spikes combustion temps.
It will get worse, and the worse it gets the more likely the engine is to get some damage from preignition at the wrong time and engine load.
The other interesting thing going on here is that you said an aristo block and what looks like a supra non turbo head.
So was the aristo block a GE block or a GTE block? and did you use a ge or gte headgasket?
normally carbon deposits will also show up as a higher compression than normal, but it is relative so unless you know what compression your engine is supposed to have it is hard to detect the problem that way.
Like a normal 2jzge you would be looking around 180-190 psi on all cylinders and a GTE would be lower around 150-160 psi as a rough guide.
You said yours was around 155-160 and I can see the carbon deposits which are probably increasing that number some.
That makes me guess a gte block / gte headgasket / ge head combo which would have a pretty low compression ratio (this combo would be lower compression than a gte 8.5:1 actually as GE has larger cylinder head volume) and could be the ecu is over fueling because it thinks you have a much higher compression ratio.
The o2 sensor does some correction, but only in closed loop and after a delay, so every time you press on the throttle enough to go into open loop it would be overfueling until it starts to correct again.
Combine that with a few shorter drives here and there, and all that carbon will deposit on top of the pistons pretty quick.
So I couldn't definitively say whether you have an over fueling issue due to compression ratio or oil leaking issue due to valve stem seals without actually testing things.
Those obd2 ecu's are sensitive to small changes and your compression ratio is way lower than stock.
I think you have a couple issues on your hands and none of them are the spark plugs you are running.
I returned to this thread and it just dawned on me: Why do your cam gears and IN and EX written on them? What exactly is the history of this engine? Was the head rebuilt?
I was under the impression the head was intact but there's no reason for someone to write that on the cam gears unless the cams were removed from the head at some point. If something like that has happened in the past, there could be non ordinary issues going on here that we didn't consider before.
I also am suspicious of your block. Ali knows more about this than I do BUT I will keep following this thread since I own a 97 5 speed so I know exactly how the car should perform in perfect working order.
My suspicion with the crankshaft sensor is that now that we know the block has been swapped I wonder if the crankshaft trigger wheel is missing a tooth
It's kind of a convoluted story, but I'm very certain these misfires started recently so I'm wondering if it's a seal issue and the oil is simply the problem.
The original engine that came with the car was destroyed in a nitrous mishap. The short story was that my grandfather helped me change the timing belt a few years prior and what he did to mickey mouse it came back to haunt me. He stripped part of the cam gear center hole accidentally and stuck a damned -shim- in the center to keep it from wobbling. I didn't think that was a wise decision but he made a scene about it and insisted it would be fine. When I was spraying the shim slipped and something bad happened and the head blew into a giant fireball. Bits of the cylinder walls were chipped off and the pistons were damaged. That was like almost 8 years ago now.
I then ordered a used 2JZ-GE (100% non turbo) engine and swapped it in without issue. I was curious about where it came from and traced the serial number back to a Japanese site and was pretty sure it was from a 1993/4 Aristo. I moved to another state for a couple years and when I came back to CA it would not pass smog and I had done a resistor mod on the EGR since this other state didn't have strict smog rules. After being unable to diagnose the problem (until after the head was swapped) I just replaced the head since and ordered a 1997 GE Supra head with supposedly ~77K miles on ebay. I had no choice at the time since I had no other transportation and no monetary resources (and still don't - times haven't changed LOL) to pull everything out again and have it rebuilt so I had to do the 'easiest' cheapest/fastest solution.
Also the gasket is a GE gasket 100% as I ordered the entire belt/seal kit when I swapped the head. I don't know why EX/IN are written on there, I think my grandfather did that thinking we had to remove them for something. No reason really.
So if it's an oil leak issue - it's probably coming from the piston rings or cam? I don't have any black smoke. Could be the cam seal, or the front main seal? I am very certain the front main seal was replaced, not sure about the head cam seals.
Unfortunately my grandfather passed away last November and he was the only mechanical help I had so doing any kind of bigger job is out of my reach now. I've taken the engine out and apart twice in the past but had help (albeit mickey moused) and I don't have any mechanically inclined friends now and don't have the money to take it to a proper shop who knows GE/GTE engines well.
Also to note, coolant level is not going down in the actual radiator, there's no milky color or bubbling in the coolant or the reservoir, so I'm pretty sure it's not a HG issue.
02-20-21, 02:41 PM
