Toyota Echo 2001 problem

[android25ua]

Hello folks, nice forum here!

I apologize ahead of time, I am going to copy my question from another forum that I am lurking on a regular basis, sorry for the long block of text but I don't know what to look for next...

Toyota Echo 2001 260 000km Manual Tranny

Symptoms: Last year the car started missfiring when giving a lot of gas @ lower RPM, and would gradually stop the higher the RPM. The problem was getting worse very slowly. Check engine came up - missfire cyl1 so I replaced the Ignition Coil on that one - problem went away. (I also replaced the spark plugs at the same time so since then they have about 30 000km on them)

Side note symptoms: over the last year the car started taking longer and longer to start - ~2 seconds of cranking. I asked about this in a thread earler and people suggested I clean all the grounds.

Current symptoms: Started the same way as it did last year only more abruptly: my mom completed a turn and bam missfire on heavy load @ lower rpm, quicky getting worse. The engine also died 2-3 times till she got to work which didn't happen last year. So I'm thinking to myself another coil went. I take the car and drive it back home, with the same symptoms only more severe - have to be really easy on the gas to avoid missfire which is more severe as well, the car won't pull AT ALL, engine starts dying. I drive it home like that, mostly in 4th gear and right before my exit (oh the luck) the effect is present regardless of how much gas I press and the engine slowly dies as the car comes to stop. It was getting worse gradually over the trip so I thought it had to do with heat. I tried to start the car - nothing, felt like cranking an engine with no spark plugs in it. I waited 20 minutes for the engine to cool and tried again - the car starts in the usual "~2seconds of cranking manner" and drives off better than when I took it - the missfire comes in only when I really floor it at low rpm, and after about 20 seconds of driving Check engine comes up. So in the same way easy on the gas I get home. I didn't really dare to gas it a lot to see if the effect was getting worse, I just wanted to get home. I also bought another new coil. I don't have a computer to scan the codes, and the place where I bought the coil wanted 60$ just to plug the thing in and scan it... So once home, I decide to replace coils one by one and see if the problem goes away. (Last year I replaced coil on cyl1) I start off on the other side of the block with cyl4 - throw the new coil on, start the car - starts fine, drive it, gas it in lower rpm - missfire just like before. Swap the old one in, replace cyl3, start the car - drove heavy load in low rpm - nothing, problem gone, no missfire at all. So I'm thinking yay, get back in and decide to really make sure that it's coil3 on cyl3 that was bad so I put the old coil back on cyl3 and drive the car again - NOTHINg..... no missfire... drives fine. Get back in, thinking wtf, take out coil2 put the new one in there just to see if that makes any difference, screw the bolt in, plug in - car wont start. Cranking wihout even attempting to start. After that I fiddled around with coils for ~20 minutes which yielded the same result - cranking without starting, so I went to sleep, as it was getting dark. I thought to myself it'll cool down the way it did on the highway earlier and then start.

This morning I get out and try to start it. Wont start just like yesterday. Also my friend came to help me out so we started looking at everything in the engine bay. He suggested I unplug coil 1 and give it a crank. I did that and at the same time tapped on each coil connector with a wrench a bit. Crank the car - It starts and runs on 3 cylinders. I shut the car off and connect coil4, the car starts and runs fine. So we go ahead and remove and sand down/brake cleaner/electrical cleaner EVERY ground we find in the engine bay, starting off with the ones pertinent to the ignition system. With all of that done, we also cleaned the MAF, the coils themselves and pretty much everything electrical on the way. We also took out the spark plugs to inspect (another clue I have now) and this is the closest image I could find to what I saw on mines:

Very similar with some orange powder on the ends. Again they have 20-30k km on them MAX and were replaced last year. I dare to say theyhave even less but idunno.
Reassembling done, I start the car in the usual 2second cranking manner (I would of hoped that with clean grounds it would fire right up but no) and it runs fine. I leave it idling for a good 10-15 minutes and then get out for a drive. Upon heavy load in low RPM there is a VERY faint symptom of missfire. So I expect it to get worse as then engine gets hotter - trying to find at least ONE fucking consistent cause. I drive the car around, not ripping it, just regularly, for about 10 minutes. The effect does not change, there is a faint missfire on heavy load which sometimes is almost not there, or is not there at all, all depending on how much you're sinking it with gasoline. I get back in and park the car at about ~3PM. Three hours later (~now) I get back out to see how things are going and try to start it - it cranks as though there are no spark plugs in the block. Absolutely no caughing firing or anything. Just cranking.

Anybody have any ideas? I am thinking spark plugs of shit quality and changing humidity could affect that. But I am really desperate for finding a consistent cause / symptom.

Also sorry for the long block of text, cliffs:

Toyota echo 2001 260k km manual tranny
sparks: ~20-30k km
issue: missfire upon heavy load in low rpm/engine not starting just cranking when hot after a drive
procedure: cleaned all grounds, connectors and maf
issue: mix of missfire upon heavy load/engine not starting just cranking
result: /mad

P.S. no check engine after reassembly/the drive.

additional P.S. I read up on crankshaft position sensors and symptoms and it seems like everything of what I have been experiencing is a symptom of a bad sensor - hard starting, stalling when running, and ultimately cranking with no start.

Thanks in advance folks!

[Yuko]

The spark plug shows sign of the engine running too hot in the cylinders. This lead condition can be cause by a vacuum leak somewhere in the intake, too advance of timing, or poor fuel delivery.

But in you're case, most likely it's the camshaft position sensor which affect timing and spark might have gone out.

[android25ua]

Thank you for the response! How do I know whether it's the crankshaft or the camshaft sensor though?