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engine rotation direction?

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Old 06-23-14, 08:49 PM   #1
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Default engine rotation direction?

It's been at least a week since my last stupid question, so I'm due for another...

On a '94 SC400, which direction does the engine rotate? I need to confirm my timing marks. Everything I've managed to locate so far just says to rotate the crankshaft in the direction of the engine's rotation, and that that's counter-clockwise for virtually everything out there. However, all the Toyota stuff I've found for older and newer engines says clockwise.

I suppose I could borrow a helper for a few minutes to bump the starter.

Does it even matter for these early model engines, being a belt instead of a chain, and supposedly being non-interference?
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Old 06-24-14, 08:10 AM   #2
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I had to read ahead to the re-installation steps, but I found my answer here:

http://www.lexls.com/tutorials/engine/timingbelt.html

Quote:
43) Important: Check the valve timing. Turn the crankshaft pulley clockwise two full revolutions using a 22mm socket, from TDC to TDC. See step 15 to see how it should align, then press backspace to return here. The mark on each camshaft timing pulley should align with the mark on the engine. If the marks do not align you messed something up, remove the timing belt and reinstall it.
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Old 06-24-14, 09:23 AM   #3
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toyota engine rotation is usually always clockwise, they say to avoid turning the toyota crankshaft counter clockwise, I think it has to do with which side the slack is on the tensioner and if you go counter clockwise and try and line it up to 0 you wont be at 0 perfectly, it will be off. you should approach and stop at 0 going clockwise to get it at perfect TDC.
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Old 06-24-14, 10:05 AM   #4
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Thanks. That fits everything I read elsewhere, but with the uncertainty of which direction to rotate. Good thing I checked.

I just got done with it and confirmed all 3 timing marks line up correctly. I had an issue this weekend... Two people said it sounded like it jumped timing, but I don't honestly know what that sounds like and had my suspicions that they didn't, either. You know how it is with car stuff, people repeat something definitively that they once heard...

But, I figured it was worth checking while I have all that stuff opened up. The issue was that the car would start then stall instantly after its first long/warm drive. It ran great there and back, but it was really tough to get it to catch initially, until cooling off over night. I decided to take your advice from the other thread and go for a clean slate on the ignition stuff, so I've got new Beck/Arnley distributor caps and rotors on the way, as well as a Beck/Arnley fuel pump regulator to hopefully eradicate the ignition/fuel demons! I haven't ordered new coils yet, as those seemed to pass the test.

Edit: Also with everything in that area opened up, I went to clean the coolant temp. sensor and discovered it had been serviced recently (spotless) but in very concerning fashion. The clip on the plastic plug is broken, the green wire is bare for 1/4" at the plug, and the plastic base of the sensor is almost broken off. I don't know if that contributed to the problems starting when warm, but it certainly isn't good. The plastic clip on the pass. side's coil and what I think is the pass. side crank sensor are both broken off the plugs, as well.

I took the spark plugs out prior to the timing marks check, which made it quite easy to turn the crankshaft. I've been thinking about trying the Seafoam treatment... I'm still a bit nervous about it, but what's the worst that can happen? I'll put the old plugs back in so I don't foul up 2 month old ones.
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Old 06-24-14, 03:13 PM   #5
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Yeah some people tend to just repeat everything sort of like trying to shove the same square peg into every round hole.
Your details surely will help you, as I can tell you the coolant sensor is directly responsible for that symptom, likely if the connector is cracked its not making a good connection. the breaking at the base is a sign someone tried to remove the clip and was not so successful and tweaked and damaged the sensor, it needs to be replaced. the exposed wire should be fixed if its bad or you can rewrap or slide insulation over it it if the pin is good, that will be a look at it and decide sort of thing how good it is, another sign someone couldn't get the clip off and pulled on the wire to help get it off in a bad way.

The reason its in such bad shape and looks like its broken at the base (ask me how I know.. lol) is the green coolant sensor plug is one of my arch nemesis of toyota plugs, I can take off most any other plug without breaking it but that one holds on with all its got whenever I try and take it off, I dunno its just weird like that I break it every other time which is ridiculous I avoid removing clips I don't have to on these cars in general but that, coil connector, IACV, and tps are common ones to break. So I am positive the person who replaced it broke the clip removing it from the sensor, which also broke the sensor at the base as they are very delicate, and then just put the clip back on the sensor hoping it was good and also hoping it would work =) which it never really does again =(

I would do a plug inspection and replace them all, you can get all the plugs from drift motion easily online or figure out the part numbers and order from dealer, but the $30 in replacing broken connectors is well worth it if you plan on keeping the car.

Broken ecu engine temp coolant sensor means the car never exits start up fuel enrichment, and when it gets warmed up the motor cannot stay running from such a rich mixture and it won't adjust the mixture because you do not enter closed loop until the car is warmed up... and the coolant sensor is what tells the ecu the car is warmed up... see the problem? also

Initially I was going to say check the timing also, cause that is another likely issue but then I remembered you have a sc400 and its not adjustable, but when you mentioned the connector on the coolant sensor I knew that was it, it is the 2 pin coolant sensor for the ecu not the 1 pin coolant sensor for the gauge cluster, and there are 2 separate ones which is why people think the coolant sensor must be working from seeing the cluster, but even if your cluster is reading right the ecu can have no idea as a bad ecu engine coolant sensor reads as a cold engine to the ecu generally speaking.

I say don't seafoam unless you have reason. if you have alot of buildup then you can go for it, but warning some of what dislodges goes through the whole system, cats etc.. not always as harmless as you think.
I always just tear it down and clean it by hand if its that bad, use sea foam to stabilize your gas for winter storage and thats about all I would use it for, even that I don't use it so much.

The best part about going to toyota/lexus to get service done, is that if the break a connector they generally replace it with a new one, its standard procedure.
some places on the other hand will just throw the cracked one back on there and hope it works good enough for you to not notice.
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Old 06-24-14, 03:53 PM   #6
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Has anyone ever told you that you back quite a whallop of information into each post? I definitely like hearing that the fixes in progress directly fit the symptoms!

Here are the pics I posted in the LS400 thread (linked from the Mega Stickies thread, I think) of my damaged sensor and connector:

http://www.clublexus.com/forums/8595659-post215.html

I guess I should take the tape off and do a continuity test on that pin (at the tip of the plug and at the bare wire) before putting it all back together?

I have a new coolant temp sensor on order. I've wrapped the bare wire with electrical tape for the time being. Not sure what else I can do for it, since it's right at the base of the plug. I could try putting some wiring loom flex sleeve stuff over it, but that may just cook down there by the head. I did finally locate a new part that looks like it'll fit, but I've been meaning to post a WTB in the classifieds for misc stuff, so now would be a good time to do so and try replacing some sketchy connectors. Drift Motion? Not familiar with them, will have to take a look.

"coil connector, IACV, and tps are common ones to break."

Interesting. I've removed all three of those pretty easily, but my nemesis ones are a totally different list. Things like the shifter bezel and hazard/hvac/volume plugs have me cussing every time. The last time I put them back in, it occurred to me I should have taken some sand paper to them and reduce the inner size a bit. There's no good reason for anything to be that snug. Next time...

Is the 1-pin sensor for the gauge cluster the little gray tube sticking up next to my bare-wire plug picture in the LS400 thread?

You've got me back on the fence about Seafoaming... I was choosing between that and injector cleaning, as the fuel delivery systems warrant extreme steps if the new fuel pressure regulator doesn't solve it. But then I saw how labor intensive it is to replace the injectors and figured that would be overkill on a hunch. The engine seems very strong when running, so you're right, there may not be a good reason to Seafoam. I can put the new spark plugs back in once I have all the new parts in place in a few days and see if there's still a need for it.
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Old 06-24-14, 04:11 PM   #7
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Found it: http://www.driftmotion.com/Coolant-T...n-p/dm1573.htm

I wasn't expecting something that I would have to wire up myself... "Uses 070 style terminals and small wire seals, sold separately." It must be a vampire tap type of system? Could I just clip my old wires and insert them into the new plug, making the whole thing 1/4" shorter (assuming there's enough slack)?
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Old 06-25-14, 03:28 PM   #8
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yes I do go back and write a bunch, if I get it all perfect before I submit sometimes I end up loosing the whole thing when I hit back or something pops up etc.. very annoying.
you have 2 issues, a damaged connector and a damaged wire.

normally you just pop the wires/pins out of the connector (there is special way to do this with a small flat screw drive do not simply pull on the wires) and then insert into the new connector, but since one of your wires is damaged the proper solution is to get a replacement wire and pin, and cut the damaged wire several inches down and replace that section with a new properly soldered and wrapped/heatshrink connection. then you can insert that new pin and your undamaged one into the new plug.

no you cannot just cut yours and insert into a connector, the pins on the tip is what locks into the connector and you have damaged it right there, so you need a good pin with some wire on it to replace yours.

often I just replace both wires and the plug when one is damaged, likely someone pulled on both so it may be worth it to just preventative do it, so you need that connector and 1 or 2 wire terminals with the right size pins.

the 1 pin sensor is likely the gauge one, disconnect it and see what happens but thats the one generally speaking I am used to the sc300 locations but toyota uses the same colors and pin amounts across these generation motors so its the same just different place. there is also a oil pressure sensor somewhere so not to be confused with that but again just for the cluster on that one too.

also a contuniutiy test does not do much, alot of times you get contuniuty there, only to still have a bad connection when its connector to the motor and vibrating like crazy. thats the whole point of tight connectors, to keep a good connection in the engine bay environment where those sensors are subject to constant heat and vibration, both of which greatly affect a just barely holding on connection. not always a sure test.

I have even seen the pins in there with no sign of anything wrong, except they were not pushed 100% in to lock in (you will hear the click when it locks in), and those are the hardest to find. another way connectors go bad the do not just break on the outside, if someone removes a pin badly and breaks the locking tab that pin will likely lead to some intermittent problem that is horrible to track down. thats why I say when I see a broken connector or if I break one myself I always replace it to avoid future problems.
This is the reason when they do harness work they replace everything that looks even remotely broken.
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Old 06-25-14, 04:46 PM   #9
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Man, that sounds like it's going to be a pain. There's so little slack in that wire to begin with, I'm not sure how I'm going to solder anything once I move a few inches down the line. It'll probably require carefully cutting open the few inches of bundled harness it disappears into.

Bummer that the continuity test (it passed) doesn't guarantee me any peace of mind. If it doesn't hold up to the heat and stresses, there's no visible warning signals sent...

I've got two days until the new coolant sensor arrives. (I had hoped for today or tomorrow, given the shipping proximity.) I posted a WTB ad in the classifieds, so hopefully someone with a parts car turns up some options while I'm mulling over which direction to go.
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Old 06-26-14, 09:45 AM   #10
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the part that it disappears into is just factory wrapping, its some of that split braid stuff with tape wrapped over it. you can remove it to get more slack, and then rewrap it with new stuff or the old stuff braid and re-wrap it, just depends how much it falls apart when you go to remove it they are usually brittle by now.
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Old 06-26-14, 11:47 AM   #11
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Ok, thanks. I put in an order for the coolant temp sensor connector and coil connector with Drift Motion. Two down, one to go... And my new coolant temp sensor is arriving today, after all, so I can get that in place in a few hours and have the car operational again.
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Old 06-26-14, 12:01 PM   #12
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with any luck its just the sensor and the connector might still work ok for the time being but I would change both.
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Old 06-26-14, 12:07 PM   #13
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Quote:
Originally Posted by Ali SC3 View Post
with any luck its just the sensor and the connector might still work ok for the time being but I would change both.
Absolutely. It'll take a few days for the new connector to arrive, though. I'll leave all that stuff exposed for the time being, since I'm still waiting for the new caps/rotors. No point putting all the plastic pieces back in place just to remove them again in a few days.

Hopefully, my broken old clip will slide off the coolant temp sensor easily and not require an intermediate wrestling match like your experiences.
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Old 06-26-14, 02:04 PM   #14
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Crap, it turns out I need to replace the single-wire coolant temp sensor connector (to the gauge cluster), too. Putting it back on, I noticed it didn't snap into place at all. Its clip is about to fall off... And I didn't notice it before, but its wire is also bare at the base of the connector. Drift Motion doesn't show that connector on their website, so at least I didn't miss out on combining it into the order.
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Old 06-26-14, 08:01 PM   #15
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Fairly depressing first test with the new coolant temp sensor in place. It started and ran well the first time, then went back to repeatedly starting and dying after driving 2 miles to the store. Hopefully, that means the deteriorated male end of the connector is more to blame than the cracked base on the sensor's plug, otherwise that accomplished nothing.

Additionally, the partial throttle 40 mph hesitation/bucking that I eliminated last week with TPS adjustments returned with ferocity...

I think I'll leave the ECU fuses pulled overnight and see if that helps it comes to its senses. The learning ECU on this car is either the smartest or dumbest thing ever made.
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