Timing belt skipped? Ignition timing? 1UZ woe's...
06-30-15, 10:31 AM
#1
Timing belt skipped? Ignition timing? 1UZ woe's...
My brother and I made some good progress on the SC I picked up about a month ago. It will start and run with the first two front right spark plugs pulled(1,3). However when all 8 are in it won't start.
Ran a compression test, this was the result. Left Cylinders>Right Cylinders I thought the numbers were good being 142 is the minimum.
170 160
175 150
170 145
180 150
Checked the cam sensors with multimeter, and they're at 1080 ohm's, and 1110 ohm's. Checked crank sensor, and it's at 1160 ohm's. Manual states 835-1400 for both cams and crank sensors is good.
The car is getting fuel. The car is getting spark. However with 8 plugs it won't start, on 6 it will. My brother thinks either the ECU is sending bad signals(I inspected it, looked fine, but not ruled out), or the Timing Belt skipped a tooth. Ran the engine for about 4 minutes on 6 cylinders, and sounded really good. Decent amount of smoke came out of the rear, but I don't know the last time it ever ran.
Previous owner recently replaced radiator, and reservoir. I know the thermostat housing is leaking, ordering an oem gasket seal for that now. Also coolant appears to be on the timing belt itself leading me to believe it jumped as I've read it on here occurring when someones car overheated, but the car still started just ran poorly... Any advice or opinions appreciated.
Also fully inspected the wheel wells for damage to the wiring harness since the car is lowered. No damage, tucked harness up and away for now. Still throwing CEL 24, and 31. Intake air temp sensor signal, and air flow meter signal, and wit the MAF unplugged it seems to do a hair better...
VIDEO ADDED! Just got ECU back from Tanin, car started for 30 seconds, died, started right back up, died. Now acting just as it did before.
Ran a compression test, this was the result. Left Cylinders>Right Cylinders I thought the numbers were good being 142 is the minimum.
170 160
175 150
170 145
180 150
Checked the cam sensors with multimeter, and they're at 1080 ohm's, and 1110 ohm's. Checked crank sensor, and it's at 1160 ohm's. Manual states 835-1400 for both cams and crank sensors is good.
The car is getting fuel. The car is getting spark. However with 8 plugs it won't start, on 6 it will. My brother thinks either the ECU is sending bad signals(I inspected it, looked fine, but not ruled out), or the Timing Belt skipped a tooth. Ran the engine for about 4 minutes on 6 cylinders, and sounded really good. Decent amount of smoke came out of the rear, but I don't know the last time it ever ran.
Previous owner recently replaced radiator, and reservoir. I know the thermostat housing is leaking, ordering an oem gasket seal for that now. Also coolant appears to be on the timing belt itself leading me to believe it jumped as I've read it on here occurring when someones car overheated, but the car still started just ran poorly... Any advice or opinions appreciated.
Also fully inspected the wheel wells for damage to the wiring harness since the car is lowered. No damage, tucked harness up and away for now. Still throwing CEL 24, and 31. Intake air temp sensor signal, and air flow meter signal, and wit the MAF unplugged it seems to do a hair better...
VIDEO ADDED! Just got ECU back from Tanin, car started for 30 seconds, died, started right back up, died. Now acting just as it did before.
Last edited by Biddles; 07-11-15 at 01:40 PM. Reason: Added Video
06-30-15, 03:44 PM
#3
no clue but its just a vacuum hose for the power steering If I am remembering right, you can replace it with a generic vacuum hose or similar size.
these ecu's are known to have the capacitor problem that causes overfueling like that, did you open it up and then remove the board to look underneath?
you could also have faulty injectors, if they are leaky they would also cause that hard start problem until you pulled the plugs.
to test the injectors keep the plugs in and pulling the injector clip wires on those cylinders to see if it clears out instead of stalling.
still a leaky injector can leak even without power to it, so it is not a fool proof test but if it clears up that does point to the injector.
compression being off or timing belt skipped, only way to know is to look, did you check the cam marks line up at top dead center?
I would start there, but never really hear of it happening. you hear alot of people thinking it happened but its usually something else.
vacuum leaks can also cause issues on these cars, since you have the maf code it is a definate possibility.
check that vacuum hose for hte power steering, also the other side of it that goes to the intake box behind the maf.
also check the plastic intake pipe for cracks.
also check the PCV grommet is in good shape and the hose going from the valvecover to the intake hose.
believe it or not the maf air goes through the crank case via that hose and then the pcv into the engine.
having a leak at the pcv grommet or any of those hoses will throw off the ecu / maf.
but I wouldn't still rule out the ecu, because when you disconnect the maf on these cars it should still run well, if it doesn't something else is going on.
these ecu's are known to have the capacitor problem that causes overfueling like that, did you open it up and then remove the board to look underneath?
you could also have faulty injectors, if they are leaky they would also cause that hard start problem until you pulled the plugs.
to test the injectors keep the plugs in and pulling the injector clip wires on those cylinders to see if it clears out instead of stalling.
still a leaky injector can leak even without power to it, so it is not a fool proof test but if it clears up that does point to the injector.
compression being off or timing belt skipped, only way to know is to look, did you check the cam marks line up at top dead center?
I would start there, but never really hear of it happening. you hear alot of people thinking it happened but its usually something else.
vacuum leaks can also cause issues on these cars, since you have the maf code it is a definate possibility.
check that vacuum hose for hte power steering, also the other side of it that goes to the intake box behind the maf.
also check the plastic intake pipe for cracks.
also check the PCV grommet is in good shape and the hose going from the valvecover to the intake hose.
believe it or not the maf air goes through the crank case via that hose and then the pcv into the engine.
having a leak at the pcv grommet or any of those hoses will throw off the ecu / maf.
but I wouldn't still rule out the ecu, because when you disconnect the maf on these cars it should still run well, if it doesn't something else is going on.
Last edited by Ali SC3; 06-30-15 at 03:51 PM.
06-30-15, 04:36 PM
#4
no clue but its just a vacuum hose for the power steering If I am remembering right, you can replace it with a generic vacuum hose or similar size.
these ecu's are known to have the capacitor problem that causes overfueling like that, did you open it up and then remove the board to look underneath?
Opened up the ECU on both sides, and no signs of bad capacitors, but considering all the problems people talk about with the ECU I'm looking for a replacement.
you could also have faulty injectors, if they are leaky they would also cause that hard start problem until you pulled the plugs.
to test the injectors keep the plugs in and pulling the injector clip wires on those cylinders to see if it clears out instead of stalling.
still a leaky injector can leak even without power to it, so it is not a fool proof test but if it clears up that does point to the injector.
Will definitely test this out as soon as I can, perhaps tonight.
compression being off or timing belt skipped, only way to know is to look, did you check the cam marks line up at top dead center?
I would start there, but never really hear of it happening. you hear alot of people thinking it happened but its usually something else.
When you say top dead center you mean towards center of engine or straight up like a 90 degree angle?
vacuum leaks can also cause issues on these cars, since you have the maf code it is a definate possibility.
check that vacuum hose for hte power steering, also the other side of it that goes to the intake box behind the maf.
also check the plastic intake pipe for cracks.
Stock intake was replaced with the Injen intake, and everything I've read is that it's actually worse for our car.
also check the PCV grommet is in good shape and the hose going from the valvecover to the intake hose.
believe it or not the maf air goes through the crank case via that hose and then the pcv into the engine.
having a leak at the pcv grommet or any of those hoses will throw off the ecu / maf.
but I wouldn't still rule out the ecu, because when you disconnect the maf on these cars it should still run well, if it doesn't something else is going on.
PCV is filthy, on my list of cheap things to replace..
these ecu's are known to have the capacitor problem that causes overfueling like that, did you open it up and then remove the board to look underneath?
Opened up the ECU on both sides, and no signs of bad capacitors, but considering all the problems people talk about with the ECU I'm looking for a replacement.
you could also have faulty injectors, if they are leaky they would also cause that hard start problem until you pulled the plugs.
to test the injectors keep the plugs in and pulling the injector clip wires on those cylinders to see if it clears out instead of stalling.
still a leaky injector can leak even without power to it, so it is not a fool proof test but if it clears up that does point to the injector.
Will definitely test this out as soon as I can, perhaps tonight.
compression being off or timing belt skipped, only way to know is to look, did you check the cam marks line up at top dead center?
I would start there, but never really hear of it happening. you hear alot of people thinking it happened but its usually something else.
When you say top dead center you mean towards center of engine or straight up like a 90 degree angle?
vacuum leaks can also cause issues on these cars, since you have the maf code it is a definate possibility.
check that vacuum hose for hte power steering, also the other side of it that goes to the intake box behind the maf.
also check the plastic intake pipe for cracks.
Stock intake was replaced with the Injen intake, and everything I've read is that it's actually worse for our car.
also check the PCV grommet is in good shape and the hose going from the valvecover to the intake hose.
believe it or not the maf air goes through the crank case via that hose and then the pcv into the engine.
having a leak at the pcv grommet or any of those hoses will throw off the ecu / maf.
but I wouldn't still rule out the ecu, because when you disconnect the maf on these cars it should still run well, if it doesn't something else is going on.
PCV is filthy, on my list of cheap things to replace..
Thanks for all the info Ali, I will take all this with me out to the car and report any changes.
06-30-15, 05:28 PM
#5
Cams look like they are lined up correctly. If they are off I cant see it. Injectors I have to test another time. I touched one(the easiest to access one) and the clip broke instantly. Every clip I touch on this car breaks, and it's getting dark out so I called it a night. The PCV valve hose was held on with a zip tie. It was pretty tight, but I couldn't get the PCV out itself. I wouldn't doubt the valve is completely clogged. I've done them twice in the past on my other SC's and this is definitely the hardest of the three. I'm gonna order some parts, and see if I can get some replacement hoses.
06-30-15, 07:47 PM
#6
I'm seeing some aftermarket hoses (maybe it's nothing). Also noticed the three inlets on the top of the intake mani are plugged, and one of the hoses by the intake plastic tube isn't connected. Looks like it's been maligned with, I'd definitely suspect the P/O messed it up somehow. My $0.02, anyways. GL.
07-01-15, 03:39 AM
#7
I'm seeing some aftermarket hoses (maybe it's nothing). Also noticed the three inlets on the top of the intake mani are plugged, and one of the hoses by the intake plastic tube isn't connected. Looks like it's been maligned with, I'd definitely suspect the P/O messed it up somehow. My $0.02, anyways. GL.
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07-01-15, 11:00 AM
#9
top dead center means you turn the crank with a 22mm socket until the crank pulley is pointing at zero.
then you pull the cam covers off and make sure the marks on the cam line up with the marks on the cover, the marks on the cam should be pointing straight up at the mark on the cover.
if it isn't pointing at the marks on the cover and is sort of pointing down instead, turn the crank one more time all the way around to 0 and check again, they should be lined up this time, if not then something is wrong.
the reason you have to turn the crank to zero twice sometimes is because a full engine cycle is 2 rotations of the crank, so it can take up to 2 turns to reach TDC, which is where crank and cams are all lined up with the marks.
so if you had the crank at zero and one of the cams pointing at the mark, and another cam slightly off its mark, then I would start wondering if the belt skipped.
I would not jump to that conclusion without checking it first cause I can tell you unless you have 300+k miles on the original belt and hydraulic tensioner toyota motors do not usually skip even a single tooth.
The tensioners are so tight you cannot compress it by hand or by leaning all your weight on it, you need a vice or a press or a very large c clamp to slowly push in the tensioner.
when and if they somehow did like if you had a tensioner failure which is rare then you would probably have thrown the belt not skipped it.
also just cause the marks are slightly off doesn't mean that it skipped, someone could have just been lazy putting it on as well.
then you pull the cam covers off and make sure the marks on the cam line up with the marks on the cover, the marks on the cam should be pointing straight up at the mark on the cover.
if it isn't pointing at the marks on the cover and is sort of pointing down instead, turn the crank one more time all the way around to 0 and check again, they should be lined up this time, if not then something is wrong.
the reason you have to turn the crank to zero twice sometimes is because a full engine cycle is 2 rotations of the crank, so it can take up to 2 turns to reach TDC, which is where crank and cams are all lined up with the marks.
so if you had the crank at zero and one of the cams pointing at the mark, and another cam slightly off its mark, then I would start wondering if the belt skipped.
I would not jump to that conclusion without checking it first cause I can tell you unless you have 300+k miles on the original belt and hydraulic tensioner toyota motors do not usually skip even a single tooth.
The tensioners are so tight you cannot compress it by hand or by leaning all your weight on it, you need a vice or a press or a very large c clamp to slowly push in the tensioner.
when and if they somehow did like if you had a tensioner failure which is rare then you would probably have thrown the belt not skipped it.
also just cause the marks are slightly off doesn't mean that it skipped, someone could have just been lazy putting it on as well.
Last edited by Ali SC3; 07-01-15 at 11:05 AM.
07-01-15, 12:00 PM
#10
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If ur injector connectors broke that could be why some cylinders are missing I had the same problem and had to replace all injector connectors when I got my sc. 14$ a piece at dealership
07-01-15, 03:13 PM
#11
Thanks for the info, tested each injector and they're all within the correct range, all were 13.8, 13.9, or 14.0. I didn't test the connectors themselves, but I will. Reason being I just spoke to previous owner trying to get more info on when it stopped running because I couldn't remember. He said his brother was driving it fine when it died, car just went into limp mode and wouldn't start. Definitely getting ECU rebuilt asap. He said car never overheated, or anything like that, just stopped starting and that changes my timing belt skipping a beat/car overheating theory. I replaced PCV valve and grommet, I swear it's the dirtiest I've ever seen. Trying to decide whether I should go with Driftmotion or Darryl on Ebay for the ECU rebuild.
07-02-15, 04:22 AM
#12
Emailed Darryl from Lexus Parts Now who does the ECU rebuilds. He said I'm probably running injectors all the time hydro locking the two cylinders. I'm going to send the ECU to him, after I get the ECU though I might need to unlock these cylinders manually right? Or clear the fuel in there? Or do you think the new ECU will just make it work?
07-02-15, 08:13 AM
#13
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Always remember that an engine cannot compress a liquid. Coolant, Fuel, Oil.
When you get the ecm back. Remove the spark plugs in those two cylinders that you think are filled with fuel, then cover the openings with rags. Make sure that no spark can get to that area, You dont need an engine fire. Then crank the engine over. The fuel should blow out by the engine compression. Remove the rags and clean or replace those two spark plugs.
When you get the ecm back. Remove the spark plugs in those two cylinders that you think are filled with fuel, then cover the openings with rags. Make sure that no spark can get to that area, You dont need an engine fire. Then crank the engine over. The fuel should blow out by the engine compression. Remove the rags and clean or replace those two spark plugs.
07-11-15, 01:38 PM
#14
Always remember that an engine cannot compress a liquid. Coolant, Fuel, Oil.
When you get the ecm back. Remove the spark plugs in those two cylinders that you think are filled with fuel, then cover the openings with rags. Make sure that no spark can get to that area, You dont need an engine fire. Then crank the engine over. The fuel should blow out by the engine compression. Remove the rags and clean or replace those two spark plugs.
When you get the ecm back. Remove the spark plugs in those two cylinders that you think are filled with fuel, then cover the openings with rags. Make sure that no spark can get to that area, You dont need an engine fire. Then crank the engine over. The fuel should blow out by the engine compression. Remove the rags and clean or replace those two spark plugs.
