Won't Start after Timing Belt/Spark Plug Replacement
10-15-06, 09:42 PM
#1
Intermediate
Thread Starter
Won't Start after Timing Belt/Spark Plug Replacement
Just replaced my timing belt, original spark plugs with Bosch Platinum 4+'s and replaced the coolant. Now she won't start. The battery was disconnected for a few days so I'm thinking the computer lost it's memory and needs to "relearn" the engines paramaters. Anyone have any suggestions??
Alex
Alex
10-15-06, 09:55 PM
#3
Moderator
You should rule out the computer "learned" parameteres. Things default to a state where the engine runs.
I assume the engine cranks but does not fire.
Suspect items would be:
Timing belt off (I hope you marked all gears om the belt amd none of them were spun during TB replacement {note one complete turn of a smaller gear would throw timing off}.
Ignition (spark) at thr wrong time. Get a timing gun and check.
Salim
I assume the engine cranks but does not fire.
Suspect items would be:
Timing belt off (I hope you marked all gears om the belt amd none of them were spun during TB replacement {note one complete turn of a smaller gear would throw timing off}.
Ignition (spark) at thr wrong time. Get a timing gun and check.
Salim
10-15-06, 09:59 PM
#4
Moderator
If not, the engine immobilizer will nNOT allow the engine to start.
If you intend the engine to run, you must use the master or valet key.
Salim
10-15-06, 10:15 PM
#5
Intermediate
Thread Starter
Yes, the flat key has the chip in it. The security light stops flashing when I use it.
Yes, when the timing belt was installed all three TDC marks lined up; each of the two camshaft pully marks and the crankshaft mark lined up with the "0" mark on the lower timing belt cover.
The engine did sputter the last time I tried to start it so it is firing.
Yes, when the timing belt was installed all three TDC marks lined up; each of the two camshaft pully marks and the crankshaft mark lined up with the "0" mark on the lower timing belt cover.
The engine did sputter the last time I tried to start it so it is firing.
10-16-06, 06:36 AM
#7
Moderator
Yes, the flat key has the chip in it. The security light stops flashing when I use it.
Yes, when the timing belt was installed all three TDC marks lined up; each of the two camshaft pully marks and the crankshaft mark lined up with the "0" mark on the lower timing belt cover.
The engine did sputter the last time I tried to start it so it is firing.
Yes, when the timing belt was installed all three TDC marks lined up; each of the two camshaft pully marks and the crankshaft mark lined up with the "0" mark on the lower timing belt cover.
The engine did sputter the last time I tried to start it so it is firing.
If it sputtered, I would get the timing gun out to check and then check spark plugs and wiring.
ps: I have no clue how to hook up the timing gun, with the coil over the plugs. Maybe Lexmex can tell us how.
Salim
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10-16-06, 06:44 AM
#8
Super Moderator
I still insist that even with the marks lining up, you can be a revolution or two off as the size of the gear matters. So no gear should have been spun, once the belt was removed. I hope that is the case.
If it sputtered, I would get the timing gun out to check and then check spark plugs and wiring.
ps: I have no clue how to hook up the timing gun, with the coil over the plugs. Maybe Lexmex can tell us how.
Salim
If it sputtered, I would get the timing gun out to check and then check spark plugs and wiring.
ps: I have no clue how to hook up the timing gun, with the coil over the plugs. Maybe Lexmex can tell us how.
Salim
Salim, you are right on the issue of the timing. When I put on my URD pulley, we were very careful to look at the marks on the PS and Accessory belt and even took a look at and took off the timing belt. Everything worked, but my uncles knows even dealers down here who routinely screw up this process and he ended up fixing this issue.
10-16-06, 08:53 AM
#9
Intermediate
Thread Starter
CEL's??????????
If you mean some sort of a code light flashing then no.
As far as anything moving during belt replacement I found it almost impossible to replace the belt without one or both of the camshaft sprockets moving at least a little. The main thing is to get both camshaft pully marks to line up with the corresponding notch on the rear timing belt cover while at the same time lining up the crankshaft pully mark to the "0" notch on the lower timing belt cover. This is what I did.
If one of the camshafts "spun" and I assume you mean 360 degrees then at least one of the valves would have contacted a piston which would cause the camshaft to stop turning. This is an interference engine, correct?? If that were the case then the engine wouldn't even crank over as the valves would slam into the pistons which would lock up the engine causing major damage.
Am I correct or am I missing something??
Alex
If you mean some sort of a code light flashing then no.
As far as anything moving during belt replacement I found it almost impossible to replace the belt without one or both of the camshaft sprockets moving at least a little. The main thing is to get both camshaft pully marks to line up with the corresponding notch on the rear timing belt cover while at the same time lining up the crankshaft pully mark to the "0" notch on the lower timing belt cover. This is what I did.
If one of the camshafts "spun" and I assume you mean 360 degrees then at least one of the valves would have contacted a piston which would cause the camshaft to stop turning. This is an interference engine, correct?? If that were the case then the engine wouldn't even crank over as the valves would slam into the pistons which would lock up the engine causing major damage.
Am I correct or am I missing something??
Alex
10-16-06, 09:07 AM
#10
Super Moderator
CEL's??????????
If you mean some sort of a code light flashing then no.
As far as anything moving during belt replacement I found it almost impossible to replace the belt without one or both of the camshaft sprockets moving at least a little. The main thing is to get both camshaft pully marks to line up with the corresponding notch on the rear timing belt cover while at the same time lining up the crankshaft pully mark to the "0" notch on the lower timing belt cover. This is what I did.
If one of the camshafts "spun" and I assume you mean 360 degrees then at least one of the valves would have contacted a piston which would cause the camshaft to stop turning. This is an interference engine, correct?? If that were the case then the engine wouldn't even crank over as the valves would slam into the pistons which would lock up the engine causing major damage.
Am I correct or am I missing something??
Alex
If you mean some sort of a code light flashing then no.
As far as anything moving during belt replacement I found it almost impossible to replace the belt without one or both of the camshaft sprockets moving at least a little. The main thing is to get both camshaft pully marks to line up with the corresponding notch on the rear timing belt cover while at the same time lining up the crankshaft pully mark to the "0" notch on the lower timing belt cover. This is what I did.
If one of the camshafts "spun" and I assume you mean 360 degrees then at least one of the valves would have contacted a piston which would cause the camshaft to stop turning. This is an interference engine, correct?? If that were the case then the engine wouldn't even crank over as the valves would slam into the pistons which would lock up the engine causing major damage.
Am I correct or am I missing something??
Alex
The reason I say this is that there is an error code I remember reading about in the manual that detects when something is off with the pulleys and belts.
RX300 is a non-interference engine.
The ECM should have no issue when the battery is connected. The fact that you can turn it over a bit, but it sputters tells me it could be something else that has shorted.
I might need to ponder this for a bit.
10-16-06, 09:22 AM
#11
Moderator
Lets go with the assumption that no gear was turned in multiples of 360 (both + and - degrees).
With the tensioner on, do the marks line up? or one is off by a notch or two? If off by a notch/tooth, that needs to be fixed.
Academic discussion: Assume your valve train is off exactly by 360 degreees. With 4 stroke engine you will be ok [no piston-valve collision] as compression stroke will be replaced by exhaust. This is limited to breakage, but the engine would not run .. [ie there are 2 TDC positions in 4 stroke ... compression and exhaust]. Hence the assertion that main pully and the cam pullies should not be spun once the belt is off [realistically you can spin but you must bring it back the same amount]. If they are off then tdc of compression stroke needs to be mated with spark. With V6, the other bank needs to be confimed.
Also, go over the work you did ... just in case you forgot to reconnect a sensor or a vaccum line. Or worst still pinched a sensor wire.
Another learning is ... dont combine too many changes. ie change timing belt and run engine. Then change plugs. Right now we dont know if it is the ignition problem or the valve-train timing.
Salim
With the tensioner on, do the marks line up? or one is off by a notch or two? If off by a notch/tooth, that needs to be fixed.
Academic discussion: Assume your valve train is off exactly by 360 degreees. With 4 stroke engine you will be ok [no piston-valve collision] as compression stroke will be replaced by exhaust. This is limited to breakage, but the engine would not run .. [ie there are 2 TDC positions in 4 stroke ... compression and exhaust]. Hence the assertion that main pully and the cam pullies should not be spun once the belt is off [realistically you can spin but you must bring it back the same amount]. If they are off then tdc of compression stroke needs to be mated with spark. With V6, the other bank needs to be confimed.
Also, go over the work you did ... just in case you forgot to reconnect a sensor or a vaccum line. Or worst still pinched a sensor wire.
Another learning is ... dont combine too many changes. ie change timing belt and run engine. Then change plugs. Right now we dont know if it is the ignition problem or the valve-train timing.
Salim
Last edited by salimshah; 10-16-06 at 09:32 AM.
10-16-06, 09:25 AM
#12
Intermediate
Thread Starter
Lexmex,
Yeah, I just read on the net that this is a non-interference engine. My mistake. So that means that even if the camshafts rotated 100 times in either direction while replacing the belt, as long as all the timing marks line up when the belt is installed and tightened all should be well as there is only one way to line everything up to TDC. That makes sense, doesn't it??
I'm thinking it's possible that I missed a connection when putting everything back together. I had to disconnect many electrical connections when changing the plugs, but I don't think I did. I checked and re-checked before I finished.
Might have to call Lexus on this one.
Yeah, I just read on the net that this is a non-interference engine. My mistake. So that means that even if the camshafts rotated 100 times in either direction while replacing the belt, as long as all the timing marks line up when the belt is installed and tightened all should be well as there is only one way to line everything up to TDC. That makes sense, doesn't it??
I'm thinking it's possible that I missed a connection when putting everything back together. I had to disconnect many electrical connections when changing the plugs, but I don't think I did. I checked and re-checked before I finished.
Might have to call Lexus on this one.
10-16-06, 09:41 AM
#13
Super Moderator
Lexmex,
Yeah, I just read on the net that this is a non-interference engine. My mistake. So that means that even if the camshafts rotated 100 times in either direction while replacing the belt, as long as all the timing marks line up when the belt is installed and tightened all should be well as there is only one way to line everything up to TDC. That makes sense, doesn't it??
I'm thinking it's possible that I missed a connection when putting everything back together. I had to disconnect many electrical connections when changing the plugs, but I don't think I did. I checked and re-checked before I finished.
Might have to call Lexus on this one.
Yeah, I just read on the net that this is a non-interference engine. My mistake. So that means that even if the camshafts rotated 100 times in either direction while replacing the belt, as long as all the timing marks line up when the belt is installed and tightened all should be well as there is only one way to line everything up to TDC. That makes sense, doesn't it??
I'm thinking it's possible that I missed a connection when putting everything back together. I had to disconnect many electrical connections when changing the plugs, but I don't think I did. I checked and re-checked before I finished.
Might have to call Lexus on this one.
My hunch is also something in the electrical department, but that is what I am thinking about.
Also, let me know how those Bosch plugs were out for you. I love my Torquemaster plugs and they work exceptionally well with my modifications.
10-16-06, 10:08 AM
#14
Intermediate
Thread Starter
Salim,
You have educated me on this topic. I think what happened is this. The rear camshaft sprocked did spin during replacement. But I brought it back to the timing mark not realizing that there is more than one TDC. Manuals refer to TDC on compression stroke of #1 cylinder. So I must be 360 degrees off on the rear half of the engine. So it looks like I have some work to do. I must assume that I need to spin that rear camshaft sprocket 360 back to where it was originally and all will be right with the world.
Thanks for your assistance and invaluable advice.
Lexmex,
Your right about combining repairs. This is the last time I will do that!
Alex
You have educated me on this topic. I think what happened is this. The rear camshaft sprocked did spin during replacement. But I brought it back to the timing mark not realizing that there is more than one TDC. Manuals refer to TDC on compression stroke of #1 cylinder. So I must be 360 degrees off on the rear half of the engine. So it looks like I have some work to do. I must assume that I need to spin that rear camshaft sprocket 360 back to where it was originally and all will be right with the world.
Thanks for your assistance and invaluable advice.
Lexmex,
Your right about combining repairs. This is the last time I will do that!
Alex
10-16-06, 11:58 AM
#15
Moderator
I must warn you that you are getting into trecherous territory.
One way to tell if you are in compresson or exhaust TDC (wtihout opening the valve cover) is to induce compressed air through the spark-plug opening. Getting to TDC of compression of #1 would be easier to tell. To figure out the right position of the pistons in the other bank you will to refer to the manual or infer from timing sequence.
Salim
One way to tell if you are in compresson or exhaust TDC (wtihout opening the valve cover) is to induce compressed air through the spark-plug opening. Getting to TDC of compression of #1 would be easier to tell. To figure out the right position of the pistons in the other bank you will to refer to the manual or infer from timing sequence.
Salim