- Location
- Southern Maryland
need to think about what caused that, did you fill the cylinder with gasoline or something
(resize the pic before you upload it)
(resize the pic before you upload it)
Rough Idle - No stall, No CEL
- Thread starter Ima Doit
- Start date
- Location
- Southern Maryland
Researching a bit, it seems the most common cause of a severe bend is lifter sticks and allows the rod to jump out, it gets pinched in the lifter shell and boom
Did you spray any carb cleaner through the pushrods and/or in the lifters?
Did you spray any carb cleaner through the pushrods and/or in the lifters?
blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
I'm with ehall on this. Figure out why that rod bent, or it'll bend again and you won't be so ludicrously lucky next time 
.
Also, I'd suggest starting by pulling the head and checking out the rocker and valve that went with that pushrod. Something very bad happened and its probably still happening. A valve stuck hard for a reason. At the very least, you can take the inspection as an opportunity to replace valve stem seals, as you know one is almost certainly bad now, and that will definitely cause the rough idle. Also, the associated valve may very well be damaged.
The lifter is probably ly the best answer though. Good call ehall.
*edit* wait a minute... A lifter can only get stuck in the UP position, so I can't think of how a stuck lifter could cause this. A stuck valve absolutely could, as the valve sticks open, so the rod is in the up position but the lifter drops, then the rod falls out of the lifter and binds up on the lifter edge, and next rotation "BOOM". I say it's a very sticky valve, so I still say inspect valves, springs, rockers, and replace the valve stem seals since you're already in there.
Incidentally, you can replace the valve stem seals without removing the head, but I still think your head should come off for a thorough inspection of the valves.
. Also, I'd suggest starting by pulling the head and checking out the rocker and valve that went with that pushrod. Something very bad happened and its probably still happening. A valve stuck hard for a reason. At the very least, you can take the inspection as an opportunity to replace valve stem seals, as you know one is almost certainly bad now, and that will definitely cause the rough idle. Also, the associated valve may very well be damaged.
The lifter is probably ly the best answer though. Good call ehall.
*edit* wait a minute... A lifter can only get stuck in the UP position, so I can't think of how a stuck lifter could cause this. A stuck valve absolutely could, as the valve sticks open, so the rod is in the up position but the lifter drops, then the rod falls out of the lifter and binds up on the lifter edge, and next rotation "BOOM". I say it's a very sticky valve, so I still say inspect valves, springs, rockers, and replace the valve stem seals since you're already in there.
Incidentally, you can replace the valve stem seals without removing the head, but I still think your head should come off for a thorough inspection of the valves.
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Ugh. You're probably right. I went ahead and removed all of the pushrods and cleaned them up. I had another set from a previous motor. I rolled them all on glass and installed the straightest 12 I had. They are all pretty good. Half were slightly out.
Still has a hard start though. This would make more sense to me if the pushrod bent was on the same cylinder as the low compression. But it wasn't. Is there another way to check integrity of the valves without pulling the head? I don't mind doing it, but, don't really want to do it for fun.
It's back to sounding good and running clean without any knocks or ticks. If it's a sticking valve, it's unstuck for the moment. It feels like I'm missing something easy. Although a valve issue or a problem with the head would explain all this.
I think I'm going to have to re-start the troubleshooting. I tend to bounce around too much and can't remember what I did.
Something else I noticed....check out the first rocker from the grille in either video. Notice the air bubbles in the oil. What do you think is up with that? Related?
Still has a hard start though. This would make more sense to me if the pushrod bent was on the same cylinder as the low compression. But it wasn't. Is there another way to check integrity of the valves without pulling the head? I don't mind doing it, but, don't really want to do it for fun.
It's back to sounding good and running clean without any knocks or ticks. If it's a sticking valve, it's unstuck for the moment. It feels like I'm missing something easy. Although a valve issue or a problem with the head would explain all this.
I think I'm going to have to re-start the troubleshooting. I tend to bounce around too much and can't remember what I did.
Something else I noticed....check out the first rocker from the grille in either video. Notice the air bubbles in the oil. What do you think is up with that? Related?
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blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
Which video?
- Location
- Southern Maryland
blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
Hrm... No idea on the bubbles. Was that second rocker loose like that when you pulled the cover?
blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
Sounds pretty good now. I'd drive it for a few days with some sea foam to clean stuff up, and if its still rough, then start looking at the valves. How's your oil consumption anyway?
Yes. It was loose. The worst one had the bent pushrod. The one right next to it was loose. Also the last one towards the back. I replaced half of the pushrods and they are all tight and running well. I can't run the sea foam just yet though. It's not really drive able. Having some brake, suspension, and drivetrain issues as well. Oh yea, and tires. Ha.
And I don't know about the oil consumption. I've put about 3 miles on it in a year.
And I don't know about the oil consumption. I've put about 3 miles on it in a year.
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blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
Making progress though!
blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
I've never even heard of rockers backing off. Has to be someone didn't torque them down properly at some point.
Has to be someone didn't torque them down properly at some point.I just assumed the pushrod had a slight bow not allowing the rocker to stay tight. All of them were on there good. I don't have a torque wrench. I went went to "good and tight" then went a little more.
how about to timing? Should I pull the distributer and reset it? Is it possible to produce a hard start and a slight misfire or rough idle? Keep in mind I have no CEL. This definitely could have been goofed during install of the new motor.
I'm going to re-start troubleshooting tomorrow. ugh. I guess start with spark.
Then vacuum. It has been mentioned to pick up a vacuum gauge to test with. Is this a manual pump thing with a gauge? Similar to a coolant pressure tester? Or is it a gauge alone just plugged in line somewhere? Also, I know nothing of how to perform a vacuum test.
Kinda makes me wish that new mechanics stethoscope was already delivered. I'm excited to play with it.
how about to timing? Should I pull the distributer and reset it? Is it possible to produce a hard start and a slight misfire or rough idle? Keep in mind I have no CEL. This definitely could have been goofed during install of the new motor.
I'm going to re-start troubleshooting tomorrow. ugh. I guess start with spark.
Then vacuum. It has been mentioned to pick up a vacuum gauge to test with. Is this a manual pump thing with a gauge? Similar to a coolant pressure tester? Or is it a gauge alone just plugged in line somewhere? Also, I know nothing of how to perform a vacuum test.
Kinda makes me wish that new mechanics stethoscope was already delivered. I'm excited to play with it.
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blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
Could be. If that's the case though, you've had a few valves her bound up somehow.
I don't know if this helps, but, it seems like this thing is running very rich as well. I can't tell what the mpg is like as I can't drive it. But, I'm guessing the mpg is in the toilet. Also, seems like a power loss. From stopped to flooring it feels like it's weak. I've had a few 4.0l in the past and they all seem pretty stout. This has 31s, but, it should be better than it is. I think at least.
- Location
- Southern Maryland
Could have leaking injector. lay the rail on a piece of cardboard and prime the pump a couple of times
Could also have a faulty sensor. Try disconnecting the MAP and coolant sensors after engine warms up and see if it changes anything. Could be O2 sensor as well. I always replace all of the engine electronics with new parts when swapping engine. Standard brand sensors and switches from rockauto have always worked well for me.
Could also have a faulty sensor. Try disconnecting the MAP and coolant sensors after engine warms up and see if it changes anything. Could be O2 sensor as well. I always replace all of the engine electronics with new parts when swapping engine. Standard brand sensors and switches from rockauto have always worked well for me.
I've checked for leaking injectors. All good. Did not replace o-rings though. They looked fine. One broke and I replaced that one with another used one from another set. I'll mess with the sensors next.
May have made a little progress. I went to re-set the timing and put the #1 cylinder to TDC. Then I pulled the distributer. Looked different then what I expected for an xj. See below pics for right vs. wrong. I swapped it out with another I had lying around.
Re-aligned the oil pump to 11 o'clock and put a nail punch in the distributer to line up the holes. Dropped it the distributer in with the bracket in the 1 o'clock position and it dropped into place almost perfectly. Had to remove the punch to move distributer slightly to align with the while. Very slight amount. Maybe 1/8". I chalked it up to oil pump wasn't exactly at 11 o'clock.
Anyways, reinstalled everything and she fired right up. Typically after sitting all night it's terrible. Seems to running more smooth as well. However, it still has a super slight idle stumble. You can feel it in the cab as well. Also, major loss of power. From a dead stop I punched it. Waaaay under powered. Something else still isn't right.
Again, no codes. Cat problem? Where next?
May have made a little progress. I went to re-set the timing and put the #1 cylinder to TDC. Then I pulled the distributer. Looked different then what I expected for an xj. See below pics for right vs. wrong. I swapped it out with another I had lying around.
Re-aligned the oil pump to 11 o'clock and put a nail punch in the distributer to line up the holes. Dropped it the distributer in with the bracket in the 1 o'clock position and it dropped into place almost perfectly. Had to remove the punch to move distributer slightly to align with the while. Very slight amount. Maybe 1/8". I chalked it up to oil pump wasn't exactly at 11 o'clock.
Anyways, reinstalled everything and she fired right up. Typically after sitting all night it's terrible. Seems to running more smooth as well. However, it still has a super slight idle stumble. You can feel it in the cab as well. Also, major loss of power. From a dead stop I punched it. Waaaay under powered. Something else still isn't right.
Again, no codes. Cat problem? Where next?
- Location
- Southern Maryland
fuel pressure check okay?