civicinin

1) I just replaced the camshaft on my 2001 Civic LX, and I am now getting misfires for cylinders 1-3. I suspect I didn't get the timing right when I put the timing belt back on.

2) I also tried to do an idle relearn, but the car simply will not idle--the tachometer reading just drops until the car turns off. I also have to press on the accelerator just to get the car to start.

Is it likely that these two problems are related? If it is the timing that is off, how should I go about getting it right? I put the camshaft at TDC, the crank at TDC, put the timing belt on, hooked the tensioner spring on, THEN checked the camshaft and the crankshaft to check for TDC, and they were both on. Is there some secret I should be aware of? Is it possible the tensioner's spring has lost too much of its tension? When I replaced the camshaft, I replaced the camshaft oil seal right behind the timing belt, and I didn't lubricate the inner part--could that be causing too much friction?

Maugutus

Did you properly adjust the valve lash in a 1-3-4-2 counter clockwise direction setting the intake to .006" and the exaust to .008" . Is it cylinders 1 AND 3 or 1 through 3? Timing issues will make all cylinders misfire, they are all out of timing or they aren't. The auto-tensioner being bad will cause it to jump at higher RPMs and completely ruin your engine. The seal wont cause enough friction to do any of that, but that first dry start will have reduced the seals life considerably.

If you replaced the camshaft you should have replaced the water pump, idler, cam seal, front main seal( crank) and the belt. Then made sure the rocker arms hadn't binded to the camshaft (too much toque on the holder bolts after replacing the camshaft), then done a valve lash adjustment.

Did you check the codes? What are they, besides the misfires? Is the ecu good? Did you check the cam position sensor, and the crank position sensor. Maybe you left one loose, or unplugged. (From experience that is a good possibility. Did you ruin the sensors with a magnetic tool?

civicinin

Is the idler the same as the IACV?


Do you mean the spring or the tensioner itself?


What do you mean by adjusting the valve lash in the 1-3-4-2 order? I know that 's the order the cylinders fire in, but why do I have to adjust them in that order? I did adjust the valve lash not too long ago, but not since I replaced the camshaft. It's cylinders 1 through 3 (I don't know why cylinder 4 didn't --because it has a new spark plug?). I can check the torque on the rocker arm assembly and the rocker arms themselves, to make sure they're not stuck.


The only codes are the misfires: P0301, P0302, P0303, and I think three pending misfire codes (P0301, P0302, P0303 also I think).

As far as I know, all of the sensors are good, but I don't know--how can I check them? I did use a magnetic screwdriver to tighten the link between the throttle body and the air filter chamber thing, but I don't think I probably got it close enough to do any damage to either of those sensors. They are both plugged in too.

Maugutus

The idler is the timing belt idler, the spring would take a great deal of age to wear down. And I meant more like the spring and the idler (auto-tensioner.) It shouldn't impact the timing unless you rev very high and it is old, and worn out (200k plus miles). It would cause the belt to loosen jump a tooth or two, shred and most likely bend some valves.

Misfiring has nothing to do with the idle air control valve (iacv) That will just cause very erratic (high then low then repeat) idle. Check the torque on the rocker arms, and replace the spark plugs (if you say 4 has a new one and didnt misfire that may be the cause.

To adjust a valve you must set the respective cylinder at TDCC (top dead center compression.) You have to start at cylinder 1, set the cam gear with the timing mark straight up ^ Then adjust the exhaust valves to .008" and then the intake valves to .006" on cyl #1 Real snug on the feeler gauge.

Then rotate the camgear 90 degrees Counter clockwise and that will place cylinder 3 at TDCC, adjust the exhaust then intake valves for cyl #3

Rotate the camgear 90 degrees again Counter clockwise and that will place cylinder 4 at TDCC, adjust the valves for that cylinder.

Rotate the camgear 90 degrees again Counter clockwise and that will place cylinder 2 at TDCC, adjust the valves for that cylinder.

Basically you have to adjust them in that order because that's the order of the ignition timing. They fire in that order.

The screwdriver probably didn't touch anything. Didn't you remove the crank sensor to replace the camshaft? By association of having to remove the timing belt to remove the cam/camshaft. If so check to see if it's tight, I left mine loose and it caused crappy idle and horrible misfires. The cam and crank sensors will both cause these misfires if they are loose and cause horrible idle. I know it may be silly but double check the plugs (remove and re plug in) and check to make sure they don't move. (Especially the crank position sensor.)

You can only check the voltage of the sensors. I ended up replacing both the cam and crank sensors.

And remember if you serviced the valvetrain in any way you have to adjust the valve lash properly or it will also cause misfires. That's because the valves are staying open way too long or never closing at all.

Also to make the timing belt go on correctly you have to set the cam (perfectly) with the UP arrow facing straight up and the 270deg (left) and 90deg (right) mark flush with the cylinder head. Then set the crank to slightly before TDCC and when you put the belt back on you start at 6 oclock on the crank gear putting a few notches on going towards 9oclock and then pull slightly (it will rotate just a bit and land on TDCC) while putting it on the cam gear at 9 oclock then over it. You don't want the cam to move from it's perfectly TDCC position, but you can move the crank slightly like I said to put it on correctly.

civicinin

Oh yeah, I forgot that I moved each cylinder to TDC when I did the valve lash.


Is the camshaft considered part of the valvetrain?


I will take your instructions into account when I try to get the timing right again.

Maugutus

WikiQuote "A valve train or valvetrain is a device that controls the operation of the valves., in which a sequence of components transmits motion throughout the assembly. "

The camshaft would be the main component of the valvetrain.

Send me a message if need be. I'll try to help any way I can. Good luck!

civicinin

Thanks so much. I may take you up on your offer at some point.

civicinin

Ok, here's what I have learned. When the alternator and power steering belts are taken off (I have no a/c compressor), the car will idle. However, when I put the alt. and PS belts back on, the car does what I described in post 1: the car simply will not idle--the tachometer reading just drops until the car turns off. I also have to press on the accelerator just to get the car to start.

Any thoughts? A friend thinks it is probably the ignition timing that needs to be adjusted.

civicinin

Latest issue is that once I put timing belt on and the alternator and PS belts on, the car will start fairly normally, idling around 1000 rpm, but when I start to drive, it does the same thing as it did before: it won't idle, and it won't let me do an idle relearn; the tachometer reading just drops until the car dies.

Thoughts? Maugutus?


scratch that. I learned what all of you probably already knew, that the ignition timing can't be adjusted, that it is regulated by the sensors.

Maugutus

Can you still keep it on by revving it? Is the fuel bad? Did the check engine light come on? Connect a scan tool anyways and see if there are codes. The only tso times my car ever did that was when 1. The ecu was fried. or 2. The cam position sensor was broken. That is so odd... H'mm.. keep me posted.

civicinin

Yes, I can keep the car on by pushing on the accelerator.

Don't know about the fuel. It's been in there for a few months now.

Regarding the CEL, when I turn the car on and it's idling, the CEL doesn't come on. However, when I start to drive the car (and it loses its ability to idle), the CEL blinks. But when I check the codes, there are no codes.

I finally took the thing to a mechanic on Friday.

civicinin

Never updated this.

Turns out the problem was that the valve lash way off. When this was corrected, the car worked fine.

Aaron_Wayne17

Just a note on this. The cylinder you are adjusting the valves for needs to be set on TDCC (Top Dead Center Compression stroke), not just TDC. If you're not on the compression stroke you're going to be on the exhaust stroke and both the ex and in valves will be open due to valve overlap. Also, your civic should be running a 180 deg. crank so its going to take a minimum of 180 deg. crank rotation to get TDC from stroke to stroke.

civicinin

Thanks. Yeah, someone I talked with about this informed of this a while back.