I've got an engine misfire that is most likely a bent pushrod.

Check engine light occured after a missed 3-4 shift that was actually a 3-2 shift, after I stopped and the engine was idling for a minute or so.

before I go removing them, is there a certain cylinder to check 1st or is it pretty much a random situation.

Car idles a little rough, about 200 rpms less than normal.

Also, how do you know when the #1 is at TDC? The service manual just explains to line up the marks on the crank & cam sprockets.


[Modified by Gary2KC5, 6:50 PM 5/16/2002]

 

On my 2000, I bent the #5 intake (sorta an S shape) on a missed 2 to 3 shift that went 2 back to 1. No check engine lights, just a ticking sound. Wasnt hard at all to pull all the pushrods and check them. Plus the rocker arms all torque down to spec without the need to lash them like pre GEN III motors. I have seen some more than others bend, but all are susceptible. If you bent one bad enough to get a misfire, and MIL light, then you could have possible slapped a piston. I would defintaly do a compression check on all cylinders and a leak down test also. Worst case you could run a scope down into the cylinder that had bent pushrods and see if the valves stamped some eyelashes into them. If so, then I would look into verifying if the valves are bent.




[Modified by kewlbrz, 8:39 PM 5/16/2002]

 

One more thing to spook the **** out of me going to a c5. Seems every other day, someone has clutch trouble, gas gauge trouble...now this? JESUS!

 

Mishifting isnt good for any engine.... ;)

Remember this is a forum that see's every little problem. The vast majority of C5's are fine.

Motortrend gave the C5 the best engineered car of the 20th century, and JD edwards #1 quality awards year and year to boot. :cheers:




[Modified by kewlbrz, 9:13 PM 5/16/2002]

 

JD,

I've been a little ticked about some of the issues with C5's but I've got to admit from what I dish out it takes it pretty good.

I'm still ticked about the restrictor in the clutch m/c line and the few other engineering issues but for the most part C5's are street sports cars that are nearly race cars.

If I ran my GF's C4 on the track as hard as I run my C5 the body would literally crack apart, Jeez the freak'n roof is part of the chasiss structure.

Also remember that this is not a C5 defect but driver error...I shifted at 105 mph from 3rd to 2nd.

Kewlbrz,

My engine still runs strong and after zinging the rpm's the thinking in the paddock was that it could be a fouled plug ( :bs ) so I did another session. the misfire only occurs at under 1500 rpm.

The car ran strong through the session and still only at low rpm's does it misfire...when I clear the codes and drive it, it will only have the check engine light on after it comes to an idle.

from what I've gathered it does sound like an intake pushrod is bent.

I change oil before and after each track event, the mag plug or the oil didn't look unusual.

Do you think I could have really bent a valve?

And if I did, would that mean it's time to get the H/C done?

BTW: awesome new ride!! :yesnod:



[Modified by Gary2KC5, 11:23 PM 5/16/2002]

 

Thanks for the new ride comment :)

Regarding the valves. Hard to say. Take it one step at a time before worring to much. Pop the valve covers off and the rockers and pull all the pushrods and roll them on a smooth surface. Depending how mangled one or more are, i would then go from there. If you bent a whole bunch like 3 or more or so, then it could be piston slap rather than simply floating the valves. Did your rear tires lock up hard and/or did you clutch out of it quick? By the way, mine was just fine, compression check and everything. Even if you tapped a piston, is can still be ok as long as you didnt bend a valve. I kinda think you didnt bend a valve.


[Modified by kewlbrz, 11:21 PM 5/16/2002]


[Modified by kewlbrz, 11:22 PM 5/16/2002]

 

It really depends on how you drive ... plus you have to think that the forum C5 owners are only a small percentage ... and you may just hear about it alot but it isnt really that common ..

 

Before the track event I finally changed the trans fluid to Red Line synthetic. since then I have done the 3-2 shift 4 times.

Once on the hiway and i clutched in real quick. the othe 3 times were at my last track event. the next 2 times i clutched in quick also, but the last time the fuel cut-off engaged...not so quick on the clutch this time.

The car sputtered some and then cleared it's throat and seemed o.k. it wasn't until after the session that it threw the code.

The tires never locked up, it never got that far.

you mentioned that "the rocker arms all torque down to spec without the need to lash them" the service manual want's you to get the engine to TDC before tightening the rockers and then in a specified sequence.

I don't know how to get the engine to TDC (sm only shows to align the crack & cam cogs)

Can I remove the rockers and then just torque them down or do i need to follow the re-assemble instructions in the manual. If so how do you determnine TDC without the crank/cam sprockets exposed?

 

I did the same thing on my '98 and on my 2000. Both times I told the service manager exactly what I did and they fixed it under warranty. Both times I was going around a slight bend in the road. So far so good on my '02. Good luck...Don't feel bad, A lot of people have done this. :cheers: :seeya

 

Might not be a bad idea to have a dealer take a look.

 

I made a similar shifting mistake on saturday. Lucky for me that it still sounds and runs fine. No codes, has good power.

I'm glad I dont have a stock valvetrain. I estimate I reved it to 7500-7800.

Eric

 

gary, regarding the rockers. You dont have to do the TDC thing. I, and many others, just torque all to about half of the torque spec, then (with the coil pack harnesses disconnected, I cranked the engine over a few revolutions and went back over them to full torque spec. I then cranked the engine a little more and rechecked them to make sure.

Since they all tighten to a specific torque spec its much easier than the old days.

 

wow, great idea kewlbrz!!. since you can't get a socket on the UD pulley I was thinking i might have to pull all the plugs and pull the belt to get it turned over. I didn't think to use the starter.

kewlbrz, thanks a lot for your help & input! I'm all over this now. I will let you know how the pushrod check goes and what i find bent.

 

To get to TDC, pull the #1 plug, cover the hole with your thumb, tap the starter until compression blows air past your thumb, and then bring the timing mark to 0 degrees.

 

I've missed a shift here or there before getting my shifter fixed.
As long as you are FAST, Johnny on the Spot with pushing the clutch back in, you won't hurt the engine.

I never bent a pushrod or a valve. On my missed shifts, it mighta hit 7200rpm before the clutch pedal was full pressed back in. Probably missed 3 or 4 times with the bad shifter.

 

kewlbrz,

If the left bank is the drivers side and the cylinder order is from front to back is: 1,3,5,7, I bent the same pushrod you did: the #5 intake.

thanks for your help and the tip on torquing down the rockers.

 

willi,
where are the timing marks? I know there are aome on the crank/cam sprokets but without the engine apart you can't see those.

 

MellowYellow,
I agree about the stock shifter, it really should have a stiffer spring like the aftermarket ones do.

This would not have happened if it did.

 

 

Thats interesting that it was the same one. How bad did it look? Did that get you all fixed up?