Made a vid of my "flywheel noise" , is it the flywheel? ---

[alwayscode390]

There is a description in the video area for more info on my car and the issue.

I was thinking this was the dual mass flywheel making noise. Its a timed cam car and I heard they are even noisier than usual.

Its louder near the end of the vid.

I only hear it when the car is warm and at idle.

1990 LPE Topend ZR-1 with 43k miles.

THANKS!!! ---

http://www.youtube.com/watch?v=ja1Kq339uNM&feature=youtu.be

EDIT:

2nd vid. --------------------------------------------------------------------------------

I took a new vid of the flywheel from the passenger side after my trip to the track. I can almost picture the weights bottoming out. :

http://www.youtube.com/watch?v=jaGDqqvrMjY

[XfireZ51]

Are u sure you're not thinking about single mass flywheel?

[rhipsher]

Does it go away when you push your clutch peddle in?

[QB93Z]

Do you have headers and is the Air Pump plumbing still in place?

Jim

[scottfab]

If it goes away when you press the clutch in then it's possibly the pilot bearing at the tip of the input shaft to the ZF6.

[alwayscode390]

As far as I know its the stock clutch and flywheel.

The last owner said he didn't replace anything, and there is no info on the Lingenfelter receipt for a clutch/flywheel swap.

There are Watson headers on there, and a spot on the drivers side welded up. Where should I look to see if the Air Pump is still in place?

I don't think it goes away when I press the clutch in ... I will be driving it again in a few minutes and will check for that.

THANKS :) ---

[batchman]

My Watson headers have fittings on the primary tubes that plumb together and pipe over to the air pump, which I think was in the drivers' headlight area. I took that out a long time ago so I can only dimly recall.

The one time I got what I now think was a flywheel noise it was hella louder than that. You may have an exhaust leak. Could be the air system.

Good luck,
- Jeff

[alwayscode390]

In person I think the noise sounds SO much louder, but when I heard it on the video I was surprised how quiet it was.

I just took a drive, it does NOT go away with the clutch depressed.

It is silky quiet and smooth on cold startup ... sound starts up immediately on a 2nd start/warm start. ---

[Blownrunner]

Do you have original injectors?

[rhipsher]

My next thought is that it either does have a single mass flywheel or a bad lifter. I'm leaning more to a single mass flywheel because they tend to get louder as the car warms up.

[alwayscode390]

A couple owners ago told the owner before me that he changed the injectors. I have a receipt for the FORD yellow/red injectors and was given 15/16 black / silver stock injectors back ... and ONE spare yellow/red. I keep wondering if they reused a stock one and left out a Ford one?

The car stutters before the secondaries open up if I am not on the throttle atleast 1/3 of the way. I guess I could be having injector issues, but Haibeck mentioned in a post he hasn't seen any issues with the Ford replacement injectors.

The car also starts up in different crank time lengths. I thought it was the weather , but its been warm awhile. Sometimes it literally starts up in 1 second, sometimes it takes 3 seconds. It could be a leaky injector?

The car runs great though , put out a solid few runs on the Dyno with zero issues.

If it was an injector, how would that make the rattle sound from the back of the engine?

If it was a single mass flywheel ... is it easily detected with the car in the air?

I am at the point where I would hate to replace the injectors and spend $1k on parts I don't need ... or same with the clutch/flywheel.

I guess if I replace them I know whats in the car, but I don't exactly have $2k to throw at parts at this moment.

I actually planned to take the car down the 1/4 mile on Wed next week ... should I scratch that idea until I figure out whats going on?

Thanks guys , I know its hard to diagnose through the computer but I don't know anyone local with a ZR-1 to compare the car to , especially not a LPE topend car. I also know my car will have quirks that the stock ZR-1s wont have. :)

That vid I posted was mainly a test vid to see if I could even hear the issue , I will try and get a better one to post soon!!! ---

[Kevin]

are you going to the gathering? spend a $1000 there and i'm sure someone will be able to help you

[alwayscode390]

No I cant make it.

That actually reminded me that the previous owner told me he took it to Bowling Green 2 years ago. Drove it all the way there and back for a ZR-1 / Corvette gathering.

People there said the car seemed solid and had no issues. He keeps telling me its the dual mass , and they are louder on cam timed cars because of the lope at idle.

What he says makes sense.

I was just wanting to make sure before I blew something up on the track, so I made the vid to ask you guys for a 2nd opinion. ---

[Schrade]

Sounds too 'light' to be flywheel, although it does sound like something in a 'chamber' of a sort with resonance - perhaps inside bellhousing ... exhaust rattling against something ...

Need a scan, to see if the knock sensor is picking it up. I HAVE seen KS pick up tranny / clutch issues in B-body...

[alwayscode390]

I really need to fix my laptop and run a scan. I bought Datamaster for the car a couple months ago.

I will get on that, now that the weather is nice again.

I took pics of under the car , I didn't notice the exhaust hitting anything ... but its possible.

I heard the dual mass flywheels can get worn out , or broken ... could that be a possibility too?

Car put down 402rwhp with a broken middle resonator rattling away (which has since been fixed with an x-pipe)

The screwed up thing is nobody has even mentioned the sound to me, not even my mechanic ... and the car has been in there for multiple things recently.

Thanks :) ---

[QB93Z]

I have a Lingenfelter 368 cuin 1990 ZR-1. I had a noise similar to what you recorded (but not as loud) that made me think it might be a bad lifter or valve.

I had Marc Haibeck listen to the car a BG and he diagnosed (correctly) that the noise was from a torn rubber fitting and a bad check valve in the Air System. I fixed the problem my self.

The Air System is a pump the injects air in to each exhaust runner during the first few minutes of engine operation. It is an emissions related system that helps the Cats get up to temperature quickly.

The system has pipes, Tees, fittings, and check valves that run from the area forward of the left front wheel and runs to the left side exhaust piping, and crosses under the engine to the right side exhaust piping. The fittings and check valves, if they were not removed, should be visible just below the cam cover (easier to see on the left side).

On my engine, there was a rubber tee on the right side that was twisted and split. This allowed the Air check valve to click shut on each exhaust cycle for that cylinder.

Some cars with headers still have the Air system attached to small pipes welded to each runner of the header. (Mine did after Lingenfelter worked on it.)

On a separate issue, I have heard many ZR-1's that have flywheel noise that goes away when the injectors are replaced. It is a common occurance. I am not saying that this is definetly your problem, but it might be worth investigating. There is a procedure to measure the coil resistance of each injector, which may help diagnose an abnormal or failing injector.

You mentioned that you car starts in one second sometimes and 2-3 seconds other times. I consider this normal. The ignition system needs to detect the crack position signal before it will start firing plugs. Start time, therefore, depends on how far the engine has to rotate before the crank position slot passes the detector.

Good luck.

Jim

[alwayscode390]

Looks like I have a little investigating to do under the hood.

Sounds like the Air System may be the culprit.

Would it throw a code for the Air System or not necessarily?

I don't have cats installed currently, LPE took them out when they installed the Borla Exhaust ... maybe they tuned out the emissions stuff then?

Next I will try to see if my mechanic can tell what flywheel is installed, and ohm out the injectors.

Thanks! ---

[WVZR-1]

If you're going to have it checked by your mechanic I would think that if it was "airborne" and running a stethoscope would pinpoint the source/location of the noise. An inexpensive automotive stethoscope is sometimes a very valuable diagnostic tool.

[QB93Z]

The Air System does not throw a code if it is removed.

There is no tuning aspect to the Air System that I know of. Nothing has to be done to the ECM or the tune when the system is removed.

If the Air system is installed, you will have to cap (plug) the connection tubes to the headers to remove the system.

There is an excellent write-up on Marc Haibeck's website about measuring injector coil resistance. CAUTION: the procedure requires disconnecting the plugs to the ECM and probing the connector terminals. I would make sure that the mechanic doing this understands all of the precautions for working on electronic equipment.

Jim

[RyanChappel]

flywheel trying to compensate for bad injectors....Marc replaced the injectors with Accel units and the noise went bye-bye..

[alwayscode390]

Thanks guys for the heads up.

I will replace the injectors with the Accel units also ... they are good with the new gas , and shouldn't go bad again ... right? Does anyone have the part numbers I need off hand? Is Jegs the best deal on them?

Why does the injectors cause anything with the flywheel ... sorry Im being ignorant here. Could someone explain what exactly is happening?

Should anything else be replaced while the plenum is off for the injectors ( starter? ignition stuff? ).

Would I be safe running down the 1/4 mile a couple times the way the car sits right now, or should I wait until I get all this situated? ---

[RyanChappel]

As the efficiency of the injectors begins to decrease, the 'timing' becomes erratic, and the dual-mass system tries to compensate for this....hence the 'clacking' noise

But I'm sure there is a much more accurate technical description of what is happening...I was scared sh*!less that I had damaged the engine and I put it on a truck and sent it up to Marc. I gave him carte blanche to completely review and repair every flaw he found.

I have twice the car now, thanks to Marc.

[alwayscode390]

Thanks for that Ryan ... it made it a lot more clear to me :) ---

[alwayscode390]

I just talked to the previous owner who installed the headers. The Air System has been totally uninstalled.

Its looking like I either have a single mass flywheel ... or I am having issues with my Ford injectors.

Would a vacuum leak cause any noise?

If I run at the track Wed. , and it is the injectors ... whats the worst that can happen? It will stutter and I get out of it, or can I possibly cause a lean condition? The Dyno showed solid A/F ratios throughout the 7k rpm pull.

THANKS ! :) ---

[XfireZ51]

Typically, a SMFW will stop knocking once the clutch is depressed. You're saying that doesn't happen. So....

[Pete]

Check for loose exhaust screws.

Pete

[alwayscode390]

I will test my injectors and the exhaust screws first.

I was told by a respected member through PM that I should have no problem going to the track ... it would actually be a great place to test everything out.

If I am having a miss the car wont pull the numbers its supposed to ... if its running strong , I shouldn't worry about anything major happening ; but there are things I can do to quiet down the flywheel. He also said it could very possibly be the way my flywheel reacts to the cams at low idle.

I appreciate everyones advice and troubleshooting for me. I feel like I have a direction to follow , and I am not in the dark anymore :) ---

[alwayscode390]

I was also told by someone I spoke with at LPE that most Dual Mass Flywheel noises are caused by a mis-fire.

Should I just plan on swapping out the plugs and wires? Besides those , what else causes a misfire ... the injectors or coils?

Would I have a code?

The car idles STRONG and smooth when you look at the tach. I don't hear a miss

Here is the dyno vid and graph. This is with a rattling broken center resonator , it now has an x-pipe in the same spot. The A/F seems solid, the graph seems smooth ... and the car drives GREAT as long as you are over 30% throttle when the secondaries kick in (then all other times its great). Its also putting out the power I would expect it to, its the 465hp LPE package with Watson headers. 43k on bottom end, 20k on top end ---

http://i50.tinypic.com/1tmule.jpg

DYNO:



http://www.youtube.com/watch?v=bMdFUoaL6R4

IDLE Vid :



http://www.youtube.com/watch?v=6ESq4xpNY88

[alwayscode390]

Im thinking more than likely I will find injector issues.

How many hours should I expect a shop to charge for the injector swap?

Is this something I should take to a Chevy Dealership , or use my normal performance shop ... so they can get more acquainted with the LT5? I am pretty sure they had never seen one before I drove mine in.

I don't have anywhere to do it , or it would be neat to pull the plenum and learn more myself. I will find the time and place someday.

What tool do I need to buy to check the injectors using Haibecks method?

THANKS! ---

[alwayscode390]

I took a new vid of the flywheel from the passenger side after my trip to the track. I can almost picture the weights bottoming out. :

http://www.youtube.com/watch?v=jaGDqqvrMjY


Track Vid / Time Slips thread :

http://www.zr1.net/forum/showthread.php?p=172940#post172940

[batchman]

New video link didn't work for me. To re-iterate, start with the easiest and most likely stuff first:

You may have an exhaust leak.

Check for loose exhaust screws.

We will all find injector issues at some point but your first video was not the sound of a dual-mass getting hammered by a misfire.

Is this something I should take to a Chevy Dealership

I think it's pretty safe to say you should *NEVER* take a C4 ZR-1 to a dealer under almost any circumstances. The only time I would even consider it was if a friend or fellow enthusiast who knew these cars happened to work at one.

It can be a very trying moment to find yourself with an unhappy sound coming from something nearing exotic. Try not to over-google the problem - you will convince yourself the world is ending. What you really need is a relationship with a corner garage whose work in process includes unusual stuff and whose chief mechanic is a non-megabuck racer of some sort. Maybe that's your "performance garage" or maybe it's not - a lot of those shops are intent only on lightening your personal carry gear (wallet) in my experience.

Best of luck,
- Jeff

[alwayscode390]

Thanks Jeff ... sorry about the dead link , I just updated the first post with a link that works.

If you have time, please listen to it for me.

It doesn't seem like a typical exhaust leak sound to me where you can usually hear an "echo". It sounds metallic to me ... but I will double check the bolts on the headers/exhaust.

I appreciate the advice ! :) ---

[WVZR-1]

A "lift and a stethoscope" revealed "nothing"? I find that hard to understand. I can't imagine there being an easier method to "locate" the racket. I didn't say diagnose correctly but at least "locate" the source. Once the actual source was revealed I would think suggestions of what is causing it could be maybe more than a "WAG"!

[alwayscode390]

OK, point taken.

I haven't had a chance to get the car on a lift yet.

Once the happens, I am on the hook for a bill from the shop. I was just trying to get a direction to point them in , which I guess has already been done.

Thanks! ---

[WVZR-1]

OK, point taken.

I haven't had a chance to get the car on a lift yet.

Once the happens, I am on the hook for a bill from the shop. I was just trying to get a direction to point them in , which I guess has already been done.

Thanks! ---

If you "steer" a shop or "point" you're "on the hook" - if it's on a lift and the stethoscope is used to locate then it becomes a "discussion"! That discussion would be between you and a technician I'm assuming you've got confidence in!

The lift actually wouldn't likely be a requirement - you should be able to likely confirm for yourself the source and the diagnostics also with the car on "all-four" and you on the ground also. You just can't imagine the diagnostics that can be accomplished with a "stethoscope"!

[alwayscode390]

I just noticed the other day that if I move the stick shift left to right a few times in neutral I can hear the clunking in the same area that the other sound was coming from... and it usually sooths the other sound down so its not so bad.

Wondering if I probably have some crap fluid in the transmission that may be too thin and not quieting down the gears?

Just throwing this out there.

I still haven't had the car on a lift ... but it seems like the more miles I put on it , the better the "flywheel noise" has been getting. ---

[BigJohn]

when was the last time you changed your trany oil?

[XfireZ51]

I was also told by someone I spoke with at LPE that most Dual Mass Flywheel noises are caused by a mis-fire.

Should I just plan on swapping out the plugs and wires? Besides those , what else causes a misfire ... the injectors or coils?

Would I have a code?

The car idles STRONG and smooth when you look at the tach. I don't hear a miss

Here is the dyno vid and graph. This is with a rattling broken center resonator , it now has an x-pipe in the same spot. The A/F seems solid, the graph seems smooth ... and the car drives GREAT as long as you are over 30% throttle when the secondaries kick in (then all other times its great). Its also putting out the power I would expect it to, its the 465hp LPE package with Watson headers. 43k on bottom end, 20k on top end ---

http://i50.tinypic.com/1tmule.jpg

DYNO:



http://www.youtube.com/watch?v=bMdFUoaL6R4

IDLE Vid :



http://www.youtube.com/watch?v=6ESq4xpNY88

Based on these numbers, I would bet u have a SMFW. AFR is a bit lean at 13.3. Take it to the dyno again and check AFR if you swap injectors.

[alwayscode390]

The tranny oil hasn't been swapped since I bought the car in late December. He told me it all had fresh fluid, but its definitely on the "to do" list. I will use that Castrol that's recommended.

I have only put 1500 miles on the car since then though.

I will do that XFire, thanks guys ---

[SteelBlueZR1]

Definately change the trans fluid to the BMW dealer sourced Castrol product... When I bought my Z I changed tranny fluid to Dexron GM fluid and had gear rattle at idle and whining at revs. Then I got the Castrol fluid for my tranny and could not believe the huge difference it are over GM Synchromesh! Gear rattle and whine gone and shift quality was much better.

[alwayscode390]

Thanks for the confirmation. I will definitely swap that out sooner than later :) ---