Jump to content
Sign in to follow this  
TexasPilot71

Engine noise - “popping” or “missing”

Recommended Posts

4 hours ago, Hatem said:

Are you sure? looking at your pic here and others of he 5.0 MPI, it looks like the wires to the distributer go right over the fuel rail, and you need to pull the fuel rail with the injectors on it out about 4" or so before you clear the intake to slide it out all the way.  Not a big deal anyway if you had to, just be sure to mark the wires! lol

 

We did it yesterday. Did not have to disconnect. Wasn’t in the way.

Share this post


Link to post
Share on other sites
17 hours ago, cyclops2 said:

Walk away for enough time to regroup your self.

I wish you some good luck with this.

Thanks. Ordered a new throttlenposition sensor, crank position sensor, and new regulator for the fuel rail. If these don’t do it, we will have a computer put on it to get live telemetry when it’s popping. Otherwise we’re thinking something mechanical. Ugg. My next post may just be photos of the boat being lit on fire. So done with this. I feel defeated. 

Share this post


Link to post
Share on other sites

And again, it’s only happening when reducing power through the 3900 to 3200 rpm band. Otherwise it purrs like a kitten. Good power, acceleration, everything. Just in that band when reducing power. 

Share this post


Link to post
Share on other sites

We have to narroe it down to electrical or mechanical.  Somehow.

Electrical should be quicker................Check timing since it is across the full rpms.  I would  play retard  a little.  Then advance a little. I am SPECIFYING ALITTLE . With a timing light by someone who knows how to keep track of how much the timing is being changed.  Keep the rpms under 3500 rpms when playing with the drive tests...........Do not change more than 3 degrees + or - . on each test run. That should give some change / feeling for better or worse..  Your mechanic said it was at all speeds way back. 

Does your engine have a adjustable cam timing ?  If yes that might be stuck in fully retarded.  Any way ignition  timing is changed ?

forgot.  Is the miss steady or erratic ? Very important.

You say the power is good?   

Do not buy more parts.

Need to I D the failed part

The good power is weird.  Should only be 1 cylinder.............Reason I would do a .............Short out 1 cylinder at a time test & find the 1 or more bad cylinders.  Missing stops that is a big help. CHECK ALL CYLINDERS !!!!!!!!!!!!! DO NOT stop on the first cylinder changing the backfiring.

 

Share this post


Link to post
Share on other sites
7 hours ago, TexasPilot71 said:

Thanks. Ordered a new throttlenposition sensor, crank position sensor, and new regulator for the fuel rail. If these don’t do it, we will have a computer put on it to get live telemetry when it’s popping.

Shouldn't your VesselView7 isolate the sensors if there's an issue with any of them?  

7 hours ago, TexasPilot71 said:

Ugg. My next post may just be photos of the boat being lit on fire. So done with this. I feel defeated. 

Upside is you didn't have to pay for all those parts.  Did your mechanic try tweaking the rotor?

 

Share this post


Link to post
Share on other sites
On 3/3/2019 at 4:53 PM, cyclops2 said:

Electrical should be quicker................Check timing since it is across the full rpms.  I would  play retard  a little.  Then advance a little. I am SPECIFYING ALITTLE . With a timing light by someone who knows how to keep track of how much the timing is being changed.  Keep the rpms under 3500 rpms when playing with the drive tests...........Do not change more than 3 degrees + or - . on each test run.

I just picked up my truck after an oil change and I showed my mechanic the video and he said the same thing, Clops.  I told him all the work TP had done and he said it's probably 1 of 2 things.  First try exactly what you said by turning the rotor maximum 1/8th of an inch in either direction and see if it goes away.

The other thing he said is it could be what he called "valve float" which is basically a valve spring is tired and isn't springing back fast enough, leaving the valve open a little longer and you're getting more fuel in the cylinder(s) causing the popping.  He said that's more likely because it's happening right at throttling down.  Makes sense.

If anything it gave us something interesting and fun to talk about while I was waiting for the oil change.

Share this post


Link to post
Share on other sites
55 minutes ago, Hatem said:

I just picked up my truck after an oil change and I showed my mechanic the video and he said the same thing, Clops.  I told him all the work TP had done and he said it's probably 1 of 2 things.  First try exactly what you said by turning the rotor maximum 1/8th of an inch in either direction and see if it goes away.

The other thing he said is it could be what he called "valve float" which is basically a valve spring is tired and isn't springing back fast enough, leaving the valve open a little longer and you're getting more fuel in the cylinder(s) causing the popping.  He said that's more likely because it's happening right at throttling down.  Makes sense.

If anything it gave us something interesting and fun to talk about while I was waiting for the oil change.

Hmmm....interesting.  You say the rotor.  Do you mean the actual distributor?  The rotor is held in place with two screws, so there is no turning it.  I have heard of this problem being the distributor being "a tooth off", but I'm afraid to try that and my mechanic says if that was the problem, we'd be experiencing it at all RPMs.  I'm not convinced either way, though.

The valve float seems to make some sense too.  But now we're talking a top rebuild, right?  Uggggggg

 

Share this post


Link to post
Share on other sites

Can't believe I never found this other Chaparral thread on the same problem, but here's how they fixed it.  What say you all?

"2007 Merc 350 mag I to had popping noise and was driving me nuts, replaced, fuel filter, plugs, cap and rotor, was going to wires and more expensive parts. Found Merc had a hotline you can call. I explained my problem and he walked me thru some things that I had already done. Here was the fix for me, I happened to be on vacation and was on the water. He said drive the boat till you hear the popping and while at that speed loosen the distributer and turn one way or the other and see if it clears the problem. I moved mine just a little and cleared right up and has ran fine since. If that didn't do it he said could be fuel pump. Check to see if Volo has a hotline to call. you will need the motor serial # and year. Good luck"

 

Here's the thread:

 

 

 

Share this post


Link to post
Share on other sites

Put a computer on it. Both issues can be identified and ruled in/out. To check if a valve(s), and a good bit simpler, an ole fashioned compression check cylinder by cylinder. It’s hard to stop guessing when in the middle of it.

Share this post


Link to post
Share on other sites

Jeff

Dont be discouraged.

I had a starting problem with the starboard engine going on for three months.

I bring it in and it would start fine at the shop.

Bring it back to the dock and it won't start.

Finally they changed the rotor and cap started right up.

I go for a ride and and the engine stalls.....its always the one that controls the power steering.

I bring the boat in, and out of process of elimination they want to change the wiring harness.

The only one available is in Europe and has to be shipped here.

I am also off warranty.

On a 310 any work done to the starboard engine may require the back portion of the boat removed.

I am looking at a $4,500 repair.

I call Volvo and explained all the problems I have had with the engine.

No luck, I ask the repair shop to call. VP ends up covering the part and shipping, saved me $1,500.

Boat is running great now......persevere!

 

Share this post


Link to post
Share on other sites
16 minutes ago, jeffk said:

Jeff

Dont be discouraged.

I had a starting problem with the starboard engine going on for three months.

I bring it in and it would start fine at the shop.

Bring it back to the dock and it won't start.

Finally they changed the rotor and cap started right up.

I go for a ride and and the engine stalls.....its always the one that controls the power steering.

I bring the boat in, and out of process of elimination they want to change the wiring harness.

The only one available is in Europe and has to be shipped here.

I am also off warranty.

On a 310 any work done to the starboard engine may require the back portion of the boat removed.

I am looking at a $4,500 repair.

I call Volvo and explained all the problems I have had with the engine.

No luck, I ask the repair shop to call. VP ends up covering the part and shipping, saved me $1,500.

Boat is running great now......persevere!

 

Thanks, Jeff!  We leave Saturday to spend a week in Florida with RRRR and family.  Have a house on the ICW with a dock.  Praying I can get lucky tomorrow, fix this thing, and bring the boat as planned.  Glad your issue is resolved!!  Give my best to your bride!

Share this post


Link to post
Share on other sites

Rent a boat down there.   I have done rentals need to do some phoning now to book.      I LOVED not towing.  :wub:

Share this post


Link to post
Share on other sites

What seems concerning on the "turn the distributor one way or the other to see if it goes away" would indicate it jumped timing, but if you hadn't touched the distributor and this "just all of a sudden happened", then there are other forces at work, not just "turn the dist". Quite a few of things would allow that. 1. The dist / cam gear moved on the dist shaft. 2. The cam jumped timing on the cam chain.  3.The crank or cam position sensor is not right. 4. Throttle position sensor, MAP sensor, MAF sensor, temp sensor, as Jeffk said, harness????    If Cam, crank and dist are all timed correctly, the ECU is getting wrong info from something, since you have eliminated the fuel system.

Maybe something as simple as the position sensor in the dist loosened up and moved a tad (if there is one in there) or the dist shaft has too much play / worn shaft bearings in it. Have seen aftermarket dist caps and rotors cause weird things to happen too, where the OEM was spot on. Just because it's new, doesn't mean it's good.

The computer should be able to show where the timing is in relationship to the crankshaft, but if the cam is out of time (timing chain), then those readings will be skewed. It would also show exactly what is going on with the sensors.

Physical position / timing  can be readily checked, but one needs to put a timing wheel on the crank end and check the cam timing vs: the crank position using a dial indicator on the cam at #1 Cyl TDC. to do it right. As an eye ball, can be checked by turning crank to TDC (#1 compression stroke w/ plugs out) w/ the crank damper TDC mark and dist pointing toward #1 plug plug wire.

Checking the distributor gear is easy, once the distributor is out.

These computerized engines are hard to troubleshoot without a computer / anylizer but are easy with them and help stop swapping parts till it runs right (or Easter Egging to repair).

Hope you figure it out soon. Hang in there and it'll probably turn out to be something simple, but not obvious..

Share this post


Link to post
Share on other sites
16 hours ago, TexasPilot71 said:

Hmmm....interesting.  You say the rotor.  Do you mean the actual distributor?  The rotor is held in place with two screws, so there is no turning it.  I have heard of this problem being the distributor being "a tooth off", but I'm afraid to try that and my mechanic says if that was the problem, we'd be experiencing it at all RPMs.  I'm not convinced either way, though.

Yes, distributer cap.  Sorry was typing on my phone while driving and trying to keep everything he said fresh in my head while at the same time, people at work are texting me like crazy. 

Even that thread you posted (which I actually saw a few weeks ago which made me suggest tweaking the cap) was the same, exact issue and it fixed the same popping problem for him.  Worth a try for sure.

There was another fella with a Volvo and he replaced the distributer, rotor and cap with aftermarket parts and had everything lined up perfectly and it ran great until he reached about 4,000 RPM and suddenly it would run like @#$%@# as if it was going to stall.  He tweaked the distributer cap ever so slightly (I think to retard timing) and the problem would go away except now it would be set at a completely different cam retard than what he was told by Volvo and the dealer and everyone else he spoke to, hence why he was asking.  I told him @#$^#^ it, don't worry about what the true cam retard setting is and put it where it runs perfectly and leave it alone!  He just wanted to know what the actual number was for his own peace of mind.  Bottom line, you might not necessarily hear it at all RPM ranges like your mechanic says.  Things like this aren't always black or white.

I also asked my mechanic if it could be a vacuum leak somewhere and he actually said yes and that would be somethign that would be part of his ruling out diagnosis.  He said to crank the engine, leave it in idle and spray some carb cleaner into the throttle body and watch the spray.  If it gets sucked into the intake manifold, you have a vacuum leak and what happens is once you throttle up to 3,500 RPM or whatever, then start to throttle down, throttle body closes and extra air gets sucked into the intake manifold which creates a leaner mixture in your cylinder and hence pop pop pop.  You should also see a spike in RPMs when the spray gets sucked into the intake manifold.   

That would definitely be worth checking along with retarding or advancing the cap.  Both of those are really easy diagnoses to make and at least rule them out or find out one of them is the problem and then you can fix it before buying all those new sensors etc.

16 hours ago, TexasPilot71 said:

The valve float seems to make some sense too.  But now we're talking a top rebuild, right?  Uggggggg

Let's hope he's wrong with that.

I'm still curious, though, wouldn't your VesselView show you all sensors statuses?  I thought that was one of its functions.

Share this post


Link to post
Share on other sites

Defective V V ?

I am not sure if you have a distributor or not.  Do you?   Yes.  Then we can go after any PHYSCIAL part of the system that has come loose & changed the timing.

I screwed up the timing on a 50 Olds V8 so badly, it did 20 mph WOT  :clapsmiley:  Black smoke ?

If Compression , timing are good enough. 

Did you ever post the sound & rythem of the miss ?     Steady miss ? sharp pop ?  Dull random like 1 cylinder at idle ?  or very erratic popings ?

Does the backfire sound come out the flame arrestor ?  Or sound like it could be in the exhaust ? 

Are we all sure that this noise is NOT a preignition hot spot ?

Edited by cyclops2

Share this post


Link to post
Share on other sites

Update!!

 

So I went up to change the spark plugs (again). My mechanic who helped me this weekend thought they might have already fouled with all the testing since the marina put new ones in. I also changed the throttle position sensor, took off the cap and rotor for inspection, and even changed the dirty IAC valve muffler since it was dirty. Also disconnected and inspected several wiring harnesses but not all of them. No noticeable corrosion or other problems.  

Went out to test with the intake bare (flame arrestor removed). Got RPMs up to 4200 or more then decelerated and right on cue at 3900 it started popping just as bad as it always has all the way down to 3200. 

Tried it a few times and same result. Put it in neutral and revved it up to about 2000 rpm and sprayed carb cleaner around the intake to check for leaks. Nothing. 

Brought it back to idle and reinstalled flame arrestor. Took it up above 3900 then decelerate. No popping!!  Tried it about 20 times and couldn’t get it to pop not even once. 

So I have no idea!  But we’re loading for Florida tomorrow. Lol.

Share this post


Link to post
Share on other sites
4 minutes ago, Phillbo said:

Keep a supply of carb cleaner on hand for the trip...  

LOL.  Plan to!  But I can't imagine that did anything.

Share this post


Link to post
Share on other sites

The cleaner got to something for sure. T P sensor in a tube like opening ?  That would be about it ??   Mass airflow sensor blockage ?   Something in the ductwork .

Happy you did a GREAT D I Y    :wub:  Is there a inlet air temperature sensor there ?          Enjoy the trip      :clapsmiley:

Share this post


Link to post
Share on other sites
12 hours ago, TexasPilot71 said:

Brought it back to idle and reinstalled flame arrestor. Took it up above 3900 then decelerate. No popping!!  Tried it about 20 times and couldn’t get it to pop not even once

Was the engine under load, or rev’d in neutral?

Share this post


Link to post
Share on other sites
13 hours ago, TexasPilot71 said:

Update!!

 

So I went up to change the spark plugs (again). My mechanic who helped me this weekend thought they might have already fouled with all the testing since the marina put new ones in. I also changed the throttle position sensor, took off the cap and rotor for inspection, and even changed the dirty IAC valve muffler since it was dirty. Also disconnected and inspected several wiring harnesses but not all of them. No noticeable corrosion or other problems.  

Went out to test with the intake bare (flame arrestor removed). Got RPMs up to 4200 or more then decelerated and right on cue at 3900 it started popping just as bad as it always has all the way down to 3200. 

Tried it a few times and same result. Put it in neutral and revved it up to about 2000 rpm and sprayed carb cleaner around the intake to check for leaks. Nothing. 

Brought it back to idle and reinstalled flame arrestor. Took it up above 3900 then decelerate. No popping!!  Tried it about 20 times and couldn’t get it to pop not even once. 

So I have no idea!  But we’re loading for Florida tomorrow. Lol.

That's great.  Funny how things like that work themselves out in the least expected way. 

13 hours ago, TexasPilot71 said:

LOL.  Plan to!  But I can't imagine that did anything.

Actually quite the opposite.  I bet you the throttle plate had gummy build-up and/or carbon residue and when you would push the throttle to 3900 RPM and then decelerate, the throttle plate wasn't closing back correctly because of that grime and buildup and the plate was probably sticking in the open position letting more air in and hence the popping.  Once you sprayed the carb cleaner into the intake at the flame arrestor, it took that one try with no results for the air to get the cleaner all the way into the throttle body and plate and cleaned it right up.  Now it's opening and closing right when you come off the throttle and you're not getting that extra air causing the popping anymore.  Makes a ton of sense.

At some point you might want to actually take the cover off the throttle body and clean the whole throttle body itself.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...