Rough Running

[Sidewinder]

Every once in awhile my car would have a spaztastic surging idle that would go away after a couple seconds on startup, but generally this only happened maybe once a month if that. Well this week the engine has been doing this almost every time I restarted it after some use, yesterday was the only day it didn't do it at least once. It is generally idling bad now though, but it seems to be running fine otherwise (as fine as 280000KMS can be). I've noticed throughout the week a high pitched whine coming from the front end that has been getting louder day by day and seems to be coming from the engine. The engine also ticks (though it has been doing that for awhile and is generally getting worse).

I have some theories as to what it may be, but I wanted to get some other opinions. I took a video of it as well, though the sound quality isn't incredible hopefully you can catch the way its running. Unfortunately I only caught the later edge of the surging by the time I started the camera, but it does it right at the beginning of the video.



I also wanted to quickly point out that this video was taken after I drove the car for about 30 minutes from one end of the city to the other on my way home from work. Normally the ticking would go away after the engine warms up (which apparently is a normal thing with these engines), but now its starting to become more constant.

[chadicenhour]

Did you check for vacuum leaks? Thats what it looks like it would be. Check everything vacuum related, even the pcv system around where it pushes into the intake under the throttle cable bracket. Also, a stuck IAC could be a possibility. Good luck.

[Azrael]

For the whining sound try turning the a/c off and on and see if it changes. If it's still there in either case, temporarily pull the accessory belt. If it's still there after that, it might be the torque convertor or the trans fluid pump due to low transmission fluid.

The ticking is usually the timing chain due to stretch and often mis-diagnosed as lifter noise.

There's a reason I refer to my 3100 as a "rattle-can" lol.

[Tbay99Venture]

Timing chain? Hummmm

We have about 150,000 miles on our 99 Venture, that compares pretty well to the total KMs you have. I think for 2 years I've been trying to get rid of the annoying vroom-vroom-vroom idle I believe I hear in your video.

I suspected a vacuum leak but have just about eliminated every possibility. (Head gasket just failed two weeks ago but the vroom was still there after I started it with the new gaskets. FYI, cylinder #2 had the low compression (front, passenger side, next to the water pump. That bolt right under the engine bracket was much easier to remove than the others when I took the head off. You might want to budget for gaskets or have an exit strategy!

As for the idle, manually raising the RPMs makes everything smooth out. It's not the IAC valve, the original one jammed up about a year ago but hte problme persists. There computer never has any codes so it thinks things are fine.

When the engine is totally cold the idle is fine & the vacuum is right up around 20 inches and steady. Once it goes to closed loop mode the problem comes on and vacuum drops to 15 inches. Yes, parts warming up could cause a leak but even with fresh gaskets & injector O-rings the problem stays. I will probably block the brake booster to see if that changes things, blocking the other hoses hasn't helped. PCV & plastic elbow were replaced, grommet is tight. Many of the other breather hoses got replaced as casualties of my heater hose replacement.

About the only other tests I have left are fuel pressure and blocking the EGR port into the mainfold. I doubt fuel pressure is the issue with the engine running fine otherwise. The care always starts up with a steady idle so I don't think the EGR will turn out to be it.

I looked at the 24x (crank) sensor signal with a scope and it's perfect. The cam signal is great too, but I haven't compared it at the same time as the 3x sensor. Retarded spark can bring low vacuum and I wonder if the chain is stretched and offsetting the cam sensor signal enough to make the computer mess up the spark advance.

Output from the upstream O2 sensor was going up and down, up and down so I replaced it but that didn't help. (Too slow to be a particular cylinder, too fast to match the rumble. This was *after* the head gasket replacement.) I replaced the knock sensor as well with no improvement. The other sensors, intake air temp, etc. produce good output on a computer scan so I don't think they are bad.

Hope that helps you.

[Sidewinder]

Did you check for vacuum leaks? Thats what it looks like it would be. Check everything vacuum related, even the pcv system around where it pushes into the intake under the throttle cable bracket. Also, a stuck IAC could be a possibility. Good luck.

I'll have to check for those, that'll be the first thing I do.

For the whining sound try turning the a/c off and on and see if it changes. If it's still there in either case, temporarily pull the accessory belt. If it's still there after that, it might be the torque convertor or the trans fluid pump due to low transmission fluid.

The ticking is usually the timing chain due to stretch and often mis-diagnosed as lifter noise.

There's a reason I refer to my 3100 as a "rattle-can" lol.

That'll be the next thing I do. I have a feeling its not the ac since mine doesn't have refrigerant and I haven't used it for 3 years (lost it all when a tube disconnected itself). But I should give removing the drive belt a try and check my trans fluid.

I'm starting to think it may be the timing chain since I'm not sure if it has ever been changed out, that may also explain why it runs better when its colder now.

We have about 150,000 miles on our 99 Venture, that compares pretty well to the total KMs you have. I think for 2 years I've been trying to get rid of the annoying vroom-vroom-vroom idle I believe I hear in your video.

I suspected a vacuum leak but have just about eliminated every possibility. (Head gasket just failed two weeks ago but the vroom was still there after I started it with the new gaskets. FYI, cylinder #2 had the low compression (front, passenger side, next to the water pump. That bolt right under the engine bracket was much easier to remove than the others when I took the head off. You might want to budget for gaskets or have an exit strategy!

As for the idle, manually raising the RPMs makes everything smooth out. It's not the IAC valve, the original one jammed up about a year ago but hte problme persists. There computer never has any codes so it thinks things are fine.

When the engine is totally cold the idle is fine & the vacuum is right up around 20 inches and steady. Once it goes to closed loop mode the problem comes on and vacuum drops to 15 inches. Yes, parts warming up could cause a leak but even with fresh gaskets & injector O-rings the problem stays. I will probably block the brake booster to see if that changes things, blocking the other hoses hasn't helped. PCV & plastic elbow were replaced, grommet is tight. Many of the other breather hoses got replaced as casualties of my heater hose replacement.

About the only other tests I have left are fuel pressure and blocking the EGR port into the mainfold. I doubt fuel pressure is the issue with the engine running fine otherwise. The care always starts up with a steady idle so I don't think the EGR will turn out to be it.

I looked at the 24x (crank) sensor signal with a scope and it's perfect. The cam signal is great too, but I haven't compared it at the same time as the 3x sensor. Retarded spark can bring low vacuum and I wonder if the chain is stretched and offsetting the cam sensor signal enough to make the computer mess up the spark advance.

Output from the upstream O2 sensor was going up and down, up and down so I replaced it but that didn't help. (Too slow to be a particular cylinder, too fast to match the rumble. This was *after* the head gasket replacement.) I replaced the knock sensor as well with no improvement. The other sensors, intake air temp, etc. produce good output on a computer scan so I don't think they are bad.

Hope that helps you.

That actually helps a lot and gives me some ideas of what I may need to check. The only other thing I am considering checking is the cat and maybe it is destroyed to the point that its starting to block exhaust gases from escaping.

Thanks for the help guys, I'm gunna start diagnosing it when I get back from my vacation and try to figure out whats wrong. I may bring it in to get someone to look at it as well. I'm hoping it won't be too expensive but if it comes anywhere near $1000 in repairs I'm pulling the car off the road.

Don't get me wrong, I actually wanted my engine to die just not this fast. I'm planning on building an engine for this car so dumping a grand on a motor I'm going to replace in a year (or less hopefully) is entirely pointless. I've already started looking or a beater car awhile ago so I'll see how things go from here and decide once I figure it out.

Thanks for the help

[Tbay99Venture]

Strategy

I'm planning on building an engine for this car so dumping a grand on a motor I'm going to replace in a year (or less hopefully) is entirely pointless.

Heh, then no worries about the head gaskets at least

[Tbay99Venture]

Followup: EGR block-off

Blocking off the EGR doesn't seem to help. But we'll give it a day or so of city driving to make the final determination. Here is how I did it.

[Tbay99Venture]

Stamping a hole for the EGR pintle

It didn't look like the pintle needed the room but I made a hole for it with a washer and a socket slightly larger to make a blanking die. Hit with a hammer and then work the rest free with pliers.

[Sidewinder]

I have some work to do on it still. I actually was in the States the past 5 days so its been parked for awhile. I'm hoping to get at it this weekend see how things go.

[60dgrzbelow0]

The whining can also be caused by the bearing(s) in the alternator getting a little sketchy. They actually have a fairly substantial axial load that pulls and tugs on the armature shaft in odd ways ...even with the help of the spring-loaded idler pulley to attentuate that dynamic. After a while... the bearings call wallow out enough to get loose and at certain rpms...will "sing" harmonically and transmit the sound and vibrations into the rotating shaft. So it might be time to scout a decent replacement that has some heavy duty diodes, too.

The "Ticking" can occur when the occasional bit of junk, gunk or "mung" wends its weary way inside the offending spring loaded innards of your hydraulic lifters and impedes one or more of them from sort of "plumping" up completely... leaving all the intermediate parts like the pushrod(s) and rocker arms to either "tick" or clatter. A good seafoam treatment might break that stuff loose...followed by a fresh oil change along with the best filter you can afford...and see if that helps.

About the whining issues... I had a similar problem recently that I isolated to the right front seat of my car... that seemed to come and go intermittantly , depending upon whether my wife was in the car... or not...

[Tbay99Venture]

EGR valve test results

It didn't look like the pintle needed the room but I made a hole for it with a washer and a socket slightly larger to make a blanking die. Hit with a hammer and then work the rest free with pliers.

First, that block off didn't change anything but did produce a trouble code for low EGR flow so I'm back to the stock configuration. I also checked that the fuel pressure regulator would hold a vacuum so that part is OK. (All this regarding the rumbling idle.) Once I get a fuel pressure gauge I can rule that out. What's left is comparing the 7x sensor and cam sensor on the same scope to see if their timing relationship stays constant. All in all an awful lot of trouble to get rid of an annoying sound.

Also, I looked at my last post and it looks like I should have been calling that valve a poppet rather than a pintle.

[pocket-rocket]

The whining can also be caused by the bearing(s) in the alternator getting a little sketchy. They actually have a fairly substantial axial load that pulls and tugs on the armature shaft in odd ways ...

My friend with a 95 S10 SS had to change the pulley on his A/C compressor. When he pulled up I told him his power steering fluid was low and he said it was the A/C compressor bearings. Now that the pulley (and associated bearings have been changed) it doesn't make a peep. I also know someone with a Lumina LS that had the A/C pulley actually freeze up from going bad (after making a horrible scraping sound for a long time) that it actually kept the engine from turning over fast enough to start the car...

[Sidewinder]

Well, something was definitely VERY wrong with it, this is how my day went yesterday...



Never do I want to see my car on the back of a tow truck...

[Tbay99Venture]

Towed

That's a bummer. Was that due to the whine that got worse? Or did the engine quit running?

[Sidewinder]

Hey sorry I missed this been busy all week. It quit on me the day I was going to do the tune up on it. Turns out the fuel pump had quit and the gas tank wasn't far behind. Both have been replaced and I got it back and did the tune up. It's running better than it has for as long as I can remember now, the whine is still there though.