Poor Performance

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  #1  
Old 09-19-08, 08:30 PM
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Poor Performance

Thanks to all for the help with my other recent threads regaring our 1991 Dodge Caravan. This one touches on a problem that is becoming bigger slowly.

Lately, we've been running shakily almost to the point of stalling, specificaly when shifting from P to R coming out of driveway, and also when we brake before the engine warms up. Besides this, our engine had always made a "whining" noise on acceleration, that sound got worse a while ago and may or may not be related. More concerning is this unsteadiness. It is also important to add that this vehicle burns oil, it has the infamous Mitsu 3.0 L V6, FWD. Do I need new plugs, which haven't been changed since we got the vehicle 1-2 years ago, or is this directly related to the burning of oil/whining?

I've been considering attempting the valve guide seal repair for a while now, what does everyone think regarding that?

Thanks to ANY info!
 
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  #2  
Old 09-19-08, 09:59 PM
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Hi Codyy,
I read some of your other posts. If I read right, you've got close to 260000 km on that van? What was the mileage when you got it?

Have you been running regular oil? You may want to consider swapping over to synthetic and seeing if that makes any difference. It does cost more, but may be worth it.

Doing the plugs and wires would be a lot less aggravation than a valve job. What you could do is replace the plugs and wires ($60 USD in parts I'm guessing). Then see how the van runs.
If you can, take pictures of your old plugs and post them here. One can tell a lot about an engine by looking at the plugs. If you scroll down to the part about normal firing end on the below page, you could see if the pictures there match up with the old ones you pulled.
http://dodgeram.info/Engine-Gas/Spar...plghnbook.html
 

Last edited by mobile_man; 09-19-08 at 10:01 PM. Reason: kant speel
  #3  
Old 09-19-08, 10:24 PM
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Thanks for the reply!

You are correct about the mileage, by now actually we have over 260k kms, around 261k or so. I believe we got it around 250-251k kms, so it had already been around the block a few times. Funny thing is, we got winters down to -45 windchill here, and this thing started all winter, while people with newer vehicles were plugging into block and heaters and having trouble. We maybe plugged in once.

I am running conventional 10W30. Always run that now constantly all year, since 5W30 being less viscous burns even worse. Perhaps synthetic would be worth a shot.

I'm guessing my plugs will look oil fouled, at least some of them. Everywhere I read says new plugs is only temp because they will foul again, but we seemed to have went some time without getting fouled to the point of poor performance or misfire. I'm not sure how much oil it takes to slip by to cause smoke, because some days we REALLY smoke, namely very hot days. I will get pics of the plugs and post them, I'd like to check 1 first maybe, just to see the condition.

Thanks!
 
  #4  
Old 09-20-08, 09:09 AM
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How many miles to the quart of oil?

With that whine - if you pulsate the gas pedal like on, off, on, off the pedal while cruisng, will you also hear a clunk?, as if some shaft has too much end play?, and some shaft is traveling in and out too much affecting relationship of gears or something? And have you tried to go up to cruising speed and then let off the gas and see if it coasts good without feeling like something is slowing the car down worse than you'd expect?
 
  #5  
Old 09-20-08, 05:19 PM
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How many miles to a quart... great question actually, I've never really measured it, usually just check it once every 1-2 weeks, we drive nearly everyday.

The whining sound is biggest on acceleration. Like I said it always made that sound to a degree, but at some point during the summer it seemed to become worse, thought it was P/S at first. Regarding a clunk, I haven't tried pulsating the gas pedal, but lately we have heard an occasional clunk when accelerating from a dead or nearly dead stop, can feel it through the floor almost. When accelerating and then letting go, we do cost fine. Funny you mention that because earlier on when we got this vehicle, we would let go of the gas and it would come to a dead stop - ended up replacing the master cylinder.

This summer we took it on a trip of 2-3 hours this summer, on highway, at about a 100 km/h constant, now at that speed when letting go of accel. I did notice it would slow fairly fast, not sure how normal that is. Other than that, like mentioned, not terribly noticable.

Hopefully you can put some of this information together. I did purchase spark plugs and stuff today, however if these symptoms are those of impending doom, I have my receipt.
 
  #6  
Old 09-20-08, 06:32 PM
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put the vehicle up on jack stands and invest in a mechanics stethscope, use it on each control arm as the vehicle is idleing in gear to see if you can isolate the noise, keep moving it around including on the engine in different places my guess is you will find a wheel bearing or cv joint that is starting to go.
pull your pvc valve and see if the bottom is coated with fresh oil, if so you may be smoking from sucking oil into the pvc valve. that usually comes from a valve cover baffle comeing loose, of course with that high of milage i would run a compression test to see what that is, before spending much money on the vehicle.

life begins when the kids leave home and the dog dies.
 
  #7  
Old 09-20-08, 07:27 PM
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Regarding the click noise, I should also add that when we change gears, P to R, P to D, etc., we get a click or a thump. And also when shifting (Automatic) we have a fairly noticible shift bump. Do you think I perhaps have bad motor mounts instead of CV?
 
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Old 09-22-08, 08:21 PM
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possible. one way to check the motor mounts is foot on brake with hood up so engine can be observed, in gear rev engine some and see how much engine moves, shouldn't be very much, try in drive and reverse.

life begins when the kids leave home and the dog dies.
 
  #9  
Old 09-26-08, 01:08 PM
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Spark plugs changed out. Was pretty smooth save for the more difficult rear bank, but all got changed.

The engine now idles and drives more smoothly and the shake/misfire is basicaly gone!

Here are the pictures of some of the spark plugs. #5 cylinder plug was most fouled with ash. I was expecting awful oily completely fouled plugs, but from what the Haynes manual says this gray/white ash I have is indicative of oil burning as well.









 
  #10  
Old 09-26-08, 03:37 PM
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Did they reinvent the spark plug? Where are the metal tips that usually stick out past the insulator inside?
 
  #11  
Old 09-26-08, 03:59 PM
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as you can see the plugs are Bosch platnium the electrode does NOT stick out on these plugs more than an 1/32 nd of an inch. Bosch and Champion are not my favorite...but Champion seems to run best in Chrysler products and lawnmowers,(same thing).
 
  #12  
Old 09-26-08, 07:34 PM
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Yep they are the Bosch Platinum, came with them. I replaced with the listed Champion plugs. Frankly I was suprised to see anything "Platinum" in our old junker! :P
 
  #13  
Old 09-28-08, 04:29 PM
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Just thought of a question - awhile ago we were told we needed ball joints. We picked them up and never got around to installation of them as of now. My question is, could ball joints cause that pop/clunk noise when accelerating/changing gears. I also heard it once when moving backwards from a stop in neutral.

Cheers.
 
  #14  
Old 09-28-08, 07:07 PM
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This guy who had a ball joint problem describes exactly the thump/clunk/pop we feel:

I have had so many ball joints go out, I know the sound all too well.
It's a thunking noise on starting up from a stop or sometimes when you
stop. It's not a clicking - it's harder and deeper than that. You can
feel it in the frame of the car.

We also get some thumping/clunking type noises over bumps.

What do you think? Also, a Mod can merge these posts if need be, I keep finding new information lol.
 
  #15  
Old 09-28-08, 07:21 PM
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yes a bad ball joint can cause those problems, but the best way to check is to remove the spring pressure on the ball joint and feel for movement, if you can easily move the joint up and down it is bad. pretty much any movement in a ball joint that you can do easily by hand is not good. most of the time a good ball joint is very stiff to move any direction and has no noticable slack. you could also have bad rubber bushings at the frame end of the lower control arms. if you disasemble the front struts for ball joints or control arm bushings check very carefully the bearings on the top of the struts where they bolt to the body. with this many miles they are probably worn also.

life begins when the kids leave home and the dog dies.
 
  #16  
Old 09-28-08, 07:26 PM
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Great info. What would anyone say regarding ball joints, DIY job or not?
 
  #17  
Old 10-02-08, 10:00 AM
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Any ideas? Is this task easy enough for me to learn and complete? From what I've heard, shop prices are very high for this job, and if it is something I could learn, I don't mind attempting/buying needed tools. We already do have the ball joints purchased from before.
 
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