bucking and jerking is back

help me out guys. I had a bucking and jerking in my 99 for a while. It seems to be worse the colder it gets. As the van warms up, the problem goes away. I've had the fuel pump, fuel pressure regulator checked out. Both were good. replaced fuel filter and seafoamed it. Seemed to help it run better but it still bucks when cold. I have no idea what to check next. I've had this problem for about a year. Looks like my last choice is to take to my mechanic and spend gobbs of money just to diagnos the silly thing.

the 3.8 windstars have problems with upper intake gaskets and mounting bolts that cause cold start missfires - as the engine warms and the intake expands the problem goes away

the 3.8 windstars have problems with upper intake gaskets and mounting bolts that cause cold start missfires - as the engine warms and the intake expands the problem goes away

Thanks Rivguy. What is the remedy? replace gaskets and/or bolts? I replaced the isolator bolts about 4 months ago but didn't help. Should I go ahead and replace the gaskets as well?

the bucking and surging could be from the IAC. Just under $100.00 for a new at the dealer. I just got one and it is designed slightly different from the original.
A quick way to check to see if your seals are the problem, press down on the intake with some force. If you can get the engine to idle well when doing this your problem is probably from the seals.
Ken

the gaskets are a very known problem - you should replace the gaskets and bolts as a set - if you have new bolts then just the gaskets - the rubber in the gaskets gets hard and stopps sealing - also when replaced you will noitce a different color due to the new rubber being used to prevent this problem from happening again

also check your plug wires, mine has came off the plug a bit and caused the same problem! good luck
Harper

Hi! I just had my van in the shop for what sounds like the same thing. When I got in to start it in the morning, when engine was cold, it started to buck but when it warmed up it was fine. Well i took it to my mechanic and he did diagnostics to find that the cam sensor was broke. If it is only the sensor which thank goodness it just was, it is only $20. But, he of course had to charge me $180 for labor!! So, try that and I hope this helps!!

That's good to know. The CPS was one of the things I was going to check next. I did replace both upper and lower o-rings today. I noticed that bolt number 10 would not tighten as the insert was just spinning in it's hole on the lower plenum. I replaced with a nut and bolt (slight pain in the neck) and managed to get it tightened down to the 89 in lbs. I won't know until in the morning if that fixed it or not. If not, I will definately check the CPS. Thanks.

Well, shortly after this post, the van finally threw up a CEL. Had it read at Autozone. 340 Cam Position Sensor broken circuit. Pulled off the connector and it practically fell in half in my hand. $10.12 (got good connection) PROBLEM RESOLVED!

I think I may have the same problem. My CEL came on a couple weeks ago, but no noticeable drop in performance at first. Since a few days ago, it will stall at the beginning of acceleration and during idle.

About a week before the CEL came on, I heard, and continue to hear, a screeching sound, which I thought (think) is coming from the water pump bearing.

My wife got tired of wondering & took it in to get the codes read. The mechanic, who is about as trustworthy as a mechanic can be, said about 8 different codes came up. He said it's usually a CAM sensor. I could've killed my wife for not getting the actual code numbers.

Any way, my question is: 1) assuming it's a bad CAM sensor, could that cause a screeching sound; and 2) how much of a pain is it to change it myself? The mechanic told her it's about $35 for the part, and $25 to put it on.

I know it's Christmas, but any help would be greatly appreciated.

I replaced the Camshaft Position Sensor on mine.
Very easy.
There are 2 screws on the top of the sensor and the electrical connection. Do not mess with ANY other screws or bolts as you do not want to change the position.
The Camshaft position sensor is all that is left of the old distributer that cars used to have.
It is on the passenger side of the engine, on the top...but down under the upper intake manifold....more like between the upper intake manifold and the drive belt (alternator, water pump, power steering).

They are not that hard to change but I would have to actually loosen my p/s pump so that it would clear it. First, get a long screwdriver or socket extension and put it against the base of the cam pos sensor assembly and the other end to your ear. (extension works best) If that is causing the screech, you'll know without a doubt. Be sure to mark clearly where the cps is positioned before loosening the hold down bolt. When you take the cps (the plastic part) off of the assembly, take careful note of the position of the rotor and put the rotor of your new cps assembly the same way before removing the old one. This is the process I was using when I realized that it was getting late and I had to go to work in the morning. So to get me by until I could have more time with it, I just lifted the old one as high as I could before hitting the p/s pump and gave it a good shot of WD-40. That was back in september. It hasn't screeched or bucked since. Took new part back and got my money back. Cheap fix. How temporary remains to be seen. Just to clarify. If you hear it screeching, and the cps is the culprit, you will be dealing with the whole assembly not just the top. Sometimes, when the plastic sensor breaks, a small piece can get into the assembly causing the screech. Just changing the plastic sensor will not solve your problem. Changing the whole assembly is a quite a bit more labor intensive as you will have to loosen the p/s pump, remove the lines and the w/p inlet. Trust me. try the WD-40 trick first.

I replaced the cam position sensor cover, and it looks like it needed to be replaced. My new one has a flat piece that looks like it rests on the contact inside the CPS. On my old one, nothing at all was there. So it was definitely a good thing to replace it.

My van no longer acts like it's going to stall out now during idle. Just need to take it out for a test drive now. When I re-connected the battery cable, the CEL was off. I let it run for about 10 minutes. When I cranked it up a few minutes ago, the CEL was back on! :banghead:

The screech is still there, too, and I think I know what it may be. As I was checking out the belt as it was running, I saw that my A/C pulley wasn't turning. I turned the A/C on full blast, & it still didn't turn.

My question:
1) does the A/C pulley only turn when the A/C is on? If it's supposed to turn, maybe it's putting too much strain on the belt, maybe damaging a bearing somewhere else? Is it safe to drive like that if the A/C pulley is supposed to turn?

2) Will I need to drive the van for a while for the CEL to go off if it was the cam sensor causing it to come on?

I was really hoping the cam sensor cover would solve the problems. I should have known it wouldn't be that simple.

As always, any advice is greatly appreciated.

If I were to take a guess, I would say that your A/C compressor has gone amuck. Does the air get cold? The compressor has a clutch on the pulley that engages and disengages allowing the pulley to turn at all times while the compressor turns as needed. (Your A/C compressor also engages in the winter when you have your defroster on to reduce moisture in the air therefore defrosting more effectively) If that clutch goes out, it will sieze and the belt will just slip over the pulley (screech). If you've never done an A/C before, you should let your mechanic tackle that one. You would also probably smell a burning rubber smell. I wouldn't drive any great distance. Once the belt goes, you lose everything, most importantly, water pump. Then engine is soon to follow. If your cam pos sensor assembly was screeching, it would be sporatic and only when cold. If it is a constant screech, have that A/C checked out...Hope it helps

So if I'm understanding correctly, the A/C pulley should always be turning, right? If it is, then that's my problem, all right. I'll be taking that in right away. In the meantime, would keeping the defroster turned off make a difference? Is there anything I can do to minimize potential damage?

Regarding my other question, will the CEL reset or go out once I've driven it for a while?

Yes, they pulley itself (grooved pulley that the serpentine belt travels on should always be turning when engine is running. When A/C compressor is off the clutch (center part of pulley facing the right hand side of car should be stationary) When a/c compressor engages, that part should be spinning with the pulley as well.

I cant believe the pulley is not spinning and the belt hasn't self destructed yet. This usually happens within a few minutes of siezed pulley.

As for the CEL light, depends on whether it was a hard or soft code. Soft codes will drop after a number of driving cycles. Hard codes have to be reset with a scan tool

Yes, they pulley itself (grooved pulley that the serpentine belt travels on should always be turning when engine is running. When A/C compressor is off the clutch (center part of pulley facing the right hand side of car should be stationary) When a/c compressor engages, that part should be spinning with the pulley as well.

I cant believe the pulley is not spinning and the belt hasn't self destructed yet. This usually happens within a few minutes of siezed pulley.

As for the CEL light, depends on whether it was a hard or soft code. Soft codes will drop after a number of driving cycles. Hard codes have to be reset with a scan tool

Thanks for the advice. I'll double-check, but I'm positive that the pulley isn't turning at all. So running it at all could snap the belt, whether the A/C or defroster is on or not, right? If it is indeed seized, it's been running for 3 weeks or so now.

Could this pulley not turning put stress on the other pulley bearings, like the water pump pulley or idler pulley? Because that's where it sounds like the screeching is coming form.

Sounds like I might need some A/C work. Does this sound like a problem with the compressor, or just the clutch? Or can they even be replaced separately?

Also, is there a way to know if my CEL code is a hard one or soft one? I'm going to call the repair shop back & see if they still have the codes from last week.

Correct. The outside of the pulley will always turn. The inside (clutch) will turn and stop as the clutch engages and disengages respectively. If you have another vehicle, watch the compressor with the a/c or defrost on. You will see what I mean.
If your compressor is bad, it wont matter whether you run defrost or not. I wouldn't since it's not functioning anyway. If you have AAA or something, I would recommend having it towed. Try not to drive it if you can avoid it, if that is indeed the problem. Like I said, all your critical systems i.e. cooling, charging, P/S all depend on this one belt. If it breaks, you lose it all. Your mechanic can also read the code that is up. It may be something entrirely different. He can also reset it to turn the CEL off.
You could try to tackle the job yourself but it is somewhat labor intensive and is under pressure.

Yes, the AC pulley should always be turning. Likely the clutch has siezed but possibly also the pump.

If you want to put off replacing the compressor/clutch assy (I don't recommend it... now's the time when AC maintenance will be cheap), then go down to the Auto parts store and buy a new serpentine belt, telling the sales rep that you DO NOT have an AC. There are a couple sizes and corresponding paths for the serpentine depending on whether you have an AC installed or not. You will want to replace that belt either way.

To turn the CEL off yourself....
Remove the Negative Battery cable...
Leave it disconnected for about 5 minutes or so.....reconnection right away may not clear the CEL.
Reconnect.....
This will cause the CEL to be off.....
If the CEL comes back on......(and you have left the negative cable off long enough) you still have a contition causing the light to come on.

NOTE: Removing the Negative battery cable will also clear out your preset radio stations and your "drivability" information in the computer.
The computer WILL "Re-learn" this information.
You may notice that your transmission sift points may be slightly different until the computer relearns all the data. The relearn process is pretty quick...and not a big deal.....

I looked at my air conditioning pulley today......
I did it with the engine off.....and the drive belt off......The "outer" part of the pulley turns very easily....and the center part (the main body of the pulley) does not turn.

If you look at the pulley (use a flashlight) with the engine running (be very careful to not get yourself into the belt)....You should see the metal "lip" on each side of the belt.....the part that keeps the belt from sliding off the pulley......This metal that you can just barely see on each side of the belt....SHOULD BE TURNING. The part of the pulley that you can see from looking from the side......will not be turning......THIS IS NORMAL.

Just the small surface that is at the belt surface turns.....it is a ring.

I double-checked, and that sucker isn't turning at all on the outside. If that's what has bene causing the screeching, it's lasted for over 3 weeks, and the belt seems to be all right. The belt just slides over the grooves on the outside of the A/C pulley. I haven't let my wife drive it at all since I began to suspect the water pump might have been the problem.

The mechanic shop is just around the corner, so I feel OK driving it there, but not any further. Thanks a million for the tip about getting a belt that doesn't route through the A/C. If the repair is too much, I might do that. But I agree with you - now is probably the best time to have that fixed.

I expect I'll probably have to get either a new water pump or idler pulley. I think that the extra friction caused by the A/C pulley not turning has over-stressed one of those two bearings, causing the screeching sound. What do you guys think?

UPDATE: OH MY GOD!! I just called the auto parts store for availability on the compressor/clutch assembly, and just for the clutch. $254 for a reconditioned compressor/clutch unit ($344 new,) plus about $164 for the new filter dryer & another warranty-required part. :crying: The clutch by itself is $102. Man, I hope it's just the clutch!

Stan

The "Pulley" on the air conditioner will turn all of the time. The "air conditioner pump" will only turn when the clutch on the pump is engaged.

Start up your engine and look at the pulley on the airconditioner pump. If you see smoke coming from the pulley the bearing is locked up and so is the pump. If no smoke your noise may be coming from another area.

I'd pull the belt and check all of the pulleys. It's the only way you'll find the problem.

Regards

Dan

I doubt that there will be harm done to the other pulleys if the ac is locked up. In the scheme of engine belt things, the crankshaft pulley supplys the power (force x velocity) ...every other pulley is a power "load". The ac compressor is significantly the largest load of all so it is placed "first" on the belt after the crank pulley ... then comes the alternator, power strng, etc. Idler pulleys are inserted as necessary to increase the "wrap" of the belt around particular pulleys. As it travels over each load pulley, the belt loses a bit of its tension (force)... when the belt gets back to the crankshaft pulley, almost all the tension is gone... an ideal location for the spring loaded tensioner, if there are no other considerations.

So a locked-up ac pulley will cause increased belt forces on the ac pulley and the crank pulley ... little increase on anything else.

I wouldn't worry about the other pulleys either unless by feel they have play, resistance, wobble or squeals, then replace as necessary. As for the A/c compressor, it is relatively easy to replace yourself but you need to have a qualified tech, remove the refrigerant first. If you do replace, do replace the accumulator too as it is the only thing that dries the system. Make sure you measure any oil that pours out of the two parts as you will need to replace that much in the system when you install new parts. Check that your lines do not have a black film in them; if they do you will have to have the lines, evap and condensor flushed out before you can proceed.
Replace the compressor, accumulator and then take to shop (if you dont have access to an a/c vacuum pump) vacuum the system down as close to 29" Hg as possible and run vac for 45minutes. The system is now ready to recharge with r134.

Haven't posted back to let everyone know how it all turned out.

The problem was the cam sensor. There was a semi-circular piece that spins inside the housing that was bent. It was tearing the heck out of the plastic inside the housing as it spun.

It was covered under the extended warranty I got, except for the $100 deductible. But the screeching is gone, it doesn't stall out, and the CEL has stayed off for several day snow.

I'm glad it's fixed, and I appreciate everyone's help here.