No Codes, Violent Bucking, Bad MPG, lost!

P

Phil04

Registered User
No Codes, Violent Bucking, Bad MPG, lost! Update, prob is back

UPDATE:... well, all was good for a few days, then back to the same old probs. Runs good cold, then gets exponentially worse as the temp rises and rises to about 7/8 up the norm range. Back to pulsing acceleration that eventually turns to bad bucking and not being able to go anywhere unless i only give 1/4 throttle. So, anybody have any other ideas? Now I have a new cam sensor, tps, maps, mafs. I don't know what to do next. Could a clogged up radiator cause these problems? Or bad oil pump perhaps cuz my oil pressure drops really badly, i wonder if it is because i used synthetic. Wouldn't think so though. Could be a vacuum leak, but i haven't found one yet. Only happens when the car heats up, so there must be a corrilation. Could be ECT, haven't changed that out yet, but hate to keep changing sensors without knowing if they are actually bad. I have absolutely no codes. Problem is I can't pull them while the car is under a load, like accelerating. HELP!!!


I already posted once, but its time for an update and a bit more detailed description of my probs.

First, NO codes. New MAPS, MAFS, TPS.

Car runs awesome for first 5-10 minutes
Slowly gets worse afterward
After driving around for a while, engine gets hotter than usual and when I try to give anything over 1/4 throttle it bucks violently so I have to let off. The boost goes to 10lb when I do this.
I also often get a lot of what seems like chatter when in first starting from a complete start. Feels like when you let the clutch out too fast and not enough gas, but I'm not!
The car absolutely guzzles gas when I do anything other than granny it.
When I just drive it around barely giving it anything I can get up to 350mi on a tank. When I drive normally, I am lucky to get 200mi.
The problem is definitely progressive.
Runs awesome at first, then has little hesitations under acceleration, then after time gets worse and eventually violently bucks and won't accelerate unless I barely give it gas.
Car gets much hotter than usual
I filled the coolant the other day and today after a few hr drive I noticed the collant reservoir is empty!!!
Turned the car off and heard this gurgling noise coming from the radiator and the tube coming from top center of radiator to engine.
If I park the car for a while after the bucking gets really bad, it has a rough start but is much better driving.
I know I am going to get varied suggestions:
As far as spark plugs and wires, wouldn't that be a continual problem, not just after long drives?
Wouldn't cam sensor effect tachometer and be a problem from the get go?
Vac leak would give me low vac at idle correct? I am at 20
Seems to me something must be heating up and having probs once hot. I have read dis could get too hot and cause probs.
I find it very strange that I have no codes, cylinder balance test comes back no probs.
Pulled one plug a few weeks ago and looked brand new.
Could be fuel filter or pump, but those are a pain to get to, hoping to have some other suggestions before I go to the hard stuff like pumps/filters, plugs, etc.
 
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antifreeze

Phil04 said:
I already posted once, but its time for an update and a bit more detailed description of my probs.
First, NO codes. New MAPS, MAFS, TPS.

Car runs awesome for first 5-10 minutes
Slowly gets worse afterward
After driving around for a while, engine gets hotter than usual and when I try to give anything over 1/4 throttle it bucks violently so I have to let off. The boost goes to 10lb when I do this.
I also often get a lot of what seems like chatter when in first starting from a complete start. Feels like when you let the clutch out too fast and not enough gas, but I'm not!
The car absolutely guzzles gas when I do anything other than granny it.
When I just drive it around barely giving it anything I can get up to 350mi on a tank. When I drive normally, I am lucky to get 200mi.
The problem is definitely progressive.
Runs awesome at first, then has little hesitations under acceleration, then after time gets worse and eventually violently bucks and won't accelerate unless I barely give it gas.
Car gets much hotter than usual
I filled the coolant the other day and today after a few hr drive I noticed the collant reservoir is empty!!!
Turned the car off and heard this gurgling noise coming from the radiator and the tube coming from top center of radiator to engine.
If I park the car for a while after the bucking gets really bad, it has a rough start but is much better driving.
I know I am going to get varied suggestions:
As far as spark plugs and wires, wouldn't that be a continual problem, not just after long drives?
Wouldn't cam sensor effect tachometer and be a problem from the get go?
Vac leak would give me low vac at idle correct? I am at 20
Seems to me something must be heating up and having probs once hot. I have read dis could get too hot and cause probs.
I find it very strange that I have no codes, cylinder balance test comes back no probs.
Pulled one plug a few weeks ago and looked brand new.
Could be fuel filter or pump, but those are a pain to get to, hoping to have some other suggestions before I go to the hard stuff like pumps/filters, plugs, etc.
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does the antifreeze hit the floor or just seem to disappear? As difficult as this sounds "you need to do a compression check"!! i fear you are having the early signs of head gasket failure!! check the compression before driving it much more . antifreeze in the oil can do "BAD THINGS"!!!! the gas mileage isn't to far out . i get 500km's under normal driving and really bad if i am leaning on it alot . the tank is only 70 liters so around 24 miles to gal isn't to bad...
 
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I am doing head gasket on 94 Cavalier 2.2 today for a customer, It does exactly what your your explaining to a tee, runs great cold but as soon as you drive a bit it gets real hot and starts bucking and chugging, Coolant tank going empty couple times a week roughly.

Pulled plugs and they look almost normal just a hint of leaness, done a compression test 3 cyl. were 120 psi other was 150 psi, so I pulled it down and head gasket was just starting to go (2 cyl. between each other and other was going from port to cyl.)

Hate to be bearer of bad news, but pull your heads before you end up chewing up you bottom end bearings with coolant in the oil, not to mention possibly seizing and doing real bad damage.

I`m not saying 100% this is your problem, but symptoms are identicle and since I just pulled apart about 2 hours ago, I would say you have same problem.

Hope this helps even with bad news.

Garett
 
Thats not what I was hoping to hear. So, I guess the next question is before I go tearing the heads off and replacing the gaskets, is there any way to know for sure if it is the gaskets or something else?
 
Cylinder balance test ??? Is this done using an air compressor and a leak down kit ?? IMO this is the best way to test,,, putting compressed air into each cylinder, with valves closed and recording IF and how long the air bleeds past the rings. Either buy the equipment or get someone to do it for you, B4 you jump in blindly.
 
Exactly.

Check your compression, man. Bring back the numbers, or check them in a manual. I'm pretty sure they should be pushing about 135 to 150psi, with something like a 4 or 5psi variance.
 
unplugged cam sensor, couldn't get it to start. Maybe I just wasn't patient enough. I did a balance test with my code puller, came back fine. I will have to find out if I have the means to actually measure pressure. I don't exactly have a garage full of tools, or a garage for that matter lol. I will try to start it w the cam sensor unplugged again in a bit. When I tried earlier, it would kinda start, studder, and die, even after giving it gas. Car is def running hotter than it used to. Just doesn't feel right when I drive it. I am really hoping for the bad cam sensor thing, but just curious as to why it would not be bad from the start instead of getting progressively worse as I drive?
 
The problem you described is consistent with a classic cam sensor failure. It will take 3-4 tries key off between tries to get the engine to start; however, once running, if the problem stays away, then replace the cam sensor. Give it a day or 2. ;) If it fails to ever start or runs poorly, then reconnect it; its not the main problem.
 
Phil04 said:
Thats not what I was hoping to hear. So, I guess the next question is before I go tearing the heads off and replacing the gaskets, is there any way to know for sure if it is the gaskets or something else?
Click to expand...


i have the smae problem but im on auotmatic and i head my engine rebuilt and its still doing that so it might not be mechanical check your electrical system and if you figure it out let me know cuz i cant
 
Wow, that is incredible. Took a few secs but started on first try, idle was a bit rocky for a min, but soon was smoother than its been in a while, took it for a drive, wow, no hesitation...and thats w no sensor at all...must be even better w a good one!!! My check engine light is now on since I have the sensor disconnected, but at least I know the reason its on. I wonder why I didn't get any trouble codes pertaining to the sensor. I will change it out tomorrow and give the final results afterward. Also, my oil pressure gauge, which has been goin crazy, stayed right in the normal range like it used to. go figure? Engine temp stayed down also. Could all this be caused by one little sensor? At any rate, thanks so much for your help. You were right I, cam sensor it is. Now I just hope that was my only problem.
 
Phil04 said:
Wow, that is incredible. Took a few secs but started on first try, idle was a bit rocky for a min, but soon was smoother than its been in a while, took it for a drive, wow, no hesitation...and thats w no sensor at all...must be even better w a good one!!! My check engine light is now on since I have the sensor disconnected, but at least I know the reason its on. I wonder why I didn't get any trouble codes pertaining to the sensor. I will change it out tomorrow and give the final results afterward. Also, my oil pressure gauge, which has been goin crazy, stayed right in the normal range like it used to. go figure? Engine temp stayed down also. Could all this be caused by one little sensor? At any rate, thanks so much for your help. You were right I, cam sensor it is. Now I just hope that was my only problem.
Click to expand...
You're quite welcome. The cam sensor provides the CID signal. You will have a code now because there is a complete loss of CID which the EEC can detect. A flakey cam sensor about 1/2 the time doesn't cause a code to get set. The EEC compensates for a missing CID by guessing at the coil sequence using the crank sensor (PIP) signal. CID could well affect the running temp by causing timing to advance, but shouldn't have anything to do with the oil pressure. However, 1 thing a time and if it the problem stays away, we won't look a gift horse in the mouth. :cool:
 
well, that lasted a few days...and now i am back to the same problem. Runs good cold, then quickly gets bad, runs hot, bucks badly, the works. I am at such a loss.
 
Well ,if the problem was fixed you must be in the right area. Start with the wires going to the cam sensor, be sure they didn't get rubbed by the belt and are seated properly. Screws are secure etc. If you fixed it once you can do it again. :p
 
Phil04 said:
well, that lasted a few days...and now i am back to the same problem. Runs good cold, then quickly gets bad, runs hot, bucks badly, the works. I am at such a loss.
Click to expand...
Hmm.... unplug cam sensor again, only this time, drive it for a couple of days that way.. If the bucking happens again, you migh want to swap out the DIS for a spare if you have one.. If you don't, see if you can borrow one, or get on the sellers forums and track down a spare. :)
 
Have had this problem on a 35th Anni I Had

Its a simple but extreamly frustrating fix. Fuel Pressure Regulator, its Right By the Fire Wall Behind the Supercharger intake Several Hours and $20 and problem is fixed. When you give it gas it makes it worse. till you have to basically stop let it sit and buck and then out of no where it goes away and you can go again. I went ahead on my other 90 and replaced it when I was doin a head gasket replacement just in case :)
 
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