Shifting out of OD

[19Cutlass94]

when Im driving up a hill in OD, and I step into it so my piece can actually attempt to make it up, theres like this horrible moaning noise/knocking noise/possible grinding noise. Ive been thinking maybe its due to piston slap, but I duno its pretty bad. Does anyone else know what Im talking about/have the same problem? I mean it sounds so bad, I just let the car coast up the hill till is slows down enough its out of OD then I step into it. Also is this something I look into rather soon. (Ill try to get a video clip up soon, as soon as I get a new computer.)

[Crazy K]

try attmpetiong the same hill in regualr drive and see what results!!!

 

and a vid would be good.

[19Cutlass94]

well about that is, its like a highway that turns into a street, and I usually go like 70mph on it and I dont wanna be like 4500+rpm for about 10 minutes.........

[birdman]

4th should only be like 2500ish. and 3rd like 3500-3800. to take it out of TC lock all you have to do is take your foot off the gas and put it back down.

[soya_sauce]

just a thought but it might be ignition timing advanceing itself too much and giving you a pinging noise. the computer automatically adjusts your ignition timing but, if the knock sensor it shot then i could see the timing advancing too far.

[1990lumina]

Yeah man I wouldn't worry aout driving out of OD....you shouldn't be revving too too high....Hell I pop mine down to D all the time because this stupid car has no passing power in OD.

[19Cutlass94]

its not really about driving in OD and how it has no power, (I guess I should change the topic name) but when going up a hill in OD, and when I step into it, it makes a horrible noise, right before it shifts out of OD ( if I step into it hard enough) But the noise is more evident when you step into it up a hill, although just goin on a flat road, it will make the same noise when I step into it.

[birdman]

well i would check the knock sensor then. the moaning is probobly just the sound of the motor straning but the grinding/ knocking sounds like a timing issue.

[19Cutlass94]

But then wouldnt I hear it through all the gears and not just in OD?

[birdman]

so no matter how hard you push it in any other gear it wont make the same sound??? try and put it in 2nd at a low speed and give it alot of gas and see if it does it, that'll tell ya if its just OD and help narrow the problem down.

[GP1138]

if the knock sensor it shot then i could see the timing advancing too far.

 

If the knock sensor is shot the timing will be retarded anyway.

[Crazy K]

I think the sensor could fail and never tell the car it has a problem.

[19Cutlass94]

No matter how hard I push it in any other gear (havent floored it but 4500 is close) the only sound it makes, is like that lifter tick or some might say its piston slap, but its not very loud at all, in fact you can barely hear it, then the muffler takes over at about 3000 and it just screams. It only happens in OD from what I can tell, but when I drive it 2m to school well find out.

 

Ill also check the timing when I can too to see where it is.

[1990lumina]

Could it be a "ping"??? My dad's old Suburban used to ping under stress, but that was because he never ran the correct octane fuel in it lol.....maybe you have some bad gas or something.....that's a long shot though

[GP1138]

I think the sensor could fail and never tell the car it has a problem.

 

No, if the sensor doesn't send a signal, the car would throw a code.

[19Cutlass94]

The car isnt throwing any codes. Unless the SES light bulb burnt out and I duno about it

 

 

1990lumina, I doubt thats the problem, its not really a pinging sound. But Im only at 1/4 tank so Ill throw some 89 in there. Ive always used 87 and its alwas ran fine on it. But I dont think the gas is gonna fix like the moaning/ low groaning noise

[19Cutlass94]

well the drive into school was pretty fun......lol, but I found that it only makes that noise from around 45-to-50 (roughly 50) because going 60 and really stepping into it, nothing.

[SigEpCutlass]

I think the sensor could fail and never tell the car it has a problem.

 

No, if the sensor doesn't send a signal, the car would throw a code.

 

I agree. When my knock sensor went, it threw a code and turned on my check engine light. Well that and the fact it felt like it was working on 3 cylinders.

[soya_sauce]

hhhmmm just a thought, but how many kilometers on the engine? im not sure what engine you hve in your car but i know that the 2.8l, 3.1l and 3100 all used a timing chain instead of a belt. if theres a alot of slack in the chain you might be hearing the chain slapping against the cover or guide. This would explain why it only happens in overdrive. you would only hear the chain slap at relatively low rpm and while the engine is under lots of load.

 

to check for alot of play in the chain, remove one of the valve covers and turn the crank shaft pulley in one direction till the valvetrain moves, then turn the pulley in the oppsisite direction and note how many degrees the crank pulley rotates until the valve train starts to move again. THe only thing that would make this check inaccuracte is if the hydralic lifters bled down while you were taken the valve cover off. so after you have the cover off start the engine briefly, be prepared to clean up some spilt oil.

 

i'de say anything close to a quarter turn would mean that the chain should be replaced

[JoroCorona]

Its when the TCC is active. I could be a host of problems. It should be shuddering of the TCC. It could be that the timing is just far enough off that with the TCC not engaged, the TC absorbs the noise and with the the TCC active it transmits it through the driveline. It could have a dead cylender, like above only transmits sound when the TCC is active. You need a power balance test.

[19Cutlass94]

I think the best place to start would be the timing. But whats exactly involved in a power balance test?

[JoroCorona]

You'd need a scan tool to do a power balance test. You could do a by ear power balance by disabling the fuel injectors and cranking to hear if the crank speed goes fast-slower-faster-slower. This would be a cylender not making compression and thus being dead. This doesn't show a timing issue though.

 

I'd find a known good ICM and coils and see if that clears up the problem aswell. A coil not firing properly would cause a studder.

[19Cutlass94]

but wouldnt that do it throught the whole entire rpm range and in ever gear?

[JoroCorona]

If its slight, no, it would only transmit the sound when its under load with a locked up TCC