surges at 4000 rpms

[dman]

I have a 92 euro with a 3.1. it surges when it reaches 4000 rpm in park. same surges/stumbles when in drive not in reverse. changed MAP, ECM with same prom. reset idle speed. no cmputer codes. replaced three coils and ign module. fuel pump pressure is 40 psi and steady while surging. surges occcur while accelerating in drive and may die when coasting. any ideas? does this car have a rev limiter. what about the knock sensor? what would happen if the knock sensor was bad?

 

 

tks

[Cam'ron]

maybe reving to 4k in park isnt so good for the engine...

 

i know my car will retard the throttle if i rev it in park

[19Cutlass94]

Did you try plugs? wires? fuel filter?

[GP1138]

If the knock sensor was bad, you would have a SES light and a code 43, and you would just be sluggish all around. That most likely is not your problem.

 

My gut says your Park/Neutral switch is somehow out of whack. If you don't get a surge in Reverse (how would you go about testing that, anyway? ) but you get it in Park and Drive, that says there's a problem. Maybe I'm off, though.

[19Cutlass94]

sorry I missed the reving in park, part. Does it do this in drive above 4k or at wot? if not I wouldnt worry about it, cuz I mean cmon who revs it in park

[dman]

in park surges start @4k.

in drive, holding brake surges throughout full rpm range.

in rev, holding brake, no suges.

new fuel filter.

plugs & wires less than 5000 miles.

where is the park/neutral switch and how could that be related. not sure what it does and how it works.

 

thks

[Cam'ron]

is anyone else confused readin that? are you talkin about the engine not idling evenly through the rpm range when your doing that or am i reading this completley wrong

[19Cutlass94]

maybe a vacuum leak...

[dman]

this is moms grocery getter. i said surges but it is more like sputters and light backfire in drive from idle through the gears. WOT seems to be ok, but WOT is not always best for a 65 yr old granny!!

[19Cutlass94]

then its more like a vacumm leak then. cuz at WOT, theres next to no vacuum, but when its idling if theres a vacuum problem, youll notice it, even when driving it.

[dman]

checked for leaking vacuum. theres only three lines. all are good.

[1990lumina]

If you don't get a surge in Reverse (how would you go about testing that, anyway? )

 

I have bounced off the rev limiter several times with my car in reverse......when getting unstuck from deep snow, etc.

[Cam'ron]

are you talkin about surging like this...

this was constant pressure on the gas, it just bounces like mad when you get high enough on the throttle... completley different cars but i dunno

 

http://media.putfile.com/MVI_0012

[19Cutlass94]

Thats a good surge

 

EDIT: took the pic out

[Cam'ron]

lol i dont know what happend there i thought i caught it quick enough but i guess not the link i wanted to put there is there now

[dman]

yes, steady accelleration. bouncing like mad is a pretty good discription. also spitting and sputtering.

[Cam'ron]

would there be a limiter like on my monte on the older cars? my guess is it is there to prevent damage from over revving the engine unnescesssarily... never spell that right

[dman]

yes constant pressure on the gas. bouncing like mad is a pretty good discription. also spitting and sputtering.

[dman]

does the limit happen in the ECM or is it a speed sensor on the crank?

[Cam'ron]

[dman]

does anyone know where the vacuum ball or the canister is on my 92 euro?

[3pt1lumina]

Front drivers fender. Take the inner plastic fender off and bingo, there ya go.

 

 

FYI, my 90 Lumina 3.1 has a rev limiter at 4k in park/neutral. If you are revving it up and that's occurring, well, then you are hitting the limiter.

 

That's not so good for the motor either. I'm real confused reading this post.

 

and yes nametnom your car has a limiter too at 4k. So does my mom's 03 Impala, and every other car that I know of except my old school rides.

[Crazy K]

Front drivers fender. Take the inner plastic fender off and bingo, there ya go.

 

 

FYI, my 90 Lumina 3.1 has a rev limiter at 4k in park/neutral. If you are revving it up and that's occurring, well, then you are hitting the limiter.

 

That's not so good for the motor either. I'm real confused reading this post.

 

and yes nametnom your car has a limiter too at 4k. So does my mom's 03 Impala, and every other car that I know of except my old school rides.

He's correct. I believe the ECM/PCM cuts off the fule injectors when you hit the rev limiter.

[GP1138]

I'm totally confused by your description of the problem, but reading your further comments, I stand by my original hypothesis.