Thread: Engine takes a long time to rev down

I have a 3800sc series 2 (96) and it's attached to a manual trans and when I push in the clutch and let off the gas , the engine doesn't seem to want to rev down. It's like it's freewheeling with no compression. When I rev it in neutral in the driveway it also doesn't want to rev down . I was advised that it was prob a dirty tb so I cleaned it spotless but it is still the same . Any suggestions?

Thanks in advance !

best to post a vid so we all can see what its doing.

iirx we covered the cables and vac leaks already didnt we?

Yeah, I'll try to post a video today.
Thanks scotty !!!

Manual pcm file?
If it's still an automatic file do you have the range switch wired so that the computer thinks it's in neutral or in Drive?

hes got a tuned pcm from a fiero guy. id have to think its set up for a 4 speed.

its a 3800 swapped set up.

I don't know of too many 96 PCM files that are very well mapped. But I do know that the 9899 Regal and GTP files are.... so if they don't have access to the throttle follower gain for the IAC.....

i think the engines a 96, not sure what year bin or pcm hes running. its a canned tune. ive offered up help if he needs it being hes somewhat local.

if you dont have a matching maf installed for the year bin file your running, that could make it act a fool too.

I didn't know about the matching year MAF sensor. Supposedly the computer is from a regal but it's programmed to be a 2000 Grand Prix I think I can email the guy and ask him

the pcm is not a issue, but you need to call and see if its a 2000 bin, then if it is you'll need a tb and maf. iirc the 99-2000 maf is different then a 96. in the way the maf fits only pretty much.

and then there the change the maf file to a 96 maf in the tune too. the other option. if your using the 96 maf.

The Maf im using is from an unknown car (i can contact the guy I bought the tb from) I bought a throttlebody with all centers but I only took the MAF off and put it on my tb my Maf was broken physically crushed.

If that's the only issue I guess I COULD live with it.

Did it have a small Tower about the length of your pinky joint. Or did it have a large Tower similar to your thumb

Why would it be flashed with a 2000 file when you should not have need of any of the digital cluster outputs...aside from the pita enhanced obd2 with all the additional onboard tests that non emissions Vehicles find annoying when tuning

I know my car will rev hang a little if I bog it and the idle air has to take over from a stop. Then 1st to 2nd it rev hangs when I clutch because it still hasn't closed. Doesn't do it normally tho, does it search for idle at all normally on startup?

Originally Posted by Turbocharged400sbc

Did it have a small Tower about the length of your pinky joint. Or did it have a large Tower similar to your thumb

sorry for not understanding , but what is meant by "tower"? And when you say "did it have", what is "it" that you are referring to..

the tower is the portion of the sensor that goes into the air flow path, youll see two thin wire/sensor elements, the small tower has them inside a hole in the tower, the "big" tower has a 90* airpath to the sensor filaments.

you cant put a big tower into a small tower throttle body, but you can put the small into the later model years "big" tower TB, it just doesn't like it since there's no ducted metered airflow path past the sensor filaments which can cause annoying low load/airflow drivability problems

Ijust dug out the old one that I removed and it's hard to tell what kind it is but it has the same number on it (as part of the plastic /not engraved into the plastic) that the one I replaced it with does AFH50M-04

the engrave numbers on them are different the old one is 5Y13 and the new one installed in the tb is C7Z13

okay so is the tower the size of your pinky or the size of your whole thumb?