Masochist

iTrader: (1)

The old 'bird has an issue I've been trying to nail down and was hoping for some help on. Some details; she has H/C/I, full bolt-ons, rebuilt lower end w/ stock crank and a 24x conversion.


After a hard pull she does not like to idle correctly. The idle drops to about 4-600 and starts to chug, lights go dim etc UNTIL I come to a complete stop, then the issue corrects itself until I'm moving again or shut the car down for a while.

As I said If I turn the car off and leave it off for a half hour or so the problem seems to reset itself. It also has thrown a code for the MAP sensor which I have since pulled and cleaned.


Any ideas what this is? A faulty MAP sensor? I love my bird but I am f-ing selling this car after I nail this issue down.

97lt1camaro

iTrader: (3)

I have eficonnections 24x swapped lt1 with the same issue.

After hard runs it will drop idle while rolling. Usually comes up when it's at a full stop.

It's in the tune somewhere as far as I can tell

Masochist

iTrader: (1)

I'm not happy to hear you have the same issue as well as the same 24x conversion I have. The cam in this car is rather large and the tuner I used specializes more in imports so this car kind of kicked his *** a bit. It's decently well tuned but there is a bit to be desired.

Has anyone else experienced this issue? Again it popped a MAP sensor code for me after a while.

AdsoYo

iTrader: (1)

so this wasn't happening before 24x? how long do these hard pulls last? if you don't come to a complete stop, will it idle poorly forever or eventually fix itself? if you shut the car down then immediately start it back up, that won't fix it? it has to be at least 30 minutes? I think the MAP code is more a response to the low idle and not a cause of anything. The car performs fine in all other conditions correct? cruises fine, accelerates fine etc? sounds like your tuner needs to dial in the throttle cracker and follower tables (and possibly more) or he has your cars transmission wrong. what kind of trans is it?

SS RRR

iTrader: (2)

Do you have an underdrive pulley? Aftermarket TB? Has a code been thrown since you cleaned the MAP sensor?

Masochist

iTrader: (1)

The car is an M6 and no it wasn't doing this before the 24x. The hard pulls that trigger it don't need to last long sometimes just to 4-5k and back off in second gear. The issue does seem to clear up after I restart the car but can sometimes can back right away if I don't leave it off for a little while(around 30 min). The car runs and drives perfectly fine despite running rather rich. It doesn't hesitate under acceleration at all and feels strong.

I was not able to erase the MAP sensor code, it never went away after it appeared even post cleaning. No underdrive pulley but it does have an alt relocation kit that deleted A/C. TB is aftermarket dual 58mm.

97lt1camaro

iTrader: (3)

I as well have an aftermarket 58mm BBK throttle body. I have modified the back of it as well to resemble the factory throttle body with the plenum air and iac air being separated.

My car seems to run decent once it's hot. But when it's cold if I rev it up it will idle lean (as per wideband) and idle shitty then eventually just clear up.

If I drive it hard before its fully warmed up. With clutch in and rolling to a stop it will chug and idle low until it fully stops. As soon as it comes to a complete stop the idle bounces back up

moehorsepower

iTrader: (3)

Its in the tune, depending on the software used, there is a running airflow table that needs to be adjusted on the airflow vs temp..

AdsoYo

iTrader: (1)

Not sure what program your tuner uses but on hptuners I'd be checking throttle follower, throttle cracker, rolling idle, base idle airflow, and trans type. The fact that it goes away when turning the car off has me thinking that MAYBE this isn't PCM related. Did you repin your harness or buy a new one for 24x?

97pontta

iTrader: (10)

My car does the exact same thing, kind of annoying. I really don't drive it hard enough on the street to notice it but at the drag strip when rolling up to the time slip shack after a run it wants to die from low idle. Just as described above once it comes to a complete stop it instantly corrects it's self and will drive/idle fine again. My car runs great otherwise, pulls hard and smooth, cruises great ect. I need to go back to my tuner to update for the 4.30 gears and would like to have this issue fixed as well. I know my tuner does mostly American V8's and uses HP tuners so if anyone has any suggestions that I can take with me to the tuner that would be helpful.

ACE1252

You need to figure out what is causing the MAP code. if something is wrong with the MAP sensor or it's input to the PCM, then drivability issues will certainly follow.

What is the PXXXX number the PCM is throwing?

Masochist

iTrader: (1)

The P code was P0107, specifically for the MAP sensor. I'm thinking I might replace it just to tick that off the list since it's only about 40 bucks.

My tuner was using HPTuners and had never worked with a 24x LT1 before so it left a little to be desired. As far as the harness it was new so it must be in the tune or the MAP sensor itself which is far less likely... from what I understand these units are actually built to last unlike most everything else on these cars lol.

AdsoYo

iTrader: (1)

yeah id be extremely surprised if the MAP sensor is bad

moehorsepower

iTrader: (3)

The reason you are throwing a map code is because of the low idle, LT's with healthy cams will throw a map code if when started its immediately at the desired idle, this is why with large cams, even moderate ones, I will have the cold start up at a high idle in order to prevent a map code.