vetteboyc5

iTrader: (9)

I put a MS4 in my 99 LS1 corvettte.. I took it to have it tuned (I wont mention who tuned it at this time)

they tuned it and now its having problems Idleing when u first crank it up, and it dies allot of times when even hot when u push the clutch in to come to a stop light.

so It constantly dies and you have to keep reving it up with the gas pedal to keep it to stay running. EXPECIALLY when cold.

The p0101 code never went away after it was tuned. it comes back every time. It runs extremely rich at idle... my clothes smell like fuel everytime I stand behind it.

What gives? the tuner is going to look at it again but What exactly is wrong... How can I get it to always idle for me and what to do about the p0101 code?

Mike@Diablosport

iTrader: (2)

So, this code was present before the tune as well?
Did the code only show up after the cam install?
Is it a stock GM MAF?
Also, did you tell the tuner you were getting the code?
The MS4 needs some time spent on idle tuning generally, so I'm sure it will come around when they get another look.

vetteboyc5

iTrader: (9)

the code came on after the cam was installed..

stock 99 Maf.

Is there ways to tune the fuel mixture at idle, and idle so it will idle good even cold?

The tuner is a long way away from me so Id like to verify that it is indeed fixed before i go home..

Cam72aro

iTrader: (28)

Yes, timing and fuel mixture at idle are very tuneable. Timing has alot to do with startup along with fuel mixture.

TAQuickness

iTrader: (28)

With P0101 present, the car is running in Speed Density mode. It's likely the VE table is not representative of that cam. I'd take it back to the tuner and have him go thru the tune. You might also want to consider picking up your own tuning suite so you can have control of these types of situations.

VH5150

Tuning an MS4 is cakewalk...

vetteboyc5

iTrader: (9)

The tuner hasnt looked at it yet, but they keep wanting to point the finger at the Mass air flow meter. Without even looking at it.. a $350 dollar part, That seemingly worked fine before the cam install

I personally believe its more in the tuning at idle because when u first crank it up it wont stay running but you can make it idle after you pedal it a little bit.

I need to be armed with information when I return, because I dont want them to give me the run arround. The Maf code comes and goes every drive cycle. Even with the code NOT present, the Engine still wont idle sometimes..

even if the maf had a problem "all of the sudden" is there a way these two issues can still be corrected at their place and me replace the maf later.

What do I tell them to look at? I just dont want the run arround and find out it still the tune.

HPE Chick

that code is the MAF-- any where between a dirty maf sensor, connector, or actual maf....

Doc99SS

iTrader: (2)

I'm getting the same error code, P0101. I have been tuning my own car, however, as with vetteboy, the code only showed up having I installed a big cam. I even switched back to my factory MAF (after erasing the P0101 code) and the code came back. So with two known good MAFs, I get this code. Specifically, what can I do about this? The answer should help "arm" vetteboy also.

HPE Chick

i would try changing out the connector, or a bad ground wire on that circuit...

2xLS1

iTrader: (25)

If the scanner shows the MAF is working then the solution could be the Max Delta Airflow P0101 Error table needs adjusting.

Thimble

iTrader: (2)

P0101 is a very common code after a large cam install. It is caused by a conflict of MAF and MAP predicted air values, and big overlap cams skew MAP values enough to trigger this code. I had the same after my G5X4 cam install.

I'm a bit concerned your tuner wouldn't have seen this one before.

I use EFI Live, and with that software, you need to up the "MAF rationality test" diagnostic table (C2911) to eliminate this code. It is just a diagnostic table, a safety check...no effect on how the car runs. Up the whole table 200% and that should cure it.

HPT can adjust for the same, but I'm not familiar with that software to say how.

Doc99SS

iTrader: (2)

Big cams will cause the P101 code cause the PCM picks up differences between the MAF fueling and MAP fueling, and then the computer throws the P0101 code and goes into speed density mode. I increased the values in the MAF max error table (as mentioned above) and I have not gotten the code back. However, keep in mind that once you erase the code, it will not came back on until the second key on occurrence. So vetteboyc5, increase the values in the MAf error table and see if this helps.

gametech

iTrader: (1)

While those "fixes" will work, it still doesn't fix the fact that you have a half-assed tune. A proper tune would run just fine without the MAF, as our cars also have SD to fall back on in the event of a MAF failure. In the event that both fail, they also have a "fail-safe" Alpha-N mode to fall back on.

BLK02WS6

iTrader: (2)

Looks like you need a new tuner...

LS1BLKSS

iTrader: (36)

i just got my car tuned as well and that code poped up also... before the tune my car was running like ****, the rpms would dip down and come back up again i took it to the tuner about a week ago and everything was fine until 2 dayz ago that code popped up! car still runs fine, im just wondering is it safe to drive it like this, my tuner isn't that far but i just don't have time to take it since im working 6 dayz a week! also sometimes i turn my car on and the code isn't there and i drive a bit and pops up again!! i have a granatelli MAF, im not sure but i think i heard that with this MAF its a bitch to tune?? should i switch back to my stock one? or SLP?? sorry for

Doc99SS

iTrader: (2)

LS1BLKSS: If I were you, I would have the tuner fix the MAF error table. If the P0101 code is on, then you are running in SD mode, the PCM will not fuel the car according to anything from the MAF, it has assumed there is something wrong with the MAF. There is no problem with driving around in SD, many people have discarded the MAF all together and run SD always.

LS1BLKSS

iTrader: (36)

Thanx man, i talked to my tuner he said i should just switch out my MAF to a bigger one the 85MM and he will retune it for me later!

Mike K.

from the sounds of it, some time spent on VE tuning might be necessary, if the code is saying that MAP calculated value aka VE is too diff than MAF calculated value I'd have to guess that some calibration is needed especially of the VE table and then the MAF.

You can get it to idle correctly its a matter of getting the air/fuel right as well as the timing tables, plus you can't be scared to let it idle at 1k either IMO.

It takes a long time to dial this stuff in, like a few days worth of time. Make sure your tuner does the drivabilty tune and not just a WOT tune.