Hemi Car Lazy Acceleration ?

[broadfca]

Does anyone know anything about this for the 09 SRT 8 Challengers? Mine has become so lazy on acceleration that I almost can't take it any more.

Even the Diablo tune doesn't help.

I saw this on one of the forums:

Turn off your engine. Then, open the cover on the IPM (Integrated Power Module or Engine fuse block/power center) and pull Fuse F2 (25 amp, beige) for a count of approximately 15 seconds.

Pulling Fuse 2 does the following:

- All PCM DTCs erased.
- All OBD2 monitor results erased.
- All long term fuel trim adaptive values reset to Zero.

After you clear the PCM "drive your car like you stole it" to get your Challenger accustomed to that type of driving!

In the photo shown, it is the middle beige fuse located in the second bank of triple fuses from the lower right.

[mikel]

So, even stock, you say it feels slow?

Got a catch can?

[broadfca]

So, even stock, you say it feels slow?

Got a catch can?

Yes and Yes. I also cleaned out the manifold when I installed the catch can. There was some oil in there, and that was about 7,000 miles ago. been draining the can regularly and getting a little oil each time.

The issue: When I quickly depress the accelerator pedal in DRIVE, the engine rpm increases fairly slowly. If I put the car in PARK or Neutral and hit the pedal, the engine rpm increases instantly.

So... apparently you're not familiar with this process to erase the PCM adaptation memory (if in fact the PCM does have an adaption memory ???) This is what I'm trying to verify. Please post up if you come up with any info on this "pull the fuse" theory.

Also wondering if I do this, will it affect the Diablo Tune?

Just had the car to the dealership (restored stock tune first, of course) and (of course) they said they could find nothing wrong. They did flash the PCM with an update (for driveability issues for the autostick cars ???), but no noticeable difference. After the PCM update, I did have to download a calid update in my Trinity before I could re-install the 91 Perf Diablo tune, and still have the same acceleration issue.

Thanks to all for any educated input

[abuelo]

The "adaptive memory" DO exist. One on both on PCM & TCM sides. To check if it actually reseted you should read the LT Fuel trim & knock retards before and after; it should come back from whatever it has to zero.
On the TCM side you will feel the more noticible side; speciale on how it reacts in part throttle driving. But you can do this with the DS (at least on predator) on the quick adjust menu; only for transmision.
The bad thing is that all this adaptive memory wont do a very noticible diference on performance, at least not to make a 6.1hemi a slow car as you describled. There must be something else wrong with your car.

[broadfca]

The "adaptive memory" DO exist. One on both on PCM & TCM sides. To check if it actually reseted you should read the LT Fuel trim & knock retards before and after; it should come back from whatever it has to zero.
On the TCM side you will feel the more noticible side; speciale on how it reacts in part throttle driving. But you can do this with the DS (at least on predator) on the quick adjust menu; only for transmision.
The bad thing is that all this adaptive memory wont do a very noticible diference on performance, at least not to make a 6.1hemi a slow car as you describled. There must be something else wrong with your car.

Thanks abuelo.... ya, I tried the fuse pull and you're right, no difference. Since the dealership says they can find nothing wrong, do you have any ideas at all of some things I might go off and consider?

Even tho the car is stock (it does have a K&N drop in air filter with 10,000 miles on it), I'm going to go ahead and log it and send in my readings. I'm hoping I'll get lucky and find that it just needs a WOT fuel and or timing adjust.

It runs pretty good until I lay into the pedal (50 - 100% 1st gear in autostick mode). then it accelerates like it's in 2nd or 3rd gear when it's actually in 1st (in auto stick mode). Relatively "VERY" slow engine rpm increase.

When it's in "drive" and I lay into the pedal... after it automatically down shifts it goes pretty good.

It also runs much better first thing in the morning with 40* - 70* ambient temps. But it's hard to imagine that there's enough heat soak to make it this sick. I'm running a 180* stat with all fans lowered 20*. Still, when everything is at running temp... she just goes to sh*t on acceleration.

[ricks]

The issue: When I quickly depress the accelerator pedal in DRIVE, the engine rpm increases fairly slowly.

Good Morning,

When you say in Drive:
If you are moving, already into 2nd gear or higher, and the rpm's aren't real high, and you "press" the pedal; that is just how the car is. Meaning: If you are just cruising/driving and give it a good bit more gas, that is just how the car reacts. Slow. There's nothing you can do about that situation, in Drive.

In the same situation: If you floor it, the car should downshift and jump to life. And I do mean floor it.

When you're in the above situation and you decide you want the car to react faster, slap the shifter to the left at the same time you're giving it more gas and it will downshift one gear and bring the rpm's up. If you're cruising in 4th or 5th at cruising rpm's, slap it left twice and it will downshift 2 gears. Experiment with it to learn how it reacts.

Resetting the TCM's adaptives is good to do once-in-awhile, but the car quickly re-learns to shift too quickly and softly.

The easiest way to make this car drive like a sports car is to drive in Autostick: Shift it when you want to, without having to push a clutch pedal.

There is another product on the market that lets you adjust the transmission to what you want it to do. But, you have to be comfortable with it, personally tuning your car, and splicing into your wiring harness.

Don't be afraid to drive the car hard, such as in Autostick. You won't break anything. It can take it. In fact, it likes it.

[ricks]

Here are a few other thoughts. I have the same car.
Just trying to help. . .

On a warm/hot day, after you've been driving for at least 25 minutes:
Use your EVIC and record a few 0-60mph runs for us. From a dead stop, floor it. Tell us what you get and if you get any tire spin.

I know you are in California but I forgot where. As you know, outside temperature affects this car drastically.
1. Warmer temps heat up the road and your tires, giving you a lot more traction.
2. In my experience, outside temps above (around) 78* really, really slow the car down.
3. Do you have the A/C on? That puts another load on the motor.

I'm simply trying to help you determine if you do in fact have a problem, or if it's a case of, "That's just how these cars perform."

Sincerely,
Rick

[abuelo]

One other, what fuel are u using (octane).
What is strange here is that u say that the car performs good in drive but bad in autostick?

[broadfca]

One other, what fuel are u using (octane).
What is strange here is that u say that the car performs good in drive but bad in autostick?

Mobil 91 gas. I said it goes "pretty good" when it downshifts. Sorry for that bad choice of words there. I meant that when it down shifts it goes better than punching it in 1st gear auto stick. However, as embarrassing as it is, I found a vacuum leak..... problem solved. I'm going to post an explanation and a big thank you to all of you that chimed in to help me. I had asked the dealership to do a vacuum test when they had the car, but they didn't. So I found the leak myself yesterday... it was on the catch can hose that goes to the under side of the manifold. The hose clamp there was striped and the car was sucking air.

Thanks again to all ... what a mental mess this was. But I did learn some things from you guys and for that I am very grateful.

[broadfca]

The issue: When I quickly depress the accelerator pedal in DRIVE, the engine rpm increases fairly slowly.

Good Morning,

When you say in Drive:
If you are moving, already into 2nd gear or higher, and the rpm's aren't real high, and you "press" the pedal; that is just how the car is. Meaning: If you are just cruising/driving and give it a good bit more gas, that is just how the car reacts. Slow. There's nothing you can do about that situation, in Drive.

In the same situation: If you floor it, the car should downshift and jump to life. And I do mean floor it.

When you're in the above situation and you decide you want the car to react faster, slap the shifter to the left at the same time you're giving it more gas and it will downshift one gear and bring the rpm's up. If you're cruising in 4th or 5th at cruising rpm's, slap it left twice and it will downshift 2 gears. Experiment with it to learn how it reacts.

Resetting the TCM's adaptives is good to do once-in-awhile, but the car quickly re-learns to shift too quickly and softly.

The easiest way to make this car drive like a sports car is to drive in Autostick: Shift it when you want to, without having to push a clutch pedal.

There is another product on the market that lets you adjust the transmission to what you want it to do. But, you have to be comfortable with it, personally tuning your car, and splicing into your wiring harness.

Don't be afraid to drive the car hard, such as in Autostick. You won't break anything. It can take it. In fact, it likes it.

I found a frickin vacuum leak on the lower catch can hose. Watch out for those guys/gals. Whew.... what a relief. Everything good now.

Are you talking about the ESP Off Mod? I am comfortable working on the car. Been wondering about that mod and would like to know if it's worth installing. Any input here would be appreciated.

I can't thank every one enough for all your help. You guys are the best... including Diablo Sport !

[ricks]

PM sent

[bamachips]

The throttle response can also be modified with a custom tune, but you have to find a dealer that knows what they are doing. Do your research or just call tech, they can recommend a good tuner that can help.

[srt8-monster]

Throttle boost at 20% helps and in the future just unplug the battery for 10 mins and it resets everything. Also I would recommend using 93 octane gas with the 91 tune or just load the 93 octane tune instead. It's way more punchy with the 93 tune.