Gen 3 Bucks at a constant speed

[cash84]

2006 Gen 3

It's been a while since I've been on here. For the past 3 years probably put on little over 1000 miles. Very rare of me to even do that. lol

The issue has been since I rebuilt the engine about 4-5 years ago. The engine was stock with bolt-ons and Blew up on turn 1 at Mid-Ohio. Gave me a chance to rebuild and put forged bottom end in.

The bucking I thought was more because of the cam, big TB, and lighter Flywheel. But I've been doing research and haven't found much solid info that is the cause. It's worst from 1st gear and better when in higher gear. 3rd at 2000rpm really bucks.

The list

upped the CR 10.2:1
Roe racing 710 cam
Dual valve springs
Cleaned up burrs in the ports of the heads
Light flywheel, not Alum (I can't remember what brand it is)
BBK twin 67mm TB
K&N air intake
Mopar race exhaust (stock headers no cats)
AB wires/ Bosch +2 plugs (recommended by Roe)
Dry sump system built by me (this bucking was done before this install)

What I have checked

Vacuum leaks
Compression Test average of 175 all within less than 5%
data log with A/F ratio and everything looks very good except at idle the timing seems to jump quickly of 10-15degrees. I would assume because of not enough vacuum from the big cam.
Spark plugs looks great.

What I will check tomorrow are my coil packs. I've always wanted to upgrade to Screamin' Demon packs.
I thought I still have my stock TB but I may have sold it. This is another try but I have to see if I can find a used one or if someone local around Milwaukee/ Madison, WI that I could quick use.

I would love to hear some inputs what may cause this. I have spoke to Sean from Roe Racing about the situation awhile back and I've gotten busy with other things and forgot about it.


I normally can figure this out myself but there are so many variables that could cause this.

[J TNT]

The 710 cam can be hard to tune for driveabilty . Dan Craigin may be able to help you out .

[cash84]

I should have mention that I got a tune from Roe that was made to my setup but wasn't live tuning on dyno. I may have to contact Dan if he doesn't get to this when I do.

[PaulP]

Curious of pics of the dry sump?

[Thom]

For your bucking problem, try replacing the throttle position sensor. I think they cost about $40.

[Rocket]

TPS is a good start and there is also a minute portion of play/adjustability in your existing TPS that might make a small difference. Bucking did not start on my gen 3 until I added the large single throttle body. Many others also felt their Bucking problem was from the throttle body (various manufacturers) with limited success in fixing the problem. Good luck.

[cash84]

Curious of pics of the dry sump?

Sorry, I'd like to keep this to myself. I plan on seeing if there is an interest in a complete setup with tank. This setup is a close to a direct bolt on but still needs to be revised to make it complete bolt on without having to modify anything. Nothing is removed. I still do have my A/C and tank in an excellent location. Can hold up 20qts but no need to have that much once the lines are full. I only put 10qts in for just street driving. Will be a topic brought up about it and will be very reasonable price compare others out there.

[cash84]

For your bucking problem, try replacing the throttle position sensor. I think they cost about $40.

TPS is a good start and there is also a minute portion of play/adjustability in your existing TPS that might make a small difference. Bucking did not start on my gen 3 until I added the large single throttle body. Many others also felt their Bucking problem was from the throttle body (various manufacturers) with limited success in fixing the problem. Good luck.

I did some datalogging with the TPS, it works flawless. I did notice that when pedal is not pressed down, it shows 10% and when full pressed down, it shows 79%. After doing some research. This is normal, if the sensor gets close to min or max limit, it would throw a code saying its out of range. So I was messing with the TPS at idle and started to run a bit smoother once i adjust the TPS. I decided to adjust my idle stop more open and recal. my TPS and it started to run smoother. I still have the buck but no where near what it used to be.

I've was roaming around with like the vettes forum and it seems to me that it is very hard to tune out such a big cam but its possible with enough time involved in the tune, its possible. As of right now, I'm much more comfortable where it stands. I see that it starts to run very rich during WOT so I may have to take it to a dyno and send the Graph to Sean @ Roe to get the tune tweaked more.

[J TNT]

Look forward to your finished results !

Sorry, I'd like to keep this to myself. I plan on seeing if there is an interest in a complete setup with tank. This setup is a close to a direct bolt on but still needs to be revised to make it complete bolt on without having to modify anything. Nothing is removed. I still do have my A/C and tank in an excellent location. Can hold up 20qts but no need to have that much once the lines are full. I only put 10qts in for just street driving. Will be a topic brought up about it and will be very reasonable price compare others out there.

[viper04]

cash84
How is it going? Hope all is well. Give me a call when you can. Nice seeing you posting again.

[Doorman]

I have a 06 Paxton car that bucks wildly above 4500 rpm. I too changed the TPS, Idle control motor, plugs and the problem still exists. I'm sending it off to Serious HP in Houston to see if they can figure it out. I'll let you know how we solve it. Keep posting- Thanks!

[WestminsterSlim]

TPS is a good start and there is also a minute portion of play/adjustability in your existing TPS that might make a small difference. Bucking did not start on my gen 3 until I added the large single throttle body. Many others also felt their Bucking problem was from the throttle body (various manufacturers) with limited success in fixing the problem. Good luck.

Hmmm... This doesn't give me the warm fuzzies. Was planning on doing an intake and big single blade TB over the winter.

[Doorman]

Got the bucking problem fixed. It was a short inside the VEC3 controller. We replaced the VEC3 with the SCT tuner and they made a custom tune. Car ran great for a month. Now a similar problem, not as dramatic as the bucking before but a power loss and jerking power band under load. Going to look into the fuel system. Anyone else have this issue?

UPDATE: The problem was the engine wiring harness, had a short. Todd at A&C diagnosed the problem in less than an hour and fixed me up right. Still running great!

[GenIIIDave]

Hmmm... This doesn't give me the warm fuzzies. Was planning on doing an intake and big single blade TB over the winter.

Yeah and I am looking into doing the 710 cam in my Gen 3.

[Mopar'er no car]

Sorry, I'd like to keep this to myself. I plan on seeing if there is an interest in a complete setup with tank. This setup is a close to a direct bolt on but still needs to be revised to make it complete bolt on without having to modify anything. Nothing is removed. I still do have my A/C and tank in an excellent location. Can hold up 20qts but no need to have that much once the lines are full. I only put 10qts in for just street driving. Will be a topic brought up about it and will be very reasonable price compare others out there.

Yeah because pics would just fubar your entire plan. Cool story, bro!

My Friend from NC was having the same problem when he did the cam and heads on his coupe.