Hennessey 600 Running Like Sh......t

[TOPDOG RACING]

Im Looking For Help With My 1995 Rt/10 Venom 600.

I Know Its A Hennessey & I'm Familiar With His Lack Of Honesty. However I Bought The Car From Some Old Gizilionaire In Nj Who Gave Up On The Car After He Bought It New As A Venom 600 & Paid Like $100k For This Thing. When I Got The Car It Had 4600 Miles On It And Was Completely Screwed Up. Apparently The Owner When He Got It From Hennessey Didnt Like Driving It Because He Said It Was To Hard To Drive & To0 Fast So He Had Someone Try To Detune It By Taking Off The Hennessey Parts Like The Headers, Exhaust, High Flow Air Cleaner & Put Back The Stock Throttle Bodies. Needless To Say It Ran Worse, So He Parked It In His Mega Garage And Forgot About It.

Since I Had It I Have Been Unscrewing This Car By Bringing It Back To Alledged Venom Spec. I Installed Belanger Headers & Side Exhaust Kit (no Cats), Side By Side Cone Style K&n Air Filters Also From Belanger, Low Temp Thermostat, Wires, Plugs, New Motor & Trans Mounts & Roes Fan Kit.

The Car Seemed To Run Ok For A Couple Of Hundred Miles But Always Had A Stumble On Take Off No Matter How Many Time I Adj The Trottle Cables. It Also Boggs At A Low Rpm Cruise To The Point That It Seems To Be Starving For Fuel But If You Downshift And Give It Gas It Will Take Off . When You Go Into A Low Rpm Cruise Again It Will Do The Same Thing So I Changed The Trottle Position Sensor Now I Cant Even Make It Down The Street, The Car Bucks, Pops, And Completely Boggs Unless You Go About Half Peddle Then She Will Take Off But Still Running Like Crap.

I Checked To Make Sure The Sensor Was In Right (its Not Rocket Science), And Even Put Back The Original Sensor And The Same Thing. The Car Starts Fine But Is & Always Did Run Real Rich, I Always Thought It Ran Rich Because Of The Cam, Which You Can Definitly Hear The Choppy Idle. Also I Know Hennessey Installed The Aluminum Flywheel & Short Throw Shifter But I Never Pulled The Valve Covers To See If The 1.7 Td Rockers Are There, The Invoice From Hennessey Lists Them In The Pkg But Who Knows.

I Really Had The Car Close To Top Form But I Have No Idea What The Hell Is Up With It Now. Does Anyone Have A Clue ? Respond Or Call Me 862-703-0159 Thanks All

 

[kcobean]

1. Is it throwing any codes?
2. Have you checked timing?
3. What did the plugs look like, and did you replace them plugs that Hennessey put in it with identical plugs?
4. What's your fuel pressure look like?
5. Is it a 708 cam?


You might go back to an OEM clutch/pressure plate. I believe cars with lightweight flywheels are more prone to low-speed bucking at constant speeds.

 

[CitySnake]

You seem to be local. You should PM Bobby C. or Tom R. in the NJ region and they can give you their suggestions.

I'd point you to Chuck Tator whose already "re-worked" some of Hennessy's older re-sales. 914.763.3136

 

[TOPDOG RACING]

I Dont Have A Scanner That Reads Obd1 Codes But I Did Order One, As Far As The Plugs Yes I Did Change Them, The Wires, Oil, Filters & Everything Else Hennessey Might Have Done, The Fuel Pressure Is Between 50 & 55 Psi At Idle, I Dont Know What It Is Under Load. I Have No Idea What Cam Was Incl With The Venom 600 Pkg But It Definitly Has A Cam With A Pretty Choppy Idle, Like I Said I Dont Know If The Td 1.7 Rockers Are There Or Not. But Aside From The Car Bogging And Laying Down At A Low Cruise Rpm At Least It Was Drivable. The Real Problems Started Over The Weekend When I Changed The Thottle Position Sensor, Now The Car Cant Make It Down The Street However In The Driveway It Starts,runs (very Rich), Idles & Revs Smoothly No Problems. Is It Possible The Pcm Has To Be Reset ?

 

[kcobean]

I would give Hennessey a call and see if he has any documentation on that particular build to see if he can tell you what cams/rockers are installed. It can't hurt to reset the PCM. Another thing I would try is to reinstall the old TPS and see if your problem subsides. Perhaps possible you have a pad TPS that's giving improper signal at certain ranges?

 

[TOPDOG RACING]

I Called Hennessey And Hes The Poster Child For Arrogant. I Have The Build Sheet That Lists The 1.7 Rockers, Head Work, Air Box, Aluminum Fly Wheel & Hp Clutch, Aluminum Radiator, Throttle Bodies, Plug Wires, Headers / Side Pipes, Short Throw Shifter, Aluminum Pulleys, Yada Yada Yada. I Tried Putting Back The Old Tps & There Is No Change Which Is Funny Because Prior To The Change The Car Was Drivable. I Know I Never Reset The Pcm, The Only Thing I Did Is Disconnect The Hot Line On The Starter When Installing The Belangers & New Side Exhaust Last Year. Then Found That I Couldnt Start The Car After The Battery Was Temp Disconnected Due To The Electronic Lockout Which I Disabled After I Got The Car Running Again. As I Understand It To Reset The Pcm I Need To Disconnect The Battery At The Source And Hold The Pos Terminal To A Chassis Ground For 10-20 Seconds ? Then Reconnect The Pos To The Batt & Presto. Boy What Ever Happend To The Good Old Days Of Carburetors & 1 Wire For The Magneto.

 

[pteam]

That takes a lot of work to capitalize each first letter in each word!

I would definately change plugs and wires to start if you havn't.

 

[REDSLED]

What is the condition of the battery? These cars do very funny things if the battery is not fully charged. Also check the IAC.

 

[TOPDOG RACING]

Not Much Work I Just Leave The Caps On. I Chahged The Plugs & Wires, As Far As The Batt Its Fully Charged. Ive Redone Everything That Hennessey And That Bozo That Tried To Detune The Car Did Except For Adj The Rockers Providing There Is Td's In There, I Also Left The Stock Throttle Bodies Since Everyone I Talked With Said To Leave Them Alone For The Street At This Point So I Did & It Was Running Ok Except For The Minor Problems I Mentioned Earlier. What Is The Iac ? And Does Anyone Think The Reset Will Work ? And Is That The Correct Procedure For The Reset ? Boy I Thought Ferraris Were A Pita. I Also Have A 3.33 Rear Gear Set From Alan Perf But I Havent Put It In Yet, I Want To Get Through This First.

 

[ViperGTS]

WIZARD - his nickname is probably your way to go ...

 

[RTTTTed]

I'd probably use some ether to check for vacuum leaks. It's an old car with few miles on it. Cuprit could be a leaky gasket. If your problems started with the TPS perhaps it's the connector?

It's possible that the problems you have are the ones that caused the original owner to park the car in the first place. Perhaps he changed the parts in the same attempt you're making to fix the car? Or he made the changes causing the problem. Whenever parts are changed on modern engines the electronics also need to be changed to match up to the physical changes. That normally requires a 'tuner' and a dyno.

Ted

 

[uvbnbit]

Not Much Work I Just Leave The Caps On. I Chahged The Plugs & Wires, As Far As The Batt Its Fully Charged. Ive Redone Everything That Hennessey And That Bozo That Tried To Detune The Car Did Except For Adj The Rockers Providing There Is Td's In There, I Also Left The Stock Throttle Bodies Since Everyone I Talked With Said To Leave Them Alone For The Street At This Point So I Did & It Was Running Ok Except For The Minor Problems I Mentioned Earlier. What Is The Iac ? And Does Anyone Think The Reset Will Work ? And Is That The Correct Procedure For The Reset ? Boy I Thought Ferraris Were A Pita. I Also Have A 3.33 Rear Gear Set From Alan Perf But I Havent Put It In Yet, I Want To Get Through This First.

Idle Air Control Motor

 

[jpa99acr]

the OP didn't capitalize the first letter of each word, he used all CAPS and the site has a filter that changes the words that way.

OP, turn off your CAPS lock.

 

[Shelby3]

TOP DOG RACING, huh.

 

[TOPDOG RACING]

The Car Only Has 5,200 Miles On It Now & I Had It Running Pretty Good Until I Changed The Tbs Then Everything Went To ***. Im Probably Going To Have To Take It To Someone But Ill Try The Reset To Seen If That Helps.

 

[Venom-US]

Do a search on Throttle Position Sensor. Found this: http://forums.viperclub.org/rt-10-g...ank-you-tom-sessions-erratic-idle-solved.html

Sounds like your PCM will need to learn the new TPS at wide open throttle. After you reset your PCM, BEFORE you fire the car up, turn it to the "on" position and push the gas pedal to the floor a couple times so the TPS can learn the voltage at WOT.

Hope this helps

 

[99 R/T 10]

Tator's Dodge or 914-763-3136.

If you still have the oversized TB's, you might want to put them back on to see if there is any change. When you put the stockers on, did you take off the TPS or buy a new one?

You might want to try to disconnect the PCM(power control module) for 20-30 minutes. That might help too.

 

[TOPDOG RACING]

Thanks For All Your Help Guys, Ill Try Reseting The Pcm & See What Shakes. Shes A Great Car Theres Just A Few More Bugs To Work Out. I Do Have A Set Of 3.33 Gears, Does Anyone Know If They Work Better Through The Rpm Range Over The 3.07. I Tried A Set Of 3.55 On A 95 Viper My Friend Had, It Was No Venom 600 But It Did Run Better & Had A More Usable Power Band.

 

[99 R/T 10]

3.33 is a great gear set and will only add to the fun of driving the Viper!

 

[RTTTTed]

The gears depend on your power and useage of the car. The 3:55s caused my car to need an extra shift during the quarter mile and slowed the car down drastically. 3:07s went back in. The Roe sc makes huge bottom end and that used to overpower the car until about 100mph (no traction). Now that I've installed PS2s I have tons of traction. 1st gear is still mostly useless, except to save the clutch, but if you want to change your gear for more torque at lower rpms ... ?

I drive my car in 6th gear at speeds as low as 50mph and get 20mpg. Tons of torque for passing and driving through the mountains.

As I said, depends on your useage and personal preference.

Ted

 

[plumcrazy]

Tator's Dodge or 914-763-3136

and where are you from ?

 

[GTSjbud]

I would give Hennessey a call and see if he has any documentation on that particular build to see if he can tell you what cams/rockers are installed...

I also called Hennessey to see about documentation in regards to my 96 Venom 550 and guess what? Hennessey kept zero documentation. In other words no documentation exists on any of the Venom packages that he sold.

I have no idea when and if he started to retaining records for Venom packages sold.

Only way to verify that you have Hennessey engine parts/mods etc. is to take the engine apart and examine it.

 

[TOPDOG RACING]

Sence You Asked Im From Nj & The Name Topdog Racing Started Back In Early 1990 When I Built A Street Cuda Known As Suicide Blonde That As Far As I Know Is The Only Retired Undefeated Street Driven Drag Racer From That Time In The Tri-state Area,chrysler Used To Have It On Display At The Englishtown Mopar Nationals, The Drag Race Event Not The Car Show Every Year When They Used To Host It, The Car Paid For Itself 10 Times Over. I Know Of Hennessey Is A Real Piece Of Work, Im Amazed At The Factory Support He Must Have A Real Good Bs Line, Maybe He Should Run For President. Anyway The Only Records I Have Are The Invoices & Docs I Got From The Original Owner. To Really Be Sure Of The Head Work You Have To Take Them Off Or Drop An Optical In There If You Have Access To One. But I Know The Cam Is There, I Do Love That Choppy Idle.

 

[1BADGTS]

Definately go see Nick at Modern(done alot of stock-heavily modded Vipers of all generations.He is about 1 hour from you (105 on the GSP) He is not just a mechanic but an in house machine shop with a local dyno ran by famous hot rodder Bob Ida nearby.

 

[crazyspeed]

Boy, your use of caps is sure bugging me

Sence You Asked Im From Nj & The Name Topdog Racing Started Back In Early 1990 When I Built A Street Cuda Known As Suicide Blonde That As Far As I Know Is The Only Retired Undefeated Street Driven Drag Racer From That Time In The Tri-state Area,chrysler Used To Have It On Display At The Englishtown Mopar Nationals, The Drag Race Event Not The Car Show Every Year When They Used To Host It, The Car Paid For Itself 10 Times Over. I Know Of Hennessey Is A Real Piece Of Work, Im Amazed At The Factory Support He Must Have A Real Good Bs Line, Maybe He Should Run For President. Anyway The Only Records I Have Are The Invoices & Docs I Got From The Original Owner. To Really Be Sure Of The Head Work You Have To Take Them Off Or Drop An Optical In There If You Have Access To One. But I Know The Cam Is There, I Do Love That Choppy Idle.

 

[TOPDOG RACING]

Get Over It, Thanks Joe Im Going To Call Him Tomorrow & Ill Let You Know How I Made Out.

 

[Username]

Get Over It,

I think you may've just bit the hands that could feed you...good luck with your Hennessey bomb and caps lock button.

 

[RTTTTed]

Username has a point. You post that Hennessey is dishonest and then ask him for help?

John Hennessey developed much of what the Viper now is and that's why Chrysler works with him. His Venom 1100s are about the fastest car you can buy under a half million, period.

Ted

 

[RTTTTed]

With all the research and wins Viper has gotten from J. Hennessey I think he deserves our respect and he's earned it.

I also ordered a Venom spoiler for my GTS, just because I go to the track once in a while. It also happens to be the only spoiler that doesn't look like it came from a REAL racecar or a Japanese copy of a racing spoiler.

Ted

 

[Rick530]

this is a bummer. I personally have had nothing but good experiences with Hennessey.