VIPER COMPUTER ISSUES

[tristan rizzi]

Someone PLEASE HELP me......

My 94 has been completely rebuilt (with LOTS of mods) and is not running right. It appears that the computer is staying in an open loop and not delivering the correct A/F mixture. On initial engine start-up and run in on the chassis dyno it looks good for over 500RWHP but without the correct fuel delivery we cannot test the car. Adding to the issue is that I am in Japan for a year. The car is at the Dyno Shop in San Diego!!! Does anyone have any ideas as to what might be wrong??? The engine has the following mods:

Honed Intake (4 rib) w/t 68mm Throttle bodies
Smooth tubes & K&N filters
1.7 rockers (full roller)
Stage III heads
Light weight coated pistons (stock compression)
Lightweight HIPO conrods
Hi energy Cam
Headers
3" Pipes (no Cats)
Full balance & blueprint
Aluminum flywheel....etc


At this point the engine builder and instaler are sure that the engine is sound, and that the problem is fuel delivery related.
Everything has been checked, and is correctly hooked up - any one have ideas??? Should I just have the car put back into my garage and take it to a viper specialist when I get back to the States??? Thanks for ANY advice offered


Tristan

 

[Bad_Byte]

Seems like there are several good techs in the San Diego area. I have used

WEST COAST VIPER
43124-C Rancho Way
Temecula, CA 92592
Phone: (909) 676 1204

John would probably even pick up your car and then deliver it where ever you want.

Are you in the military, is that why you're in Japan for a year?

 

[Doug Supercharged Vipers]

At this point, you need to put a DRB scan tool on it. If it's staying in open loop the DRB will advise you what the problem may be -- we would only be guessing for you.
You can also use a generic scan tool that can plug into the data port. Keep in mind, the OBD II will not work for your model year Gen I car.

Regards,
Doug

 

[tristan rizzi]

Thanks for your replies - I will follow up on all of your suggestions

Tristan

P.S. Yes I am in the military....

 

[ceieio]

<FONT COLOR="Black">Tristan - you should probably get a scan tool on the computer. There are many things that can hold the PCM in open loop mode. For example (I have a '96 - caveat emptor), the PCM stays in open loop mode until the engine coolant temperature sensor reaches 80 degrees (F). The coolant sensor passes a 0 to 5 volt signal to the PCM, BUT it is reverselogic. This means that it send a 5 volt signal (logic high) when cold and as it warms up it drops in voltage towards ground (a logic low).

When the sensor is cold, it is high impedance (resistance) and drops in impedance to conduct more current as it heats up. An open circuit in this device could possibly look like a cold signal. Also a short to +12v would definitely look like a logic high.

On the '96 a good thermal sensor will measure 11K Ohms on a volt meter. Since you had extensive work done to the car, I would check for damaged wires, bad connectors, and a damaged sensor.

Typical causes for a low temp indication problem are:
connector terminals, bad thermostat, engine coolant temperature sensor failure, PCM failure, and bad wires.

A second way that this could happen would be a problem in throttle position sensor (TPS) circuit. A bad TPS, a bad connection or broken wire on the TPS, or an open in the ground on the TPS will cause the PCM to see a wide open throttle (WOT)signal that would cause the PCM to run in open loop off of the WOT fuel map.

There is bound to be many more ways to hold the beast in open loop. I would think scanning the operation of the PCM and going from there is the best way.

Good luck!
</FONT c>

 

[SVS Turbo]

Tristan,

We can solve your concerns (simply) as long as nothing is hurt in your engine. Increasing the demands of a viper engine places strain on the very system you have added to it. The stock computer was designed for a stock Viper, nothing more - nothing less. It was engineered at Dodge to drive your 400 Horsies all day and every day. Carbs are history - Fuel injection rules the land. Computer fuel management is King. NOW! take time to think about this and ask yourself; Should I put all my efforts into a real nice saddle, stirrups, blinders and a nasty riding crop and try to slap the BeJesus out of my 400 Horsies and try to make them act like 600 Horsies? OR - try this!!!! ADD all of the above and include a improved diet management and proper fuel/food intake nurturing and then you eliminate the need to wonder why my horse(snake) will not perform. Now your system is prepared to run the Kentucky Derby every weekend. IT IS NOW A PROPERLY MANAGED AND WELL BALANCED SYSTEM.

Yes the stock computer can handle upgrades of immmmmmmmense proportions with BAND AID FIXES. Some of these fixes include Huge FMU's with larger injectors and monster fuel pumps to {{{{{{{{TRY}}}}}}}} to make the system run like it should. Believe me WE (SVS) understand this because we tried it in 1994. We switched to running Motec computer systems in 1996. Yes NOS is awesome/cheap Hp, but you still need to properly deliver the fuel at the same time your 300 shot nearly blows up your engine! It would be much safer and properly balanced if the fuel (injection)and the NOS were in harmony. NOW CLASS!!!! Why do we place water injection into a engine? ----RIGHT!----- To keep it from detonating. Detonation is BAD and if we properly manage the fuel in our systems we dont have to inject water into our engines. VERY GOOD! Think of all these things as pumping your snake with STEROIDS. Sure, your snake will look bigger - ACT Stronger? and SEEM like it runs PURELY. Maybe even win the Kentucky derby!!!! BUT you will be caught out, disqualified, your *enis will shrivvle up and you'll probably get cancer. Not the way I want to run my system!

Tristan, It would be an honor to help you purely run your system. (or anyone who needs proper fuel management tuning on any system) Dont be fooled by silly quick fixes that SEEEEEEEEEM to suffice. Help support us to help support you! You will not regret how awesome your Viper will run and feel.

GIVE ME SOME SYSTEMS AND THEY WILL BE NURTURED TO THEIR OPTIMUM BALANCE AND HARMONY.

Hello everyone if this is to heavy let me know. We strive to improve our relationship with Viper owners. We value your opinions, comments and suggestions. Help us to help you. Please tell us how we can improve our image, value to owners, faith in our systems etc. What things have you heard about SVS that would steer you away? I'm very passionate about doing whats best for Viper owners.

None of the above comments are directed at anyone that has posted above.

jR.

 

[Sean Roe]

Oxygen sensors not warming up properly can cause the car to stay in open loop also.
It took me days to figure out my car wasn't running right just because the ground wire for the upstream oxygen sensor heater circuit was loose (bolt on the A/C compressor was stripped though we had never touched it in 3 years). All the PCM would do was set a rich code, due to the sensors staying cool, or cooling off at idle.
Good luck with finding the cause. Let us know what you find.

Sean

 

[JonB]

Tristin....... Japan has GOTTA be better than the Phillipines, your last gig as I recall.......

I agree with Sean and Craig:

Simple Solutions Likely:

O2 sensors, TPS, Wires, even the BATTERY could be part of the problem.

You can also count on Dan Cragin, at The Viper Shop in LA.
West Coast has mostly G-2 experience. Dan is Da Man G1+2 in your general area.

 

[Eddie N]

did i just read an infomercial?

is the motec a stand alone ecu specifically for the dodge viper? aem makes similar units for other vehicles in the range of $1500.. now since its for a viper, i'm sure its alot more, but the question is, how much more?

does it give the tuner total control over the a/f ratio, timing, etc? i prefer stand alones to piggy back controllers..

- eddie -

 

[SVS Turbo]

Eddie,

It is stand alone. You completely get rid of the stock computer.
You start with a blank piece of paper. You create the inner workings of your engine to run in complete harmony with the fuel.
Its not rocket science, but it is the only way you will have complete control over your higher Hp systems. Everything else is WitchyPoo and her caldron of Tinker Toys.

Do you think that when Dodge raced the GTSR they sprayed water into the engine because they were afraid of it detonating. They (Caldwell) ran the V-10's with Motec. They ran the V-10's for 24hrs under the umbrella of a Motec computer system that completely balanced the fuel with a 800 Hp system.......................wait...................................I can feel another infomercial coming on......................


Reminds me of a story.

Guy goes to buy a bird. Salesman trys to sell him the special bird that talks for only 12.99. Guy takes his bird home. Comes back the next day and says "My bird dont talk"! Salesman says OH well didnt I tell you that the bird needs this special swing and he'll talk just fine! Its only 22.00. Guy buys it and goes home. Bird still dont talk. Comes back next day and says my bird wont talk! salesman says OH well you need the ladder for the bird to crawl up to the swing and then he'll sing --- Thats only 15.00. Guy buys it and goes home. Still no singing. Comes back next day very impatient and says Hey! my bird still wont TALK! salesman Says HHHMMMM well... oh yeah you need the mirror, so when the bird crawls up the ladder and swings on the swing he'll see himself in the mirror and then he'll sing.....and thats only 18.00. Guy buys it and goes home. Think he sings? ......NO.
Guy comes back for the last time and says HEY!!! Whats up with this Bird? IT STILL WONT TALK. Salesman says I FIGURED IT OUT! YOU need the Bell! THATS IT.... When the bird crawls up the ladder he'll swing on the swing, see himself in the mirror, ring the bell and then he'll sing. For sure! and thats only 25.00. Guy goes home and puts in the bell and his bird crawls up the ladder, swings on the swing, looks at himself in the mirror, rings the bell and falls over dead.
The guy goes back to the pet store sad and says to the salesman, my bird died. The salesman says Oh you forgot to buy birdseed.

Ive seen this more than you can imagine.
The basics= Fuel runs engine=Motec runs fuel.

Think of where you started.

yeah 4cyl is 2k and 10cyl is 5k

When your finished wasting TIME and ready to start enjoying give me a call.

jR.

 

[FrankBarba]

Do as JR. suggests. A sand alone fuel management system is absolutely the only way to go. Forget about trying to tune a dodge computer as he states "band aid fix". With the motec which is the CADDY of fuel management systems you will not go wrong.
Listen to SVSI (Jr & Sr) they know their Sh?t.

 

[Eddie N]

i was just checking out the motec and saw that their top fuel management systems can still only control 8 high flow injectors, or 12 low flow injectors.. whats the deal with that? what do you use for the viper?

sorry for the minor thread hijacking..

- eddie -

 

[SVS Turbo]

I have no idea what your reading?

That information is not correct.

jR.