computer learning and plugged cats?

[varanus]

Hi all. Just got the roe sc installed and car is not running tip top yet. First problem was the car overheated. (this had nothing to do with the supercharger). The thermostat was changed to a 180 degree one during the install which was a poorly designed one (won't mention where it came from-it was not from Sean). It wound up sealing off the water flow completely so that the engine pegged the temp gauge while the fluidyne radiator was cool. After several hours of of trying to figure out what was wrong, the techs solved the problem and replaced it with another thermostat and reinstalled the sc.
Somewhere along the line of thishappening the cat on the right side got really hot and the right side sill now has a big yellow spot from discoloration of paint.(about 2 feet long) This happened just over the last day.

Right now the car runs poorly so i have a few questions.

1. How long does the computer take to learn the mods? 50 miles, 100 miles??

2. How did the sill get discolored so fast? Could the hi flow cat be plugged or something? Sills are very hot to the touch-so hot one of the plugs to cover up the screw holes was melted on the bottom.

3. I had magnacore wires put on . Is it possible they got put on in the wrong order or maybe one got knocked loose. Car runs like its not firing cleanly. Also on a roll when accelerating lightly car will hesitate momentarily before accelerating.

Please do not take this as any complaint on Sean or the SC.
The car had roller rockers, magnacore wires, 70mm throttle boddies all put on at the same time as the sc so maybe the computer is trying to learn for all the changes. Sean has been great. He even called me this morning from VOI when he heard the car was overheating with some suggestions. One thing about Sean is he will always talk to you and return calls promptly.
I know this will be sorted out soon. The one little goose I did with the sc put on pulled very well. Felt like about a 125 shot of nitrous hitting. it looks AWESOME on the motor. Quality and finish were outstanding and my Viper tech was impressed on how well it went on and the overall quality of the kit.
Hopefully by next week everything will be sorted out and I can dyno the car.

 

[LTHL VPR]

The car's learning process usually has very little to do with drivability like you are talking about. The learning process of the computer (which I think is what you are referring to)should not effect the symptoms you are describing. I am not sure which brand of high flow cats you are using, but I can tell you that we have had customers bring their cars into us with other brands/types of high flow cats that literally burned the side sills black and crispy.

Check the no-brainers: spark plug wires, plugs, injector connectors, idle air motor/tube/connector, etc.. Then move to injectors, etc..

Did you put the 70mm TBs on at the same time? If so, then look there too. Make sure the TPS is not set too high and that the TBs are not opened to much at idle. The accufabs usually require a mod before installation to work properly (don't know which brand you are using).

Obviously reset your computer too. If you have any extra computer hooked up to the system disable it temporarily to see if this helps.

Lots more to check out, but this should be a good start!!
Hope this helps!

P.S.- If you want to really tune the car right for a supercharger, give us a call. We can program a custom chip for you on the dyno which can ensure the car gets max. power and max. saftey margin everywhere (much more tunability than you have now)
-Wayne

 

[ElDiablo Viper]

You need sims ASAP! I had the same problem VEC1 would also be good and add more power.

 

[varanus]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ElDiablo Viper:
You need sims ASAP! I had the same problem VEC1 would also be good and add more power.

<HR></BLOCKQUOTE>

What are sims? I do have the vec 1

 

[LTHL VPR]

I think he is referring to cat. converter sims.
I think you may have something else going on though. If you want some sims we have several sets of our new updated sims (about the size of a small lighter). However, I think you have other issues at this point. You have a 97 GTS, so your car does not necessarily need the sims.

Do you want us to take a look at your car for you?
-Wayne

 

[Dixter]

Hate to say this, but if it were my car I'd just put one mod
on at a time and test and tune for that mod and then move on
to the next one... I know lots of time and time is money...

But if you get one mod just a little wrong and then another mod
a little wrong, they all add up to a bad car with some very
nice parts, and in the long haul it will take longer and harder
to get it tuned correctly.

 

[VPRVENM97]

Kevin,
Did that fix solve your problem? It sounded good leaving the lot.

 

[varanus]

Dave, the car runs absolutely horrible. But I think I know what the problem is. The random tech hi flow cats after 6 months are going bad. The right one for sure, That is why the sill is discolored after one day. Also somone told me they saw "white paper and water was spitting out of my tailpipes" Also my exhaust is a nice sooty black. I think the plugged and overheated cat is throwing off the computer so badley the sc doesn't have a chance in hell of running right. So when I yank those crappy random techs out and do the replacement on thursday i suspect all will be well.
I will let you know

 

[99 R/T 10]

Cut the cats out completely, see if that does the job. Fast job, instant gratification(with sound and power).

Mike

 

[VPRVENM97]

Kevin,
Be careful driving it with those cats. It looked like your passenger door was starting to get discolored too. Hope you have the fire extinguisher near by. Good luck with the new and improved cats.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by varanus:
Dave, the car runs absolutely horrible. But I think I know what the problem is. The random tech hi flow cats after 6 months are going bad. The right one for sure, That is why the sill is discolored after one day. Also somone told me they saw "white paper and water was spitting out of my tailpipes" Also my exhaust is a nice sooty black. I think the plugged and overheated cat is throwing off the computer so badley the sc doesn't have a chance in hell of running right. So when I yank those crappy random techs out and do the replacement on thursday i suspect all will be well.
I will let you know

<HR></BLOCKQUOTE>

 

[Tomer]

Kevin, do tell what brand of cats you are going to put on!

Hope you have some luck soon!!!

Tomer

 

[ceieio]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
<FONT COLOR="Blue">I've talked with some factory guys about the learning aspect of the PCM and didn't get a definitive answer-- I wanted to know if the WOT fuel ratio is learned by monitoring during the normal closed loop operation. My question was not answered- Anyone KNOW this one?</FONT c><HR></BLOCKQUOTE>

<FONT COLOR="Black">
I have studied GM and Ford methods for the WOT map, and those are all fixed at development time. Hot-rodders spoof them with larger flow injectors and/or boosted fuel pressure at the rails matched with the right mass air sensor. You can also modify the base map in some of these units with chips or flashing the EEPROM depending on the unit (need and engine dyno to keep the shrapnel down here). If the Viper PCM modifies the WOT map, it would be the first I have heard of (and I am by far not an authority).

If you would like to learn more in general about engine management there are some good background articles on the "do-it-yourself" efi web site at: http://www.diy-efi.org/

Happy motoring!</FONT c>

 

[ewave]

I'm not an expert on this, but I do have an opinion.

Unless the cat is blocked, it shouldn't have any effect on how the computer meters the fuel to the car:

There are two sets of Oxygen sensors per side of the vehicle. The first one on the exhaust manifold is monitored by the computer to fine tune the air/fuel mixture. The is BEFORE the cat. The second oxygen sensor, AFTER the cat, is just there so the computer can detect a faulty catalytic converter. If it detects that the catalytic convert isn't working (like you removed it... , it will set a fault code, and your check engine light will come on. (I think this started after the 1997 model year.)

When the car is at WOT, the computer runs in open loop mode, meaning that it doesn't even monitor the oxygen sensors to set the air/fuel ratio.

I've talked with some factory guys about the learning aspect of the PCM and didn't get a definitive answer-- I wanted to know if the WOT fuel ratio is learned by monitoring during the normal closed loop operation. My question was not answered- Anyone KNOW this one?

There are two kinds of check engine light indications:

When the computer detects an error condition in one of the sensors that is used to set the fuel/air mixture, then the computer goes into limp home mode, and very poor performance will result.

If the computer detects a failure of an emission control device (like the cats, or charcoal canister) then is just sets the error code, but continues to operate the engine normally.

A very hot cat suggest too much fuel in the exhaust.

Finally, an opinion about catalytic converters:

Catalytic converters reduce emissions by helping the combustion process take place of the unburned fuels and other undesirable by products that should have been used up completely IF the engine was operating perfectly. There is a catalyst in the converter that aids in the chemical reaction. ALL modern cats use the same catalyst. Cats need to run at high temperature for this reaction to take place. When the reaction takes place, heat is generated. The heat that is generated is the by product of a chemical reaction. Cats will only run cooler if less conversion takes place (the limit here being just a straight pipe). If the case of side sills on the Viper, the main concern is the exterior temperature of the cat. From a chemical reaction and thermodynamic perspective the only two ways to reduce the external temperature would be to have less reaction take place (less effective converter), or have a better insulated cat.

 

[varanus]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by tomer:
Kevin, do tell what brand of cats you are going to put on!

Hope you have some luck soon!!!

Tomer

<HR></BLOCKQUOTE>

Probably some special ones made by ted.

 

[Matt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by varanus:
Probably some special ones made by ted.

<HR></BLOCKQUOTE>

Just ask for his patented "cat back" system. He'll know what I'm talking about.

-Matt

 

[Tomer]

Varanus, do you think Ted's "special" cats will reduce heat, or mainly improve flow?

Tomer

 

[SmokinV10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SilverSupra:
Hey Varanus...

Did you ever get your problem fixed with the Cats???

When is the next time you are heading up to Sac Raceway.....???

Supra is almost done........Tell Treynor he better have his traction problem taken care of.....hahhaa

Steve
aka.....Poopra

<HR></BLOCKQUOTE>

Steve,
Ive saw treynors car run at VOI. Be scared, be very very scared.

 

[SmokinV10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SilverSupra:
I know......I saw It too.......hahahha
Very very very niceeeee.........
Treynor and I once talked about the difference between power and putting it to ground, and HP curves. As SOON as I saw the video I said to myself, "**** , that looks like a high HP supra run...hahaha"
Hopefully I will get us all to go up to Sac when the weather cools down a little.

How is your car doing??? Ever deal with all that crap from the dealerships about the oil???

<HR></BLOCKQUOTE>

All the problems with my car are non-car related now. Its a long story, I'll tell you at the track sometime.

 

[RedGTS]

So how's your car running now?

 

[varanus]

Car is still misfiring so I can't get an accurate idea of how fast it is with the blower.
The cats were removed and the right one was so burned out that it was completely hollow like a straight pipe. The left one was starting to disintergrate. Heat sure does take it's toll. Also my speaker wires along the right side were completely melted into goo.
I did get a few 3500 to 5500 rpm sprints and even with the miss it pulls quite quickly. After the misfiring is solved-hopefully by this weekend, I will start addressing the detonation at low rpm issues.
I am pretty sure it will be pretty fast when sorted out. California gas is really the pits.

 

[LTHL VPR]

Varanus-
Let us know if we can help. We can custom tune your computer on your Viper to eliminate pinging and improve drivability. In addition we have aftermarket high flow cats which have never caused any problems and dramatically reduce the temperature of the sills.

We have installed hundreds of supercharger systems on cars, and can probably resolve your issues quickly.
You know how to reach us.
-Wayne

 

[varanus]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by tomer:
Varanus, do you think Ted's "special" cats will reduce heat, or mainly improve flow?

Tomer

<HR></BLOCKQUOTE>

More flow. Got them on-very toasty on the sills.

 

[varanus]

Thanks Wayne. If I can't resolve the problems i will look you up. I'm pretty sure its either a faulty injector or plug wire

 

[GASDOC]

Varanus,did you ever find out what was wrong?

 

[varanus]

Not yet, but will be working on it Friday and sat. Hope to get it runnung smoothly by next weekend as I am participating in an exotic car cruise with lots of Ferrari's, lambos, Lotus, and others.
Usually there's about 8-10 vipers there too. If the car is running well I'm sure it will stir up a lot of interest!

 

[VPRVENM97]

Kevin,
Any update?