Need advice on resetting PCM

[jpa99acr]

I started a thread last week about my car running rich with the newly installed headers/catback. The overwhelming consensus was to reset the PCM. Well, after doing a little investigation I am back here

Where is the PCM? Just unplug it and wait 30 min before plugging it back to reset right?? Any way a non-mechanically minded person can screw this up?

 

[dave6666]

-> Disconnect pos+ battery cable at battery and short to chassis.

-> Wait about a minute.

-> Reconnect cable.

-> Turn ignition key to on (NOT start) and push fully and release gas pedal 5 times to set WOT.

-> Turn key off. Wait about a minute.

Enjoy...

 

[GTS Bruce]

Take it to a dyno with AF after driving around for a while. Send to DC to reprogram using your dyno charts. One of the best mods I have ever gotten. GTS Bruce

 

[PhoenixGTS]

Do it the easy way - just pull the fuse for awhile. Look on the fuse box lid - it is labled and easy to find.

 

[dave6666]

Do it the easy way - just pull the fuse for awhile. Look on the fuse box lid - it is labled and easy to find.

According to our Great Wizard, the Chuckster himself, you have to short the pos+ battery cable to the chassis. Pulling fuses don't cut it.

Now I know not everyone endorses everything that Chuck says, but are we too lazy to yank the rear wheel and get to the battery or what?

 

[jpa99acr]

thanks for the help guys. I will post my results after the dyno and tune.

 

[RobZilla]

Can't you just pull the three large black connections under the positive post that Dave is talking about.... won't that achieve the same result?

 

[dave6666]

Can't you just pull the three large black connections under the positive post that Dave is talking about.... won't that achieve the same result?

That isn't the positive post I'm talking about. I'm pretty sure Chuck sez at the battery, not the PDC. Sean Roe uses the disconnect the PCM connector method.

 

[ViperTony]

See here, specifically post #6. http://forums.viperclub.org/rt-10-gts-discussions/614653-resetting-pcm-ecu.html

 

[PhoenixGTS]

See here, specifically post #6. http://forums.viperclub.org/rt-10-gts-discussions/614653-resetting-pcm-ecu.html

Absolutely no offese to Chuck (I have no standing to contradict Chuck forcefully in any event) but after previously using the removal of the three conenctors to the PCM method successfully I am having the same success with simply pulling the PCM labeled fuse. Maybe because I pull it for an extended period of time. But I have to go to emissions this month so I guess we will see.

 

[dave6666]

See here, specifically post #6. http://forums.viperclub.org/rt-10-gts-discussions/614653-resetting-pcm-ecu.html

Nice post Tony. Like I said, what Chuck said.

Don't be afraid to pull that rear wheel fellows...

 

[Garron]

Absolutely no offese to Chuck (I have no standing to contradict Chuck forcefully in any event) but after previously using the removal of the three conenctors to the PCM method successfully I am having the same success with simply pulling the PCM labeled fuse. Maybe because I pull it for an extended period of time. But I have to go to emissions this month so I guess we will see.

Under certain circumstances some of the capacitors internal to the pcm can become charged. This can set a erroneous fault or running condition. The only way to discharge the capacitors is to disconnect the battery and short the positive and negative terminals together. Unplugging the pcm will clear it's memory but the capacitors will stay charged. So i agree with Chuck.

 

[jpa99acr]

well I lucked out and found a local Dyno about 20 miles from my house. The guy sounded real knowledgeable and made several of the same comments posted above. He suggested that the 02 sensor may be bad? but that he would do a scan and see if the A/F mix was off before he dynoed, and short the pos/neg connections after disconnecting the battery... he mentioned the capacitors being discharged through this, so it sounds like he knows his stuff.

He thought the computer should have adjusted by now, since it was still blowing out black smoke 90 miles after the install.

May not be anything major, but I would like to get it addressed. I am bringing it in next tuesday. The guy said he just dynoed a B/W GTS and his shop was recommended from a local muffler shop that I have done biz with. Guess we will see what happens.

I will post dyno sheet after I get it next Tuesday.

 

[dave6666]

well I lucked out and found a local Dyno about 20 miles from my house. The guy sounded real knowledgeable and made several of the same comments posted above. He suggested that the 02 sensor may be bad? but that he would do a scan and see if the A/F mix was off before he dynoed, and short the pos/neg connections after disconnecting the battery... he mentioned the capacitors being discharged through this, so it sounds like he knows his stuff.

He thought the computer should have adjusted by now, since it was still blowing out black smoke 90 miles after the install.

May not be anything major, but I would like to get it addressed. I am bringing it in next tuesday. The guy said he just dynoed a B/W GTS and his shop was recommended from a local muffler shop that I have done biz with. Guess we will see what happens.

I will post dyno sheet after I get it next Tuesday.

I have seen comments before that the PCM will take much longer than 90 miles to adapt. Maybe, maybe not. But I would get out there and drive the snot out of it before fixing what may not be broken. Have you even gotten the oil hot in those 90 miles? What is your longest drive in that period? What is your average drive in that period?

 

[jpa99acr]

well after the exhaust was installed it was driven 30 miles at a time, longest being when i went to tonys house for the bbq and back probably 45 miles at one stretch. i don't know if the oil got hot or not but i would think so.

Since the O2 sensor wires had to be replaced TWICE (they were not properly heat wrapped the first two times and melted on the pass side) I thought maybe the sensor had gone bad?

is it not dangerous to drive it with it running rich?

 

[dave6666]

well after the exhaust was installed it was driven 30 miles at a time, longest being when i went to tonys house for the bbq and back probably 45 miles at one stretch. i don't know if the oil got hot or not but i would think so.

Since the O2 sensor wires had to be replaced TWICE (they were not properly heat wrapped the first two times and melted on the pass side) I thought maybe the sensor had gone bad?

is it not dangerous to drive it with it running rich?

Rich fouls plugs and can damage cats, but lean can overheat an engine. If I had to pick an issue to have, it would be rich.

If you've gotten the sensor wire issue fixed, and are not throwing codes, I would drive it some more. I think it was V'Tony, but I seem to remember him mentioning like 700 miles before everything kicked back in on the PCM.

I know after my Belanger install, 1000 miles down the road it decided to throw a sensor preheat code a couple times - 0135. I cleared them, and they haven't come back, but I kind of suspect it was the PCM finally kicking in all of the stuff it does. Maybe not, but I'd say fix your sensors and drive.

 

[ViperTony]

I posted something about 700 miles regarding passing emissions testing earlier this year. I think the PCM relearning is much sooner than that. It's also possible, that one of more of your O2 sensors went bad. It may not be the PCM. Also, I've read here that if you have a leak somewhere along your exhaust system that may contribute to the rich condition too. I had a rich condition but I ended up fixing my leak and replacing the O2's at the same time so I don't know which fix ultimately solved it.

 

[dave6666]

I posted something about 700 miles regarding passing emissions testing earlier this year. I think the PCM relearning is much sooner than that. It's also possible, that one of more of your O2 sensors went bad. It may not be the PCM. Also, I've read here that if you have a leak somewhere along your exhaust system that may contribute to the rich condition too. I had a rich condition but I ended up fixing my leak and replacing the O2's at the same time so I don't know which fix ultimately solved it.

The leak would have to be prior to the O2 sensor to affect it then. In my case with the Belanger headers, using the single tube as supplied for the sensor, the leak would have to be on the head at that tube.

Of course, I have no problems I'm trying to solve, but that's what it would take on my car.

Good suggestions and comments though Tony. Beer and pizza for you through the weekend!

 

[ViperTony]

The leak would have to be prior to the O2 sensor to affect it then. In my case with the Belanger headers, using the single tube as supplied for the sensor, the leak would have to be on the head at that tube.

Of course, I have no problems I'm trying to solve, but that's what it would take on my car.

Good suggestions and comments though Tony. Beer and pizza for you through the weekend!

My leak was the collector area just before the turnout pre-cats. But beer and pizza sounds pretty darn good. Thanks for the dinner tip!

 

[dave6666]

My leak was the collector area just before the turnout pre-cats.

I seem to remember that you have your sensors on the merge collectors right? If the leak was on the 3 bolt flange, which is right near the sensor in your case, it is possible that on the larger diameter pipe there could have been an affect on the upstream sensor due to flow pulsations and the lower velocity there. But on my single tube, with the sensor located about halfway between the head and the merge collector, there's no way that gas flow pulsations could be mixing upstream from the merge collector area.

Did you whack the pickle out? Can't remember. That would also slow velocity in that area, making upstream mixing a possibility.

 

[jpa99acr]

interestingly, the right tip had all the soot on it (and was covered), while the left did not. the right side was also where the 02 wires had to be rewired twice because they melted. so I am thinking perhaps the 02 sensor went bad.

I do not want to mention the dealers name on here that did the install, but they will fix this on their dime if that is the case I had to have the car towed TWICE because of the 02 wires melting and the car dying. To their credit, they did send their wrecker to tow it and properly did so (first time I barely pulled away from the dealer so they used a golf cart to pull it back)

You must be registered for see images attach

<---- Rich on right only?

 

[gcoe]

Can you reset the PCM using a high end scan tool? I spoke with Chuck & he said this is possible with the dealer grade scanners.

 

[ViperTony]

I seem to remember that you have your sensors on the merge collectors right? If the leak was on the 3 bolt flange, which is right near the sensor in your case, it is possible that on the larger diameter pipe there could have been an affect on the upstream sensor due to flow pulsations and the lower velocity there. But on my single tube, with the sensor located about halfway between the head and the merge collector, there's no way that gas flow pulsations could be mixing upstream from the merge collector area.

Did you whack the pickle out? Can't remember. That would also slow velocity in that area, making upstream mixing a possibility.

Yes, originally I moved the O2 sensor from the #3/#4? primary tube locations to just beyond the pickle areas. I was leaking at the Y-collectors just before the O2 sensors. So, I had lou fix the flanges, I bought new O2's and moved the O2's back to the primary tube locations. I'm fairly certain the freshly machined flanges and air tight seal (feverishly following Lou's directions) took care of the leak and rich condition.

 

[ViperTony]

Can you reset the PCM using a high end scan tool? I spoke with Chuck & he said this is possible with the dealer grade scanners.

Yes, in fact Chuck reset my PCM with the DRB tool. Or, you can buy one for several grand.