Roe Performance PCM

[Purdue_Boiler_Viper]

OK you Roe SC guys. I'm getting ready to do a DIY Roe install. Roe has suggested the Roe Performance PCM as part of the upgrade. Even the Roe description of this "upgrade" is not very convincing:

"This PCM (Powertrain Control Module) is needed to correct the following conditions: 1998 and newer Vipers that set a check engine light after header installation (oxygen sensor heater circuit malfunction), check engine lights due to catalytic converter removal, hanging idle and misfire codes on modified engines (Supercharged or otherwise)."

$540 to correct a few codes? Anyone have experience with this?

Thanks,
Pat

 

[DAMN YANKEE]

Purdue,

I have a 2000 GTS inwhich I installed a 5lbs Roe S/C.

I, like you, had to content with both the issue of the new PCM and the strong recommendation by Roe that I install high flo cats. IMO, Sean Roe is recommending both a new PCM and hi-flo cats because he wants everybody that buys his S/C to be satisfied 100% right from the onset.

I did not buy the new PCM, I did not install high flo cats.
So far, the engine runs like a top, no lights and no sill heat issues.

The PCM Question:

It was susggested to me by Chuck Tator that I should finish my install and see if I threw codes. If I threw codes, we would then see what the codes were and then consider if a new PCM was part of the solution. I finished the install and I have not yet thrown codes.

The issue most sommonly found is that the stock PCM found in later models recognizes that the engine is building RPMs faster than expected...and throws an engine light. In other words, the S/C allows the RPMs to build so fast that the PCM just KNOWS that something must be wrong. If that happens the PCM does not effect the operation of the motor, it just recognies the condition and throws a light, it is benign.

If this condition does throw a code (missfire):

1. I can reset the code (with my $65 OBD tool or my $200 EASE software)
2. I can get a new PCM ($540)
3. I can cover the light with tape (.02, some do, I just couldn't)

So far, so good.

The Hi-Flo Cat Issue:

I didn't want the extra noise. Again Tator strongly advised me that gien my 5lbs unit and my style of driving, I would have no issues with sill heat if I:

1. Got a good quality high-flo cat back (I went Corsa, loud enough!)
2. I should insulate my sills (I went with Roe Sill Kit)

My sills are just fine, car sounds great. There are a numbr of guys around here that run higher LBS than me and still have stock cats. Many also use W/M.

Hope this helps.

 

[KenH]

You can definitely take a wait and see approach. That is what I did on my '01 and I ended up getting the Roe PCM anyway to take care of the misfire codes and in the pursuit of chasing gremlins in the system.

Having the check engine light on is not necessarily benign. In at least some cases it causes the PCM to run the car very rich (safe mode) which can overheat cats, lose power and lower gas mileage. Not sure if the misfire code falls under that heading however.

 

[Purdue_Boiler_Viper]

Thanks for the help guys. I already have high flow cats, so sills should not be a problem. Sounds like the wait and see approach for me.

Hey Ken, did you paint your SC air intakes or go with powder coat?

 

[Brian GTS]

Pat,

I also have an 01 yellow GTS and just ordered a ROE. I'm getting my tubes powerdercoated yellow. I'm also having some powdercoat work done on the valve covers so I ordered my ROE unit uncoated. That way, I could have the powdercoating done at the same place for the closest color match on both the ROE and valve covers.

 

[Purdue_Boiler_Viper]

Brian,

I know you're stoked. Are you going with the anodized compressor or polished, or are you going to powdercoat it as well? I can't make up my mind. I painted the valve covers racing yellow when I did my rolling rockers install. Ken did this also. The paint is holding up just fine.

 

[Steve 00RT/10]

Having the check engine light on is not necessarily benign. In at least some cases it causes the PCM to run the car very rich (safe mode) which can overheat cats, lose power and lower gas mileage. Not sure if the misfire code falls under that heading however.

I'm not sure about the misfire code either, but I think any O2 code puts the car in the 'safe mode.' A lighter flywheel (I have) also adds to the potential misfire problem listed above due to extremely fast revs. I think the Roe PCM upgrade is basically a new 'pre' 2000 Viper computer. I think mine was the '96 PCM. I had a history of setting codes with Belanger headers and no cats. I had worked that out years ago with Rear sims and drilling out the OEM front sensors(a Roe solution), but opted to eliminate any potential problems with the SC and bought the 96 PCM. (another reason was that the new front O2s I bought for the install couldn't be drilled out--they had little slits instead of holes to enlarge)

Steve

 

[Mr Hemi Head]

Like others I stuck with the stock PCM and had no codes, however it was a PITA to tune.

Along with a fuel spike, at the trasition from closed loop to open loop, the A/F would become erratic while street tuning.(on a closed track of course)

A/F would be OK on the first couple of runs then turn to crap.

The Roe PCM fixed that nicely. Be prepared to go with the Roe.

 

[Knight Viper]

Would the Roe (older PCM) be better than having DC perforce "reflash" you computer and change some other things while they are at it (skip shift, fan on off ect...)??

 

[KenH]

Thanks for the help guys. I already have high flow cats, so sills should not be a problem. Sounds like the wait and see approach for me.

Hey Ken, did you paint your SC air intakes or go with powder coat?

I had the intake tubes and valve covers painted Race Yellow to match the car. PBJ is now making me an intake that will be painted to match as well. There was no powder coat in yellow that matched well enough for my taste and the paint has held up fine for 2 years now. I was told that as long as I did not put clear over the paint, I would have no problems from the heat.

 

[Mr Hemi Head]

Would the Roe (older PCM) be better than having DC perforce "reflash" you computer and change some other things while they are at it (skip shift, fan on off ect...)??

The Roe PCM has the stock program original to the early GENII Vipers. This version and the VECII software are more compatible.

There is no performance advantage to install the Roe PCM on a unmodified engine.

 

[DAMN YANKEE]

Mr. Hemi Head has it exactly right. In fact many feel that if your lucky enough not to fire off engine lights, the newer PCM has some real technical advantges and well worth keeping.

 

[Brian GTS]

Pat - Sorry for the delayed reply. I am going for the black anodized compressor on my unit. My valve covers will be black also. I wanted to have some black in the mix since my car has the black stripes.