CHECK LIGHT...

[creekman]

Coming home in the middle of the day, probably high 90's, good oil temp and water temp

was good when all of a sudden my gas pedal went away and the LS3 V8 cough and quit.

I tried to restart without success, Finally it started and got me home without further incident.

 

I plugged y OBD II reader in to the GM port and it wouldn't clear, then plugged it into the

Porsche port and it cleared.  I have 90,000 miles on the 2003 C4S model and 25,000 on the LS3 motor.

 

NMy question is this a routine mileage event or something else?  Certainly it was more of

a "have your car service" event since the gas pedal went away and the engine stopped.  I was surprised that I

cancel/erase it on the Porsche OBD port.

 

I was hoping for some rare insight which has its complications, but still puts a smile on my face...

 

Thanks,

 

Mitch

[DBJoe996]

A check engine light on simply means one of the parameters the ECU monitors was off, and it always records a code that tells you specifically what was wrong.  There are literally thousands of various codes that will throw the CEL.  Next time, read the code before you clear codes.  That code or codes will point you in the right direction.

 

Also, I would  get in touch with whomever did the LS3 conversion and ask them how they rigged the "fly-by-wire" throttle conversion.  There is going to be a lot of frankenstein parts involved with an LS3 conversion.  Just the fact the GM OBDII port didn't work but the Porsche OBDII port did is really questionable.  Did they somehow "marry" (connect) the Porsche ECU to a GM ECU?  How?

Edited August 18, 2020 by DBJoe996

[creekman]

No, I believe both ECU's have their own job...  The Conversion utilized the GM gas pedal, so like you I was surprised when the Porsche OBD port cancelled the check light.  It has been years since I hooked up the Durametric program, but I did today with these results...

 

I just thought I need to see if I can date when these codes were thrown...  At the top of the attachment it says, "Current /Fault Codes.  I want to get to the bottom of

this pretty quick, I've never have been flat bedded home so far.  I did get stuck in Winslow, AZ for one night with the original engine.  The idler pulley bolt backed out, 

a local towing service came out with his flatbed, took me to the Chrysler dealer, charged me $85..   They had the Porsche dealer in a neighboring town overnight

the parts.  I was on the road again by 10:00 the next morning...  All in all it was a memorable experience and meant some nice people.

 

 

\

 

 

 

 

Edited August 19, 2020 by creekman
Uploaded an extra pic...

[creekman]

17 hours ago, DBJoe996 said:

A check engine light on simply means one of the parameters the ECU monitors was off, and it always records a code that tells you specifically what was wrong.  There are literally thousands of various codes that will throw the CEL.  Next time, read the code before you clear codes.  That code or codes will point you in the right direction.

 

Also, I would  get in touch with whomever did the LS3 conversion and ask them how they rigged the "fly-by-wire" throttle conversion.  There is going to be a lot of frankenstein parts involved with an LS3 conversion.  Just the fact the GM OBDII port didn't work but the Porsche OBDII port did is really questionable.  Did they somehow "marry" (connect) the Porsche ECU to a GM ECU?  How?

Joe,

 

I know I'm in dangerous territory pushing this conversion, but it's been a fun to drive car, gooobs of power and reliable.  My point Joe is the electrical was the most challenging part of the conversion snd was a major expense to get it done right. It does bring together different parts, but the word Frankenstein might be a little over the top...  Today the after market people have develop easier programs that tend to be plug and play where as 8 years ago you better have your Phd in order...

[judgejon]

Well Joe and Mitch , all I can add is the thought that “she’s real fine, my 409.”

good luck with this, the Chevy is supposed to be pretty reliable. The conversion must have been a challenge indeed, but I’d call the conversion a transgender switch to “bride of Frankenstein.”

Best to all y’all, j

[creekman]

Jon,

 

The Bride of Frankenstein would blow the doors off your ''409'...  With a taller ring and pinion she clocks out

on paper at 206 MPH at redline in 6th gear, but not with me in it...

 

On an earlier post I mentioned that the idler pulley bolt backing out which is not good...  If you ever have to replace that bolt

I would recommend using loctite.