Basal Skull

Just a thought, did you have a PPI done and did they remove the intercooler? If so, check to see the connection for the post intercooler temp guage is plugged in correctly (black connector, the right side of the intercooler outlet). If not, the ecu can go into limp mode and the cel light will go on just like you describe while driving.

Kevin R.

I'll check that intercooler temp gauge connection. Good suggestion. Thanks for all the input guys...

Perhaps ca993twin can comment as I have a 1997 993TT Ruf like his and would be curious to know if they (Ruf) put a blank in when they changed the gauges (Ruf gauges). Of course, they also modify the ECU which could be another reason???

ca993twin

Kevin R,

The Ruf gauges are the only option I don't (yet) have. But it seems very odd to me that the CEL would be disabled on any OBDII car. It not only provides some essential warning for some major issues, it is generally required to be demonstrated as working (in most of the U.S.) in order to pass smog.

Texas993

Yep, my Turbo R converted in Germany came with CEL bulb blank. They come that way from the factory. Fortunately, we simply removed the blank, installed a real bulb, and it works fine. I do NOT have RUF gauges.

Ziad

Hi
Can a data logger read off a modified/custom ECU ? What about deciphering non Porsche error codes (from custom ECU)?

Thanks

Felix

If it's just a chipped ECU the OBD2 reader will work fine.

Ziad

Hi Phelix

Forgive my ignorance, but I'm guessing that my UMW Stage 1 ECU is a "chipped" ECU? I'm asking cos about a year ago we got a few error codes which no one could work out... So I assumed that custom ECU have a whole set of codes that are proprietary?

Cheers

Felix

Hi Ziad,

If it's still the Motronic ECU using a MAF then I think just the fueling and timing maps are changed and the base code and OBD2 circuitry are still in place and working as before. Do you recell what the codes were?

Ziad

Hi Phelix

The knock sensor fault gives a value of "11111111" and the intake air temp sensor fault gives a value of "01011111" - this was quite a while ago.

There was a whole other bunch of errors like
"2 Unknown DTC" which gave a value of "00000000"
"128 Unknown DTC" value = "10110011"
"254 Unknown DTC" value = "11111110"

I have the actual report somewhere... Sorry for hijacking this thread!

Thanks

Felix

Hi Ziad,

I've checked the Porsche info I have and have found the following:

IAT Sensor = 124
knock sensor 1 = 210
knock sensor 2 = 211
there is no error listed for code=2 but your binary value=0 (no error listed for 0 either)
there is no error listed for code=128 but your binary value of "10110011"=179 in decimal (no error listed for 179 either)
there is no error listed for code=254

So not sure I've been of any help at all. Please post more info if you have it.

Ziad

Felix

Many thanks for find out all this, much appreciated.

I'll find the actual report and post it.

Thanks again

Ziad

Hi Felix

I found the report. Please see below. As you can tell, it was done a while ago....

Cheers

Kevin R.

Originally Posted by pjconner

Yep, my Turbo R converted in Germany came with CEL bulb blank. They come that way from the factory. Fortunately, we simply removed the blank, installed a real bulb, and it works fine. I do NOT have RUF gauges.


Thanks Patrick. Good to know I was not the only one with a Turbo R where the CEL bulb was left blank from Ruf. I wonder what reason they do it this way though???

Texas993

No idea. The PO of my car told me about how Alois promised him that the car would be US emmissions compliant. After the conversion the car lived in AL, CO, TN and briefly in FL. The bulb blank was never an issue.

RUF Dallas told me that is how they come from the RUF Germany factory. Very strange.

bb993tt

Mine was the same. Converted in DE, passed smog in NY but we did have to replace the bulb.