Hello everyone. I have a question that I have not been able to find an answer for using the search feature here on the forums. My tbi conversion runs great once in closed loop but runs horribly rich when started on a cold morning. It runs rich enough that I have a cloud of black smoke coming out my tailpipe until it goes into closed loop. The temperature is usually between 20 and 30 deg. fahrenheit when I first start it. I have found a choke afr vs temp in my chip. Is this what I need to adjust and how do I interpret the data here? For example at -4 deg celsius, it shows a value of 6.5. Is the 6.5 subtracted from the afr ratio at that given temp? Any help on this would be greatly appreciated. Thank you in advance.

 

What did you convert from? What fuel pump are you using? Any idea what your fuel pressure is?

 

I did the conversion on my 1976 chevy c10.

 

Sorry about the last post. I accidentally hit enter. What I was saying is the conversion was done to my 76 chevy c10. It had a quadrajet prior to the conversion. I am using the stock fuel tank and stock ac delco fuel pump. Last I checked the fuel pressure was at 14 psi. Would turning the fuel pressure down about a pound maybe solve the problem? If possible, I would like to do this through the chip though because the fuel pressure has my blm across the table just about perfect.

 

what is your engine combo. it is an open loop issue. either with the open loop AFR vs temp or Choke AFR. how long does it blow black smoke? choke will only last about a minute. if it does it longer than that its an open loop problem

 

That makes perfect sense whitelightnin. It does happen for well over a minute. Shall I just keep leaning out the Stoichiometric AFR under Open loop AFR parameters or what?

 

Before you alter the choke and open loop AFRs, make sure your VE table is correct. In closed loop, the PCM may be removing lots of fuel, which may explain why it runs better once warm. If you haven't altered your VE table, you should start tuning there and make sure that it matches the engines VE.