i have a 1994 c1500 w/4l60e auto trans. I just replaced the 4.3 v6 with a 355 w/zz4 cam and holley intake and tbi. I cannot get the truck to run in closed loop at all. When i turn the key the service engine light blinks very fast, without being started. The truck will run a bit rich and will not run good at WOT. I replaced the knock sensor, tps, cts, o2 sensor. I cannot get this figured out please help me get it back into closed loop.

 

does the truck run good, what temp is it running in, what all codes is it throwing?

 

When the SES light blinks real fast like that there is a computer or prom problem. Did you replace the prom chip too in this swap? Most times it has been someone plugging the prom chip in backwards or its not making a good connection in the computer. With that light flashing like mad, you are in limp mode. Limp mode = runs like crap. I have chip install directions on http://www.bharris.org/chipintall.htm but the notch should be towards the center of computer. If you changed the prom make sure that the chip prongs line up in that plastic holder really well.

Feel free to email me brian@bharris.org if you need any more help.

 

yes i did put a chip in it! i will check that today. The truck is running like a big piece of ****, it drinks gas and runs rich as hell.
but that makes sense about the prom i guess it could have a bent pin or something. Thanks!!!

 

I second the PROM problem, my 92 did they same thing after my own stupidity. It started to run really funny and the SES light started flashing real fast. Just ended up I hadn't pushed the chip far enough down into the computer( even though I have done the chip swap thing so many times i can't remember anymore). Check for bent or damaged pins as well, one never knows.