I have an '86 305 TPI that I just installed in my pickup, I had the complete wiring harness (as far as I know) and just got it running. I put about 200 miles on the engine this weekend and it runs great down the highway, but off the start it is sluggish and it has a poor idle. It died out a few times when putting it into gear and starting out. Fuel pressure is good, and vacuum should be ok, no leaks as far as I can tell. It smells like it is running rich, could a bad O2 sensor be the cause, or do I need to go over everything again: IAC and TPS, EGR, etc... It initially had a problem with idle surge, but that fixed itself after driving a little.

Also, I wasn't able to find the diagnostics plug (ALDL) on the wiring harness. I think I have it, but it is on a string of wiring with a few other plugs that isn't plugged into the rest of the harness. Where does the check engine light wiring go back to, is it some pin on the ECM? Can I just get a bulb and hook up to an ECM pin to get the trouble codes, or do I need the ALDL plug?

ECM # is 1227165

...to add to the list of problems the engine refuses to start when it is cooled down (i.e. in the morning after sitting all night, or after several hours of sitting). It will just crank endlessly but doesn't start until it gets warmed up from cranking. I did set the timing already, its perfect, so what could cause cold start problems?


Thanks for the help.

 

I dont have my wiring diagrams in front of me, but the easiest way to check the codes is thru the ALDL connector and counting the blinks in the SES light. Grounding the ALDL connector does ground a pin on the ECM to put it into diagnostic mode, but again, I dont have my diagrams to know which one.

 

ok, that is helpful, I'll see if I can trace the wires back to the ECM. Do you have any idea what the cold start problem could be? I am going to try replacing the MAF and o2 sensor, when I get it running it doesn't seem to make a difference whether the MAF is plugged in or not, that can't be good.

 

That sounds like a bad MAF sensor, then.

 

Yeah, that's what I'm afraid of, I am going to check it tonight. I also received some feedback from a 3GO post, so I should be able to get the trouble codes without an ALDL: http://www.3rdgen.org/bb/showthread.php?t=41413