ok. i have been trying to nail this down for awhile now and nobody seems to help too much without all the info. i finally got datamaster going on a laptop with the moates xtreme aldl.

1989 iroc 350TPI auto
problem: when cold, it starts hard - takes a few seconds to start (when hot it starts instantly). then the idle will go up and down until it warms up. on takeoff it hesitates or boggs down. it smells very rich.
when warm it idles and drives good but still smells a bit rich.

i have replaced the injectors with bosch III 22lb, new plugs/wires/cap/rotor/ign module. did not fix other than it runs smoother and better response now when warm. new optima battery. upgraded wiring/grounds. new cts. cleaned and reseald TB. new IAC and TPS adjust properly.

the stats:

coolant temp 149*F
open loop
RPM 675
AFGS 8.2
LTerm 142
STerm 128
TPS .67 (i set it at .55 at the sensor)
IAC pos 40
INJ BPW 2.33
INJ DC 2.6
EGR DC 0.0
Spark aDv 14.4
knock counts 201
knock retard 0.0
IA temp 127*F

a couple minutes later...

coolant temp 174.7*F
closed loop
RPM 625
AFGS 5.8
LTerm 160
STerm 134
IAC pos 16
INj bpw 2.01
Inj DC 2.1
EGR DC 0.0
spark adv 15.8
knock counts 201
IA temp 124.7*F

does this info help anyone. any info helps please.
is that intake air temp high?? should i replace it? also, shouldn't the EGR be functioning? anything else i should look at? MAF? i hove no dtc's. i now have all the info but not sure how to use it. can someone point me in the right direction?

thanks

 

Go back and check your spark advance with a timing light after a cold start-up. Your advance should be much higher than 14* & 15*.

No, EGR should not function during cold-start warm-up.

Once warm and in closed-loop, what do your fuel trims look like at idle?

 

ok. yes now that you mention it my advance should be up in the 30's right? i know my base timing is at 6*, how would i check the advance with timing light? wouldn't it just show 6* or do i need to rev it to a certain rpm?

i thought the fuel trims were the LTerm and STerm counts?

thanks

 

You just hook the light up to the #1 plug wire and compare the reading to what you see on your datalog.
Make sure your ald file is doing the conversion for SA correctly.

Yes I see the ECM says it's trying to add tons of fuel once in closed loop. That is odd.
It must be extremely lean. Have you checked your fuel pressure?

 

ok checked the advance with my light at idle and it is 23.5*. base timing was actually 6.5* (don't think that matters much though).

i checked fuel pressure again and it is good - 44.5 with vacuum on and about 38 with it off.

so in closed loop it is putting too much fuel, correct? makes sense because it does smell very rich...

when checking timing, i found a bad plug wire arcing. crazy, cuz it's an msd super conductor... so i will be changing wires hopefully this weekend and see what happens. it doesn't feel like a misfire though but i gues it could affect my idle fluctuation.

anything else i can check as far as the fuel or advance? if the computer thinks it's lean it adds more fuel, but what tells it it is lean, jsut the o2, right? how can i test the o2 sensor? the voltage readings in DM fluctuate a lot so not sure what to look for there.

also, how do i know my ald file is correct or how can i fix that?

what should my intake air temp be and how does that affect the computer?

thanks for the replies!

 

update----- i changed the plug wires, had 2 bad. it definately runs and responds better, however the cold start issue is still there. and my BLM's didn't change. im still at 160... any ideas?

 

well it's getting hotter here in california so my cold start crap doesnt last long or doesnt happen lately. i still have 160 BLM in closed loop and need help....
i have new bosch platinum 2 plugs, msd 8.5mm wires, mallory ign module, msd cap/rotor, new CTS, thoroughly cleaned and re gasketed throttle body, o2 sensor was replaced over a year ago, new TPS and IAC adjsuted properly.
the rich problem was there before and after all these parts/tune up. the car runs really well.
it is a 350TPI w/ 700r4. the rear end was changed to a 3.73 so the computer thinks i am going faster than i am (don't know if that affects anything) but the high BLM is at idle anyway.
what's next? MAF? o2? iat? cats? i don't know...

i also just found out that datamaster apparently doesnt support my platform - just 89 fbody 5.0 or y body 5.7. i was told from datamaster that it won't work right with my car - weird. i am going to try tuner pro RT this weekend. and we'll see but it smells really rich out the tailpipes...