fbody_brian

I really am thinking that injector timing adjustment is what I really need. If i give the motor the mixture it wants to run the best the exhaust smells strongly of raw fuel, but if i lean it out to get rid of the fuel smell the exhaust still stinks, just differently.
There appears to be no happy medium.

If i could delay the injector firing I could prevent some of the raw fuel dumping out the exhaust during overlap, and not have the fumes from being overly lean
so..
There's a parameter that I can adjust called "injector offset adder", it's description says "For low injector pulses, an offset in microseconds can be applied to further fine tune fueling."
I was thinking that this might be what I need to adjust, but I was really unsure about what to do with the numbers and if it was even the correct parameter. What I really need is access to the EOIT that ChopperDoc was referencing, but I could find nothing like it in my parameters list in tunerpro. I figured it just didn't exist or hadn't been found yet for the OBD1 pcm.

I'm browsing through the gearheadEfi forum this morning, and low and behold, there's a discussion about cam overlap and EOIT in the lt1 OBD1 pcm. Apparently there is an "End of injection target location vs coolant temp" parameter. I just had to load a different definition file to access it.

so I am going to crunch some numbers and do some experimentation with the setting. If i get anywhere with it, I'll update this with the relevant information.

it's crazy that there is still active work on the tuning options in the obd1 pcm.

ChopperDoc

You can always email support@hptuners. Those guys are very smart on this stuff, and they usually get back to you pretty fast. When I have a question of this magnitude, I just ask the source directly. They might even have an OS that works with your pcm and includes EOIT in it. I don't see why it's not possible at all for it to work on the LT1.

Zmg00camaross

iTrader: (11)

What Kinda hippie talk is this!!

fbody_brian

hey man,
we got to love mother earth.

atlantadan

If there is a place around that'll actually smog test the car, I'd advise you to do it. Smog tests are actually a great tool to assess the overall running condition of the car. The results will help point you in the direction of what's wrong and where.

ACE1252

I think what you are referring to is "End of Injector Timing". I could be wrong, but I don't think that adjustment is present in JetDST. That's why I asked for the table.

I know it's present in LS1 setups as Banish refers to it in order to try and get bigger duration cams to run better.

ChopperDoc

That's exactly what I'm referring to. For his situation, that would be the best fix for cleaning up the raw fuel smell due to cam overlap. It works great for this. However, he stated he does not have this table being that he is on an LT1 OBD1 setup. I only deal with gen III and IV. Haven't got to play with a gen V yet. My car is a gen III and I use the hell out of that table to tone the eye watering smell down. My old cam had 13* of overlap at .050, new one is at 20, (93 total). Definitely going to need another adjustment or two.

fbody_brian

The adjustment is probably there in the OBD1 pcm, from the discussion about it, there may even be a EOIT vs load/rpm.