$0D TBI to MPFI conversion, how is your idle quality?

[96lt4c4]

That is pretty odd. I have not experienced that issue first hand. Then again the engine I was working with had a much larger cam. Might need to look into the ECM code and find out what it is doing with the Injector Firing. By logical reason if you have a longer duration cam than stock your system should be fine with an earlier fuel pulse. If your engine runs better with the initial at TDC than +10*, you might have benifit retarding the injector pulse even more. If memory serves Injector Timing can be varied substantially without changing physical timing. If you advance the base timing 10* and retard the injector timing 10* in theory you should end up at the same place.

It has been years since I played with this and I have probably forgotten more than I remember with these PCMs, but I remember having to make adjustments to a $0D bin I made for a 95 Camaro 3.4 in an 87 S15 Jimmy. I had to make adjustments to the EST settings, initial setting and the like to run the DIS system on that engine. The DIS system runs at a 60 or 70* (I forget) offset to TDC#1 and the EST system has to command a negative timing value via the PCM to make the system work correctly. Its a pretty weird feeling to put the initial timing at 60* and the command timing minimum at -70* and the maximum at -10* IIRC which gave a range of -10 to 50* of total timing. Just goes to show what these PCMs are capable of doing with the right research and calibration changes.

So base mechanical timing set to 0*, set initial in the bin to +10, and retard injector timing how? by "Degrees of Delay from DRP to injector firing" I played with this setting and it didn't seem to do anything. I only bumped it up to the 15 degrees that the stock CPI motors had. If I could figure out my emulation, I could try some of this stuff while its running.

[96lt4c4]

I have a bit of a vibration at idle when the weather is hot... fuel mixture is fine, but it seems like there is some issue with evaporation of the fuel when it's hot outside that is causing a vibration. when it is cooler than 70* ambient, truck runs smooth as glass. Do you guys think firing the injectors earlier will help with this problem?

Not real sure about that one, are you running a MAT or IAT sensor? The PCM shouldn't be changing much if it has no way of knowing what the ambient air temp is? You might try moving your 02 voltages around to see if it needs more or less fuel while its doing this.

[1BadAction]

Not real sure about that one, are you running a MAT or IAT sensor? The PCM shouldn't be changing much if it has no way of knowing what the ambient air temp is? You might try moving your 02 voltages around to see if it needs more or less fuel while its doing this.

7060s have no provision for MAT or IAT, I have everything I need to swap to a 7427 so I CAN have a MAT, but just for my sanity I'd like to make the OEM ECM work before I swap to another. I've fooled with the mean o2 voltages at idle from .150 up to over .530 (noticeably lean to noticeably fat) and I can't seem to get that small bit of vibration out of it.

[brian617]

So base mechanical timing set to 0*, set initial in the bin to +10

That would remove 10 degrees from your entire spark table at crank.

Setting mechanical to 10 degrees advanced will add 10 degrees from table, to actual at crank, unless you put the 10 degrees initial in .BIN then what you see is what you get, except now you have advanced the injector firing 10 Degrees.

To zero out the injector firing, or add Delay at 0 degrees mechanical, you need to add XX amount of Delay from DRP to injector firing.

Again with MPFI the fuel is fired much closer to the valve, no transit time (intake runners TBI), so there should be a delay between DRP and injector fire.

Atleast thats the way I'm understanding it.

[brian617]

7060s have no provision for MAT or IAT, I have everything I need to swap to a 7427 so I CAN have a MAT, but just for my sanity I'd like to make the OEM ECM work before I swap to another. I've fooled with the mean o2 voltages at idle from .150 up to over .530 (noticeably lean to noticeably fat) and I can't seem to get that small bit of vibration out of it.

MAT is next on my list as well, I'm getting too big of swings in BLMs from hot days to cold days. Partially my fault I assume as I divorced all the heat riser equipment.

[JeepsAndGuns]

AFR at idle was all over the place going from high 15's to mid 13's. I put it back and it quit. I think Jeepsandguns said he was seeing some thing similar.

Thats exactly what mine used to do. It even did it when driving. AFR was all over the place. It never did that when I was still tbi. I never touched the distributor or timing when I converted to mpfi.
But I fought and fought for the longest time to figure out why my afr was all over the place. Then one day (I cant remember what prompted me to do it) changed the base timing to 0 and it brought the afr back to steady.

[1BadAction]

MAT is next on my list as well, I'm getting too big of swings in BLMs from hot days to cold days. Partially my fault I assume as I divorced all the heat riser equipment.

Thats exactly what mine used to do. It even did it when driving. AFR was all over the place. It never did that when I was still tbi. I never touched the distributor or timing when I converted to mpfi.
But I fought and fought for the longest time to figure out why my afr was all over the place. Then one day (I cant remember what prompted me to do it) changed the base timing to 0 and it brought the afr back to steady.

hmmmm... I think this is all related to what I'm experiencing... I need to do some experimenting.

[96lt4c4]

hmmmm... I think this is all related to what I'm experiencing... I need to do some experimenting.

I thought you were already running 7427. If it were me I would go ahead and do the swap to see what happens.

[1BadAction]

I thought you were already running 7427. If it were me I would go ahead and do the swap to see what happens.

I know man, I've looked over the bins and the ADXs and XDFs, it's so much more advanced, it's ridiculous.

[96lt4c4]

Figured out couple things with the idle and with the start and die issue. My idle was still slightly erratic. I notice I was moving in and out of BLM cell 18 and 20 at idle. I set my low BLM cell vs MAP to 40 KPA which is where I idle at. I also had too much timing at idle, set it to 25 degrees across the board and now my idle is way smoother. I zeroed out my AE vs map at 40 KPA, and at 0% throttle on my AE vs TPS to keep it from adding fuel when it goes into AE at idle.

I added air in my "IAC Counts vs. Desired Airflow" table and it starts cold every time now. Now I get a little flare when it first fires up cold, then it settles down to idle, which I kind of like. The reason this needs adjusting is because most aftermarket throttle bodies IAC ports are too small. This is a big problem in the LS world. Some guys hog them out and make them bigger. If this route works I will leave it alone instead of modding the TB.

I also put in some more high performance transmission parameters from an LT1 Corvette.

[96lt4c4]

So the truck is still starting and dying....I thought I had it. I experimented today by hooking my wideband to an external battery, so it wouldn't reset when i cranked the truck. The truck starts and jumps up to around 10.1 AFR , then fuel drops off fast and the truck dies. Here lately it was taking around 3 cranks to start it and have it stay running. I have been suspecting my fuel pressure regulator. So, I unpluged the vacuum line from it and capped everything off. Hit the key and it fires right up and stays running. I don't know...

[JeepsAndGuns]

So its dropping off fuel right after it starts to the point of stalling? How high does the AFR go? All the way to no fuel at all, or just really lean?
I wonder if it could be a decay setting somewhere for startup fuel, "choke", or whatever its called in this code mask? Maybe it could be lengthened to keep it a little richer for a couple seconds longer?

Edit:

Ok, you got me a bit curious so I took a quick look through the XDF. What about 0x491F "time before choke afr decay" In my bin its 2 seconds. Wonder if changing it to maybe 4 seconds might help?
I also found 0x4C3A "choke afr decay time Vs temp" But I would assume the above timer must finish before this one starts? So thinking possiably it could be the first one?

[96lt4c4]

So its dropping off fuel right after it starts to the point of stalling? How high does the AFR go? All the way to no fuel at all, or just really lean?
I wonder if it could be a decay setting somewhere for startup fuel, "choke", or whatever its called in this code mask? Maybe it could be lengthened to keep it a little richer for a couple seconds longer?

Edit:

Ok, you got me a bit curious so I took a quick look through the XDF. What about 0x491F "time before choke afr decay" In my bin its 2 seconds. Wonder if changing it to maybe 4 seconds might help?
I also found 0x4C3A "choke afr decay time Vs temp" But I would assume the above timer must finish before this one starts? So thinking possiably it could be the first one?

The fuel would go from about 10.1 to not even reading on the wideband, lean, pretty sure I have it figured out now though. Something with the FPR. I started it dead cold this morning, without vacuum hooked to FPR, and it fired right up and ran without dying. AFR was steady on the wideband. Never went lean. So that's fixed now I just need to re tune my VE because now its rich as hell at idle.

[Roadknee]

With vacuum to the FPR unplugged the fuel pressure is not decreasing as manifold vacuum increases after startup. The additional fuel pressure with the FPR unplugged could be covering a lean condition that exists in the tune when the FPR receives vacuum and reduces pressure after startup. I think JeepsandGuns is on the right track. If you leave the FPR unplugged you'll need to retune the entire VE table under 100 kpa; not just idle.

I've messed around a lot with trans parameters in my stock 1995 K1500. Have you considered locking the TCC in third gear? It makes a big difference if you spend much time driving around town under 40 mph. I see your tune still has the ramping pressure reduction in the upper TPS areas of the 1-2 shift. You can firm up the shift in this area if needed by zeroing out the table. Do you have any internal mods to the 4L60E?

[96lt4c4]

With vacuum to the FPR unplugged the fuel pressure is not decreasing as manifold vacuum increases after startup. The additional fuel pressure with the FPR unplugged could be covering a lean condition that exists in the tune when the FPR receives vacuum and reduces pressure after startup. I think JeepsandGuns is on the right track. If you leave the FPR unplugged you'll need to retune the entire VE table under 100 kpa; not just idle.

I've messed around a lot with trans parameters in my stock 1995 K1500. Have you considered locking the TCC in third gear? It makes a big difference if you spend much time driving around town under 40 mph. I see your tune still has the ramping pressure reduction in the upper TPS areas of the 1-2 shift. You can firm up the shift in this area if needed by zeroing out the table. Do you have any internal mods to the 4L60E?

As far as I can tell the AFR is steady after startup with the vacuum unplugged from the FPR. I am sure there is something going on with it hooked up but I cant find it. It starts perfect now so thats the way I am leaving it. I drove it around town today for about an hour and ran the VE tables through the VE spreadsheet. BLM's are all back in check now. WOT was not effected.

I found the ramp table you were talking about with all the negative number -35 to -60. Thats taking a lot of line pressure out. I zeroed that out, we will see what happens

Yes my 60E is built, it has a wider band, and a Corvette servo in it, lots of other stuff done to it as well. So at what MPH are you locking and unlocking the converter in 3rd? How does this effect towing in 3rd? I have thought about doing this in the past but never did.