Can't get rid of lean condition, part throttle low rpm

[shimniok]

Good thought, I will try looking for vacuum leaks.

What is the syn air fuel ratio for?

[ony]

it is combination the computer uses to feed the engine the right fuel air ratio, the chip i got from a 88 model 350 the syncronized air fuel on it was way high, mine runs about 14.7 to 1.the man said the engine was bad at that lean of a mixture it proble was .

[EagleMark]

You mean stoich? It's always been 14.7 to 1 on all chips I've seen. Although most ethenol fuel now is not 14.7 to 1.

[shimniok]

Ok, here's a bin and log for review. Using $42-1227747-V4.xdf, $42-1227747-V4.3.adx

The bin started out as ASDU 5.7L auto. I checked the manual trans (no p/n switch, wire is not connected to anything). I disabled the following MALF flags: VSS (I have none), EGR (vacuum control but physically disabled), No DRPs (stock), Knock Sensor (I have none), ESC (no knock sensor), Cal-Pack...

NOTE: I was getting a "Cal-Pack missing" error code... ???? Is that the secondary prom? it's in there... ??

I set Initial SA to 9.84 (static timing on dist was set to 10)

INJ bias set to .458 (played with it yesterday, values between stock and .65 ... for logging, didn't want to go overboard with changes). BPW is nudged slightly up to 140. I calculated BPW with the spreadsheet you posted. Assuming about 60# @ 12psi for 360cid, I get a BPW of 142. If I assume 60# @ 13, it's more like 148. I didn't want to make radical changes, so set to 140 from 135.

KNK - Min CTS to enable -- set to max to disable knock retard since I have no sensor.

DFCO enable Temp - set to max to disable

Minimum Coolant Temp for EGR - set to max to disable

TCC - Minimum Temp for TCC Lock - set to max to disable

Min Temp for AIR diverter - set to max to disable (stock)

VE2 is left alone. VE1 is modded based on the correction spreadsheet "42~E6~OD~OE~31 VE Correction Table for TunerPro.xls" I went through a few iterations.

SA - Knock Retard - zeroed out to just to be sure to disable

PE - left tables and scalars alone; I didn't want to disable it since the truck's already running lean at higher kPa

For today's first drive, I plugged PCV/charcoal canister line because I seemed to have problems with this with the carb. One problem is the fuel filter is full of rusty goop from running out of gas last night. :(

I unplugged the ECM for awhile plugged back in, flashed with autoprom, and started up. Right off the bat driving up the hill from my house it was barely able to run, way too lean, tried upping inj bias to .55 not enough. Now trying inj bias at .6, bpw 148... still lean. After awhile the idle started richening. Still stalling under load though.

Then, tried 140 bpw, inj bias .55, pcv still disconnected. Logged drive to parts store to get fuel filter --- 0928dr1, 0928dr2

Replaced fuel filter (was 5/16 now 3/8), reattached pcv line to charcoal canister. Drove home. Definitely drove much better, but numbers were still rich at idle, lean above. Took a log driving home: 0928dr3

I've attached the bin with bpw 140, .55 inj bias.

[shimniok]

have you tried spraying throtle body cleaner around the intake an brake boster to check for a vacuam leak?

Did a lot of spraying around throttle body base and brake booster. No change in idle. Only way the idle changed was me squirting a load of carb cleaner right into the throttle body. It was running open loop. I'm not entirely sure I trust my skills in finding vacuum leaks this way. So I can say I didn't find one -- yet.

Michael

[EagleMark]

There's lots of safe ways... I don't know any?

Short bursts of starting fluid (open area, safty glasses, long arm). Just a short squirt and if a vacuum leak is near the motor will rev up. Carb cleaner sucks. Remember this is flammable so it will also find any spark any where. In 1000 short squirts I have not had a flame up yet...

[ony]

i told you the man said the engine was bad, you would not belive what a bin file come out of that chip, even the trans part of the chip was defiled. he junk the truck iam useing the ecm, the chip was at fault. if i had look at the chip file he would be driven the truck,now its being turned into chinesse steel. 14.7-1 is right check you chips to see if they have been defiled.

[shimniok]

I was able to get the BLMs around 128 by upping injector bias to 1.2 msec and setting bpw back to 135, had to adjust down the idle areas a bit, but it's already pretty close to 128 in all the cells even those pesky 50-80 kpa cells at 1200-2000 rpm ... more testing to follow... *shrug* ?!!?!

[EagleMark]

You must have misunderstood, I've been trying to tell you that...

Havn't had time to look at your stuff yet but glad your getting it tuned.

VE1 and VE2 can be added and when added work properly with Dave W spreadsheet since 100% of VE is in one table. BPW setting is a calculation, use the injector size spreadsheet. VE1 can only go to 100 but your better at 90 high. Injector bias can add some fuel without skewing the BLM like if trying to add or subtract fuel by using BPW. Can change BPW about 10% but I have changed Injector Bias by 40% so far with accurate BLM readings.

Fuel pressure is still an issue, especially with the small line your running. Watch high RPM WOT with a wide band O2 sensor.

[shimniok]

You must have misunderstood, I've been trying to tell you that...

Inj bias? I understood --- but was afraid to go too high. Finally got fed up and just went for broke. And it worked great.

But I upped INJ bias by a factor of 300% (0.396 to 1.2), 40% did nothing for me.

What exactly is injector bias? How does it relate to duty cycle and bpw?

Havn't had time to look at your stuff yet but glad your getting it tuned.

Don't worry about the logs-- that was before I mucked with injector bias. Was WAAAAY off.

VE1 and VE2 can be added and when added work properly with Dave W spreadsheet since 100% of VE is in one table.

How does the VE2 above 3200 rpm work?

BPW setting is a calculation, use the injector size spreadsheet.

I wished I had injectors with known rating@psi :( I will have to work towards saving up for that I guess so I can refine/nail the bpw.

Fuel pressure is still an issue, especially with the small line your running. Watch high RPM WOT with a wide band O2 sensor.

Ok... I will plan to save up and get one before I play with WOT at higher rpms... hopefully it's safe to use NB to tune the lower throttle positions at higher rpms?

I'll look at upgrading to 3/8" line soon, too.

Michael

[EagleMark]

Injector Bias is Added to the total BPW. used to compensate for injectors that open slowly.

VE above 3200 RPM uses the last cell it was in.

Having correct injectors, fuel pressure, fuel flow and settings sure makes tuning easier...

[shimniok]

Is BPW actually a unit of milliseconds then?

[EagleMark]

Well that's how it is measured in the end. But it is a calculation of load X times RPM Y = BPW. Which is all we have to work with in this ECM.

If you look at 4.3L, 5.0L, 5.7L and 7.4L you'll see they are all differant BPW and Injector Bias. Matching parts to bin is the easy tune if you have correct fuel pressure calculated to BPW.

A better calculation is BPC in newer ECM. A constant derived from the ratio of injector flow rate to engine displacement.

[shimniok]

VE above 3200 RPM uses the last cell it was in.

Hmmm... a light bulb just went off... :) VE2 "could" be used to tune above 3200... it's last cell + VE2 cell. Mine reads like this:

800...3200 39.06
3600 41.02
4000 39.06
4400...6400 37.11

If you're designing a TBI system with a 4k memory limit, would you really need the VE1 table to range from 0-100 kpa from 3200-6400? Or would gross VE tuning above 3200 be good enough and save space? I'm curious to see what the VE tables look like for a newer ECM/PCM.

Michael

[dave w]

Hmmm... a light bulb just went off... :) VE2 "could" be used to tune above 3200... it's last cell + VE2 cell. Mine reads like this:

800...3200 39.06
3600 41.02
4000 39.06
4400...6400 37.11

If you're designing a TBI system with a 4k memory limit, would you really need the VE1 table to range from 0-100 kpa from 3200-6400? Or would gross VE tuning above 3200 be good enough and save space? I'm curious to see what the VE tables look like for a newer ECM/PCM.

Michael

LS PCM goes to 8000 RPM from 15 Kpa to 105 Kpa, screen shot is not the entire VE Table.

dave w