ECM Timing/Fuel Tables

[BA_051]

Now that all my wiring issues are resolved, i am now in the stages of programming the ecm...

When I run WinALDL, I drove about 90 miles (about 2 hours) in all sorts of driving conditions, but only got about 80 BLM data points... I thought it gets a point every 1.9-2 seconds so i figured I would have a lot more...

Anyways, I used the BLM numbers and adjusted the VE1 accordingly... Now my BLM's are between 124-132 after just the first datalog... But they range from ~12-13 all the way to 82, without VE2 Adder table added in... Those numbers just seem so high compared to other tables i have seen (most ive seen go from 10-12 to 80-90 with the VE2 adder table added in!)

Now the issue... Sitting in the parking lot, the 360 will idle good and rev to 6k without a hickup... When I drive it, 60+ MAP has great power, but sometimes, it goes lean (18+ AFR on gauge) and Backfires through TBI and has 0 power... I have to pull over, let it idle for about 20-30 sec, then i can drive it again... Its random when it wants to do that.... Im ripping my hair out over it...

[Bill USN-1]

Sounds like it's your install and not the EFI.

Start at the tank and work forward.
The system should match the factory GM with no short cuts.
3/8 line all the way with min connections and the pump mounted back at the tank with a filter before the pump.
Pumps push, not pull.

Install the pressure gauge at the inlet of the TBI and run the gauge under your wiper blade, then drive. Pressure should not fluctuate more than a pound under heavy load.
Pressure should be 11-13psi.
For a 360 with 5.7 injectors I normally increase pressure to 14psi.

[BA_051]

Yea, im going to go over everything again... it has to be fuel delivery if its going so lean under heavy load...

[babywag]

Food for thought...if your tank has a separate fuel pickup in the tank?
Modify that and install a pump inside the tank.

I went that route in my '88 with new 3/8" fuel hard line, reused the old 5/16" hard line as the return, and chucked the 1/4" return line.
Used a stocker style GM in tank pump.

[Achilles]

babywag you got a write up or pictures of this. Part number for the pump etc. Never mind I found what I needed. I am going to have to replace the sending unit. So I think I might go this route.

[Billygoat]

Food for thought...if your tank has a separate fuel pickup in the tank?
Modify that and install a pump inside the tank.

I went that route in my '88 with new 3/8" fuel hard line, reused the old 5/16" hard line as the return, and chucked the 1/4" return line.
Used a stocker style GM in tank pump.

X2 for both tanks on thumper I did the in tank pump, I did find it best to run a return line down inside the tank pointed right at the pump, then I can run the tank almost dry, I had some up hill run out issues before I did that.

[BA_051]

Well, quite a bit has changed since my last few posts...

I finally installed my 33 gal 1990 Van tank under the bed...
Installed a 1994 454 TBI on a holley aluminum adapter...
Installed a 1994 fuel pump in the 1990 sending unit in the tank to run my TBI at 30 psi...

Little tuning on the '7747 and viola, idles great, great power from idle to 6k, starts within seconds of turning the key and just runs better than it has ever before...

So I upgraded to a 16197427 PCM so I can control my new 3200 CFM Taurus fan...
Imported my timing table from my 7747, tweaked some values, disabled AIR, EGR, and all the transmission controls...

But im getting a Code 43... (wasnt with the 7747)
Here is the pinout I used:

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?173-7747-RIP-ECM-to-427-PCM-Swap-with-Wiring-Pinout-Directions!&highlight=16197427

B7--------(3*)-------BLK---------------Knock Sensor *** Not used on 87 GMC W/454***

(3*)= A.) Wire like 1995 P30 Step Van, ESC Module output to B7
(3*)= B.) Wire like 1995 C10 Truck, Bypass ESC (Blue to Brown) and use Late TBI/TPI 305/350 Knock sensor

So I wired it like the P30 and moved my ESC to B7.
Does the 1994/5 use a different ESC/knock?

[babywag]

The module is removed for 7427, it's built into memcal.
Knock sensor goes directly to pcm.

[BA_051]

Yea, I just pulled the harness from under the dash this evening and removed those 3 wires to the ESC and ran the blue strait to B15 on the PCM. Lights off! One less module to worry about and find a permanent home for...
Its interesting that the 94-95 P30's still use the ESC module...

Now that its running without codes and as it should, its a definite improvement in the idle over the 7747... it stays 14-14.2 AFR at idle vs the 7747 was always between 11.5-12.5...

Now to modify the code to control my electric fan.... 40-50HP is a lot of power for a fan....

[babywag]

More like 5-15hp...

[Bill USN-1]

Now that its running without codes and as it should, its a definite improvement in the idle over the 7747... it stays 14-14.2 AFR at idle vs the 7747 was always between 11.5-12.5...

It's the tune not the ECM that makes the difference.
The faster PCM just helps to compensate for an improper tune.

[BA_051]

The off idle 1200-6000 is pretty much the same as the 7747, its just the idle thats better.

Im still figuring out the PCM's fueling tables. The 7747 was quite simple...