randy4762

First off, I am so glad to find this site with so many knowledgeable people.
I am having problems with tuning my 91 TBI 5.7L (has cam, headers, bored .030, tbi mods, and 9.5 to 1 compression) I have been having success so far with my Autoprom and my first 5 chips. For example I have smoothed out my VE tables and have great driveability and cold starts idle, etc..
Here are the problems I have run into:
1.)Cannot get the engine to rev past 4500rpm
2.)Poor accelleration when I floor it, actually revs faster if I lift the throttle to 3/4! (maybe lean?)
3.) My datalog shows the A/F lean at the same sites no matter how much I add to the VE. (it is at one specific RPM site at cruise in OD)
RPM \ MAP 20 30 40 50 60 70 80 90 100
1600 0.000 0.075 0.071 0.849 0.071 0.053 0.062 0.049 0.000
4.) I turned off my egr with the temp method and locked my BLM at 128
now, all of a sudden on my last chip, the INT locked itself at 128!
would this mean I am in open loop?

Any help would be greatly appreciated, especially from RBob or Reaper or other senior members.........Thanks,Randy

Grim Reaper

I don't work on that particular bin/ecm combo very much so I am not familiar off the top of my head of what it is capable (and not capable) compared to other bin/ecm combos.

1) It sounds like it's overly rich, try leaning it a bit especially at lower rpms or in the PE table.

2) As for the 4,500 rpm ceiling, check if there is a Rev or Fuel Limit/Cut-off that's kicking in.

Hope that helps you out to start.

Fast355

iTrader: (2)

It does sound rich in PE mode or the timing is off.

Too much total advance will make it fall over at higher rpms too.

As for the 4,500 rpm ceiling, I am putting my vote in on the injectors going static.

randy4762

Thanks Fast 355 I was hoping you would chime in. I have read everywhere searching for info on datalogging my BPW. I have the autoprom, winaldl, and an old auto xray. Which is the best to use? I know the xray shows it, but hard to watch while driving. Also I am buying a LC-1 wideband today.
can that be datalogged with the autoprom aux in, as well as its own software
so that the logs will "sync". I read that has been a problem in other posts

randy4762

Just want to thank everyone for their help so far.
The base timing was off, it was 19 degrees!, easy fix.
My fuel filter was really bad! , so the injectors weren't static, but now they are. I got to 5600 rpm today before the O2 started falling off.
Installed new header gaskets due to lean conditions (burned up), I used the
Percy's gaskets, hope they last. Wideband coming soon for tuning WOT better.
Now for the next challenge. I have been trying to implement the code to
show the injector PW in the Prom ID.

Quoted from RBob in a previous thread:

"Then to get the sync PW on the ALDL line make these changes at the addresses shown:

Addr: Value:
$D4E7 $00
$D4E8 $AB
$D4E9 $00
$D4EA $AC

This puts the PW into the PROMID field of the scan tool. Take whatever value is displayed and multiply it by .01526 and add in the injector bias value (from $D2DA) and the end result is the PW in milli-seconds. So if the PROMID is 232 and the injector bias is .397 msec, then 232 * .01526 + 0.397 = 3.94 milli-seconds."

I looked at my bin in the hex editor in TunerPro, and I can't seem to find the correct location. Could anyone help with this?
After that my next challenge is Highway spark patch.....
I always like a challenge, but I have been on this one for a week.
I have searched and read everything I could to no avail.
Thanks, Randy

dimented24x7

iTrader: (2)

The address $D4E7 refers to the location within the computers addressable memory. The prom occupies address $D000-$DFFF. The actual address in your tuning software will be $4E7-$4EA. Change those to whats specified, and you should have the PW in your datalogs.

randy4762

Thanks, I will try it and post my results tomorrow

randy4762

I got the code to work. What i found is this:
448 X .01526+.396=7.23248 correct?

Where: 448 = number output from Prom ID after patch
.01526 = multiplier
.396 = injector bias (added)
7.23248 = injector pw in milliseconds
Is this correct?

If it is, that means I need more fuel pressure and possibly even larger
injectors! I kind of knew this already because of my engine combo.

Just for info, the 448 value was during PE and my O2 mV were .851
But this was at only 3600 rpm and 95% tps and 99.7 map.

Looks like I will need larger injectors...oh well.

HaulnA$$

That works out to 87% duty cycle. Not quite static but no headroom left. You're going to need quite a bit more injector.