7747 First scan after replacing injectors and 1853% duty cycle!?

[87GMC]

Picked up this 87 GMC R1500 LO5/700R4 2WD a couple months ago... Been going through it and noticed the injectors were leaky and the spray pattern was nonexistent. So I ordered a couple of Standard injectors (TJ7's) off of Amazon. Threw them in and went for a drive to do a little datalogging. I was shocked to see that the peak duty cycle for the injectors was 1853%!? What have I done wrong?
Using:
TunerProRT 500.9513,
ASDU-$42-5.7L-Auto.bin
$42-1227747-V5.9.3xdf
$42-1227747-V5.2.adx

I've attached one of the logs from yesterday’s run. Appreciative of any assistance, TIA!

[PlayingWithTBI]

You need to apply the "BPW and Spark Advance Hack" for that to work.

17457

[87GMC]

You need to apply the "BPW and Spark Advance Hack" for that to work.

17457

Applied the patch and duty cycle is still showing in the low hundreds... Is there something I may be missing? Thanks

[1project2many]

Silly question.. did you burn a new file to the chip after applying the patch?

[87GMC]

Silly question.. did you burn a new file to the chip after applying the patch?

I've only used TunerPro in a diagnostic capacity. I haven't done any tuning (not super familiar with the process). Thanks

[1project2many]

That patch changes the code in the chip. BPW is not reported to the scantool in a stock calibration. You can see "something" in the datastream that the diagnostic software thinks is BPW, but it is not really BPW. You have to burn a new chip to take advantage of the patch.

[87GMC]

That patch changes the code in the chip. BPW is not reported to the scantool in a stock calibration. You can see "something" in the datastream that the diagnostic software thinks is BPW, but it is not really BPW. You have to burn a new chip to take advantage of the patch.

Ah... Well there we are... I still have all the tuning stuff I used to use on my old TPI Camaro. Is any of this stuff still relevant for TBI today? This was 18-20 years ago and I honestly I can only remember a portion of what I used to. I'm definitely not against learning, just need to see if what I have will work or if I need to start looking into an EBL or the like.

Super appreciative of you guys taking a couple of minutes to lead me in the right direction.

[1project2many]

All of that still works. I believe I have the same Thinkpad squirreled away... Along with Windows 98!
Is that a white Datarace I? That's some vintage stuff alright. :)

I don't believe your emulator will work with the 7747 without making an adapter socket and changing file locations in the chip.

Before spending a bunch of time learning to tune the 7747 with your hardware, maybe consider changing to a 7427 from a 94-95 truck? Compared to the 7747 it's a very advanced pcm. Better code, better idle strategy, better low speed driveability, much faster and better ALDL data. And it plays much better with the hardware you have there.

[87GMC]

All of that still works. I believe I have the same Thinkpad squirreled away... Along with Windows 98!
Is that a white Datarace I? That's some vintage stuff alright. :)

I don't believe your emulator will work with the 7747 without making an adapter socket and changing file locations in the chip.

Before spending a bunch of time learning to tune the 7747 with your hardware, maybe consider changing to a 7427 from a 94-95 truck? Compared to the 7747 it's a very advanced pcm. Better code, better idle strategy, better low speed driveability, much faster and better ALDL data. And it plays much better with the hardware you have there.

Right on! Fired up the ThinkPad and its rockin Windows 2000 Pro. Password protected of course... ...and I haven't got a clue what it is... Probably a good thing, I don't want to relearn any bad habits I may have picked up chasing that 13 second time slip 20+ years ago rotflmfao! The Datarace is a little UV box for erasing chips.

Now thoroughly inspired, I pulled the TPI box down and found some additional goodies. Several 7730 TPI speed density ecu's, few chips, and the old GM ECU Bench! Totally forgot I had this thing...

In regards to the running the 7427 over the 7747, I'm all about it! Would a reman unit from a big box parts house work, or would you recommend sourcing it elsewhere?

[1project2many]

Right on! Fired up the ThinkPad and its rockin Windows 2000 Pro. Password protected of course... ...and I haven't got a clue what it is...
Well that would work. I use XP on my tuning laptop. Browser is having trouble with a lot of web pages though so may have to upgrade.

[quote]Probably a good thing, I don't want to relearn any bad habits I may have picked up chasing that 13 second time slip 20+ years ago rotflmfao!
LMAO! Don't worry. It will come back to you quicker than a college student returns on laundry day.



The Datarace is a little UV box for erasing chips.
I've only ever seen black ones. I bought mine in '96 and it's black.


Now thoroughly inspired, I pulled the TPI box down and found some additional goodies. Several 7730 TPI speed density ecu's, few chips, and the old GM ECU Bench! Totally forgot I had this thing...

In regards to the running the 7427 over the 7747, I'm all about it! Would a reman unit from a big box parts house work, or would you recommend sourcing it elsewhere?

The parts store remans don't come with a memcal. So that would be an additional expense. If you can find a used one with the memcal installed for a smallblock you might save some $$.

It's also possible to install a late TPI intake on the truck and run TPI. TPI is the best damn truck intake GM never installed on a truck.

[87GMC]

The parts store remans don't come with a memcal. So that would be an additional expense. If you can find a used one with the memcal installed for a smallblock you might save some $$.

Based on some research I've been doing over the past couple of days... I'm thinking I may go with an EBL given the speed, tune ability, and lack of need for all this old chip burning hardware. Sure, its a little pricy but I'm looking for a one and done solution. Thoughts?


It's also possible to install a late TPI intake on the truck and run TPI. TPI is the best damn truck intake GM never installed on a truck.

For performance, I definitely wouldn't go TPI as a stock base, runners, and plenum hit the wall at 4500rpm. On a low horse cruiser... Damn skippy! I've got a little nugget I've had for a few years that was originally supposed to be for a destroked 350 to 304. Low torgue, high horse as it was going to go behind a WCT5 (glass jaw of a transmission) in a 3rd gen Camaro. Far too big (sewer pipe) for a bone stock L05. However, down the road... If I happen upon a killer deal for a nice set of heads and cam, absolutely!

[PlayingWithTBI]

Based on some research I've been doing over the past couple of days... I'm thinking I may go with an EBL given the speed, tune ability, and lack of need for all this old chip burning hardware. Sure, its a little pricy but I'm looking for a one and done solution. Thoughts?

That's what I did after playing a while with the 7747, ZIF socket and SST 27SF512 flash chip on my 88 5.7L. Now, with the VE Learn and a WBO2, it runs better plus I gained more ponies fine tuning SA and VE up to WOT.:thumbsup:

[tayto]

if you don't need E-trans control, hands down EBL. they also make a EBL P4 for the 730/727

[1project2many]

Based on some research I've been doing over the past couple of days... I'm thinking I may go with an EBL given the speed, tune ability, and lack of need for all this old chip burning hardware. Sure, its a little pricy but I'm looking for a one and done solution. Thoughts?
Definitely a great choice if you can afford it. It works well and Rbob has been involved with aftermarket tuning of GMEFI since the earliest days.


WCT5 (glass jaw of a transmission) Agreed!

[87GMC]

Got the EBL in and a handful of VE learns under my belt. The difference is truly remarkable! The idle went from small block smooth to sewing machine quiet. Crisp is the word I believe best describes the overall feel since swapping over.

Now for tuning… Can anyone recommend where to begin? TIA

[PlayingWithTBI]

Got the EBL in and a handful of VE learns under my belt. The difference is truly remarkable! The idle went from small block smooth to sewing machine quiet. Crisp is the word I believe best describes the overall feel since swapping over.

Now for tuning… Can anyone recommend where to begin? TIA

Got a WBO2?

Here's a link to where @84Elky developed a way to fine tune your SA tables
https://www.thirdgen.org/forums/diy-prom/761049-spark-advance-table-example.html#post6301288

[87GMC]

Got a WBO2?

Here's a link to where @84Elky developed a way to fine tune your SA tables
https://www.thirdgen.org/forums/diy-prom/761049-spark-advance-table-example.html#post6301288

Perfect! Thank you