Hello! Lt1 issues, rich but lean.

[92rslt1]

you can display it if you install a wideband; i did, worked fine.

the pcm runs a proprietery operating system designed just for the purpose of running an engine. it's all in assembly code if you want to try to reverse engineer it.

pulling arbitrary parts of flash memory is doable but seems to be a closely guarded secret that's only known by guys like tunercat and the guy that wrote lt1edit. pulling arbitrary RAM is a different matter, some gm ecms have an aldl request for it, this one might? nobody has found it. it's also possible to log a byte of ram by swapping that ram location for another in the aldl stream. but this pcm is actually two pcms, so sometimes it can be extra tricky. this is not lightweight stuff

I see, that clears things up. I found someone on another website who was able to create a program in C for his iphone and extract a dumb from the cars computer. I had tried to reach out to him to see if he ever made anymore success, but he has vanished. I guess this is over my head to begin with. I am a computer science student, but first year. By student I dont mean kid either, I'm actually mid thirties. I might submit this proposition to my teacher, hes always looking to get into trouble. Hes a electrical and software engineer so maybe he has some insight.

Back to my original problem, do you suggest I do anything further before upgrading the injectors? Im goign to verify fuel pressure real quick first. Should I wait to touch the tuning though? I reset the BLM and the cat doesn't glow, its creeping up though, its up to 145 again. Whats wierd is I can coast down my road(downhill like a mile) engine braking the whole way and when I pull into my driveway the cat is glowing. I was looking at the tables in the computer and it shows the car pulling timing and I can see the 02 voltage drop to almost nothing, indicating its pulled fuel too.. yet my cat is still glowing. Maybe residual heat?

Anyway, thanks for the help, I will get this figured out. I'm off to go load up my PI.

[EagleMark]

Today's computer science is not going to help, this is old stuff. We have a collage teacher here who teaches java and? IIRC and I don't want to say old but he's my age. He does very well at disassembling the Motorola processor code and re assembling. But finding what it all means and how to adjust is the hard part! If you have any experience or someone at school that can help there is a dissasembly in the $EE info thread. Steveo has been the greatest asset to LT1 in finding new stuff in years! At the time the LT1 was out and people started doing this all the talent went to LS1 and LT1 was left in the dust.

Your BLM creeping up I would check fuel pressure. The LT1 IIRC has fuel pump voltage in data stream so that would be a good thing to watch along with charging system. We had an LT1 here that would go lean at WOT in upper RPM and he was already upgraded to the hot wire kit to a Walbro fuel pump. Ended up his alternator belt was slipping in the higher RPM, we could see charging system flatten out and fuel pump voltage drop!

It was sitting for years and with today's E gas that could mean some water in bottom of tank. Have you drained it? Or at least gone through a few tanks of fuel since storage? One thing I do that has worked to check is pull fuel filter and try to keep as much gas as possible in filter. Then dump it in a glass jar and let it settle. You'll see the water puddle in bottom, the water settles in bottom of filter...

[steveo]

Steveo has been the greatest asset to LT1 in finding new stuff in years!

you're too kind :P

The LT1 IIRC has fuel pump voltage in data stream

not really; since it's vac fpr and static voltage pump from a seperate relay, and the only voltage the ecm reads is ecm voltage.. you could have good ecm voltage and shitty fuel pump voltage and never know from a log.

[EagleMark]

It was a long time ago, he must have had a voltage gauge hooked up...

[92rslt1]

Today's computer science is not going to help, this is old stuff. We have a collage teacher here who teaches java and? IIRC and I don't want to say old but he's my age. He does very well at disassembling the Motorola processor code and re assembling. But finding what it all means and how to adjust is the hard part! If you have any experience or someone at school that can help there is a dissasembly in the $EE info thread. Steveo has been the greatest asset to LT1 in finding new stuff in years! At the time the LT1 was out and people started doing this all the talent went to LS1 and LT1 was left in the dust.

Your BLM creeping up I would check fuel pressure. The LT1 IIRC has fuel pump voltage in data stream so that would be a good thing to watch along with charging system. We had an LT1 here that would go lean at WOT in upper RPM and he was already upgraded to the hot wire kit to a Walbro fuel pump. Ended up his alternator belt was slipping in the higher RPM, we could see charging system flatten out and fuel pump voltage drop!

It was sitting for years and with today's E gas that could mean some water in bottom of tank. Have you drained it? Or at least gone through a few tanks of fuel since storage? One thing I do that has worked to check is pull fuel filter and try to keep as much gas as possible in filter. Then dump it in a glass jar and let it settle. You'll see the water puddle in bottom, the water settles in bottom of filter...

Yea, the first tank was brutal, the knock sensor was never reinstalled after the swap because it was too sensitive with the cam and I couldn't find and lt4 module. So it was detonating like crazy until I filled the tank with 93 and VP 110 and ran it through it. Since then it has seen a tank of 93 with no deto.

Today I am going to swap injectors from one side to the other to see if it follows the injectors.

[92rslt1]

SO I ran a data log last night and wanted to run it by someone else to see if anything looks bad. its just a 5 min trip around the neighborhood, but you can witness the blm go up about half way through. the o2 sensors seem to be cycling fine once it enters closed loop. I'm not sure what KPA and AFGS are telling me, or of they are normal. It runs great in open loop though.

Sorry for bombarding you guys.