Hello! Lt1 issues, rich but lean.

[92rslt1]

Hello, I finally got my car on the road and its running good but I have a few issues.
My brand new CAT is glowing cherry red and smells bad. I think its burning pig rich at idle, it was so bad before I put the cat on it was burning my eyes.
Also, I started data logging about 100 miles ago and today I got a code that says right bank O2 lean which really doesn't make sense. Also it has maxed my BLM all the way to 160 making it even worse.

I have tried to attach my bin file, trying to find out if its something in my tuning or maybe my injectors are going bad. How can I log the entire rpm range so I can see if its a fuel delivery problem or tuning issues? If I could log the O2 data I could pin point the air leak or injector issue.

[steveo]

blms at 160 mean its dumping a TON of fuel because it thinks its lean, but that glowing exhaust means its probably not actually lean.

initial diagnosis? exhaust leak before o2 sensor, o2s are bad, or both.

other stuff such as a spark missing from a cylinder can do that, that cylinder is just pumping air, so it thinks its lean, then dumps fuel, which reacts in the exhaust even worse from all that extra air being pumped in there.

[92rslt1]

blms at 160 mean its dumping a TON of fuel because it thinks its lean, but that glowing exhaust means its probably not actually lean.

initial diagnosis? exhaust leak before o2 sensor, o2s are bad, or both.

other stuff such as a spark missing from a cylinder can do that, that cylinder is just pumping air, so it thinks its lean, then dumps fuel, which reacts in the exhaust even worse from all that extra air being pumped in there.

So the O2 are both new, and I dont hear a leak at the header surface. I think that maybe its the injectors, one or more. The car sat for a long time, about 5 years. I'm thinking maybe I need to replace the injectors with 30lb.

Is that as easy as installing the 30lb injectors, then setting the computer injector size to 30lb injectors? right now it has 24lb stock injectors, but its set to 24.57

[steveo]

Is that as easy as installing the 30lb injectors, then setting the computer injector size to 30lb injectors? right now it has 24lb stock injectors, but its set to 24.57

assuming the new injectors are flow rated at 43.5psi, then yeah, that'll get you in the ballpark.

there's also the difference between n-heptane or gasoline flow ratings, which is a small difference, but it does make a difference.

depending on the level of ethanol in your fuel, you may have to account for that in your injector flow constant as well, since the stoich afr variable (if it exists) in EE is unknown.

then there's your offset table.

you should make sure before you buy injectors that a proper datasheet including a proper offset table is available.

30lb injectors are a bit big for a stock-ish engine, but will give you some growing room.

why dont you confirm this is the issue by doing a homemade flow bench? disable the ignition coil for safety then, hang the rails and put a container under each injector.

keep fire extinguisher handy

first just run the fuel pump to check for leakage. then just crank the thing until you get a good sampling. if you have one injector flowing more than the rest, you'll see it real quick in the jar.

you should also check fuel pressure and the other basics while you're in there

[92rslt1]

assuming the new injectors are flow rated at 43.5psi, then yeah, that'll get you in the ballpark.

there's also the difference between n-heptane or gasoline flow ratings, which is a small difference, but it does make a difference.

depending on the level of ethanol in your fuel, you may have to account for that in your injector flow constant as well, since the stoich afr variable (if it exists) in EE is unknown.

then there's your offset table.

you should make sure before you buy injectors that a proper datasheet including a proper offset table is available.

30lb injectors are a bit big for a stock-ish engine, but will give you some growing room.

why dont you confirm this is the issue by doing a homemade flow bench? disable the ignition coil for safety then, hang the rails and put a container under each injector.

keep fire extinguisher handy

first just run the fuel pump to check for leakage. then just crank the thing until you get a good sampling. if you have one injector flowing more than the rest, you'll see it real quick in the jar.

you should also check fuel pressure and the other basics while you're in there

Sorry, I should have specified more, its a cc306 cam, mild ported heads, 36mm TB, aftermarket ignition, hooker headers and 3 inch cat back. Tuned by a very reputable tuner who no longer offers lt1 services so I'm trying to learn on my own. It ran amazing before being parked, it had stock fuel pump in it then too. When I started it up after its 5 year slumber it ran terrible, was missing several cylinders. I took the injectors out and soaked them over night in carb spray and blew air through them and when I reinstalled them it ran good. It now has a walbro 225 with stock regulator still. It actually still runs really good, but is too rich and lopes a bit more then it should at times. I'm leaning toward the injectors being suspect. I will try to get them to flow like you said and see what happens. My friend has a snap on scanner that will fire injectors, so I will try to rig up a pump and clear glass tank to spray test.

[92rslt1]

Well I pulled some of the plugs today and much to my surprise they look OK to me. I expected them to be black.IMG_4088[1].jpgIMG_4087[1].jpg

[steveo]

that is on the rich side for sure but not enough where it should make your cat glow?

not that i'd know, i never run cats on builds like that.

still with all those issues you should replace them, injectors need to be perfect.

keep in mind there are lots of ways to make a cat glow like that, not just sketchy fuel injectors....

[92rslt1]

that is on the rich side for sure but not enough where it should make your cat glow?

not that i'd know, i never run cats on builds like that.

still with all those issues you should replace them, injectors need to be perfect.

keep in mind there are lots of ways to make a cat glow like that, not just sketchy fuel injectors....

I know what ya mean about the Cat, it is becoming a pain. With modern day Cats I didn't see a reason why not to run one though. I hate the smell of a cammed up car without cats and my last build had no cats and every time I got out of it I would smell like I just mowed the lawn.

Did you write the Raspberry pi code? I clicked on the link in your sig and was pretty excited to see that. I have a pi that's been collecting dust on my desk, I wanted to make a fuel injector pulser with it just for fun, but just haven't gotten around to it.

[steveo]

Did you write the Raspberry pi code?

yep, sure did

you should build one, it works out of the box with your car..

http://fbodytech.com/aldlrpi.html

[92rslt1]

yep, sure did

you should build one, it works out of the box with your car..

http://fbodytech.com/aldlrpi.html

That's awesome. I'm going to order up the parts. Is it possible to display the air fuel ratio too?

do you know what type of operating system the PCM runs? I was trying to figure out what functions I could use to write a c program that would allow me to pull the memory off the PCM... Kinda like winaldl does. But first I needed to figure out how to establish that communication.

[steveo]

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

[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...