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Thanks!

D

danny12

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Hello to all I know this is not the introduction area but since this is where I found what I needed I thought I'd just post it here.

back story:doah: 2 years ago a friend gave my daughter a 1988 c1500sb it had a 4.3 that died and he decides to "build" a hot rod so he "buys" a 5.7 and hires some "gentlemen" to do the swap they keep it a year or so never get it running. So he takes it to another "gentleman" he gets it to crank but not drive. so It sets in the yard a couple years with a new rebuilt engine. one day he says your daughter is getting her licenses I'll give her that truck if you'll fix it for her.( I was a diesel mechanic 20 years ago ALL mechanical no electronics) I say OK:haha:this thing had been butchered to hell an back no sensors had a ecm out of a manual shift truck that was fun to figure out any way finally got most things figured out fixed up and going
Except it keep throwing code 13 been chasing it for a year off and on looking on the net talking to buddies an such. she has been driving it with the light on. So I'm looking on the web some more and I see this site I start reading and thinking these cats are on to something but Pay to join a forum:dunno:

Well 20 min. after I paid the $25.00 and could see the pictures that eagle mark had kindly posted I had my code 13 fixed. just wanted to say thank you sir and thanks to every one else that takes the time to do so.

Thanks again, Best money I ever spent please keep it that way.

Danny
 
Welcome aboard, don't be a stranger! We can help you spend some money on that "free" truck!:haha:
 
This place has saved me tens of thousands of dollars over the last 10 years with technical support and troubleshooting help. It has also cost me tens of thousands of dollars by providing me with an endless list of upgrades I can make to my trucks haha!

CK5 is more than just a forum - This place is a community full of like minded people and is more of a family then a forum. We just all happen to have a certain love for our trucks LOL!
 
Danny, glad to hear that your money was well spent.

Makes me feel good to know that even after his passing Eagle Mark is still able to help people. He was a great guy, I doubt you will hear anyone say otherwise.
 
dyeager535, sorry to hear that eagle mark has passed I'm sure he was a good guy just by his post's.

I'm curious about his signature

1990 Chevy Suburban 5.7L TBI ECM 1227747 HiWay Lean Cruise!
1998 Chevy Silverado 5.7L Vortec RoadRunner Lean Cruise!

I'm sure it falls under the category of if you have to ask! but I have to ask because that was the fault code I was getting.

And thanks to all for the warm welcome,
I'm not much of a poster just sit back and listen

Danny
 
I don't know all the GM ECM's that it was incorporated in (pretty sure it was coded into the TBI setups by individuals, not GM), but when GM was designing their GM OBD1 systems, they incorporated something that has become known as "lean cruise". I've seen it called highway mode as well.

The way I know it works with at least TPI is the ECM goes open loop during cruise (so no O2 sensor feedback) when certain criteria are met: engine load, time duration, etc. Then after a set time period, if other conditions don't kick it out of lean cruise first, it drops out of lean cruise (not sure if that is both to keep the cylinder from getting too hot, help the converter, and/or to ensure everything is still ok), then goes back.

So basically it switches from running lean to running at an AFR of ~14.7:1 during cruise.

Obviously running lean will save fuel. IIRC, Mark was able to get 19MPG out of his Suburban during cruise.

I recall reading somewhere that when GM first implemented this, the EPA caught it somehow in the emissions certification process, and GM had to disable it. It was probably due to NOx production, as running lean creates heat which fosters NOx production. So the software "code" is in many of the ECM's GM built, just deactivated. Once people cracked the code, they were able to manipulate whether it's used or not.

Pretty complex process, and without an active piston cooling system, it's fairly dangerous to mess around with. If you change the parameters and run lean enough long enough, eventually you will start to melt pistons and cook whatever oil makes it to them for cooling.
 
Dyeager535 I was looking back at the sticky where I found the trouble code chart and realized you were the one who posted the PDF Thank you
 
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