Esplain ECM programing to me

[Sharpe]

As some of you know, the slow-fitty-fo in my crewcab has been giving me **** for about a year. I've replaced everything ****ing thing that is considered replaceable and its still being a *****. The main problem right now is intermittent hard starting. Most mornings, when there is no one around and I'm going to work, it will fire right up. Later in the day (particularly when there are alot of people around) it usually takes 5-10 seconds of cranking to fire up. Then people laugh at me. It sucks. I'm going to do a compression test this weekend but it doesnt burn any more oil than "normal" and runs fine once going so I'm skeptical that that is the problem. Clarke speculated that the computer might be FUBAR because they have had similar problems with cars at Lance's shop and swapping out the ECM has usually fixed it.

My ECM says "remanufactured by GM" on it so it has ****ed up before. The part number is 09366810 and a new one costs $284.20 from GM (Rockauto is ~$220) and still has to be programmed. The parts guy I talked to said I could take my truck to a dealership and have them diagnose it, but I get the feeling that will end up being a "There is nothing wrong with it, that will be $200." Is there anywhere else in town that can do this kind of diagnostic scan (Flemco)? I can easily remove the puter from the truck or take the whole damn thing. It should be noted that my exhaust is completely ****ed up and leaking from prety much every joint as well as a few rust holes in the muffler. It sounds like total **** and is my next priority for fixing but I dont know if that would contribute to the hard start issue.

[uglyota]

Not throwing any codes? Is it consistent that it starts fine in the morning, then won't start later in the day? Crank/cam position sensor?

[KrazyKarl02]

I know on the half tons Chevy put a switch on the oil pressure that would kill the fuel pump. Such that if you had low oil pressure the fuel pump would not turn on. That could be your issue, later in the day when it is hot your oil is not as thick and does not build pressure as quickly.

[Sharpe]

No codes, crank and cam sensors have been replaced within the last year. Oil pressure switch has not been replaced but the fuel pump primes when the key is in the hot position.

[uglyota]

Is it consistent that it starts fine in the morning, then won't start later in the day?

1 2

[Sharpe]

For the most part but sometimes it will fire right up later in the day.

[uglyota]

Try and wiggle the distributor? Seems like timing

[AggieTJ2007]

if you come to corpus and bring me some fenders I can read the ECM w/ EFI Live. i can also reprogram a new one if you have to go that route

[Hot Pocket]

Most mornings, when there is no one around and I'm going to work, it will fire right up. Later in the day (particularly when there are alot of people around) it usually takes 5-10 seconds of cranking to fire up. Then people laugh at me. It sucks.

Sounds like an easily fixable problem...





Oreilly has a good deal on camo paint. :flipoff2:

[AggieTJ2007]

^^^^ see i like that

[Sharpe]

So its time to revisit this issue. It has gotten worse and the truck is a mother****er to start prety much every time now. The 7.4L Vortec originally came with Rochester injectors (p/n 17109596) that are A) a ****ty design and B) at the absolute max end of their operating range. I am going to replace my bunk injectors with Bosch units (p/n 0280150973). I have read mixed reviews in this thread

http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/213662-96-99-454-vortec-owners.html

about whether a tune will be needed with the new injectors so I might have to hit up Creighton's EFI live. Do I have to buy a subscription or something? I will need to get the EGR and rear O2 sensors programmed out regardless.

I am going to do *something* with the exhaust too. As far as I know there are no complete kits available for crewcabs of this body style. I dont want to buy headers and I'm ditching the cats. I think I'm going to use the crossover pipe from my stock exhaust and just run new tube the rest of the way. Not sure what muffler I'm gonna run yet.

[Hot Pocket]

Mufflers are for pussies!:flipoff2:

[Sharpe]

Mufflers are for pussies!:flipoff2:

And jettas are for faggots. What's your point?

[FJAggie07]

So much anger....

[Hot Pocket]

At least my **** runs

and gets good gas mileage
:flipoff2:

[AggieTJ2007]

So its time to revisit this issue. It has gotten worse and the truck is a mother****er to start prety much every time now. The 7.4L Vortec originally came with Rochester injectors (p/n 17109596) that are A) a ****ty design and B) at the absolute max end of their operating range. I am going to replace my bunk injectors with Bosch units (p/n 0280150973). I have read mixed reviews in this thread

http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/213662-96-99-454-vortec-owners.html

about whether a tune will be needed with the new injectors so I might have to hit up Creighton's EFI live. Do I have to buy a subscription or something? I will need to get the EGR and rear O2 sensors programmed out regardless.

I am going to do *something* with the exhaust too. As far as I know there are no complete kits available for crewcabs of this body style. I dont want to buy headers and I'm ditching the cats. I think I'm going to use the crossover pipe from my stock exhaust and just run new tube the rest of the way. Not sure what muffler I'm gonna run yet.

yeah you have to buy a license, you will have to talk to ed about that since it is his EFI live and I think he can get a discount on licenses. other than that we can program out the rear O2 sensors and the EGR

[Sharpe]

How much is the license?

[AggieTJ2007]

$80-$100

[Sparling]

What all can the EFI live tuner make tunes for?

[Sparling]

Nevermind, it looks like it's all gm stuff