Mpfi upgrade reviews.

[62barsoom]

Reprogramming required listed on that listing. EPA must have busted GM for doing a non-certified injector replacement. All calibrations and parts replacements have to be re-certified for GM to sell them as emissions compliant and the MPFI upgrade kit throws the stock programmed fueling out of the window. Probably the whole reason that kit was discontinued anyway. Rather than spend money to correct the calibrations and re-certify, cheaper to just quit making the part.

Well damn. I just ordered this unit. So it won't run right out of the box?

 

[L31MaxExpress]

Well damn. I just ordered this unit. So it won't run right out of the box?

It will run just not as well as it could.

 

[kylenautique]

One shorted out, popping the ecm fuse. One started dumping excess fuel, filling a cylinder with enough gasoline to hydrolock. One had a sticky injector that would cause misfiring at hot idle.

The one I’m using now is trouble free for over a year now though I’m sure it’s on borrowed time. I hate them. Lol.

You may want to keep an eye out for the marine intake. That would solve your problem.

 

[kylenautique]

Aftermarket PCM reprogram using the correct data. 96-97 is hard to find anyone that can tune it. 98+ is much easier.

I second this. Call around for local tuners. If you have a 98, there's not much that can be done, but the ECM can be tuned. I had mine done by Black Bear originally. I was happy with the results. I ended up installing the 0411 ECM, which honestly, if you are going to tune your truck, I would go the 0411 tuning route. I'm finishing up my tuning with Black Bear. Just dialing in a few more things, but overall the truck runs amazing. David from Old School EFI can get you set up with a starter tune with the 0411. Hit him up if you are interested. [email protected]

 

[Road Trip]

Does not surprise me because GM to my knowledge has not corrected any of the calibrations on these trucks for anything for years. Once they went out of warranty that was the end of GMs support and updates atleast with PCM tuning related issues. The only thing that would have required them to make any changes would have been something emissions related under the Federally mandated emissions warranty. Those emissions warranties are long expired and we are well past the designed life expectancy of these trucks now. So long story short GM does not care. If an old truck cannot pass smog, they don't care, buy a new one that can in their eyes.

I saw a chart break down of the emissions stuff a while back that was written by GM in 1994. The Vortec trucks were only designed to meet the emissions requirements for like 70K miles and they predicted that 95% would have a 50% degredation from those design standards by 140K. At 140K miles GM predicted they would run too dirty to pass an actual emissions test and were thus considered at the end of life. Aka junk it and buy new. This was a writeup prepared for the EPA as well for part of the certification process for the 96 Vortec engines. As we now now some of these trucks just keep on going, I actually wonder how much emissions degredation a 350K mile truck has on it in real life.

This is a great thread describing the state of the art of keeping one of these on the road circa 2024.

FWIW I've been researching how today's ethanol fuel would affect the fuel trims that were calibrated
a decade before the forced adoption of ethanol gas, and L31MaxExpress's explanation of how E10
cuts into the successful self-correcting area of the factory feedback loop is spot on. (Reply #26)

Given that I remember seeing these trucks on the road when they were brand new it's hard for me to
remember that bringing one of these today to a Chevy dealership service department would be like
bringing a darkened Dynaco 70 tube amp to Best Buy and expecting the folks behind the counter to
bring it back to life. (The color of the sound of your very favorite music)

I may exaggerate a little, but the point is that in 2024 GMT400 owners no longer have the luxury of expecting
to find a shop capable of delivering excellence in the engine bay on every other street corner. This doesn't mean
that one should panic, but it does suggest that you become as self-reliant as possible. Even if you choose
to pay someone else to implement the fix, just knowing your way around this stuff will help you interview
potential mechanics and know which ones to partner with, as well as the ones to run away from.

And if you really want to enjoy your GMT400 free of fear, while your vehicle is running well, *now* is the
time to start a small collection of potential showstoppers and have them on your shelf. And I'm not
talking about buying new parts and stocking the shelves with them. Instead, you buy the new part,
replacing the perfectly good part on the vehicle, and (assuming the new part is good) you drive on that,
with the proven 'known-good, flown-good' part carefully stashed on your shelf. From personal experience I find
this method gives that elusive 'carefree' feel behind the wheel.

Again, great thread. Lots of sage advice shared here -- good stuff.

 

[John DeWitt]

This is falling in line with some of that BITOG technical information type stuff that I just mentally overindulge in with great interest.

 

[62barsoom]

I second this. Call around for local tuners. If you have a 98, there's not much that can be done, but the ECM can be tuned. I had mine done by Black Bear originally. I was happy with the results. I ended up installing the 0411 ECM, which honestly, if you are going to tune your truck, I would go the 0411 tuning route. I'm finishing up my tuning with Black Bear. Just dialing in a few more things, but overall the truck runs amazing. David from Old School EFI can get you set up with a starter tune with the 0411. Hit him up if you are interested. [email protected]

I'm working on a 99 Tahoe. I'm having a hard time wrapping my head around the tuning operation. I would like to go the 411 route. The repinning no problem. Then I'm a bit befuddled. It also looks to me as after buying everything for the HP Tuners set up I'm in about a thousand bucks

 

[62barsoom]

And a local tuner for me is at least a 4 hour cruise. Without Ginger.

 

[62barsoom]

This is a great thread describing the state of the art of keeping one of these on the road circa 2024.

FWIW I've been researching how today's ethanol fuel would affect the fuel trims that were calibrated
a decade before the forced adoption of ethanol gas, and L31MaxExpress's explanation of how E10
cuts into the successful self-correcting area of the factory feedback loop is spot on. (Reply #26)

Given that I remember seeing these trucks on the road when they were brand new it's hard for me to
remember that bringing one of these today to a Chevy dealership service department would be like
bringing a darkened Dynaco 70 tube amp to Best Buy and expecting the folks behind the counter to
bring it back to life. (The color of the sound of your very favorite music)

I may exaggerate a little, but the point is that in 2024 GMT400 owners no longer have the luxury of expecting
to find a shop capable of delivering excellence in the engine bay on every other street corner. This doesn't mean
that one should panic, but it does suggest that you become as self-reliant as possible. Even if you choose
to pay someone else to implement the fix, just knowing your way around this stuff will help you interview
potential mechanics and know which ones to partner with, as well as the ones to run away from.

And if you really want to enjoy your GMT400 free of fear, while your vehicle is running well, *now* is the
time to start a small collection of potential showstoppers and have them on your shelf. And I'm not
talking about buying new parts and stocking the shelves with them. Instead, you buy the new part,
replacing the perfectly good part on the vehicle, and (assuming the new part is good) you drive on that,
with the proven 'known-good, flown-good' part carefully stashed on your shelf. From personal experience I find
this method gives that elusive 'carefree' feel behind the wheel.

Again, great thread. Lots of sage advice shared here -- good stuff.

Know good flown good, what a great idea ! And that amp driving a JBL Paragon, oh my. This post is turning just as I'd hoped it would. Thank all of y'all for sharing your knowledge.

 

[Caman96]

Aftermarket PCM reprogram using the correct data. 96-97 is hard to find anyone that can tune it. 98+ is much easier.

But someone like Black Bear( i know you don’t like them, just an example) would be able to reprogram a 96…right?