Mpfi upgrade reviews.
- Thread starter 62barsoom
- Start date
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L31MaxExpress
I'm Awesome
Yep in big bold black letters with parenthesis around it. "(Reprogramming required by automotive professional)". Does not even state that a GM dealership can do it.
That would be you…right?
L31MaxExpress
I'm Awesome
I have the data and I did share a tune file with it in the 0411 swap sticky. Not like I am calling GMs own data out of a newer 4.3L that had these same injectors my own. I robbed the GM injector data right out of like a 2010 4.3L van.That would be you…right?
That being said that injector shows up for me as $409 if it is available. I would jump on it if I needed one and it is actually available.
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John DeWitt
Newbie
Wow wow wow wow wow....wow...........wow, hold up. You mean after 6+ years of driving around on upgraded spiders I was supposed to reprogram something?!?!?
L31MaxExpress
I'm Awesome
I drove on mine for a few years before I discovered the injector data was not correct. Swapped to the correct data and my engine went from having somewhat high fuel trims (PCM correcting for a lean condition) to basically zero trims and ran a lot better. The high fuel trims was one of the reasons I tuned my van to start with. The fuel here is also 10% ethanol which also causes it to run leaner on stock tuning. Injector data correction plus a change to a stoichiometric air/fuel ratio of 14.1 corrects the lean tune and gives the PCM an ability to actually compensate for a problem that would make the engine run lean.
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John DeWitt
Newbie
Please, do go on & into further detail
L31MaxExpress
I'm Awesome
The newer style spider is actually 22.1 lb/hr in flow. The stock spider is 23.1 lbs/hr the PCM is calibrated to open the injectors based off that flow rating to deliver the correct amount of fuel. The newer style injectors also have a different amount of dead time. That is the time delay between the PCM sending voltage to the injector and the fuel actually starting to flow. That also makes a difference in the total volume of fuel injected. At lower rpm and load like idle a dead time calibration error can signifigantly throw off the fuel delivery. Then you throw E10 fuel into the mix. The system is still injecting 1 part fuel to 14.7 parts air although the new fuel has a stoichiometric air/fuel ratio of 1 part fuel to 14.1 parts air. When I read data with a scan tool my PCM was showing consistent fuel trims of +10-15%. That is close to setting lean fuel trim codes. When you hit that upper limit of adjustment the PCM can no longer add fuel for any real problem such as a small vacuum leak, weaker running fuel pump, plugging fuel filter that is causing reduced fuel pressure or a dirty MAF.
A few months ago, this same topic was being discussed, so I specifically asked the question on the Acdelco site. I got the typical “Message Received” after hitting Send and it also said “Thank You, We Will Respond to You”. They seem to have ignored that particular question.
