injectors, calibrated meter and NO GO!

[leon_reynolds]

Just finished up upgrading to 42# injectors, along with a pro-m 80mm maf. The meter was calibrated for my supercharger and I was excited to get back on the road. The car barely starts, acts like it is flooded......sounds like it is missing, stalls immediately, only starts only under full throttle. I was hoping I could just plug everything together and off I go. Anyone experience this after swapping injectors? Is this also something that could happen from being lean? Not sure what to do next, any help is appreciated.

 

[shttygtstang]

pull codes .. thats all we can do with our efi systems...on another note do you have a fpr if so you say it flooded then turn the fuel pressure down see how that works out. also change your plugs i had simlar problem after i fixed it i was chasing a demon of fouled plugs.. good luck

also alot of people are gunna say your crazy for getting 42s for a paxton only putting out 7 #s of boost

 

[Blown86]

I had almost the same problem with my car. 30lb injectors, calibrated c&l 76, d1sc 14lbs. It would start but very rich, tried tweeking the fuel pressure but didnt help. Took it to get dyno tuned and it starts and idles fine now, gets way better mpg now too. Tuner told me i need bigger injectors and would fine tune the driveability when they are installed.

 

[Daggar]

This seems to be a farly common mistake lately. Tossing in 42 lb injectors and a calibrated meter is just part of what needs to be done. The EEC fuel ramps and injector breakpoints are not designed for the amount of fuel a 42 lb injector is capable of providing. Even the minimum pulsewidth for the injector is way off (imagine for instance, the minimum (idle)for a 19 lb injector being 10% and carrying that same 10% over to a 42 lb injector (EEC commanded) on the same engine combo.... that's considerably more gas). You're in need of a custom tune whether it's a burned chip from a good dyno shop or something like the TwEECer or Anderson PMS. Since you've already got a meter calibrated for the injectors you're using, I'd suggest the Anderson. It's much simpler to learn and use than the TwEECer although more expensive. If you don't have a lot of plans for further modifying then your best bet may be a customed burned chip.

Good Luck.

 

[leon_reynolds]

Thanks for the info.......I was looking into getting a tweecer so i could calibrate myself when upgrades arrive. I didnt know anything about the anderson pms although they seem considerably more expensive. Does the tweecer do the same functions, or does the anderson have a better product? I do not care much about the ease of use, I would rather spend a little more time researching and learning then spending the additional money if accomplishes the same thing.

 

[Daggar]

Thanks for the info.......I was looking into getting a tweecer so i could calibrate myself when upgrades arrive. I didnt know anything about the anderson pms although they seem considerably more expensive. Does the tweecer do the same functions, or does the anderson have a better product? I do not care much about the ease of use, I would rather spend a little more time researching and learning then spending the additional money if accomplishes the same thing.

They are "different" products. It will totally depend on what your preferences are for their use as to which one you get.

Instances for what little I know about your combination:

42 lb injectors
MAF calibrated for 42s
Supercharger

The PMS is easy to use. You can add or subtract fuel at an portion of the RPM range as a percentage to bring your AFR up (or in your case down) to the appropriate level. The PMS will make use of BAR/MAP which makes it simple to add fuel based on a boost reference. There is not a huge learning curve required to make the PMS perform these functions

The TwEECer on the other hand, will give allot more control over engine tuning. It allows you to make modifactions to the MAF transfer curve (something that you do not necessarily require if your meter calibration is accurate). It allows modification of a HUGE number of scalers within the EEC. It can not make use of a BAR/MAP for boost referencing but instead require tune of the fuel ramps, spark tables, injector breakpoints, dapshot settings, and a host of other things to perfect the tune for the combo regardless of what that combo happens to be. The learning curve is very steep. It will require a considerable amount of time to learn and many hours spent on the forums to help figure out what does what and why.

My reason for thinking that the PMS would be better suited to your application comes down to your not needing to modify the MAF transfer curve. With a Tweecer you can use pretty much any meter. You would load the transfer function into the Tweecer then tell it what size your injectors are (there's a bit more to it than that but that's it in a nutshell). In your case, I think that it all be done a ton easier with and Anderson PMS.

Read through each of their forums and decide which one you think would work best for you. Then throw your hands up and say "screw it" and go out and get a custom chip and tune.

P.S. A custom tune and chip will cost your roughly $600 and another $100 for each for each subsequent tune after modifactions are made.