55# injectors

[rick13]

I replaced my 42s with 55s. I got em from Lindsey. So specifically, what do they program differently to make them work? Just curious???

The reason I ask is because although I have chip upgrades...I was using 42# injectors.

No worky so good right now.

So what do ya'll think?

[kdjones2000]

First off, are the new ones high or low impedance? The originals are high impedance, and you will need to put in some resistors if yours are low impedance or you risk blowing out your injector firing circuitry in your DME.

Secondly, the chips you have in the car are programmed for what size injectors? Unless they have put different programs in the FQS switch or something, you are going to need a new set of chips programmed for the injectors you have.

Too bad you didn't go through all of this before you bought the new ones....

[rick13]

They are programmed for 42# and a 3 bar FPR. I have a lightly modded turbo, stainless headers with 3" exhaust, shimmed wastegate, and MBC.

I guess I'll be ordering some chips eh ? Would this be a good time to go with an MAF setup? Or can I put that off?

[rick13]

Ah yes...and they are siemans 2.8 ohm

[mreid]

Your computer is sending a signal pulse width to the injectors based on a 42# injector. The injector is opening for the prescribed period of time and dumping 31% more fuel. I wonder why it's not working so well?

Why did you change injectors? You need a new program.

[rick13]

I was having sypmtoms that led me to believe that my 42# injectors were bad...( wet plugs, backfire/popping, missing, studdering). Plus they had 175,000 miles on them. So I figured let me upgrade to 55's...and I want to go MAF down the road.

They were cheaper than the stock replacements too!

[968 GUY]

Rick read the ..frustrated...thread.

[968 GUY]

Turbo injectors are 4.2 or so ohms.

[Tzimis]

Drop the fuel pressure to compensate for not having a maf and chip that can remap the voltage to it's known variables.