Fuel Injectors?

[Angel Rivera]

Hey everyone!
I recently done a full PI swap and car has been running a bit lean. It still using stock injectors so I have been thinking about swapping for some new fuel injectors. Both LateModel and American Muscle have 19lb and 24 lb ev1 injectors, but which option would be better suited? The rest of the fuel system is stock as well.

 

[Three50won]

You should be fine with the 19 pounders. I have a full bolt-on 03 GT and the 19 pounders are more than enough for my engine.

 

[Angel Rivera]

Okay, did you go with the Accels? Also, did you need a tune or was it a direct swap with no issues?

 

[wmburns]

How are you measuring the AF ratio?

Consider that there are several "other" possible causes for a lean condition:

• Exhaust leak
• low fuel pressure
• intake vacuum leak
• Clogged fuel injectors. Consider an injector cleaning service such as injectorRX.com

 

[Angel Rivera]

I data logged the a/f ratio percentage. I checked the pressure in the rails which is fine, and check all vacuum leaks and actually improved the ratio (mechanic forgot to put on the air filter). Clogged injectors maybe be possible since they are original, and I am not sure which fuel was used prior to my ownership. I currently run 91 no eth. and I think the 3 hole spray would be more effective than the stock one hole injector design. I could possibly clean them but it might be time for an update anyways.

 

[TeamCaffeineGT]

The PI swap raises the compression ratio by increasing the cylinder volume resulting in greater air flow. This went from 9.30:1 in the non-PI engines to 9.74:1 in the PI engines. The increased airflow could be causing the lean condition, but your MAF should be picking up the increased airflow and the ECM would adjust accordingly.

What is your A/F Ratio right now?

Garrett's website puts it best: " A lower AFR number contains less air than the 14.7:1 stoichiometric AFR, therefore it is a richer mixture. Conversely, a higher AFR number contains more air and therefore it is a leaner mixture."

 

[Sharad]

Correcting the AFR through the tune, rather than installing bigger injectors without calibrating the MAF, will give you better driveability and fuel economy.