SweetZRag

I am about to put my new setup back on the road. I am still using stock injectors. What symptoms should I look for to determine if bigger fuel injectors are required? Since I do not plan to race my car, I don't plan to buy them just for the sake of more speed. I would buy them if needed to make my car run correctly or if the stock injectors were a choke point in my new setup.

In general, what are the real world fuel injector symptoms I should look for when the car is back on the road in the next week or so?

shoebox

I would assume you would use a logger like Datamaster to monitor O2 readings and it's calculated injector duty cycle register as a guide.

SweetZRag

Shoebox,

Would I look for a duty cycle that is much larger than stock readings. Would that be an indication that the stock injectors are working too hard?

Or would you not have to worry unless the duty cycle hits 100%.

How does the O2 sensors factor in? Would the engine go lean under full throttle indicating the injectors couldn't keep up?

I have Datamaster and will use it as suggested. What other symptoms might I hear or feel?

Am I on the right track? Thanks for the help.

Jeff

maybe2fast

I too have this question. CC503 and port and polish Impala HG, madz28 tune

Injuneer

If the engine isn't getting enough fuel, you will see lean readings on the O2 sensors in PE mode (WOT), low fuel pressure, and high injector duty cycles. In theory, the injector would be open all the time at 100% duty cycle, but good practice is to keep the duty cycle to no more than 85%. TTS DataMaster DC values are "suspect" and appear to be higher than actual.

Also... wrong forum. Moving to "Fuel & Ignition".

SweetZRag

Thanks Fred. Sorry about the wrong forum. The items you mentioned make sense to me. Once I get the engine broken in and do some WOT tests, I'll look for these signs in DataMaster.