Long story short, GTA has been sitting in storage for 10+ years, when I got it back in the garage I put a new fuel pump and injectors in, replaced the IAC and MAF (with a bosch), new heated O2, all new plugs, and replaced all the vacuum lines.

The injectors I got were probably not the best choice as they were the cheapest on RockAuto. FJ680 is the model#.

After getting things running, it has tons of power, but a terrible and shaky idle. Hooking up and learning the scan data, I noticed that I'm running very rich (confirmed by the plugs being completely black), with my BLM bottomed out at 108, which is the minimum setting for this ARAP prom (I had a custom chip made many years ago, and wanted to get back closer to factory.)

I figured the aftermarket injectors might be causing issues, and while I wasn't able to find any factory info on the flow rate, this site https://www.racetronix.biz/p/24-lb-h...jector/d1810xx had them listed as 24 lb/hr. I changed the BIN and updated the Single Fire/Double Fire FI Size to 24 (I believe it was at about 22.6 before). My thinking was the ECM would decrease the IBPW to compensate for the additional flow... But I'm still seeing my BLM drop to 108, and start to idle terrible. FP is right at 39\40 lb with vacuum line on. and 43 with it off.

I'm sort of at a loss of what to do next, other than buy stock injectors, or send my old ones in to get cleaned and flow tested (they were totally blocked.)

Should I keep trying to tune? or is there something else I should be looking at..

edit: only mods are headers. and plugs were Accel 576S

 

The correct way to replace injectors is to either...

1.) Get Delphi's in the same flow rate as your stock ones (if you want to avoid tuning, as it appears to be the case that Delphi's that they are direct replacement, though they are pricier from what I understand).

2.) Get a set of Bosch-III's. They're overall fantastic injectors (I love mine), but ensure that what you're buying comes with a legitimiate data sheet, as you will very likely need to do some tuning to change the voltage offset table (even if the advertised flow rate is the same). You may also need to change the flow rate constant by a point up or down as well to get the fuel trims back into line.

But simply buying any old injector often doesn't cut it... The ECM makes assumptions about the electrical characteristics of the injector when it fires them and those assumptions are based off of values entered into various tables in the calibration. If the tables don't match the injectors, you'll often have problems.

 

Those injectors appear to be stock 5.7l re-mans. Nothing wrong with that.

Check the MAF airflow value at idle, IIRC, it should be in the 8 - 10 gms/sec range. The MAF sensors for these cars are real hit and miss today.

RBob.

 

the photos on some sites are misleading, as they are disc injectors. Didn't realize that until after I got them.

MAF is hovering around 7-10, if I unplug the MAF, I get the same results.

Besides tuning flow rates, what additional tuning is possible with the 6E?

 

The voltage offset table. But you need the datasheet for the injectors if they have such a thing.