New TBI injectors causing surging

[youcancallmedusty]

Are the "new" injectors for a small block or the big block? Food for thought is if you purchased larger flowing injectors and had a custom chip burned for the SBC OEM flow rates that will cause drivability/idle issues

The new Injectors are what ACdelcos catalog say fits my vehicle, the part number for the original ones is 5235206. Tonight I swapped the originals back in and it idled as it should, so at this point I am confused to be honest. I’m going to be putting this on hold until Monday because I ordered some different injectors that I will try out, see what happens and report back.

 

[mtbadbob]

My '87 does the same thing, even after I rebuilt the TB & injectors. It'll dip way down & almost stall while idling, then pop back up to normal rpm and smells rich. It'll sometimes shudder a bit while revving, like a choke is closed too far. I have not replaced O2 or CTS yet, those were my next moves.

 

[gmbellew]

My '87 does the same thing, even after I rebuilt the TB & injectors. It'll dip way down & almost stall while idling, then pop back up to normal rpm and smells rich. It'll sometimes shudder a bit while revving, like a choke is closed too far. I have not replaced O2 or CTS yet, those were my next moves.

save the money on throwing parts at it and use it to get ALDLDroid and a Bluetooth OBD1 cable to diagnose. it will save money on parts in the long run.

 

[gmbellew]

The new Injectors are what ACdelcos catalog say fits my vehicle, the part number for the original ones is 5235206. Tonight I swapped the originals back in and it idled as it should, so at this point I am confused to be honest. I’m going to be putting this on hold until Monday because I ordered some different injectors that I will try out, see what happens and report back.

are you running a stock engine and stock PROM chip? if not, maybe somebody has modded the engine and has tuned the PROM chip and installed different flow rate injectors. are there any numbers to compare on the old injectors to new injectors?

 

[youcancallmedusty]

I got a different brands injecotrs today, CS Injectors instead of ac delco. I installed them and let the truck warm up to operating temp and it did not once surge, it acted like it should. This leads me to believe that the ac delco injectors were just bad in some way, and it’s crazy that I got two pairs that were faulty. I tested the resistance of the ac delco injectors and it was in spec of 1.27, I believe 1.2 is ideal. Other then that I have no clue why they ended up being faulty, and caused a surging issue when engine got past 150f. With the new cs injectors engine sounds phenomenal, they are quieter then the original there is no more surging while idling when warm. Thanks for the help, if anyone has any ideas of how to test the ac delco injectors to figure out why they caused surging I am all ears, cause now I am so curious of what could’ve been the cause