Fuel Injector Replacement Guidelines

If an incorrect fuel injector is installed on 2014-2020 GM models equipped with a V6 or V8 gasoline engine (RPO LV1, LV3, L82, L83, L84, L8B, LT1, L86, L87, LT2, LT4, LT5, L8T, LTA), it can lead to skewed Long Term Fuel Trims (LTFT) and/or Short Term Fuel Trims (STFT) during engine operation. Vehicles with an illuminated Check Engine MIL or a possible rough idle after a fuel injector replacement should be checked to ensure that the correct injector was installed in the suspect cylinder.

Any of the following misfire or fuel trim related DTCs also may be set: P0300 – P0308, P050D, P0171, P0172, P0174, P0175, P2099, P219A, P219B.

Replacing an Injector

If a fuel injector replacement is required during repairs, refer to the Electronic Parts Catalog to verify that the correct injector is ordered and installed.

Here’s how to identify and order the correct injector. In this example, the vehicle is a 2016 Silverado 1500 4WD Crew Cab equipped with the 5.3L V8 engine (RPO L83), VIN# 3GCUKSECXGG251110.

1. Identify the 8-digit injector part number found on the injector body. (Fig. 25)

Fig. 25

2. Enter the VIN in the parts catalog; go to the fuel injector rail parts section.

3. After the injector part number has been identified in the Description column, the part number that needs to be ordered will be in the Part # column. (Fig. 26)

Fig. 26

For the Silverado with the 5.3L V8 engine in this example, the original fuel injector part number is 12668390, highlighted in the Description column. The part number to order is 12698484.


Nominal Flow Injectors

When fuel rails are assembled at the supplier, each injector installed in the fuel rail can be a nominal, low or high flow injector. The different injectors in the rail is done to get an even balance or flow across the fuel rail for emission requirements. Replacement injector kits will be a different part number than the injectors, and a kit may contain one of several different injector part numbers.

If an injector has been removed and discarded or if all injectors are on the bench and it can’t be determined which one goes where, the best thing to do is order the “NOM FLOW” injector part number in the quantity needed. (Fig. 27)

Fig. 27

For additional information, refer to Bulletin #20-NA-098.

– Thanks to Bryan Salisbury

Diagnosing DTCs P0016 and P0018
Diesel Exhaust Fluid Consumption


  1. Steve Sidwell says:

    If replacing all injectors, do we need the part number off each injector?


    I have a couple questions.

    PIP5498M (doc id 5577883) has the following note posted in it:

    “Note: If the injectors are being replaced on L86, LT1, LT4 or LT5 there are three different flow rates injectors offered. Be sure to install the same flow rate injectors back into the engine by checking the part number on the injector housing. Mixing the flow rates will cause drivability concerns, DTC setting and repeat injector replacements. ”

    If I am reading 20-NA-098 correctly, it lists all the variants of the Gen 5 LT small blocks and even the LTA Blackwing engine. So can the LV3 4.3 and the L83 5.3 have, based on the injectors removed, varying flow rates? PIP5498M leads me to believe that only the 6.2 applications (L86/LT1/LT4/LT5) you may find injectors of the 3 different flow rates. At our store, we’ve done a decent amount of injectors on 5.3 L83 engines, and I’ve ordered them for the techs based on that note in PIP5498M. All of the ones we’ve ordered were p/n 12698484 or its previous # 12687650 and 12684125.

    Should I start to make sure that I have the techs pull the old #s off the injector on these L83 engines? Is that red note in PIP5498M valid?

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