Fuel Injectors

Does anyone know how important matching the serial numbers on a set of injectors is? I have an S10 that I put used injectors in not paying attention to the serial numbers. Ever since it runs rich. I got a new set of injectors, but only two out of the four worked. So right now I've got injectors with at least three different serial numbers on them. I read somewhere that, when replacing injectors on an S10, it's very important to match the serial numbers due to the different flow rates. Can someone please tell me if this is true or not?

Yes you want all injectors with the same flow rate.....you can still have problems even if you replace several with the right numbers.....even though they are all rated at the same flow rate, the new ones could put out more than the "old" ones......

I ran into this on an old tuned port Firebird V8 engine.....guy came in with an engine idling bad.....I tried everything to no avail.....and then I noticed a couple of his injectors looked very clean at the base(whole top of his engine was dirty)....asked him about it and he said another garage put several in.....

Luckily, we had special GM tools to measure flow rates, and his injectors were all over the place, spec wise.....I told him, his best bet was to replace all 8 of them, with the correct GM #......

He agreed with me, and that turned out to fix the problem......

Yes you want all injectors with the same flow rate.....you can still have problems even if you replace several with the right numbers.....even though they are all rated at the same flow rate, the new ones could put out more than the "old" ones......

I ran into this on an old tuned port Firebird V8 engine.....guy came in with an engine idling bad.....I tried everything to no avail.....and then I noticed a couple of his injectors looked very clean at the base(whole top of his engine was dirty)....asked him about it and he said another garage put several in.....

Luckily, we had special GM tools to measure flow rates, and his injectors were all over the place, spec wise.....I told him, his best bet was to replace all 8 of them, with the correct GM #......

He agreed with me, and that turned out to fix the problem......


Thanks for your help. Can you tell me whether a bad fuel pressure regulator can cause this code?And the proper test procedure to check it?

Which code?

Also what year and engine size?

Which code? P0172

Also what year and engine size? '96 S10 2.2L L4. I R&R'ed the head gasket a while back but, during the process of pulling the head, I was using a 1/4" ratchet right up against the side of a fuel injector. As I applied torque to the ratchet, the plastic top of the injector came off. I went to the local Pull-ur-Part yard, and got some used injectors. Since then, I get code P0172(System too rich bank 1) and occasionally P1441(EVAP Purge system flow during non-purge). My question is: can the EVAP system problem be the cause of P0172?
You mentioned checking the flow rates of the individual injectors on the Firebird. Is this something I can accomplish with graduated cylinders and a stopwatch? Also, where can I find the OEM part # for my engine's injectors? Any input you can give me will be greatly appreciated.