i believe i have one bad injector, so i got a spare from a friend to try to fix my driveablility problems.

the injectors currently on the car are 'CAV' injectors with a green band on the top. i havent pulled it yet, but from trying to read it while its still on the car, it looks like a #5720D790 (i havent had much luck searching for this number, so it could be wrong)

the used injector i got is a RP #5235302

as long as they are both 22#, there should be no issue, correct?

 

i would have to say yes. but in the future id get a new set.

 

Biggest problem I see is, when one is going 9 out of 10 there are others waiting to go bad.

If your pretty sure its only the one then you can replace it without issues using a matched injector like you are doing.

Ohm all injectors before you waste your time. Stock should be 17 ohm. Serviceable above 12 ohm, any lower and they are to be thrown away.

Also, remove the rail/injectors as a unit and do not disconnect anything else. Prime the fuel system and let it sit with pressure and verify that only one injector has issues/leaking and more arent doing it as well.

later
Jeremy

 

3.8TransAm, i dont 100% know whats wrong with the injector, i just know it isnt firing. i know that because i put my finger on it, and feel no ticking. i do believe it is stuck in the open position though.

i will put an ohm meter on them all like you suggested. what does the resistance of the injector actually tell you?

 

it's an indicator that there are no shorts in the injectors.

 

The resistance test is a measurement of the wire winding inside the injector body. There is a very fine gauge long length of wire wound around a core to form an electromagnet, or some would call it a solenoid. Anyway the wire length is porportional to it's resistance. If the winding is shorted to itself at any point, it will act as if it is a shorter length, and thus measure less total resistance across the two connector leads. It is a very common problem with wire windings.

 

i just check the resistance of my injectors. they are all between 16.4-16.8ohm, even the one that i suspect is bad. the exception is the cold start injector, which is around 4.5ohm. it is a different injector though... so what should that one be at?

i'm about to pull off the fuel rails now to check for leaks.

 

I believe that a Cold start Injector should be at about 4 ohms, so I would say that 4.5 is fine. Look elsewhere for the source of the problem.

 

Have you checked to see if the injector is being pulsed by the ecm?I think you may just have an injector sticking closed,because if you have an injector sticking open,you will befilling that cylinder with gas,and blowing out a lot of white smoke.I have seen injectors stick a lot,although not as much on the older cars.To test the pulse,you will need a small noid light,you may be able to borrow one from a parts store.This will narrow it down to the injector.Also I have seen that by tapping the injector with a screwdriver,it may start to work again if it is stuck.Hope this may help you.

 

well i simply determined the state of the injectors by feeling the tops of the injectors while the car is running. i felt a 'tapping' on all the injectors except the #3, which was dead quiet. so even though the impedence of the #3 injector is good, its not firing, so it must be stuck.

 

yup, changing the #3 injector solved the cold start stalling and code 34 issue!

it still has a slightly rough, and now surging idle when cold, but there was quite a bit of black carbon junk in the plenum, runners and TB when i took it apart... maybe i just need to clean my IAC again