I'm a newbie here, I have a stock 305 tpi 91 firebird. I've searched on how to ohm the injectors. I took my meter & put the leads across the injectors connecting pins after unplugging them & got just a straight short (0.00) on the two Injectors I tried. I'm a little mystified. I should be reading somewhere around 16 ohms if I'm not mistaken. Can anyone tell me what I'm doing wrong?
Been having trouble with the car surging, loss of power, won't pass emissions tests. I get codes 33 & 43 intermittently. It starts & idles fine (a little on the high side) for a bit & will then just throw a code & start idling erratically. I've been using the Pontiac service manual to diagnose the codes. I just thought I'd check the injectors & came up with this weird reading.

Thanks in advance.. any help is appreciated.

 

sounds like a bad ground behind the passenger cylinder head or bad ecm. Are you sure your ohm meter works ?

 

The injs are seperate from anything when unpluged so a head ground won't have anything to do with a inj ohm check.
Check the meter.
You could have 2 shorted injs or more, keep testing.

 

I haven't changed the battery in the meter in awhile, but when I connect the leads together it shows continuity. I've measured voltages with it & it seems to give me the numbers I'm looking for. Could the injectors short themselves out like that? from some of the other posts I've read about the subject, I've never seen anyone get that kind of reading. It also idles well most of the time even if it's a little high. It also drives fairly well also, until the check engine light comes on & then it stumbles & surges. Recently my speedo has been dropping out when that happens while driving as well. I will borrow another meter to make sure that's not an issue. Hoping to get a break in the weather to be able to do some more testing. This problem is so frustrating, thanks for your replies.

 

code 43 is your knock sensor. Check that the connector isn't loose. Look between cylinders 6 & 8 (passenger's side of engine)for a bell shaped sensor on the side of the block. You have to go underneath to see. If that connector is loose, the car will run like crap with no power and lots of shaking. Code 33 is Map sensor code if i am not mistaken. Injector ohms vary. You should between .012 and .016 ohms or so. As long as there is not a big difference between them.

 

Make sure you disconnect neg. Battery cable for a few minutes after all is said and done to clear those codes out too.

 

Thanks ninetyone, That video makes it very clear. I'll have to check that I'm on the right setting when I try it next time. Waiting for a break in the weather for my next attempt. I checked the knock sensor, connection seems good although my problem is intermittent. I might have to look into that futher. I get all the readings so far for that circuit that I'm supposed to according to the dealers service manual. I'll post my results when I'm able to get out there.

Thanks again everyone.

 

I did get out today to check the ohms on the injectors. I did have my meter set up wrong, this time I got 15.5-15.8 across all of them. seems like they aren't an issue. I'll keep troubleshooting the codes & post when I come up with an answer... I'm trying to narrow it down by checking each component that the manual says are involved with each of the codes I encounter. I don't really want to just start throwing parts at it. That could get pretty costly I think & maybe not solve my problem. I thought a step at a time would be the best.

thanks again

 

Hi all...

Thought I'd update this for future reference. I bought a used ECM off Ebay & installed it today. It solved all my intermittent problems. Runs like a champ now & even passed inspection. The inspector ran the emissions test & asked afterwards how I got it down so low? just told him... that's what a good computer can do. He just bought a new Camaro, so he had some interest. In fact one of the other inspectors started waxing poetic about bringing back the Firebird... don't we wish? anyway... I digress. Many thanks for all your help everyone, I'm sure it won't be the last time I'll need it. Next onto new tires... I bought new ones 7 years ago when I retired her, it's a shame but they have flat spots & great tread! feels like I'm driving the Flintstones car.

again... thanks!

 

You don't happen to live in milo, ia or clifton, nj do you ?

 

I do live in Clifton... why do you ask... more importantly... how did you know! Do you have a spy satellite?

 

Lol no spy satellite I sold you the ecm lol

 

...I guess looking at the package would have clued me in huh? You know tuned ...your a godsend! thanks so much! I must say you get high honors as an ebay seller. it was packed well, shipped fast, & best of all... more than reasonably priced & ...it worked!
This problem has frustrated me for years, literally... I took it off the road 7 years ago with the intermittent issue. I am so relieved it didn't cost me a million bucks. The dealers service manual really helped narrow it down though. I will tell everyone... don't start throwing parts at it... it will only frustrate you more. I did it pretty methodically actually. I ruled out the systems when it threw a code... all came up good... all systems go. I was suspicious of the computer & one day it threw a cel, but no code. I figured it had to be the problem. So if you have a similar problem anyone, I recommend ruling everything out one by one instead of throwing parts at it.
Now I have to work on changing those flintstone tires... I apologize in advance, but I have to reference a quote from Dr. Smith from "Lost in Space" if anyone here is old enough to remember that show... he used to say... "Oh the Pain!, Oh the Pain!" ...thanks all