meyer30

iTrader: (2)

Well I've upgraded the intake and runners with edelbrocks, installed headers, and a cat back exhaust. I've posted before but haven't really gotten a response so I'll try just once more. This has the 5.7 in it about 97k miles. After all this work car runs like crap at low idle. If I stomp the gas it takes off like a bat out of hell. However barely stepping on the gas just taking off or doing 45 mph it starts to stumble.....badly. Well I've been reading and I decided to go check one more time. This time I noticed that all the injectors on the left side are not clicking anymore. The ones on the right are. I removed the connections to check if the pins were bent, and they are not. Removing the connections while it was running had no change in the way the car idled. So Is this a sign of bad injectors or a wire somewhere. We haven't messed with any wires really I don't think. I'm not sure what the guys did when they put the headers on. So what should I be checking for? I have injectors on the way, but I'd like to get an exact on whats wrong before they get here. Thanks for the help if there is any.

3.8TransAM

IF it runs like garbage after the install, somewhere in the install is your problem.

Whether u messed something up or have a defective part.

Thouroughly double check your work and see what you can find.

It takes an infitestimally small particle to make an injector not "tick" but still work fine, so its not always the best test.

Try ohming them instead. 17 for stock injectors. OVer 12 ohm is considered ok per GM anything under or wildy different numbers and I would replace them regardless.

Didnt give us much to go on here.

Any codes? Dis this happen after the install? etc?

later
Jeremy

DENN_SHAH

iTrader: (1)

with nothing more to go on, do this.
with a test light check for power on the side the injectors are not working on.

unplug any injector connector and turn the key on but leave the motor off, now with one end of the test light hooked to a good ground, touch the other end to the terminals inside the injector connector one at a time. one of them should have power on it, the other goes to the ECM. if you don't have power on either one, check your fuses, you should have a fuse box i believe over on the right hand side under your dash that will have several fuses in it, 2 of them are injector fuses, one for each side of your motor.

Joez88Camaro

You try it first and tell me how it goes

Hopefully that post gets deleted.

meyer30

iTrader: (2)

Yeah we went over everything about the install of the intake and runners. No leaks and it was done correctly. I checked the connectors and they are getting a signal, so I should be able to hear them. Makes sense to me. They use to make a rather noticable tick, the fuel injectors. Now nothing and it runs like crap. And no codes ever came up.

meyer30

iTrader: (2)

There was one other thing I noticed. The new intake had a coolant passage on the rear that the old one did not. Not sure if that would make any difference, but it was different.

tenpin842

I know I had to plug a coolent bolt hole on the back of my Edelbrock Intake. All my stock injectors worked when I took mine apart before my swap. My car ran like crap. After the swap. I went to take it to the dyno shop and have them check it out and tune it. I ended up having 5 bad injectors. And a tune will work wonders for you! My car ran like crap after my Edelbrock intake and a new cam swap.
I had it dynoed and tuned, it runs pretty good!

meyer30

iTrader: (2)

Well I checked the injectors with an ohm meter and it's bouncing all over the place. It goes to 17.?? all the way down to 3.?? ohms. So what would be causing this?

DENN_SHAH

iTrader: (1)

Originally Posted by DENN_SHAH
with a test light check for power on the side the injectors are not working on.
if this is directed at me, what do you mean by that Joe?
meyer30 stated "This time I noticed that all the injectors on the left side are not clicking anymore"
if the injectors on one side of the motor are not working what would you do first Joe, replace the MAP sensor?
with my 92 camaro system, i have a fuse box under the right side of the dash that has 2 fuses for the injectors, one is for the injectors on left side of the motor, the other is for the right side, if one of those fuses blow, i loose injectors on one side of my motor.
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DENN_SHAH

iTrader: (1)

meyer30, you do have some bad injectors, 3.0 ohms is way too low, 3.0 ohms is a shorted windings inside of the injector, that can burn out the drivers in the ECM.
i would recommend you go ahead & replace all of your injectors, you can get a set of ford injectors for a pretty good price & they are better than what GM used.
you said you have a good signal from the ECM, so hopefully its ok.

Joez88Camaro

You just answered why testing a fuel injector signal with a test light is bad. What kind of impedence do you figure your average test light has?

That's why ASE tests specifically say do not use a test light to check for a signal to the injectors. They recommend either something with a high impedence, like say, a logic probe or a noid light. There's an old 80's training video out there that shows the guy accidentally frying the ECM with a test light then having to explain how he messed up.

Joez88Camaro

Sooo.... now if I were to do this:

what exactly do you think would occur if something of low resistance, such as say a test light, were to complete that circuit?

The sad part is I did a search on the internet and only a few places actually tell you the danger about using a test light, it seems every idiot and his brother says use one.

thirdgen88

I don't believe he is wanting the guy to test the ground switching on the ECM side.. He is wanting him to see that the injectors are getting +12VDC.. The wiring is set up so that the injectors get +12V and the ECM switches one of the wires to ground to activate the injector... I'd use a digital multimeter to measure it, maybe thats the issue (using a test light instead?)?

Joez88Camaro

Yeah, I think that he was implying that you should do something that'll fry your ECM. I'm 100% sure of it.

DENN_SHAH

iTrader: (1)

i said; "unplug any injector connector and turn the key on but leave the motor off,"
i guess you didn't see that,....

you said; "what exactly do you think would occur if something of low resistance, such as say a test light, were to complete that circuit?"
have you ever put your DVMM to a test light & then to a noid light?
which is harder on an ECM, a 30+ ohm test light, or a 15 ohm injector?

"The sad part is I did a search on the internet and only a few places actually tell you the danger about using a test light, it seems every idiot and his brother says use one."

ok, so im a idiot, oh well,..... i guess thats why so many other shops in my area bring work to me they can't repair,... but i guess your right, as a 93 skylark just kicked my butt for a no start/no spark problem,......


should i mention, i have my ASE certs with L1?