C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

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Old Sep 20, 2008 | 04:26 PM
  #1  
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a friend of mine that knows everything about everything told me today that my ECM was bad and that is why my car runs the way it does.
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Old Sep 20, 2008 | 04:32 PM
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You're going to have to supply a whole lot more info to get an answer to that question. Your car runs like?.........
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Old Sep 20, 2008 | 09:06 PM
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I looked at the vid you sent you should post it here. What have you checked? What mods do you have? Any codes? Looks like it is running rich to me maybe a bad o2? None of us have a crystal ball so you need to be very specific about what has been checked.Sounds like you have a cam from the vid. I would not say the ECM is bad till everything else checks out. Do you have a FSM?

1.Pull the codes if any http://www.corvettebuyers.com/c4vettes/codes.htm
2. Check your fuel pressure and do a leakdown test to find out if the FPR is good and or injectors are leaking.
3.What size injectors do you have in it?

It does not sound too bad a WOT or idle if it has a cam if not it is stock it seems to be missing but that is a lot of black smoke which indicates a rich A/F ratio.How does it run on the road?
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Old Sep 20, 2008 | 10:40 PM
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I have replaced the 02 but I still get a code #64. The motor has just been rebuilt and as far as I know that is a stock cam, but alot of people think I have a bigger cam. The only things I have not replaced are the injectors and fuel pressure reg. Now the car was running this way before motor or anything was replaced. The injectors are stock right now but I just got some Boush III's #22. I have 2 bad injectors so thats why I am putting in new ones. No mods all stock, runs like crap at low speeds and alittle better a normal speeds.
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Old Sep 20, 2008 | 10:45 PM
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Default everything about everything

Im confused. If your friend knows everything about everything, dont you trust his diagnosis?
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Old Sep 21, 2008 | 10:50 AM
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Well you need to get that O2 working.That could be your problem as well as the injectors. How did you determine the injectors were bad? O2's can be bad out of the box but you need to verify the wiring to it is good.You can swap injectors from side to side and see if the code travels with it.You said motor was replaced?Is there any difference between when it starts cold and when it goes into closed loop?
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Old Sep 21, 2008 | 01:33 PM
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nope it runs the same either way. we ohm'ed out the injectors 6 of them were 16.5 and the other 2 read 12.4 and 03.0. If I pull the wires from those bad injectors the tune of the motor does not change.
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Old Sep 21, 2008 | 02:59 PM
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You won't know anything until you replace those injectors.....which do ohm bad! As far as the ECM goes, it seems to be communicating so I wouldn't be in a rush to replace it.
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