08-16-2010 | #1 |
Join Date: Dec 2005
Location: Delanson, NY
Posts: 916
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OEM injectors
I switched out my injectors last winter with a set I got from FIC. I am considering putting my originals back in for judging purposes after my trip to Carlisle. What is the lower threshold for injector resistance when the injector is shot?? Most primaries are in the 12-12.5 range. One is 9.0, 9.7 and 9.9 and one is 7.7. If I were to re-install them, any suggestions on which cylinders I should use them in?
Likewise my secondaries are all around 12-12.5 except one which reads 3.2. My main concern is the primaries since I can always refrain from kicking in the secondaries with a bad injector for the short trip to a judging meet. Thanks, John |
08-16-2010 | #2 |
Join Date: Apr 2004
Location: Germantown, MD
Posts: 738
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Re: OEM injectors
From Marc Haibecks article "Measuring Fuel Injector Resistance with the Plenum in Place"
The resistance of the fuel injectors is 12.1 ohms +/- .1 ohm at 70 degrees F. Resistance measurements of less than 12 ohms, indicate that the solenoid coil has been compromised. There seems to be little effect on the engine as the resistance goes down to about 10 ohms. Below 10 ohms, the idle smoothness begins to be affected. Hydrocarbon emissions will go up, affecting emissions test results. Power output at wide open throttle will be affected as the resistance goes below about 6 ohms. Solenoid coils are more likely to exhibit shorts when they are hot. It is best to perform resistance checks on a hot engine, the hotter the better. When the engine is shutdown after about 30 minutes of operation, the fuel injector resistance should be about 13.5 ohms. Since the resistance varies with temperature, and the engine’s heat soak temperature not easy to control, look for consistent resistance measurements +/- .1 ohm across the group. http://www.zr1specialist.com/HAT%20W...in%20Place.pdf Good Luck! |
08-22-2010 | #3 |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Re: OEM injectors
John, just 2 cents from the peanut gallery.
I would be very wary of using less than 100% injectors to drive the car any distance. Remember combustion chamber parts don't react very well to overly lean mixtures and something very bad could be the result. Just a thought. Tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
08-22-2010 | #4 |
Join Date: Dec 2005
Location: Delanson, NY
Posts: 916
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Re: OEM injectors
Tom,
Thanks for your thoughts. I am leaning towards just getting hit with the point deduction. Thanks again. Hope to see you in Carlisle. John |
08-23-2010 | #5 |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Re: OEM injectors
I know this is a moot point, rules of judging are, well the rules..but why would any one spend the money on parts that will not survive modern gas. I think it is unfair that a 90 or 91 gets points deducted for using injectors that will survive today's gas formulations. Okay rant off. Sorry, that is from a guy that turns a garage queen into a Driver!
Lou and I will be at Carlisle on Saturday. We are doing the commute thing to be there for the day. I did his serp belt yesterday and I have to top off his clutch M/C with fluid from my private stash. When we get back I will have to figure out where the fluid went as it was down to the add line when I looked yesterday. I already checked the carpet padding and it's not there so that leaves the slave to eye up. Oh joy! Yes I'm bringing my DOT3 with us just in case. Tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
08-23-2010 | #6 |
Join Date: Apr 2007
Location: Northern VA
Posts: 2,661
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Re: OEM injectors
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08-23-2010 | #7 | |
Join Date: Mar 2004
Location: Found Member
Posts: 4,346
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Re: OEM injectors
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08-23-2010 | #8 |
Join Date: Oct 2008
Location: Colleyville, TX
Posts: 272
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Re: OEM injectors
Jon Banner wrked up a set of Delphi injectors for my 90. Went through judging with no pint deduct. Price was very reasonable
Jim |
08-23-2010 | #9 |
Join Date: Feb 2008
Location: Vancouver, BC
Posts: 252
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Re: OEM injectors
I put the FIC OEM look alikes in my car a few months back - have been very happy with them.
Your chance of having them pass judging unnoticed is good.
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[SIGPIC][/SIGPIC] __________________ 1990 Corvette ZR-1 #2824 4.10's, Custom PROM, Flowmaster, Top End Port NCRS BC Chapter |
08-24-2010 | #10 |
Join Date: Jan 2009
Location: Portland Oregon metro area (Washington side)
Posts: 3,207
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Re: OEM injectors
I have some OEMs of both primary and secondary I could sell. Not a full set and I can measure resistances if someone wants them. There are 12 of them I think. I'd have to find them first.
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Scott Vett owner since 1979._It's about the car and the people |
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