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08-23-2021, 02:24 AM | #1 |
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Join Date: Jan 2008
Location: Melbourne, Victoria, Australia
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Tach at 3,000 rpm at idle
We have just installed a Holley Terminator EFI set up with Holley Hyperspark distributor, ignition coil and CD ignition box on SBC in my C10. The tach (5,000 rpm add on restoration one in dash) is now showing 3,000 rpm when idling, read out on Holley display is correct.
Anyone encountered this problem? Where to look? thanks |
08-23-2021, 08:44 AM | #2 |
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Re: Tach at 3,000 rpm at idle
I'm assuming this is your system? On your Tach, who makes it? Do you have a link?
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Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats? Last edited by The Rocknrod; 08-23-2021 at 08:50 AM. |
08-23-2021, 08:59 AM | #3 | |
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Re: Tach at 3,000 rpm at idle
Quote:
I believe this is the tach, was in truck when I purchased, https://www.brotherstrucks.com/1967-...tinfo/TACH772/ |
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08-23-2021, 02:51 PM | #4 |
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Re: Tach at 3,000 rpm at idle
I'm sure this is different but when I did my ls swap I used the GM factory computer and my aftermarket tack had to be switched to 4cyl mode to read correct. This may be apples to oranges but figured I would throw it in.
Dave
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Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!" |
08-25-2021, 10:57 AM | #5 |
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Location: Warrenton VA
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Re: Tach at 3,000 rpm at idle
Big difference in terminator or the sniper system, terminator has an external ECM, sniper it's all internal to the throttle body, which do you have? I have a sniper system with the hyper spark distributor, a 6al box, and blaster ss coil on my camaro that I'm tinkering with until I swap it all into my c-10. My autometer tach and handheld read identical, the tach needs to be hooked to the brown wire on the sniper. If you have terminator set up that may change.
https://www.efisystempro.com/efi-pro...gnition-wiring
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71 c-10 Long Bed, under the knife for a No Limit Engineering Wide Ride Chassis Pack and coil over static drop. 07 Silverado Classic 2wd 95 Camaro 427SBC/TH350 |
08-25-2021, 05:22 PM | #6 | |
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Location: Melbourne, Victoria, Australia
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Re: Tach at 3,000 rpm at idle
Quote:
https://www.holley.com/products/fuel...parts/550-1013 We tried swapping wires, adding diodes etc without any luck. On advice from gauge specialist we have pulled tacho, and sent to him. He advises there are two kinds of signals, a coarse signal and a fine signal which the Holley supplies. We will see how it goes. In better news my temp gauge which would not come off low is now reading more accurately? |
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08-26-2021, 08:04 AM | #7 |
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Re: Tach at 3,000 rpm at idle
Ahh ok, the terminator is nice ECU set up. It should do what ever you need it to. There are tons of settings in the input output sections was there maybe something you needed to adjust using the laptop software not the handheld.
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71 c-10 Long Bed, under the knife for a No Limit Engineering Wide Ride Chassis Pack and coil over static drop. 07 Silverado Classic 2wd 95 Camaro 427SBC/TH350 |
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