binkt
Member
Posts: 84
Reg: 04-16-06
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06-19-12 12:27 PM - Post#2239163
Ever since I replaced my HP ECU with a new version I have experienced a strange Tach output effect in that the tach works fine up to 2ooo RPM and then immediately drops to zero. I have used two different VDO/Autometer tachometers. I also have used the Data log to assure nothing is amiss in the engine RPM signal internally. The car runs great.I recently added an Autometer Tach adapter but without a change in the issue. I am using a 550-601 harness With individual coils. The tach agrees with the ECU rpm until 2000 RPM then goes downscale. Any help would be appreciated.
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Lgib
Member
Posts: 63
Loc: new mexico
Reg: 01-18-06
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06-19-12 01:08 PM - Post#2239177
In response to binkt
I have a holley HP with waste fire coils and autometer tach, works fine. I'm getting my tach signal from EST/SPOUT OUT A28 on P1A harness.Is that were you're getting your signal from?
69 Camaro 383 sb,GTK650 turbo, Holley EFI HP Stealth Ram, DIS, Holley coils,
60-2 crank trigger, water meth injection, TH350, Gear Venders overdrive |
Edited by Lgib on 06-19-12 01:11 PM. Reason for edit: No reason given.
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Danny Cabral
Member
Posts: 3149
Loc: Ellington, CT
Reg: 11-03-04
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06-19-12 01:13 PM - Post#2239178
In response to Lgib
ECU signal A28-EST/Spout Output (P1A connector) operates my Autometer tachometer just fine.
It's already "wired in" to the 10-wire ignition connector - cavity H.
It outputs a 12V square wave, same as the Tach Out on an MSD box. No adapter required.
May God's Grace Bless You
'78 BRONCO: 508" stroker, TFS heads, Dominator MPFI & DIS, A/C, Lentech Strip Terminator AOD, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim-over steering, 4" lift, 35" tires |
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binkt
Member
Posts: 84
Reg: 04-16-06
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06-20-12 08:42 AM - Post#2239432
In response to Danny Cabral
Hi Guys, Thanks for the info. There is no input from the harness attached to the ign. connector pin H.in fact there is no pin in the H position either in or out.
As to the P-1A28, I need to know how the pins are numbered or counted to identify A28 as Holley doesn't specify and I don't know the convention but would assume when facing the ECU pin one would be the upper left. The color code on the connector is BLU-White but density is high unless I know where to look. I have the 12V removed,is it safe to pull the connector with power? I am on my second ECU and can ill afford a failure.
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binkt
Member
Posts: 84
Reg: 04-16-06
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06-20-12 11:34 AM - Post#2239486
In response to binkt
Job Complete, found the A28 pin after assuming the convention I mentioned. The new tach is performing perfectly without a tach adapter interface. Thanks again Lgib and Danny for your assist.
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