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true gm one wire with holley efi

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Old 07-02-2014, 02:13 AM
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Default true gm one wire with holley efi

Anyone running this setup? I'm having issues... Car runs and learns fine without the alt. Put the belt on and the afr reads leaner, the injectors put out more fuel (in open loop) and there's no hope for the learn function. Had the alt tested and it was fine. Using 4ga charge wire. Here's a link to my issus with some data log pics if anyone cares to take a look. This is all that's keeping me from driving the car. Thanks.

http://forums.holley.com/showthread.php?14176-Help-with-tune
Old 07-02-2014, 05:06 AM
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I'm using the HP efi system. One wire alt. I dont see how the systems are effecting each other. So I hope that you don't have the 12v source tapped to the charge wire.

The biggest most important thing with the holleys is that all your grounds are exactly where they're supposed to be. A dirty ground will give you hell
Old 07-02-2014, 05:46 AM
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Grounds like mentioned above. The most likely culprit. But how do you have the car wired? Where does the alternator power go and where in the wiring harness do you tap off power for the EFI box? Hopefully it isn't powered off the old coil wire. What is the voltage at the EFI box with and without the alternator?

One wire alternators don't regulate voltage as well as ones with a voltage sensing wire. But the other possibility might be electrical noise. The battery acts as a filter, but if the alternator and box power come right off the same spot it might be seeing power supply noise.

Try charging the battery up also.
Old 07-02-2014, 11:31 AM
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Try as Pop said.. check and make sure you have good grounds... run the alternator wire to the battery and a seperate wire from the battery to you ECM and another one to your power distribution block/point.

I once had an issue with my 84 Camaro running a MSD 6AL box, it would cut out. Fixed it by running the power directly to the battery., and the ground too.. even though I thought I was running it to a good power distribution point... NOT.. !
Old 07-02-2014, 05:45 PM
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Thanks for all the replies fellas, I've never dealt with an efi swap so I just did what made sense at first. All my 12v sources for the Holley are ran to the starter lug except the main power and ground which is straight to the battery... My charge wire ran to the same lug. I got enough 4g and ran the charge wire straight to the trunk (batt). Tomorrow I'm adding a 1g from the battery straight to the block instead of the current 1g to the rear frame rail. I thought it would be ok since the engine is solid mounted... I'm green still lol. So I'm goin 1g battery to block, 1g block to frame and leaving the ground i already have bat to rear frame and alt to front frame.

Without the alternator the system starts at mid 12v and trickles down, with alt its about 14v at idle. I'll post back if these changes fix my issues
Old 07-02-2014, 09:07 PM
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Don't run it without the alt.

Get it warmed up and let the closed loop build the map. It is going to run different at 14v vs 12

Tim
Old 07-02-2014, 09:43 PM
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I run many ground.. over kill.. but it better to be safe than sorry LOL

From the battery ground, I run 3 wires, frame, block and body. I run more grounds on the block, back of the head to the body (Same lug as the harness/PCM grounds and the from side of block to frame.

Yeah, I know it is a bit must, but bad ground can cause many electrical problem with both the general car and EFI/PCM related issues.

Keep us posted on the results of the rewiring.

BC
Old 07-03-2014, 05:30 AM
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running the battery negative straight to the block is a good move. Body parts should never be used to carry current.

Earlier I was saying to NOT hook the box power and charge wire to the same point. Alternators can have some AC ripple, you want that filtered by the battery. The resistance in a length of wire can further help smooth this ripple.

The box power should ideally be off the fuse box. But the way you have it now should tell if the running issues were ground related.

I'm not a big fan of running alternator charge wires straight to the battery either, especially with a one wire alternator, cause it can lead to overcharging the battery. But to get around your current problem it is probably the way to go.
Old 07-03-2014, 05:53 AM
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I understand it may run a little different with 14v vs 12, but at 14, **** flat out ain't right. 10 gph at 900rpm fuel flow and crap idle running 17afr. To run as rich as I'm commanding takes much more than the 10gph with the alt on. It can't even get there without fouling plus and dying. No way it's that lean vs the 8gph, smooth idle, and a richer afr and lower kpa of no alt? I'm gonna ground the puss out of it lol, I'll report back with results
Old 07-03-2014, 06:13 AM
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something is def wrong-I was a first time user with FI-Holley HP, and I had no problems other than I was a poor tuner, lol
are you sure the alt is a true one wire-I ran 3 wires on mine, I think it was a CS130 or whatever, vette or Camaro one
as said, ck all grounds-if you bat is in the trunk, the alt needs to go off there if you have a kill switch
there could be some kind of interference, esp if the alt is looking for some kind of signal wiring-it needs some sort of sensing to tell it to stop charging
Old 07-03-2014, 07:10 AM
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I would also start with a total new tune hook the alt up. Make sure your leads go to a good battery 12v. The ecu main power wires need to go to the battery on their own post with nothing else. The other lead can go direct to the battery or to the starter solenoid. The back of the alternator is dirty.
What is your engine combo?

Tim
Old 07-03-2014, 09:25 AM
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I'm positive its a real one wire. Bought it new. Had to engineer a bracket for it.

How would a person run the Holley main power/ground to a battery lug by themselves? I have a normal 2 post battery, Only place I have to hook 12v sources is there or the starter, and I have to run my charge wire to one of those locals. The current setup was just the main Holley power and ground to the battery, charge wire and all other 12v to starter. Going to try it in a bit with charge wire to the battery. I'll start rearranging grounds or adding them from there. I hate electronics, just can't wrap my head around it lol.

2002 5.3L
230/236 114+4 .6xx/.6xx (installed dot to dot)
Holley Hi-Ram
Holley 120 injectors (low imp)
WBO2 is about 1' from manifold exit, with 1.5' of pipe following WBO2

Getting it running for now, twins over the winter and rod/piston motor next summer with parts transferred over, hence the overkill as I don't want to buy twice.
Old 07-03-2014, 09:57 AM
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If you don't wire it exactly like the directions say you will have problems. The pink sheet in the box covers this. Follow it to a T

Tim
Old 07-03-2014, 01:59 PM
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appreciate all the help guys, I bought 20' of 1ga and 15' of 10ga. Going to do like the instructions say. 1ga from battery to block, 1ga from block to frame and 10ga from frame back to battery. Hopefully that solves my problems. If not... lol, I did try with just the cable running to rear and I added a 4ga from block to frame just because I had it laying around, and honestly I think it cleaned it up a little more without the alt, but still junk on the alt. Going to run the new grounds tomorrow hopefully after I get done helping dad rake and roll a few acres of hay. I'll update, but for now here's a comparison of no belt and belt from today. Dashes are the junk in case you can't tell lol.

Old 07-04-2014, 11:05 PM
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Ran the grounds exactly as Holley requests. 1ga from battery --> block --> frame --> body 10ga --> battery. and not a damn bit of difference. Then ran 4ga from driver head to passenger head to block. I'm so lost. Nothing is working. got my driveshaft buttoned up however, and considering it has no power brakes or steering it was fun going up and down the road letting the car learn (with the alternator unhooked). a few passes and I gave it about 50% throttle and got a decent one tire fire as a reward lol. just have to get the god forsaken alternator issue lined out. Going to take off the Holley (small black wires) grounds to the back of the heads tomorrow or Saturday and take a wire brush to the heads where the grounds bolt. May be it's something small like that... I've spent almost 200 dollars on cable and stuff, oh, I traded in my alternator on another one today as well, same deal. Could the one wire alternators not be doing something right? May get a stock truck alternator and do the resistor in the exciter wire and see if it just needs something else. blah lol.



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