Holley EFI and Voltage Issue

TNGatorBrad

Basic User
CJ-8.com Member
City
Franklin
State
TN
#1
I recently had a Holley EFI kit installed on my 85 CJ8 and when I drove her home, the OEM Voltmeter and the new digital Holley "dashboard" showed that my Jeep was pulling 17.4 Volts.

It is in "learning mode" and I didn't realize how high the volts were until I checked about halfway home from the shop.

So, this morning, I checked the volts @ the battery = 12.6V
Alternator = 12.6V and Battery/Block Ground = 12.6V

But once I started the Jeep and let it idle, the Voltmeter showed 16.9V at every location listed above.

So, I checked a couple of other things and took it for a drive around the neighborhood and the volts started coming down to 16.2V. I confirmed that at each location above at idle with my Voltmeter.

So, the new EFI is still in "Learning Mode"... could it be pulling too many Volts as it learns my Jeep?

I contacted the shop and the owner was very defensive and said that my alternator must be bad.

I never had Voltage problems before the EFI install AND this same shop, which is an "certified installer" put a Sniper EFI kit on my Dad's 48 Chevy at the same time as they were working on mine and his had a hot short and didn't even make it home. They rewired it today but claimed no responsibility and charged my dad for hunting down the issue.

So, I don't have much trust in them now. Especially after issues with my Dad's install.

What do y'all think? Are there any other tests that I can do to troubleshoot? Should I replace the alternator?

Please help! I don't want to take it back to this a-hole unless we can pinpoint where he messed up the wiring.

Thank you in advance.
 

Mancunian

Lifetime Member
LIFETIME
City
Bridgeport
State
WV
#2
Difficult to get ~17V unless the regulator has an issue, i don't recall the Holley being wired to the alternator - should just be to the battery.
Nothing the learning mode does should affect the voltage on the ignition circuit.
Did you google the Holley forums - they are quite good.
 

mysunnshine

Legacy Registered User
City
Phoenix
State
AZ
#3
You need to verify where they connected the switched ignition wire to. Out of the hundreds of systems I have either installed or tuned, I have not seen a unit indicating a wrong voltage. The indicated voltage has nothing to do with it being in the learning mode. If anything, the indicated voltage is skewing the injector output.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#4
Holley instructions are very clear that the power feed must be connected to the battery direct. The ignition switched wire must have clean voltage away from the coil and/or starter relay.

I have my vote on a bad voltage regulator in the alternator.

As for the shop, I don’t think I would do business with someone not willing to listen.
 

TNGatorBrad

Basic User
CJ-8.com Member
City
Franklin
State
TN
#5
Thanks guys. I really appreciate the quick responses.

I pulled the alternator this morning and am waiting on a replacement...it should be here this afternoon.

I'll follow up once it's installed.
 
City
Halifax
State
UK
#6
If the volts are really that high then it can potentially cause all sorts of issues from blowing light bulbs to destroying electronics and boiling your battery .
My lesson was learnt from a mechanical regulator on a Toyota Pickup getting a bit tired and letting a similar voltage through, i can still smell the battery acid stench now, it wasn't a happy battery!..

You could unplug the alternator plug connection so it cannot try and charge and just run the engine off battery alone for a short while and see if the Holley can learn, but i guess it needs a good run to tune properly which could be risky with no alternator!.
 

TNGatorBrad

Basic User
CJ-8.com Member
City
Franklin
State
TN
#7
Welp, I replaced the alternator with a rebuilt one from Autozone AND the Volts are normal now.

14.2-4V constant at all check points + Holley dashboard.

Plus the engine is running much smoother and not as loud. I'm lucky that I didn't screw something up while driving her home, then around the neighborhood.

Thank you for all of your input and help.
 

TNGatorBrad

Basic User
CJ-8.com Member
City
Franklin
State
TN
#9
It really is the best upgrade that I've added on the Jeep.

Did you install it yourself and did you buy the internal or external fuel pump model? Did you go with the BBD Clone or 2 barrel option?
 

falconian

New member
City
St. Louis
State
MO
#10
Yeah, best upgrade for me too. I went with the BBD.

I did the install myself. Swapped out the fuel tank with the Holley tank and a new sending unit, installed the external fuel pump on the rail in front of the fuel tank, and used the stock steel fuel lines as much as possible.

Not really a complaint, but the fuel pump is loud as hell!
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
#11
Glad that you got the alternator figured out.

I've been exceptionally happy with the EZ-EFI system I put on my '77 Cherokee.

[QUOTE="falconian, post: 427660, member: 26629"Not really a complaint, but the fuel pump is loud as hell![/QUOTE]

When I put the system on my Cherokee the fuel pump was excessively loud and it turned out that there were globs of RTV sitting in the tank from where a PO had put in dual fuel tanks and used WAY too much RTV to seal the sending unit back in. One of the globs partially obstructed the line and was starving the pump.

These pumps can make high-pitched noise, but if you're really thinking it's "loud" I'd wonder if the pump is starved. Check that you have a clear line back to the tank and no pickup tube/filter sock issues. When I got it all cleaned out, the pump went from loud to just barely noticeable while idling.

Just a thought.
 

falconian

New member
City
St. Louis
State
MO
#13
Bigwalton, now you have me thinking about this and questioning why it would be so loud. I wanted to mount it high so it wouldn't get hit by anything, but also read that this pump is a pusher and not a puller. Per Holley's instructions: The pump needs to be GRAVITY FED, meaning the pump inlet needs to be at or below the bottom of the tank and as close to the tank as possible.

I mounted it on the rail in front of the tank, but it's nearly at the top of the tank. Where did everyone else mount their fuel pumps?

Fuel Pump.jpg
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
#14
Bigwalton, now you have me thinking about this and questioning why it would be so loud. I wanted to mount it high so it wouldn't get hit by anything, but also read that this pump is a pusher and not a puller. Per Holley's instructions: The pump needs to be GRAVITY FED, meaning the pump inlet needs to be at or below the bottom of the tank and as close to the tank as possible.

I mounted it on the rail in front of the tank, but it's nearly at the top of the tank. Where did everyone else mount their fuel pumps?

View attachment 83512
Wait, is the filter before the pump? Unless this image got mirrored, the feed from the tank is to the right, correct? If so, there's your problem. I put a super coarse lawnmower-style filter before the one in the Cherokee for only the biggest junk (and it's lower than the highest point in the line coming from the tank so it's gravity fed too), you don't want any restriction at all before that pump.

I put the EFI pump for my Postal's 4.0 in the same place you have yours and it is almost silent, but I know that the sound can vary widely between pump brands.
 

falconian

New member
City
St. Louis
State
MO
#15
You're correct, that's looking towards the rear of the Scrambler. The filter to the right is the Holley pre-filter (40-100 micron). I mounted the post filter along the frame rail on the passenger side just before the skidplate
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
#16
You're correct, that's looking towards the rear of the Scrambler. The filter to the right is the Holley pre-filter (40-100 micron). I mounted the post filter along the frame rail on the passenger side just before the skidplate
I'd throw a piece of tube in place of the prefilter and see what you hear at least as a test. IMO you're much more likely to kill the pump from starvation than from anything in the fuel getting into it :shrug: especially if I'm reading this right and you swapped tanks.

It might be ideal to have that filter in a properly gravity-fed setup, but with this arrangement at the top of the tank, if you pull it and find that the pump quiets down significantly, I wouldn't run it.
 
Last edited:

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#17
Holley’s ”delux” master kit includes the “out” of tank pump, a 40 micron pre-filter, and a 100 micron post pump filter.

The instructions also mention the “best” place is somewhere below the level of the tank, but it can be mounted higher.

I bought the BBD master kit, and am in the middle of figuring out where to mount this:

91F79589-D183-4BF5-A36F-164BC8619287.jpeg

9C4E0EF5-24D1-4A22-8898-A1F769E72C2D.jpeg

Mechanical pump fills the surge tank, submerged pump feeds injectors, high pressure returns to surge tank, and low pressure return to the fuel tank.

16830357-9251-43D7-A2FA-4297763A2F0A.jpeg
 

jammer1

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Maple Hts.
State
Oh
#18
Holley wants the fuel pump around the bottom of the fuel tank and as close to the tank as possible (preferably not on the frame rail in front of the tire). Electric fuel pumps are not good at sucking the fuel, but are used to pump the fuel from the pump forward. By having the pump on top of the tank there is no siphoning of the fuel, below the tank or at least toward the bottom of the tank allows some siphoning to help assist the electric fuel pump. Mounted in front of the wheel is too far a distance to get a good siphon effect. The Holley Terminator (one I have on shelf) has the same filter, I ran in the same place as Falconian. Set it up in the shop on the cj7. Made a plate to sit it on and mounted in the same place but it was a TDK frame and if I remember right the bottom of the pump sat about at the middle of the tank. Pump was definitely loud.
 
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