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Holley Pro-Jection problem


superdave1984

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I am hoping someone on here has used one of these and can shed some light on my issue. It almost HAS to be a ground problem, but here's the scoop.
My Jeep Cherokee has a Chevy 350 in it. I loathe the Holley carb on there which says a lot because I'm an old school guy. Anyway, I bought used Holley Pro-Jection system off Craigslist. Supposedly it worked fine when removed. I have everything connected and a NEW electric fuel pump. Factory Jeep unit in the tank. Wasn't getting power to the pump. Did some checking and discoverd the fuel pump relay was not there. OK, weird, but I got a new one. Still no power. Well after some google time I deduced that since the original computer and stuff isn't there anymore, the fuel pump wasn't gonna run using factory wiring setup. No biggie, the Pro-Jection has a connection for the fuel pump anyway. So I check the Pro-Jection to be sure that I'm getting power at the plug. YES. I run new wires all the way and cut the factory harness and splice in. Getting power to the pump now, but still no fuel coming out. I'm thinking it has to be one of the ground connections. I ran a hot and ground direct from the battery to the pump and fuel shot out of the line like it's supposed to. The instructions I found online don't give much help on this problem. "Check electrical connections". Duh. Do I need to ground the pump itself and ground the wire coming from the Pro-Jection system or just run a ground wire from the battery back there for the ground?
 


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doorgunner

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I eliminated the OEM computer when I installed the carbed 350. My new electric fuel pump is re-wired from the ignition switch key-on to the main fuse panel on the firewall to the fuel pump relay (a relay is needed to get 12.5v to the fuel pump)to the upside-down switch in the cab-LOL- then to the fuel pump electric connection.....and the fuel pump connection ground wire goes straight to the frame at a clean spot.

I'm guessing that your new injection system needs it's own separate good ground and 12.5v or more to it's computer.
 

superdave1984

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Well what I ended up doing last night as I was being a buffet for the skeeters, was cut the ground wire coming from the Holley harness and splice in the factory Jeep ground going to the pump. BAM! Plenty of fuel. However I have a seriously leaky injector. Gonna call Holley today.
 

BLOODBANE

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If the pump has power and is moving, charge the tank with air to make the fule get to the fuel pump. The pumps on the Pro-Jection are really a pusher pump, not a draw pump. Once the siphon starts you should get fuel. To charge the tank just put an an air chuck with a long snout on in it, in the filler neck and blast it with air from your compressor. I had to do this when I was running the Pro-Jection on my Ranger. Had tons of fuel pressure after. I ran into other problems (acted like the choke was sticking and never could get it sorted out/it ran great for a year) so I took it off and went back to the old trusty Q-Jet. Looking at propane now
 

superdave1984

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Well I have lots of fuel pressure and no more leaks. But I don't have fuel coming through the injectors. I contacted Holley and I am waiting to hear back as to what I need to test next. It's very frustrating and I may just have to cut my losses and go back to the carb.
 

BLOODBANE

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Which system SD? I just had the 2D. I never really got any help from Holley. I went through 2 TPS sensors, another HP fuel pump, lots of time on the phone with Holley, and never did get it sorted out. There tech people really needed to learn some customer service back then. Like i said it ran great for a year, then just kinda fell down on me...
 

doorgunner

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Are the injectors ticking (open & closed)? My 2.9 had a bad ground causing them to stay closed.

Are they getting voltage to them?

Dont give up yet!

(My 600 holley ran like a champ out of the box....but I had to monkey with it for a year....it got 22mpg last week with 500 lbs. in the bed...of course it only gets 12 mpg with the secondary kicked in)
 

superdave1984

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It's the 670 CFM setup. I am thinking after going over the manual again that it's not getting power to the ECM during cranking. I need to double check where the wire is connected and test voltage during cranking, not just with the key on. I also noticed I need a 40 amp relay between the power and the ECM that I do not have. I think I should be able to get this going by the weekend. If not, back to the carb.

Update: I tested at lunch and I get a steady 12 volts with the key on, but a steady decline in voltage when cranking. It immediately dropped to 9 and in about 2 seconds it had dropped all the way down to 4. I'm thinking a relay will solve that problem. Maybe?
 
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doorgunner

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I used to HATE relays.....but now I install them on everything except the radio :icon_rofl: .......

Use a nice fat (12 ga.) wire from the main power source to the relay and from the relay to the ECM---

Then check the voltage with the key in the CRANK position and in the RUN position to make sure there is no/very little voltage drop....

I had to replace my fuel pump relay (the OEM relay went bad...so I bypassed it----bad idea---voltage was too low by the time it reached the fuel pump even though the fuel pump worked )

Hang in there.....you can do it!
 
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BLOODBANE

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I can check the instruction manual if your still having fits (Im guessing you didn't get one?). I have mine and maybe be able to copy and print out/scan what you need.
 

superdave1984

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I concede defeat. The relay basically fried my electrical system and made the fuel pump run all the time even though I followed the directions to the letter. Something must be wrong with the ECM. Oh well, I put the carb back on.
 

Lil-Pony

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damn, that sad to hear, hope it didnt do to much damage.
 


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