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For the last two years I've been running my factory fuel pump and a magna fuel 4303 wired to run all the time. The car always had lots of fuel but sounded like a race car. A couple months ago I put in a Hobbs switch to turn the magna fuel pump on at 2 pounds. The factory fuel pump could barely push enough E85 to idle so I installed an aeromotive 340 stealth about two months ago. I started the car in the garage a few times but never drove it because it seemed to be working perfectly.
I went to drive it last week and I noticed the Wideband with reading very lean, in the 16.0-17.0 range at idle. I opened the hood and seeen the fuel pressure at the rail was around 25 pounds. I figured the pump I had just put in was bad so I changed it to a Walbro 450. It seems to be doing the same thing which leads me to believe that I am doing something wrong.
What am I doing wrong is my question? I thought the install was pretty straightforward for both pumps. I pulled apart the factory fuel bucket then swapped wiring harness and pumps and put it back the same way it came out. I am using the screen that the fuel pump came with inside the bucket and the factory sack. I have seen that some guys drill big holes in their buckets and I have seen other guys say there's no need to drill. Am I missing something ?
The first start up the idle AFR and fuel pressure was perfect and the car ran for about five minutes. I shut it off, threw five more gallons of fuel in it then restarted it and it was all out of whack again just like the areomotive pump. Maybe the bucket is draining and I need to drill holes?
After sitting for an hour I restarted it out of curiosity and it seem to be running where it should be as far as AFR and fuel pressure, for a few minutes. What are the chances that the hour the car sat, the fuel bucket filled up allowing the fuel system to be within range? I'm thinking the fuel bucket needs to have a few large diameter holes in it.
Time to do some work to properly isolate this trouble because throwing parts at the problem until it goes away will have you pulling your hair out in no time. I would be willing to be you have a voltage problem. Put a volt meter across your pump hot and ground, outside first. I would consider running some leads into the car for a while so that you can continue testing until you isolate the problem. What I've seen happen so many times is the relay/fuse/power distribution box goes bad on the high current connections and starts working intermittently. Fan and fuel pump connections are the most common failures I've found since they're the highest current loads. If your voltage is intermittently low, that's most likely it. If you want to throw parts at it to prove it's not the issue, in this case it's really not a bad idea since the OEM connections fail so often. You can bypass all the factory business and get your connection directly from the PCM if you choose to bypass the mess. The signal will come from pin 9 of the red plug off the PCM and will be a dark green wire with a white stripe. Use that to operate a quality relay, not some Chinese garbage. If you need to know how to wire up the entire circuit from end to end, let me know and I'll post it up for everyone. Grab your power from the back of the alternator so you get max voltage. Use a fused link, fused at the alternator end to protect the wire. I prefer to run the wires down the driver side rocker with a fish tape. For simplicity sake, you can remove the fuel pump relay and tap the PCM signal wire there if you want to save time or you're in a hurry to test it. Go back and rewire it later when you have time. To tap that relay socket position, take a mini atc fuse apart and solder your signal wire to the end of one of the fuse legs and plug that in. Also, I recommend using a 10ga wire with ring terminals to make a short jumper to go from the fuel hat to the frame. I'm guessing that you noticed how the pump also grounds to the hat inside? Running the jumper to the frame will help bolster the ground side of the circuit.
HTH
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Miraculously enough, I drilled 4 three-quarter inch holes inside the bucket to allow more fuel to be pulled into the bucket. I was standing in the garage letting it run as I read your response. At the nine minute mark everything was still exactly where it should be. As I was reading your response I heard the fans kick on and then I could hear the fuel pump change tones. I immediately looked at the fuel pressure gauge and air fuel ratio gauge and they were both out of spec.
I presume I will be investing in a hot wire kit or pulling power straight from the alternator?
PS. As of this moment I didn't even finish reading your response. I am so late for work I have to get going now. LOL
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Miraculously enough, I drilled 4 three-quarter inch holes inside the bucket to allow more fuel to be pulled into the bucket. I was standing in the garage letting it run as I read your response. At the nine minute mark everything was still exactly where it should be. As I was reading your response I heard the fans kick on and then I could hear the fuel pump change tones. I immediately looked at the fuel pressure gauge and air fuel ratio gauge and they were both out of spec.
I presume I will be investing in a hot wire kit or pulling power straight from the alternator?
PS. As of this moment I didn't even finish reading your response. I am so late for work I have to get going now. LOL
Unless you want a plug-and-play setup, I can tell you how to make one. If you want to know if that's most likely the culprit, put a volt meter across the 2 wires and observe the voltage as you experience the issue.
Unless you want a plug-and-play setup, I can tell you how to make one. If you want to know if that's most likely the culprit, put a volt meter across the 2 wires and observe the voltage as you experience the issue.
Tomorrow I'll throw my voltmeter on it and see what I got. In the meantime, how do you make the hot wire kit? Once I get to the office I'll have an opportunity to research.
Get the hot wire done and test again. The factory power for the fuel pump is poor for the factory pump.
Essentially all you need need to do is run a power cable (8 gauge if you want), from either fuse box power terminal or alternator. Put a inline fuse near the front, then put a relay at the pump side, with the factory fuel pump power as the trigger on the relay.
Racetronix makes a plug n play version which is very nice if you don't want to piece one together.
You can run the power power line down the tunnel or even through the rocker panel.
I ended up using a standard power distribution block which I put my 8 gauge wire to, and tied the relay directly off of that. Not "needed", but was giving me room if I needed to power a bap or multiple pumps.
I seen the plug and play kit at Caspers I'm probably gonna do regardless. I'm beginning to think the car is mad at me. I just started it and ran it until the fans came on and it ran well. So then I turned on the heat, headlights, radio , and supplemental trans fan. It still ran well and keeps running we'll start after start. I'm gonna have a beer at this point.
That was short lived. Started it up again and it ran good. 10 minutes later the fans kicked on and the volts at the pump dropped to 12.0 then the car dropped fuel pressure and leaned out.
Let is know what he says, you need at least 56 psi at idle, 43 is too low.
From the FPR manual:
The enclosed Aeromotive regulator is designed to be used with high flow (200 gph minimum), low pressure fuel pumps similar to Aeromotive Eliminator pump P/N 11104, Pro Series Pump P/N 11102 or A2000 pump P/N 11202. Performance may be degraded if a similar pump is not used.
13. Once the fuel pressure gauge registers fuel system pressure and there are no fuel leaks, start the engine and adjust the regulator up to the desired fuel pressure and tighten the jam nut. (Regulator is adjustable from 3-21 psi). Turning the adjustment screw clockwise will increase fuel pressure.
06-23-2017, 02:30 PM
Fuel pump install. What am I doing wrong?
