89 fuel woes
- General karthief
- Start dateToday at 2:34 PM
Today at 2:34 PMNew
Hope you don't mind if I hit you again but I've been searching low fuel pressure and I keep hitting your replies. Makes me feel less guilty about reaching out. Plus it was good of you to help me with my fuel crossover issue.
I had a fuel pump failure a few months ago. No biggie I've replaced the stock one before as I've had my car for 21 years. I put a walbro 155 lph in about 10 years ago. It started making extra noise for about a week, then it made bad noise for a few days, then the car died as it was idling (warm-5 minute drive). Turn the key and zero noise from the pump. I let it sit overnight and went back the next day and it started and got me the 5 minutes home and then it was done. I never tested it (I still have it), I just bought another Walbro 155 and put it in. Replaced the fuel filter while I was under there as well; used Ford Motorsport. So when I go to start it, it won't light. Rolls over fine but no fire. Now I have an SCT switch chip and I tried switching the position from the stock one to position 1 which is only like 5% more fuel on my tune and it did start and move around in my yard a bit but there was no power under your foot. She didn't want to move around quick or spin the tires (dirt driveway, 4.30 gears). turned it off to see if it would start under the stock setting and no dice. Tried the first position on the chip and the fuel pump ran 100% with the ignition key in the KOEO position. It did that for all 4 of the SCT chip positions but not the stock one; stock position was the normal short fuel pump prime. So now I'm thinking my chip has failed. So when the fuel pump is running 100% and the engine is off I depressed the schraeder valve to check for fuel flow. There's flow there ( you can hear the pump run ), but it didn't squirt out. 40 PSI should shoot it to the fender right; it was more of running on my plug wires. A decent flow of fuel but not high pressure. So I talked to the dynojet guy who burned my chip and he told me to remove it and go back to stock. Made sense and easy to do. Still no start and fuel pump sounds as it should when the key is in the KOEO position. So it wasn't the chip and it could be possible that the chip was detecting the lack of pressure and cycling the pump to make up for it. So roll it over and no start, check the valve and there's some fuel there.
Now it's possible I messed something up when I did the install but the positive and negative ends are a different size so you can't run the pump backwards. The sock is on and the pump is screwed back in the bracket so it's in the right position in the tank. There's between 1/4 and 3/8 showing on the fuel gauge as I put about 6 gallons of fuel in so the pickup would be submerged. The fuel lines are two different diameters so it'd be hard to mess that up when you hook them to the pump. I used the new clamps and gaskets, the plastic end plugs from the pump are out and on my counter. I checked the fuel filter and it's on in the right direction. My next move is taking the vacuum line off my Holley adjustable fuel pressure regulator to see if that bumps up the pressure. I know I need a fuel pressure gauge and I just ordered one. After that I'll pull my new fuel filter to see if I can blow some air through it. Really don't want to drain and drop that tank as it's snowy and cold on the fingers in your driveway in Nova Scotia but I'm wondering if my new pump is bad. You know if I can check the fuel pump health some way other than removing it. Are there any terminals in the computer harness I can check to get the pump voltage? I'm pretty sure I have continuity. Any ideas? It'd be great if it was something stupid I did/missed. Thanks again for your help.