Thread: Where did my power go??

I checked with Pep-Boys and they're around $45 so it wouldn't be a enormous investment. I may just go for it but I've replaced so many things already with no positive results, I'm getting tired of doing it.

Nothing against you Bio248, but yeah I was confused too why you're the only person posting. It looks like a bunch of people have read this post but I guess no one else has any ideas better than yours. Keep up with the suggestions. Thanks

Thanks guys for the replies. I ordered a FPR today and I hope to put it in this weekend. Hopefully my next post will say that the FPR did the trick.

They sell generic injector pulse width reader. It actually plugs into the wiring to test the signal to the injector. Generally they just flash when the injector is supoosed to be open.. So if it stayed on uwoudl know if u had problems electically.

I changed out my FPR earlier today and to my surprise, and disappointment, it still didn't solve my problem. I really had high hopes that this would do the trick.

With the key turned to ON, I get closer to 48psi now compared to 43psi before I changed it. After I start the car I am getting 84psi compared to the 78psi to 84psi before I changed it. I also pulled off the vacuum line with the engine running and there was no change. I was able to position the pressure gauge so I can see it from inside the car. While the car was in gear but holding down the brake, I am able to rev the engine enough so that it bogs down. The fuel pressure is still above 80psi while the engine is bogging down.

I'm not exactly sure of the mechanics behind the supercharger but it also seems that the bogging happens whenever the supercharger is giving boost according to the dashboard gauge. Could part of the problem be that the engine is getting extra fuel because of the boost but not enough air to match and is therefore dumping in way too much fuel with out enough air to back it up? Like I said, I'm not sure of the mechanics behind the S/C but I'm grasping for straws. I still don't think this would explain the reason for such high fuel pressure.

Any suggestions would be greatly appreciated.

With high fuel pressure, the first thing that pops into my head is some sort of obstruction in the fuel filter, fuel lines or fuel rail, or possibly a kinked line.

When's the last time the filter was changed?

Inspect the entire fuel path (lines/rail) for kinks/bends.

If you can get your hands on a cut-off return line with fuel rail quick-connect, you could hook that to your return on the fuel rail, put the other end into a fuel can, and check pressure then; if it's normal, at least you know the obstruction is somewhere after the rail.

I changed the fuel filter twice since since this problem with bogging down has started.

Someone else had also mentioned to me about checking to see if the return fuel line is blocked. I tried to disconnect the return line where it changes from the steel line to the rubber line (directly above the motor) but I can't seem to get it disconnected. Is there a special tool I would need to disconnect them?

I'll also try to get the car up in the air so I can inspect every inch of the lines under the car.

I checked my Fuel Pump Power Relay(I think that's what it was called) and since it is exactly the same part as the Fuel Pump Relay, I swapped them and nothing changes.
I also disassembled the relay a little bit and bench tested to see if the relay actually would switch between the 2 posible positions. It did actually switch.
I then installed it while it was open and manually made the relay switch positions and the pressure went around 93psi. This was while it was idling.
I then got my car up on ramps so I could go under to check the fuel lines and everything appears to be in perfect condition. There was no kinks or damaged that would possibly cause a blockage in the return line.

When I pulled the vacuum line off of the FPR I could hear the vacuum and then when I covered the hole of the vacuum line with my finger, I could feel the suction. I don't have any way of testing to see how much vacuum there is but YES there is vacuum.

I dug into the trunk today to get to a wiring harness that goes to the fuel pump. I was getting a reading of 11v while the car was running and the engine was idling at 800rpm. I think I was getting around 12v-13v when I turned the key to ON but then it drops after the pump would stop putting pressure in the line.

whiteknuckle - I have to deal with this problem on a daily basis as it happens every time I drive it especially on the highway. It has never died on me, it just loses all 'get up and go' until I get off the gas and ease back into it. If I give it too much gas, it bogs down again.

Originally Posted by whiteknuckle

my car did the exact same thing about 6 mos. ago. i was just driving down the highway and all of a sudden it lost power.
it would idle ok but anytime you stepped on the gas it would stumble and try to die.
the first thing i tried was a different MAF sensor. thankfully it fixed it. the weird thing is that it never threw a code.
hope this helps

Same here. Although it was on a 97 Silverado, your symptoms are the same. Replacing the MAF fixed the problem...

I can't imagine a MAF issue would cause fuel pressure to go so high.

I still don't feel that you've eliminated the possibility of some sort of internal blockage in the return line. The quick disconnects on a (stock L67) fuel rail do require a special removal tool, like this one:
Amazon.com: OTC 7660 Fuel Line Disconnect Tool: Automotive

You may find one at a local Auto Parts store.

Your voltages sound reasonable. If you can eliminate blockage in the lines, then I'm beginning to think that something's gone haywire with the electric motor in the pump itself. Does the pump sound funny when the pressure goes up? Like an electric motor spinning super fast?

I got the quick disconnect on the return line seperated. This is the one directly on top of the motor. I tried to blow some compressed air (40psi) into the line to see if there is a clog. It doesn't appear to be pushing the fuel in the return line back to the tank. Does anyone know if there is a trick to it? Does the key have to be turned to ON?

Originally Posted by Sabrewings

Return line should be a straight shot in to the tank... Pop your gas cap.

When it didn't work the first time, I did open the gas cap and tried again. It still didn't move the fuel in the line.

I'm going to take a run to the store to pick up some hose so I can run it from the return line to a gas can and then try running the motor to see if the pressure is lower.