Is my fuel pump bad or somthin else?

[2ME]

it's a 95 neon 5 speed. A week ago it ran great. it will start and idle perfectly but as soon as you press the gas it "blub, blub, blubs" like a motorcycle with the choke left on. If you let off the gas it goes back to idle. I replaced the fuel filter and it was no better. If you pump the peddle quickly you can achieve the higher RPM's. There is no smoke coming out and the oil is clear and clean. There is the oft mentioned oil in the spark plug tube in one of the cylinders but it looks like it has been there for a while. The head was redone a year ago. The plugs are good. Also, I am getting a code 51 lean fuel error when I do the ignition thing to pull codes. :help:

[RadarLove]

The PCM is sending too much fuel. Your upstream O2 sensor provides the feedback that the PCM uses to control fuel trim. If the sensor thinks the engine is running lean, the PCM adds more fuel. Once fuel trim is significantly over the programmed value (20%?), the code is set for lean. In this case, I'd bet the car is actually running insanely rich because that sensor is faulty. If you can find a NGK brand at your local parts store to stick in there, that's what I'd recommend - usually a few bucks cheaper than the dealer (also NGK). Most people avoid Bosch sensors because they have a higher failure rate.

Best of luck!

[2ME]

I wondered about the O2 because I have been down that road before. I actually had the head redone done a year ago when the problem was actually the O2 sensor. The car would warm up then often bog way down like it was loosing compression. After the head job it did the same thing. I went on the forums and saw someone with the same problem replaced the O2 and the problem was gone. At the same time I also read that the O2 sensor doesn't start doing it's thing until the car is warm and my current problem is there when car is cold or warm. But I did first notice it when the car was warm. Why don't you think it is the fuel pump instead?

[rice_eater]

check your engine codes. (turn key on, off, on, off, on, and the check engine light will flash out a series of two digit numbers - see "trouble codes for neons 95-99" in general information section). If your O2 sensor is bad the computer will pull up code 21 (two flashes, pause, one flash) If the engine idles ok and bogs when you give it gas (press the accelerator), then you are getting fuel, too much fuel. If your fuel pump was bad it wouldnt get any fuel, wouldnt want to start, idle poorly (if at all), and run slightly smoother or the same (definitely not rougher) when you gave it gas. Besides, if i recall correctly fuel pumps are quite pricey for neons (i know the 97 and up ones with the internal fuel filter are upwards of $250). Listen to RADAR, he really knows his sh#% about neons.

[2ME]

I have just put a fuel injection pressure tester on it and it only reads 9lbs. We even checked the tester on another car and it read correctly. I am not getting a 21 I am getting a 51 lean fuel error which makes sense if your not getting enough fuel.

[RadarLove]

So you're only getting 9 psi on the fuel rail? I'm surprised the car turns over at all!

If you've replaced the filter, you can try replacing the pump. The cheapest by far is the Walbro 255 lph pump from Howell Automotive ($110 or so). Much better price than you'll find anywhere for a stock replacement unit. A replacement regulator should run $50 or so if you'd rather go that route first (call Travis at Deyeme Racing, 636-462-3989). Just be sure to get the correct one for your application - the configuration changed a little when they switched over to the plastic tank (came with the little filter attached). I've never tried swapping to see if one will work on the other though. Entirely possible since the pumps are identical, just the housings are different from metal to plastic tanks.