Why is the fuel pump on my 1995 Mits. Mirage louder than the engine? And why will the engine run OK for several miles before slowly losing power? If I turn the car off for a few seconds and turn it back on, some of the pep will come back for a short amount of time. The noise problem has been happening since I replaced the fuel pump and fuel filter. I took it to a mechanic and he replaced the rusty fuel tank, which fixed the noise and power problems for about 50 miles, then it was back to the same old problem. The check engine light is on, but I haven’t had the codes read.
First - find out what the codes are. This will probably be an OBD I system so you need to see whether there is a way to read them without a reader or hit someone with the right reader. (The free auto parts store services only do OBD II).
Have you (or has anyone) actually put a fuel pressure gauge on it? You need to do this and put the engine under some load. You apparently had this rusty gas tank, but did the pump and filter before doing the tank. You very well may also have fuel lines that are degraded or clogged up with old rust. That new fuel filter might be as well. Presumably the mechanic who did the tank made sure that the filter sock was clean before putting the pump back in?
You’re totally right, the codes have to be read, which is the first thing I asked the mechanic to do when I took it to him, but when I talked to him this morning he couldn’t remember if he read them or not, which probably means he didn’t. He’s a good guy and he works cheap, so I’m going to take it back to him. He did clean the sock. Should I start over with fresh gas?
I took the fuel filter off and replaced it (just last night) after the tank was done and the inside of the filter looked clean and clear and air passed through it. I swabbed the inside of the line from the fuel filter side with a pipe cleaner and only got a small tinge of rust color on the pipe cleaner, but no flecks of rust. The new fuel tank was “guaranteed” to be rust and leak free and the car ran great, no noise from the fuel pump, no lag, for long enough for me to think that the problem was fixed. Now it’s back.
I will put a fuel pressure gauge on it. What’s the best way to use a fuel pressure gauge?
Thanks a lot for your reply.
Is there a way to get the codes without and OBD I scanner?
Actually - you are on the OBD cusp. Check under your hood for the emissions related stickers. Most 1995 and earlier cars were OBD1 but 95-96 was the transition and I think some '95 imports were OBD2 including that one. The under hood sticker will tell you if its OBD1 or 2.
Look at this thread where you’ll see a discussion of '95 mitsus and an OBD2 plug diagram:
If it turns out you have OBD1 you can look at this: http://www.extreme-check-engine-light-codes.com/Mitsubishi%20OBD1%20Decoder.htm
Generally, that loud sound is the sound of impending doom.
Buy the casket and plan the funeral, the fuel pump is not long for this world.
This sounds like the fuel pump is straining against some obstruction in the fuel delivery system. If a carburator, then it may be gunk in the float tank, if fuel injection it may be clogged injectors. but be aware than sometimes even brand new parts are defective.
You’re right, new parts are defective sometimes. Also, i replaced the fuel pump while there was still rust in the tank, so that may be a factor. The pump ran great for the first 40 miles with the new tank, but it seems like once the engine gets warm, it starts to lag and I’m wondering if the pump is the problem or a symptom of something else. I’m off to try and find an OBD scanner.
later and thanks for the replies guys.