93 525i not starting, just replaced fuel pump! [Archive] - Bimmerfest - BMW Forums

: 93 525i not starting, just replaced fuel pump!

10-13-2009, 05:07 PM
So, my car's pretty old, but for the most part I've been keeping it running for 280,000 miles so far. Recently, I went to go start it and it would crank but not start. Then about a week later I replaced the fuel pump and it started right up and was fine for about a week. With about 40 miles left on the tank, I tried starting it up yesterday and it had the same symptoms as before I changed the fuel pump. Today I put a new fuel filter in, but it didn't help. I'm pretty sure the pump is getting power, as when I take the fuel out hose off the pump gas comes out when I crank it. Not sure if it might be a clogged line or what, I just don't want to go putting a bunch more parts in without it doing anything. Any ideas?

*Also while I was looking at the engine today I noticed that there were some cracks in the air intake boot, which I'm not sure would cause the engine not to start, and think it's probably been like that for awhile but not sure?

10-14-2009, 03:03 AM
intake boot?
Don't think is your problem, since you have problems in the past with the pump I will verified that in fact is sending gas to the intake manifold, disconnect the fuel line going to the manifold maybe connect a longer hose to it and place the other end on a bucket ( you don't want gas going all over the engine area) and try starting the car, see if you get gas on the other end of the hose ( there are two hoses going to the manifold: one is the return gas, if you like i can send you a picture pointing to the correct one) If you do get gas out, now you have rule out the clogged line possibility up to that point.
I will also check for clog injectors or the spark plugs ( possibly) make sure there is electricity going to the sparks.

10-14-2009, 06:52 AM
Fuel Pressure Regulator I think is the only mechanical choke point around what Rick is talking about above. If you can determine you have fuel going into the FPR - but not coming out from the return line at the front end of the fuel rail, then the FPR may be your issue, in that it's not allowing fuel through to the rail.

10-15-2009, 01:55 PM
I checked and it looked like gas was coming out of the gas line going into the engine but not coming out of the return line...would this most likely mean it's the Fuel Pressure Reg.?

10-15-2009, 04:00 PM
ok so im not sure on this one but have you ever ran the codes on your car? and if I'm completly wrong about the code thing please tell me im on this forum to learn also! but also my dad all ways used to tell me "go back to the scene of the crime." so what ever you just fixed check it out make sure its ok. lol i have to do that alot. I hoped i helped

10-15-2009, 06:24 PM
I havn't ran the codes but have been thinking about buying a peake code tool, I tried to do the stomp test multiple times but when it starts blinking it just blinks once everytime and doesn't make sense. I'm just not sure I want to drop $100 on a code tool just to find out that I need to spend another $400 in parts, I wish autozone had them for rental or something

10-16-2009, 06:55 AM
I checked and it looked like gas was coming out of the gas line going into the engine but not coming out of the return line...would this most likely mean it's the Fuel Pressure Reg.?Yeppers - and a fairly easy replacement - just has a circlip that attaches it to the fuel rail. Be mindful of seating it fully before tightening it up, as it's basically held in place with friction - no slots or lock-in channels, IIRC.

10-16-2009, 01:04 PM
Soo I went to my car today and tried turning on just for fun, and it actually started up! It's a little shaky on idle though. So now I'm even more confused, but I am glad that it started up. Now I'm thinking it could be a wiring issue, but I'm not sure. The engine light isn't on though. I saw a used fuel rail on ebay, with injectors and fpr for pretty cheap, so I might still look into replacing that. Any other thoughts?