PDA

View Full Version : No Power to Fuel Pump 1995 525


Michael P
10-08-2009, 12:26 PM
I am new to this forum. I have owned Bmw's since 1989. I currently own 2 today and the problem one is the 1995. My shop manuel was stolen so I am sort of blind. Last week thursday turning a corner my 1995 525 died. It would start but acted like no fuel going to engine. I replaced the Fuel Filter.
It still would not run for very long and would die. I checked voltage to fuse and had crank voltage to the fuse panel. I checked voltage to the fuel pump and Had NONE. I cleaned the connector, then let it dry and re-checked voltage, NONE. I placed my meter probe into rear of connector and NONE. The upper 2 tongs did have minor .2 and .3 which I believe is the signal switch voltage for fuel reading.
I saw in the electrical diagram that the relay had a wire behind as well as in front of fuse block so I pulled all three relays from my 1994 (not knowing which of hte three it was) and placed all three into my 2005. I still have no Voltage to the Fuel Pump.
What is real bad is that My 1994 Bmw just 1 day later (Last Friday) had the fuel pump go out. I will recieve the new one today. So, I have been testing between the 94 and 95. I had voltage to the connector in the 94 but not voltage to the connector in the 95 except minor voltage in upper tongs reading about .2 to .3 which I believe is the signal switch voltage.
Any help would be appreciated. to summarize; I have cranking power to fuse block and no cranking power to the fuel pump connector for fuel pump.

Thank YOU for any help, 2 cars down is afirst for me in over 45 years.

woodnthings8
10-08-2009, 01:33 PM
So have you checked the fuse F23? Also the fuel pump relay you said you were not sure as to which one. Were you in the E-Box on the R/H fender or in the main P90 fuse panel? The Fuel pump relay is one of the three in the E-Box. The other thing to consider is the ECM. When you turn the key to run the fuel pump should start and build pressure. So the ECM may not be sending the signal to turn on, I would bet it is a fuse or relay though. You should be able to read the relay power supply and the signal power to see if it is one of those.

woodnthings8
10-09-2009, 10:44 AM
In the E-Box it is the middle relay(Fuel Pump)

Michael P
10-09-2009, 03:40 PM
Thank YOu for your Reply,
I checked and also replaced fuse incase it was to old. I also took the Relay's (all 3) out of my 94 525 and placed them into the 95. The 94 runs perfectly now with a new fuel pump but 95 still won't start with no power to fuel pump connector. I had both cars go down within 12 hours of each other.

Thank You

Shizbomber
10-23-2009, 12:36 PM
I just had my 1995 525i do virtually the same thing this morning. After letting it sit for 30 minutes it started and kind of sputtered for 30 seconds then died. I am hoping it is just the filter. Was the filter a major job to change? I have changed fuel filters on other vehicles but am new to BMWs and have never worked on one before. Is there any decent info that you know of on the www as to how to replace it? Thanks.

woodnthings8
10-23-2009, 03:45 PM
Jack the rear end up high enough you can get under the forward part of the tank by the passenger tire. Once secured on stands, just loosen the clamp on the filter and hoses. The fuel line will have a little pressure in it but I usually pinch off the hoses with locking pliers. Easy deal to do with only basic tools.

evrtimdy
05-22-2010, 11:14 AM
Can anyone Help! My 525 is getting no power to the fuel pump my relay is new and the fuse is new. whats confusing me is i just replaced the fuel pump too. and there is no power even going to the fuel pump fuse when use the test light. i fear my problem is simple and iv already spent way too much fixing it any ideas. Please Help!

jbh1989
05-22-2010, 12:04 PM
How are you guys testing for power to the fuel pump? Do you have someone cranking while you probe the connector?

jacrex1
10-24-2013, 08:31 PM
same problem....yes , someone is checking while cranking .

jnrlaw83
11-01-2013, 05:29 PM
I checked fuses relays, changed fuel pump, changed DME, Crank sensor reading over 500ohms but I'm not getting any power to the fuel pump or the fuel pump relay for that matter.... even changed the main relay! I've also searched everywhere I can... I have the service manual and the electrical service manual and I believe I'm missing something but I don't know what!:dunno: and I have all but given up:mad:

E34ZombieHunter
11-01-2013, 05:46 PM
You should no start checking wiring if everything else is eliminated

jnrlaw83
11-01-2013, 06:06 PM
checked the wiring from the DME to the relay and it has continuity. Jumped the fuel pump relay and the fuel pump runs tested the relay and it tested good... even changed it and no luck.... checked the wiring diagram on the electrical service manual and checked the related wire no luck.... it's just funny that during my web search i found a few people
with the same issue but no documented fix!

E34ZombieHunter
11-01-2013, 06:40 PM
What about the crash relay?? It cuts the power to the pump. As in it controls the fuel pump relay and will not let it send power to the pump. Give me a second to fund it in my Bentley.
Edit----So you f/p relay is in the box on the passenger side, the crash control unit is in the fuse box on the driver side, i have attached a diagram.

jnrlaw83
11-01-2013, 07:19 PM
thank you sir I'm going to check that when the sun comes up! i don't know how i missed it.... but I'll look into it.

Mamij
11-02-2013, 07:59 AM
If the pump runs when the relay is jumped (the engine should start with the jumped relay, check that), and the relays are good, then the issue is the fuel pump relay socket's contacts and the wires underneath. They get pushed down when a relay is pushed in on them, and contact is lost. Jumping it makes this less likely to happen, as you are watching directly.

Easy fix. Remove relay. Slide up socket gently as far as the wires will allow. First clean upper contacts with contact cleaner and a toothbrush. Blow dry. Then, look at the wiring under the socket. Push it up and into the socket with a toothpick. Ideally, use clear silicone sealant on the bottom of each contact to keep it pushed into the socket. This is a long term solution - you don't want this problem to reappear later through muscular driving. Let it dry, affix the relay and check to make sure the underwires hold, slide the socket back into the holder, reinsert the relay and start the engine.

[ Btw, the same method should be used to bulletproof the car's low and high speed aux fan relays, if wire slack at the slack permits. If slack is insufficient, a thin cable tie or rubber band is your Plan B. These relays are essential aspects of the car's cooling system. ]

Welcome to the best!

jnrlaw83
11-02-2013, 08:13 AM
Thanks I will also check that.... Quick question though, my crank sensor measured 512ohms and I read in Bentley that that was in spec but I read some where else that it should be closed to 1250ohms... I checked a new sensor and it read 500+ ohms... So now I'm confused about the crank sensor.

E34ZombieHunter
11-02-2013, 09:01 AM
Yes, the Bentley is wrong idk off the top of my head the spec, but someone will chime in with it.

BMR_LVR
11-02-2013, 04:29 PM
Yes, the Bentley is wrong idk off the top of my head the spec, but someone will chime in with it.

Correct reading should be 540 +/- 10%.


Sent from BimmerApp mobile app