- This topic has 7 replies, 4 voices, and was last updated 10 years, 6 months ago by
.
-
Topic
-
:sick: Hello everyone, Sort of stuck on this one looking for some help.
Condition: No Start
Fuel Pump is found to be Good. Unable to locate the fuel pump relay.Engine is 3.5 litre also known as the E24 by BMW
There is no power to the pump and the fuse 15amp is found good. Fuse number 11.
Relays are found all about the car with no indication of what does what. ANYBODY know where the fuel pump relay is located on this car?
-
Replies
-
see if this helps.
http://www.justanswer.com/bmw/1u8ga-fuel-pump-relay-located-635csi.html
With the help of College Man getting the link over for a schematic layout of the BMW 635 relay’s. Was able to locate the fuel pump relay and replaced it. Hey that worked! Well sort of any way. The engine started up and was able to drive it 10 miles no problems up to 89 miles an hour and at lower street based driving and
at various speeds due to stop lights and stop signs, so parked the Car for the rest of the day thinking that was it. Feeling pretty good about it running again. So later that same day after about 7 hours or so went to start it up and again nothing. No Start. What the heck is going on here? Back to the drawing board. Now what? :sick:When it no started the second time did the pump run? Re inspect the relay, and or by pass it to try again. Id also recommend inspecting the wiring to the pump.
CIS fuel systems require a lot of pressure and it really works the pump hard. If the pump is getting old its not un common to see relays melt or scorch, Espessialy when people change the fuse for a higher amperage. For this very reason a lot of guys with old CIS cars, even in immaculate shape add a “redundant” relay to the fuel system so that the more expensive OEM one that might control other things as well doesn’t fry. Also double check on that 15amp fuse. Most CIS pumps use 10amp. Might be a very good clue to a bigger picture.
[quote=”JS” post=99896]When it no started the second time did the pump run? Re inspect the relay, and or by pass it to try again. Id also recommend inspecting the wiring to the pump.
CIS fuel systems require a lot of pressure and it really works the pump hard. If the pump is getting old its not un common to see relays melt or scorch, Espessialy when people change the fuse for a higher amperage. For this very reason a lot of guys with old CIS cars, even in immaculate shape add a “redundant” relay to the fuel system so that the more expensive OEM one that might control other things as well doesn’t fry. Also double check on that 15amp fuse. Most CIS pumps use 10amp. Might be a very good clue to a bigger picture.[/quote]
This guy knows his BMW’s. I’d listen to him. Since I don’t know as much about them I’m going to just keep an eye on this thread.
Keep us posted.
Never owned one, worked on a few older ones. I speak the language of VW, particularly old ones. And they for along time used similar or the same Bosch fuel systems as BMW, Porsche, Audi. I like the old CIS based injection stuff. Archaic by today’s standards for sure but it worked really well. Its also fairly simple stuff to work on. Dam good throttle response for old fuel injection. You can just about fix anything CIS with a hammer and some injector cleaner.
In regards to the fuse, I never did go look to see what it should have but its very common in all old CIS cars to see higher than spec fuses. Bad fuel flow, worn pump etc keeps popping them. The end result is melted or really hot relays, and or the wiring gets really brittle really quick. I would also check out the ignition switch now that I think about fails like this I’ve seen before. A worn switch may not be powering up everything properly. If you can try pulling the switch off the back of the key tumbeler and turn it with a screw driver. That or pull the wire out of it and use other wire to bridge it, essentially hot wiring car power like keying the car on pre start to rule out the business end of the ignition switch.
Hope you get it solved, I like the body style on the 85’s.
Thank you everyone who offered help and to those who just read the post. UPDATE….NEWS FLASH!!!!!!!!
Well it seems that the real no start problem was due to a weak fuel pump. Even though it seemed to be functioning and would start up in a cold condition but would not stay running. Replaced the fuel pump with a used one out of a wrecking yard, off the same basic BMW motor anyway type car and installed that pump. The BMW is now running and is able to start up and stay running again. So why did it run on the first place upon the replacement of the fuel pump relay? Hum…not sure. Well we will see if it will stay running with easy start ups over this weekend. Parts is parts. Thanks everyone. 🙂I highly highly highly absolutely recommend not trusting the wrecking yard fuel pump for long. Who knows how long it will last ya. You can pick up OEM ones or several differant kinds of after market race pumps with adjustable pressure for the same kind of price.
Happy to hear the Bimmer goes again! Thats a true “driving gloves” kinda car 🙂
- You must be logged in to reply to this topic.