No start - think its the fuel pump.. but...

[concort]

In my 1987 BMW 325e
So i replaced just about everything fuel related... both pumps, fuel injectors (with top of the line bosch), CPS, fuel filter, fuel lines but the car still wont start. It cranks just fine and it SOUNDS like it wants to start and does for like a second or two but then putters out. So when I first replaced the fuel pump it seemed to work... I thought I heard it, but now I hear nothing. And when I stick my current tester on these wires (see attached) that power the pump i get nothing... no power. And I tried with and without the ignition on. Im stumped. Any ideas?! IMG_8911.jpg

[richardodn]

For starters, it would be helpful if we knew which car this was for. You may want to add that info.

The pump doesn't see power until the ECU sees timing data at which point the fuel pump relay is triggered. Make yourself a fused (15A) and switched jumper. You'll want it fused since the relay is connected straight to the battery. Pull the fuel pump relay and jumper pins 30 and 87 so that you have a manually controlled fuel pump. Now you can do diagnostic tests on the fuel system. At the very least do a flow test on the fuel supply hose. This is the one attached to the rail. The return is attached to the FPR. Is there any possibility you reversed them?

Have you verified spark?

If you have a later model engine with the harness connector below the throttle body, have you checked it for corrosion? A leaky TB heater can drip coolant on that connector. Is the evap hose connector still attached on the bottom of the TB?

[concort]

For starters, it would be helpful if we knew which car this was for. You may want to add that info.

The pump doesn't see power until the ECU sees timing data at which point the fuel pump relay is triggered. Make yourself a fused (15A) and switched jumper. You'll want it fused since the relay is connected straight to the battery. Pull the fuel pump relay and jumper pins 30 and 87 so that you have a manually controlled fuel pump. Now you can do diagnostic tests on the fuel system. At the very least do a flow test on the fuel supply hose. This is the one attached to the rail. The return is attached to the FPR. Is there any possibility you reversed them?

Have you verified spark?

If you have a later model engine with the harness connector below the throttle body, have you checked it for corrosion? A leaky TB heater can drip coolant on that connector. Is the evap hose connector still attached on the bottom of the TB?

Shoot sorry about that. I have a 1987 325e.

So I did the relay test with my jumper wire in the 30 and 87 pins and i swear it worked before and heard the pump like month ago but now nothing. Is it possible some other fuse blew as a result of all this testing?? So when I do this jumper wire test should my voltage tester light up when I touch it to the wire connecting to the pump at that point? Meaning... theres power now going to the pump? Because its not. There just seems to be 0 power getting to the pump.

I did a spark test already at the plugs and thats confirmed that there IS spark.

[richardodn]

Yes you should see power at the pump. Check fuse 11 and see if it popped.

[concort]

Fuse 11 is good. But I did the jump wire on my main relay which controls signals to the CPS, ignition coils. Etc and when I pulled the main relay out and jumped pins 30 and 87 on that one the pump started! Sooo I may need a new main relay. I mean I literally replaced everything else. This has to be it. I sure hope.

[richardodn]

Make sure you get the right main relay. You can't just use any 5 pin relay. I believe the current part number is 61361729004. It's a dual 87 (tied) output, diode surge suppression, diode current flow direction protected, 5 pin relay.

[concort]

Yeah I usually rely on FCP Euro to give me proper fit out and they have top quality BMW and bosche parts

[concort]

Make sure you get the right main relay. You can't just use any 5 pin relay. I believe the current part number is 61361729004. It's a dual 87 (tied) output, diode surge suppression, diode current flow direction protected, 5 pin relay.

Ok i replaced the main relay but car STILL wont start. Just cranks and cranks but it wont turn over. I dont get it! I've pretty much replaced everything fuel related at this point. Any ideas?

[OMGE30]

For starters, it would be helpful if we knew which car this was for.

Very clever, Richard!

[concort]

So I just did a fuel pressure test and pulled the fuel line from the rail and put it into a large cup tried starting the engine and I filled the large cup half full. Plenty of fuel pumping thru. Spark issue? I tested one of the plugs with a screw driver and saw spark between screw driver and the intake manifold. Should I test each plug? Why isn’t this engine starting?? If just one plug isn’t sparking would that causes engine not to start?

[concort]

Ok so car is running now. I pulled all plugs cleaned them did spark test all checked out except one plug had this paper material jammed in in the spark node area …. No idea. So after cleaning everything up and putting back together engine running good. However now there is smoke coming from exhaust manifold area (see attached) …. Any ideas why? Would it be oil? I see slight dampness in that area that could be oil… it wouldn’t be fuel would it?
67362371488__3439F3B2-098E-44AE-B182-C57475B6D5B7.jpg

[concort]

Ok so update... i found little oil bubbling out of the spark plug cylinder at piston 6 - this may be the cause of the manifold area smoking...? What does this mean? Bad piston rings? If so are these very complicated to access to replace? I'd love to do it myself.

[95BMWIC]

I'm glad you figured out it wasn't a fuel problem... pulling the hose and checking the flow is an easy way of eliminating that as being an issue.

If the car is running and driving and idling well - then drive it for a bit to see if the smoke goes away and measure how much oil you are using (if any).. if you are burning oil that brings up some more issues to check (like checking compression).

All that cranking and working on getting the engine running may have fouled the plugs and left oil/fuel wetness in the cylinder - just drive it - watch the oil and see if the smoke subsides.

[concort]

I'm glad you figured out it wasn't a fuel problem... pulling the hose and checking the flow is an easy way of eliminating that as being an issue.

If the car is running and driving and idling well - then drive it for a bit to see if the smoke goes away and measure how much oil you are using (if any).. if you are burning oil that brings up some more issues to check (like checking compression).

All that cranking and working on getting the engine running may have fouled the plugs and left oil/fuel wetness in the cylinder - just drive it - watch the oil and see if the smoke subsides.

So i drove it to work today... started and ran fine but not much power when I get on the gas... you think just fouled up plugs? I did take the plugs out this weekend before I ran it and sorta cleaned them off and ran a fine piece of sandpaper between the spark plug gap to clean off the electrode a little then stuck em back in. But they are fairly blackened around the electrode end. You think new plugs would be ideal here? Is that whats stealing the cars power when I get on it? Like when I shift and step on it the car just sorta bucks little and doesnt take off like it should. Thoughts?

***In driving home the car sorta shakes not bucks when shifting and stepping on the gas... also after driving for like 15 min the car ultimately just sorta gonks out and stops but then letting it rest for like 5 min it starts right back up. Any thoughts?

[95BMWIC]

It sounds like you have a lot of issues to contend with. If you can - replace the plugs - not expensive and you can see if they become fouled again.

Also - Just make sure you have all your vacuum leaks taken care of - I run a vacuum gauge to see that I have good manifold vacuum when running - its not perfect but if it drops suddenly I know I have a leak somewhere. Check your boot - this needs to be sealed tight. Vacuum leaks are best detected by a smoke machine.

Next work through the wiring fuses and relays, look for corrosion and check / tighten your ground strap.

I would find time to drive the vehicle and document the issues and see what issues are repeatable.

[concort]

It sounds like you have a lot of issues to contend with. If you can - replace the plugs - not expensive and you can see if they become fouled again.

Also - Just make sure you have all your vacuum leaks taken care of - I run a vacuum gauge to see that I have good manifold vacuum when running - its not perfect but if it drops suddenly I know I have a leak somewhere. Check your boot - this needs to be sealed tight. Vacuum leaks are best detected by a smoke machine.

Next work through the wiring fuses and relays, look for corrosion and check / tighten your ground strap.

I would find time to drive the vehicle and document the issues and see what issues are repeatable.

I replaced the plugs and made a WORLD OF DIFFERENCE. Runs like a dream now. So your saying that they could get fouled up again? If that happens then what?

One thing that did happen is after test driving it for like 25 min last night i came to a stop sign and was messin with the radio and all of sudden the car shuts off. Would not start either... It seems like after car cools down it starts just fine again. Strange. So i need to figure out that one. But otherwise drives wonderfully again

[aaverhulst]

Don't worry about spark plugs. Else, you'll worry yourself to death. May happen, may not.

Don't mess with the radio - see if it dies again. Then you will have something to worry about.

[concort]

Update on this issue: Same problem after multiple test drives and replacing the spark plug wires now too. The will start and idle (not super smooth) but when running down the road it will sputter a little when getting on the gas and then after 5-10 min i came to stop sign and it stopped... left me sit. Didnt want to start... just kept cranking with no start. Then after half hour it started but still with some sputtering here and there. Any ideas??

[82eye]

leaking or fouled injectors. bad intake rubber. fuel pump regulator on the fail.
one or a combination can cause it.