Help - last try on the fourms - Fuel pump relay will not activate

[theweebs]

My car has been down for 2 months now and I am at my wits end. I have tried everything I can think of but I feel that I am missing something simple. Looking for some help before I tow it to an Indy or the $tealer. Any help would be appreciated.

I had just replaced my timing guides and at about 30 miles of driving on the repair I stop at a home depot and when I go to leave the car will not start. Had to have it towed home. The car was running perfectly prior with no indications of any mechanical problem.

Now, when I got the car home I noticed I had no fuel pressure. I traced this down to the fact that the relay is not being energized from the DME. There is no CEL either.

I tried all diagnostics I could think of and researched the forums to the point that I believed its was a bad DME. I replaced the DME, had it sent out to RPM to have it paired with the EWS, but when I got the replacement DME back I still have the same problem.

So the million dollar question is what could keep the DME from energizing the fuel pump relay (besides a bad DME)?

Thanks for your help!

[JimLev]

Have you tried jumping out the FP relay to see if it will start?
When you turn the key to position 2 the relay will only pull in for ~2 seconds and then shut off until you turn the key to the crank position.
The DME then looks at the crank sensor to make sure the engine is turn over, otherwise the FP relay will not pull in.
Sure your FP isn't bad?

[jstern]

+1. There have also been instances where the syphoning mechanism in the dual fuel tanks (the suction jet pump) doesn't work so the FP sucks all the gas out of the right side tank and the syphon does not work to transfer fuel so the car effectively runs out of gas even though the left side tank has plenty of fuel in it. This usually happens when the fuel gauge is showing 1/4 tank remaining if I remember correctly.

But you really need to do what Jim says first and test that your fuel pump runs when you jump the relay.

[Cereal]

http://www.m5board.com/vbulletin/e39...pper-wire.html

Good link from M5board about checking tank levels, fuel pump relay and such... I know you mentioned you checked before but check again maybe? Don't want to have missed something when it could've been something simple like the relay all along

[JimLev]

Check fuse 17 and 31 above the glove box and F54 in the trunk.
Better pic of jumping out the FP relay.....

[theweebs]

Have you tried jumping out the FP relay to see if it will start?
When you turn the key to position 2 the relay will only pull in for ~2 seconds and then shut off until you turn the key to the crank position.
The DME then looks at the crank sensor to make sure the engine is turn over, otherwise the FP relay will not pull in.
Sure your FP isn't bad?

Jim, Yes i have jumped the FP relay. The car will crank but not start although I have a fuel pressure gauge showing +50 psi when jumped (new FP too!!)
I checked and replaced the crank sensor and ohmed it out at the DME between the 2 wires at 630 ohms so it seems to be in the loop.

The problem is that there the FP relay does not pull in at all when the key is turned even before trying to crank it. I have checked for power to the relay coil too. Could this be a bad ignition switch?

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Check fuse 17 and 31 above the glove box and F54 in the trunk.
Better pic of jumping out the FP relay.....

I jumped the contacts at the relay socket. FP runs. Also verified all fuses as good in the trunk area, in the glove compartment, and also at the DME. Haven't verified any under the passenger seat yet. Thanks!

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+1. There have also been instances where the syphoning mechanism in the dual fuel tanks (the suction jet pump) doesn't work so the FP sucks all the gas out of the right side tank and the syphon does not work to transfer fuel so the car effectively runs out of gas even though the left side tank has plenty of fuel in it. This usually happens when the fuel gauge is showing 1/4 tank remaining if I remember correctly.

But you really need to do what Jim says first and test that your fuel pump runs when you jump the relay.

Thanks. Would any of this prevent the DME from energizing the FP relay?

[geargrinder]

If you have good fuel pressure like that when jumped and it still doesnt start, i don't know why you are barking up the fuel pump / relay tree. There is another DME related reason your car aint firing ignition or injectors either obviously.

It is imperative to pull codes in a case like this. Too many people are convinced that a light will come on if there are codes. Only true if it is a catastrophic error or missions related.

It absolutely could still be EWS related. An EWS-DME miss will crank the car but not fire any fuel or ignition just like this. If EWS doesnt know the key it would not crank, so that seems OK. If you had the parts re-aligned but then ever, even once, turned key with one or the other modules disconnected, then they could have become desync'd again.

[jstern]

Thanks. Would any of this prevent the DME from energizing the FP relay?

No! Plus you get fuel pressure when jumping the FP relay so the pump is picking up fuel.

If you have good fuel pressure like that when jumped and it still doesnt start, i don't know why you are barking up the fuel pump / relay tree. There is another DME related reason your car aint firing ignition or injectors either obviously.

It is imperative to pull codes in a case like this. Too many people are convinced that a light will come on if there are codes. Only true if it is a catastrophic error or missions related.

It absolutely could still be EWS related. An EWS-DME miss will crank the car but not fire any fuel or ignition just like this. If EWS doesnt know the key it would not crank, so that seems OK. If you had the parts re-aligned but then ever, even once, turned key with one or the other modules disconnected, then they could have become desync'd again.

IMHO you need to follow up on GG's suggestion. Read codes and check for spark and/or injector pulse.

[theweebs]

If you have good fuel pressure like that when jumped and it still doesnt start, i don't know why you are barking up the fuel pump / relay tree. There is another DME related reason your car aint firing ignition or injectors either obviously.

It is imperative to pull codes in a case like this. Too many people are convinced that a light will come on if there are codes. Only true if it is a catastrophic error or missions related.

It absolutely could still be EWS related. An EWS-DME miss will crank the car but not fire any fuel or ignition just like this. If EWS doesnt know the key it would not crank, so that seems OK. If you had the parts re-aligned but then ever, even once, turned key with one or the other modules disconnected, then they could have become desync'd again.

I agree and dont believe it is a FP issue but something is the root cause for the FP relay not being pulled in. So the FP relay is just an indicator of a the larger problem IMO.
I have pulled the codes off the OBDII and it is clear with no pending codes. It has never thrown a code with this problem.

When I got the DME/EWSII back from RPM I made sure I did not desync them. Luckily I have read about that problem on this board and made sure I didn't make the mistake. Easy to do when you are playing with DME wires! Maybe they were not sync'd from the beginning? Not sure how to check. I do know that the fuel Injector relay in the DME area is energized at the RUN position.

I am not sure how to check for ignition directly from the coil pack without special tools. I tried pulling a plug and grounding it old school but did not see a spark. The plug was inserted in a precarious position and I was not sure that the conductor was contacting the coil wire at the time as my battery was going dead. So the jury is still out on spark.

My understanding is that the Fuel Injector Relay would not energize with a desync'd EWS. I will try to test for spark again but the way it turns over it does not sound like there is any spark.
Whats next if no spark? Thanks, this helps me get a better understanding.

[geargrinder]

Generic code scanners often may not show all the codes. Need to use a BMW tool and while you're at it you can resync. The EWS unit itself can be scanned for codes as well. See if you can find a forum guy w/ a laptop and INPA setup who will do it for beer. I don't know anybody in Atlanta unfortunately (well, my nephew but he's 13 and doesnt really know much about cars except he likes the cool looking ones).

The old school technique should actually work for a spark. I bet it did. I would be pretty sure something isn't kicking off a full start sequence in the DME.
You can also listen to the injectors for clicking to see if they are pulsing.

In order to start:
EWS needs to like the key to turn the starter. That's obv. OK.
Then EWS and DME needs to all be OK. Jury still out.
As Jim says, Crank sensor would be another.
Some other blown DME fuse or relay could be another. Assume you checked all the fuses in the 'E-box' where the DME lives?

Also i see you have an auto - I am guessing there's a start interlock w/ the auto tranny too. I should say I mean I know there IS for sure, but i don't remember if it's a crank-no-start interlock or a not-even-crank interlock. If there was bad mojo there (bad EGS / tranny module or related fuses or shifter selector switch...) that might do it.

[JimLev]

You said it cranks so you can rule out the tranny shift interlock, it wouldn't crank if that was bad.
Are you sure all of the fuses in the back of the DME box are OK?
There are fuses in there for the injectors, the coils, cam sensors, etc.
Pop that little cover off and check them again.
The fuses under the carpet shouldn't be your problem, they supply main power to the cabin and engine.
You'd have much bigger problems if one of them was bad.

[Cereal]

I might've missed but you ever check your crank sensor? Idk what happened after my timing job but car started then died... The sensor got chewed up from the flywheel, I obviously messed the sensor up.

Installed new one and worked after.

[theweebs]

I might've missed but you ever check your crank sensor? Idk what happened after my timing job but car started then died... The sensor got chewed up from the flywheel, I obviously messed the sensor up.

Installed new one and worked after.

Yes I have an extra from a separate debug that was still good and I swapped it out. I also verified it by ohming it out at the DME. I think the FP relay should pull in and at crank if no crank sensor it would deactivate. In this case the FP relay never pulls in.

[Cereal]

Bummer, just trying to think of alternatives and hoping for an easier fix for ya

[theweebs]

You said it cranks so you can rule out the tranny shift interlock, it wouldn't crank if that was bad.
Are you sure all of the fuses in the back of the DME box are OK?
There are fuses in there for the injectors, the coils, cam sensors, etc.
Pop that little cover off and check them again.
The fuses under the carpet shouldn't be your problem, they supply main power to the cabin and engine.
You'd have much bigger problems if one of them was bad.

I did pop the fuse pack open in the DME box and ohmed each fuse. Made sure they are seated properly too. I also verified the DME relay operation.
Good to know I dont have to pull the seat up again. I had to replace the airbag weight sensor a year or so ago. Have a airbag reset tool available for sale BTW!

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Bummer, just trying to think of alternatives and hoping for an easier fix for ya

Very much appreciate it. I am starting to lose spousal approval on this project

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Generic code scanners often may not show all the codes. Need to use a BMW tool and while you're at it you can resync. The EWS unit itself can be scanned for codes as well. See if you can find a forum guy w/ a laptop and INPA setup who will do it for beer. I don't know anybody in Atlanta unfortunately (well, my nephew but he's 13 and doesnt really know much about cars except he likes the cool looking ones).

The old school technique should actually work for a spark. I bet it did. I would be pretty sure something isn't kicking off a full start sequence in the DME.
You can also listen to the injectors for clicking to see if they are pulsing.

In order to start:
EWS needs to like the key to turn the starter. That's obv. OK.
Then EWS and DME needs to all be OK. Jury still out.
As Jim says, Crank sensor would be another.
Some other blown DME fuse or relay could be another. Assume you checked all the fuses in the 'E-box' where the DME lives?

Also i see you have an auto - I am guessing there's a start interlock w/ the auto tranny too. I should say I mean I know there IS for sure, but i don't remember if it's a crank-no-start interlock or a not-even-crank interlock. If there was bad mojo there (bad EGS / tranny module or related fuses or shifter selector switch...) that might do it.

I checked the DME fuses in the box the other day and all were good. Pretty sure the Crank Sensor is good. I swapped it out for a known good one anyway. I put the car in neutral with no change to check the interlock. The car is cranking so it usually is a no crank when this fails.

I have a stethoscope and could check the injectors again. I have listened to them before so I have a good idea what they sound like. Its worth a shot.

I'm stuck on any ability to access the low level codes from the BMW connector with a INPA setup. This is where I'm going to have to get it towed and then I am at the mercy of the shop if nothing obvious is found. I have used a indy nearby before but have not been impressed with them.

[JimLev]

You ohmed the DME fuses, but did you check to see that they had 12 volts on each of them?

[theweebs]

You ohmed the DME fuses, but did you check to see that they had 12 volts on each of them?

I just went out and tested the voltage at each fuse. All are at 12v. Had the potential for a smoking gun here!

[theweebs]

I'm resetting and starting with the basics again. I verified no spark and used a stethoscope and verified no injectors. Measured 12v at the DME relay contact. While I was measuring the DME relay I noticed that the FP pulled in twice for less than a second, fuel rail pressure went up about 10 psi each time. The good news there is that something is working correctly for a second anyway! I thought that maybe my wiggling of the wires in the DME box might have exposed a bad wire when the FP pulled in. No luck a bunch more wiggling did not get me more FP activations. Its just random at this point.

I wonder if I have a key switch problem?

[pshovest]

It's normal for FP to run for a second or two when key is turned. Newer cars like E60's and E70's run the fuel pump for 3-4 seconds as soon as you open the car door and wake up the car.
Try a different key.
Get INPA working and confirm DME-EWS sync.
RDL had an outstanding post of the various failure modes of bad key and EWS-DME sync symptoms.

[m5hoot]

It's normal for FP to run for a second or two when key is turned. Newer cars like E60's and E70's run the fuel pump for 3-4 seconds as soon as you open the car door and wake up the car.
Try a different key.
Get INPA working and confirm DME-EWS sync.
RDL had an outstanding post of the various failure modes of bad key and EWS-DME sync symptoms.

I think this should really be a very easy thing to track down. You said you had worked on car and drove home depot, so are we saying FP and all was just fine until you just happened to shut off and after that, all was dead? You say you checked voltage at fuel pump relay coil, but you did not say what you got, WHEN it was at 12V, and when coil was "hot" (had 12VDC to it that FP itself also could be heard to run). Relay should energize, build up required Fuel pressure, and then shut off. It should not stay energized while in a No-start condition and fuel pump should just kick in again if FP drops somehow on its own below a threshold and then FP should just kick in long enough( a quick second) to replenish fuel pressure. You should get a second person and check FP relays after a night sitting. FR relay energizes and FP runs. Check both.

If you are 100% sure that "whenever" 12 volts is sent to relay that it does pull-in and Fuel pumps do run at same time, you can then move on elsewhere to see why DME is not sending voltage to pumps and relays-- or it is and all is working in back ok, but because you have a no-start condition, fuel pumps will never be turned on again unless rail pressure drops too low. Timing of all this failure too coincidental to after repair, yet it ran fine and got you to home depot so all was well up to your stop.

I think you can BRIEFLY send 12 VDC using a power supply to FP relays to see that they pull in and that 1w Volts is ALSO available on a separate relay pin to power the fp. FP relay could be pulled in, but fuse might ne blown such that relay does its job by energizing, but relay on CONTACTS and not relay coil may not have 12VDC. !2 volts should be available on N/O relay contact and 12 vdc to relay coil may be a different matter. Have not looked at Bentley. b Voltage to relay coil is one thing. Voltage to relay contacts is another. Must have both and it sounds like you have observed FP go up on occasion (such as first start of the day). What does your pressure gauge tell you? Bet it sees plenty of pressure, but you have a no-start condition for any number or reasons (CPS?) and thus fuel pumps are told to shut off and they will stay off until you get a "start condition-ok) car is running OR FP at rail falls too low and key is on due to Fuel pressure bleeding off for some reason. You should be able to attach pressure gauge to rail, read pressure, disconnect gauge or have a Tee in line so you can push in Schrader valve with a screw driver and see pumps respond to come back on and replenish fuel pressure that you purposefully bled off? Be methodical. You can force FPs to run for short time with direct 12vdc to pumps (short time!) and see if car will start. If no, then move away from tanks and figure out why car won't start upon cranking with F-Pressure known to be available. Good Luck. This should not really be hard if you take all into consideration such as "permissives". Permissives are things that must be present and at right time for other things to happen. Germans are notorious for protection. You could get a no start for too little pressure, too much pressure, or sequence of things before not happening correctly. Patience grass hopper and you will get it.

[geargrinder]

Ignore m5hoot's "didn't read the thread but here's a bunch of stuff about 2 words I scanned in the OP" post. (aside from him missing all the stuff we already bin threw including decisively that it is not the fuel pump or fuel pressure, I might add that there is no 'kick back in when below a threshold' by the way - the DME and FP have zero idea how much pressure there is or is not in the rail. that does not ever happen. I have never heard of any ECU with a fuel pressure sensor let alone logic to drive FP based on it. )

Clearly the DME has issue cuz it's not firing the injectors or plugs. Now you need a computer and a cable.

Did you try posting on Diag forums for a bro to help you out for beers? That works out well often for us geeky diag software guys.

[m5hoot]

Ignore m5hoot's "didn't read the thread but here's a bunch of stuff about 2 words I scanned in the OP" post. (aside from him missing all the stuff we already bin threw including decisively that it is not the fuel pump or fuel pressure, I might add that there is no 'kick back in when below a threshold' by the way - the DME and FP have zero idea how much pressure there is or is not in the rail. that does not ever happen. I have never heard of any ECU with a fuel pressure sensor let alone logic to drive FP based on it. )

Clearly the DME has issue cuz it's not firing the injectors or plugs. Now you need a computer and a cable.




Did you try posting on Diag forums for a bro to help you out for beers? That works out well often for us geeky diag software guys.

You are such a happy soul- a true joy to me and all others. I bet you were a cute baby. Were did it all go wrong? Develop a strong ego and you won't feel it is necessary to police everyone's posts. This seems to be your M.O. on more than one recent occasion. Is your bed in the corner, by chance? With your advice I don't know why the OPs issue lingers. Maybe people won't listen to you and that's the problem.

[JimLev]

Ok guys, chill out.
Pretty sure he was just trying to correct some errors in your post.

[geargrinder]

Ok I coulda been warmer and fuzzier about the "why gee I think maybe you didn't really read the whole thread" part. But I'm used to others around here who have thick skin and aren't so easily bruised I guess.

[jstern]

OK Jim and GG. You know that my knowledge of V8s is sketchy at best, but theweebs said all this happened 30 miles after he changed timing chain guides. Is there anything that could have come loose, etc. from that job that could have caused this?