1991 e31 manual trans - crank, no start M70

[cartoonz]

hotwire the pumps at the fuses and start the car, then report back

[6speeder]

hotwire the pumps at the fuses and start the car, then report back

you mean use 2 short wires from the B+ jump terminal to each fuse? are you sure its safe to try to start it like this????

[cartoonz]

Yes

[6speeder]

ok somethings really wrong now. EML light no longer turns on at all (should light up for a few seconds with ignition on), neither dk motor hums, i have half tank of gas but fuel gauge needle does not move from its starting position of completely empty, and the reserve tank is lit up orange and stays lit. yesterday none of this was happening. what would cause no eml and both dk's not to buzz?

[Brunberg]

Burnt fuse.

[6speeder]

not fuses. did visual inspection and continuity test on every fuse under hood and in trunk.

also neither the eml light or check engine light turn on when i turn key to run (i know the eml lights up when turning key, and im 95% positive the cel does also <<<can someone confirm). both dk's also do not hum now.

[Timm]

Check for power on Fuse 1 - if you have no power then the fuseible link has failed....

[6speeder]

update. i fixed the recent problem, got both the eml + cel lights back, both dk's humming again, it was the poorly designed fusible link (the one behind the heat shrink tubing, not the one in the black fuse holder), it worked itself "loose" after i just removed and wire brushed it 2 days ago . i can confirm the eml turns on briefly when turning key to run, the cel lights up and STAYS lit with key to run.

so now im back to my original crank no start issue.

- - - Updated - - -

thanks Timm for your response. been to your site, lots of usefull info there.

[cartoonz]

so now hotwire the two FP fuses and try to start the car.
Does it start and run? Yes/no

[6speeder]

ok so i think i figured out what the issue is, but i would like to hear from some forum members to confirm my theory as to why i had a no fuel situation given the following info.


with the 2 passenger side fuel pump plugs dis-connected (fuel level sender + 2 pumps) i can now confirm the following:

both fuel pump fuses 23 + 24 get zero volts with key in run, but get over 10v while cranking.

both passenger side fuel pumps get the exact same volts as the fuses, 0v at run, over 10v while cranking.

both fuel pumps turn on when i supply 12v to the actual pins (again with the 2 plugs disconnected).

eml turns on briefly with key in run position then goes away.
both dk's hum, both butterflies open with gas petal pressed and key to run.
stomp test reveals no codes 1444 2444.
she fires up (briefly) with starting fluid sprayed in air intakes after the air filters.
all relays, fuses and both fusible links are ok

the NEW info i just learned is with both passenger side fuel pump plugs un-plugged (fuel level sender + 2 pumps) the fuel gauge reads zero and the orange reserve light is lit... when i turn key to run the gauge needle moves up about 1 millimeter from its resting position, and stays there till i take out key. the drivers side fuel level sender is the only input the car is geting during this reading since passenger side is unplugged. the car has a fresh half tank of gas, when i plug both passenger side plugs back in the gauge reads half tank and orange light goes out. based on the issue im having with "no fuel", and now confirming that everything up to and including the dual fuel pumps work there are 2 possible scenarios:

one is a broken drivers side fuel level sender and my no start is from something else but lets assume for this that the sender works and is accurately reporting that the drivers side of the fuel tank is empty because it actually is empty (but the passenger side of the tank where the dual fuel pumps are is pratically full).

given all we now know above whats scenario #2 of why im in a crank but no start, no fuel situation with everything up to and including the dual passenger side pumps working and plenty of fresh gas in the passenger fuel tank.

[cartoonz]

I can't help you if you don't follow direction.
and yeah, just so you know, I do know how to do this...lol

[BMSman]

ok so i think i figured out what the issue is, but i would like to hear from some forum members to confirm my theory as to why i had a no fuel situation given the following info.


with the 2 passenger side fuel pump plugs dis-connected (fuel level sender + 2 pumps) i can now confirm the following:

both fuel pump fuses 23 + 24 get zero volts with key in run, but get over 10v while cranking.

both passenger side fuel pumps get the exact same volts as the fuses, 0v at run, over 10v while cranking.

both fuel pumps turn on when i supply 12v to the actual pins (again with the 2 plugs disconnected).

eml turns on briefly with key in run position then goes away.
both dk's hum, both butterflies open with gas petal pressed and key to run.
stomp test reveals no codes 1444 2444.
she fires up (briefly) with starting fluid sprayed in air intakes after the air filters.
all relays, fuses and both fusible links are ok

the NEW info i just learned is with both passenger side fuel pump plugs un-plugged (fuel level sender + 2 pumps) the fuel gauge reads zero and the orange reserve light is lit... when i turn key to run the gauge needle moves up about 1 millimeter from its resting position, and stays there till i take out key. the drivers side fuel level sender is the only input the car is geting during this reading since passenger side is unplugged. the car has a fresh half tank of gas, when i plug both passenger side plugs back in the gauge reads half tank and orange light goes out. based on the issue im having with "no fuel", and now confirming that everything up to and including the dual fuel pumps work there are 2 possible scenarios:

one is a broken drivers side fuel level sender and my no start is from something else but lets assume for this that the sender works and is accurately reporting that the drivers side of the fuel tank is empty because it actually is empty (but the passenger side of the tank where the dual fuel pumps are is pratically full).

given all we now know above whats scenario #2 of why im in a crank but no start, no fuel situation with everything up to and including the dual passenger side pumps working and plenty of fresh gas in the passenger fuel tank.

You are making this way more complicated than you need to....

Connect 12V to the fuel pump fuses and report back if the car runs?

[Junglenut]

Check if gas is in the tank, a bottom of closed fist medium hit t on the tank should yield a definitive sound.

Fuel pumps humming? That's a good sign!

If gas is in the tank and fuel pumps humming, check the fuel filters.

Try to measure fuel pressure at the fuel rail, a Schrader valve with a metal cap should be somewhere on the rail.

Fuel rail pressure should be about 50psi.

If fuel rail pressure is positive and still not running, check the injectors.

[cartoonz]

Check if gas is in the tank, a bottom of closed fist medium hit t on the tank should yield a definitive sound.

Fuel pumps humming? That's a good sign!

If gas is in the tank and fuel pumps humming, check the fuel filters.

Try to measure fuel pressure at the fuel rail, a Schrader valve with a metal cap should be somewhere on the rail.

Fuel rail pressure should be about 50psi.

If fuel rail pressure is positive and still not running, check the injectors.

You are definitely not helping...

[6speeder]

I cant test if the car will run by applying 12v to the fuel pump fuses because suddenly both fuel pumps will not run when applying 12v, all this testing has killed them. Now im looking at rebuilding them (not replacing) using 2 OEM Bosch pumps but im not sure if I want to spend the time/money on this as I had the crank/no start due to no fuel before the pumps went. so before I rebuild the pumps I need to confirm my original problem was an EASY and NOT TO EXPENSIVE fix. As per my last post since im getting 12v at the fuel pump plug while cranking i have narrowed it down to be fuel supply AFTER the pumps, or fuel return.

possible reasons on the fuel supply side: 2 fuel filters, 2 FPR's, or a clog in the supply hoses/lines (highly unlikely).
possible reasons on fuel return side: charcoal filter, return valve #16131180600, or again a clog in the supply hoses/lines (highly unlikely).

NB: The symptoms point to one of the supply side options as the return should get the her to at least sputter or try to fire.

Are those ALL the possibilities or am i missing something?

Also can someone confirm the return valve is behind the passenger side front wheel well.




Since I want to confirm my original no start issue I am thinking of hooking up a temp tank that supplies pressure. I can use an ac flush can (acting as gas tank), fill it with gas, use shop air to pressurize the can (acting as fuel pump), and attach a fuel pressure gauge after the can and before the fuel lines to make sure I pressurize the tank to the required psi. I think the easiest place to attach it is under the car directly after the fuel filters, if she starts I know my original no start was either the filters, or dying pumps not supplying enough pressure. Question is... would it be OK to do this? And yes i know it should be done behind the engine but I dont want to take the time removing the air box.

[Timm]

I would say that testing the pumps would not have killed them - they are happy to run for hours and hours - so, your problem is very likely that the pumps had simply failed, simple as that!

Blocking the fuel return would increase fuel-rail pressure, and that would mean that squirting starter fluid would just make the situation worse.

[cartoonz]

Ok, so pumps confirmed not to run when powered from fuses.
Replace pumps. Don't waste time and energy with bootleg alternatives, just replace with known good pumps and test again.

[6speeder]

[QUOTE=Timm;29782027]I

would say that testing the pumps would not have killed them - they are happy to run for hours and hours - so, your problem is very likely that the pumps had simply failed, simple as that!

My original crank, no start due to no fuel happened BEFORE my pumps crapped out today.

Blocking the fuel return would increase fuel-rail pressure, and that would mean that squirting starter fluid would just make the situation worse.

I had no intention of blocking the fuel return, or using starter fluid (she already passed the "will start with starter fluid" test).

I was asking if my plan to hook up a temp tank/fuel pump (using real gas) after the 2 filters as described above would be O K. As in... is there anything wrong with doing it/trying it.

[6speeder]

[QUOTE=cartoonz;29782034]

Ok, so pumps confirmed not to run when powered from fuses

.

but they DID work yesterday so "bad pumps" was not what caused the original crank no start issue.

Replace pumps. Don't waste time and energy with bootleg alternatives, just replace with known good pumps and test again.

Takes less than 5 mins, and at zero cost. I have 2 gallons of gas in gas container here, and ac flush can and fuel pressure tester here. I dont even need to jack the car up, i can disconnect the 2 rubber fuel lines that lead to the BOTTOM of the fuel filters behind the rear drivers wheel, attach a T from the 2 lines to the temp tank/pump and inflate to the correct psi, then try to start the car. If she runs i know it was pump or fuel filters or both, if she doesnt i know its FPR's or something on the return line. My question is... would it be OK to do this.

Its alot easier for me and cheaper to rig a temp tank/pump than buying 2 oem pumps at $170 each, then taking an entire day to rebuild and reinstall the fuel pump. And even if I do rebuild it there is no guarantee it would start cause it may be a fuel filter issue which they also cost $50 each + another $100 in oem rubber hoses + clamps (cause I would never replace just the fuel filters themselves).

[cartoonz]

WHY did you come here and ask for help if you're determined to be the smartest guy in the room?
Tip : You're not.
I certainly could have shown you aftermarket pumps for waaay less than you are thinking that are actually upgrades over stock.
I could have shown you exactly how to fix the car.
But no... you had to argue every step of the way.
So, seriously, if you don't actually want help - why ask for it?

I'm out... good luck kid

[6speeder]

WHY did you come here and ask for help if you're determined to be the smartest guy in the room?
Tip : You're not.
I certainly could have shown you aftermarket pumps for waaay less than you are thinking that are actually upgrades over stock.
I could have shown you exactly how to fix the car.
But no... you had to argue every step of the way.
So, seriously, if you don't actually want help - why ask for it?

I'm out... good luck kid

I never said im the smartest guy in the room, but I will say im definitely not the biggest tool in here either,
Tip: You are.
I am a seasoned bmw owner so I already know alot about the aftermarket pumps your talking about from highflowfuel and CNT Racing that sell for cheap but if you listened to anything I said you would already know I am a _PURIST_. And those aftermarket pumps require carrier modification and have been known to overwhelm the FPR's which negates their cheaper price... especially on the early m70 e31 with the different fuel rails which FPRs are $160 each.
I wasnt arguing, I was disagreeing with your elitist, know everything, pompous attitude that you spew here and on virtually every other thread in which you "contribute"... as if we should be honored just to get your comment, and I know this about you because I have owned literally dozens of bmws over the past 30 years and as a seasoned owner Ive been visiting this forum since it started in 2000 and we all notice that you cant help but word vomit on practically every thread.

I clearly pointed out that I have 2 options, rebuild the pump carrier (which will cost at least $400, take 3 days to get parts, another day of my time to rebuild/install... and all that with no guarantee it will fix the problem)

__OR__

take literally SECONDS installing a temp tank/pump, with tools I already have in the garage TODAY, for FREE. To repeat... seconds, tools I have, for free! To everyone rational following this its clear there is only one choice... except to you, which says alot.

I hope you actually stay away from this thread and use your newly found time time TO SEEK HELP because you definitely need it pal. And when you reply to this thread after you claim to have left you will be proving me right. To anyone else who wants to actually help I appreciate it... truly, thanks.

[dragon850]

OMG..... just finished reading all of the posts, you literally made my head hurt, don't take it the wrong way but I need to go take an Advil now. For god's sake this is the fuel pumps were talking about right, not quantum physics?!?!
I think you need to go back and re read the thread yourself, you came here to ask for advice so WHY on earth don't you follow it when given and then talk shit when people get frustrated with you?
Cartoonz has been invaluable to this forum and has helped hundreds of people over the years so save it... He tried to help you but for some reason you could not follow simple directions.
I will try once more:
1) Forget the pressurized bucket experiment.
2) Replace both pumps before you do anything else.
3) If you are a purist you can buy the whole assembly for $600, otherwise here is the link to my thread on FP upgrade, they work fine at 75psi BTW and DO NOT overwhelm stock FPRs...
https://www.bimmerforums.com/forum/s...-Pump-Assembly

OR, how about 5k cash for the car and I will deal with this complex fueling issue