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E34 (1989 - 1995)

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  #1  
Old 10-15-2011, 03:53 PM
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daily is dead

hmm still its not getting fuel into the cylinders for some reason, and cant figure out why!
have replaced fuel pump, relay, Crank position sensor, intake boot and the MAF (incase it was an air issue). fuses look fine

definately getting spark, and compression is fine

anyone have any other things to look at? i realy need the car back asap! thanks in advance
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  #2  
Old 10-15-2011, 04:01 PM
ThoreauHD ThoreauHD is offline
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Assuming you replaced the fuel filters as well?
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  #3  
Old 10-15-2011, 04:39 PM
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yep
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  #4  
Old 10-15-2011, 11:17 PM
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I would check the red wire connections under the main relay. Also the two ground nuts above ecm. The ECM controls the injectors. possible problem with ECM. I have had injectors clog up from sitting a long time on one ,but don't think that your problem. does your car stomp test/self diagnostic .? check that the small hose to fuel regulator at rear fuel rail to brake booster pump is attached. I would do a fuel pressure test for 45 psi. You said the fuses look good ,but have you used a continuity tester on each one? and my personal favorite the 1" air hose from under the manifold to idle control valve some times comes loose.
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  #5  
Old 10-16-2011, 02:33 AM
robertobaggio20 robertobaggio20 is offline
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Quote:
Originally Posted by Ethrty View Post
hmm still its not getting fuel into the cylinders for some reason, and cant figure out why!
have replaced fuel pump, relay, Crank position sensor, intake boot and the MAF (incase it was an air issue). fuses look fine

definately getting spark, and compression is fine

anyone have any other things to look at? i realy need the car back asap! thanks in advance
I suspect that your fuse is getting repeatedly blown. This is if your cps is actually working fine (i.e. you are sure you're getting spark).

Why don't you jump the fuel pump relay directly and then try to start your engine? That will bypass the fuse box. The bentley manual will have instructions on how to do this. Furthermore, the relay itself, on its side, will show you which points need to be connected for the circuit to get closed (it will show you which points constitute the open circuit, you just need to connect those with a fused wire directly, do this before turning the car on if not there will be a spark).


And I assume you've looked at your spark plugs too (since you did the compression test) and they check out ok.

No start situations are (by now, after much painful experience) fairly easy to troubleshoot and deal with.
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  #6  
Old 10-16-2011, 10:56 PM
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got it sorted

the only consequence for a faulty cps is the injectors not firing. there is still spark. however i discovered that i had someone swapped the fuel lines over at the fuel pump, switched them over and started right up. is definately the CPS that was to blame though..
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  #7  
Old 10-16-2011, 11:51 PM
robertobaggio20 robertobaggio20 is offline
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Originally Posted by Ethrty View Post
got it sorted

the only consequence for a faulty cps is the injectors not firing. there is still spark. however i discovered that i had someone swapped the fuel lines over at the fuel pump, switched them over and started right up. is definately the CPS that was to blame though..
Never underestimate the trouble that simple gentle attentiveness can save you. And never underestimate the inconceivable problems that can be created by rushing through a job, or by doing repairs while being irritated or under tension.

And Ethrty, your method is exact and all should take note (even those who are seasoned, we all need reminders from time to time). If you've done everything that you ought to do, and the problem has not been fixed, then its likely that something that you did was not done right the first time. Double check.


rgds,
Roberto
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  #8  
Old 10-17-2011, 12:10 AM
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Quote:
Originally Posted by robertobaggio20 View Post
Never underestimate the trouble that simple gentle attentiveness can save you. And never underestimate the inconceivable problems that can be created by rushing through a job, or by doing repairs while being irritated or under tension.

And Ethrty, your method is exact and all should take note (even those who are seasoned, we all need reminders from time to time). If you've done everything that you ought to do, and the problem has not been fixed, then its likely that something that you did was not done right the first time. Double check.


rgds,
Roberto
very true. actually what happened is that i took the two fuel hoses off the pump and set them aside. they didnt seem to move. then i did the fuel filter and pulled the hose through and replaced that poking it back up. the feed was then shorter than the return and seemed to only fit the return. blonde moment, always check!
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  #9  
Old 10-17-2011, 05:39 AM
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BMR_LVR BMR_LVR is offline
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Quote:
Originally Posted by Ethrty View Post
got it sorted

the only consequence for a faulty cps is the injectors not firing. there is still spark. however i discovered that i had someone swapped the fuel lines over at the fuel pump, switched them over and started right up. is definately the CPS that was to blame though..
I'm not sure I quite agree with the first sentence in the statement. If the DME does not get a signal from the faulty CPS, it will not send the signal to the coils to spark and there will be no signal to the injectors to pulse, or to the fuel pump to energize for that matter.

If I understand your situation correctly, you had a no start situation. You replaced fuel pump, fuel pump relay, crank position sensor, intake boot and the MAF (incase it was an air issue) and your fuses looked fine. The car would not crank still. At this point you had spark, but no fuel to the engine. Once you realized your mistake about switching the fuel lines at the pump and corrected it, the car started.

My hypothesis of this is, originally, you likely had a failed CPS which meant no spark and no fuel. After you replaced all of the items, the car would have run if you had not made the innocent mistake of switching the fuel lines.

So, before you discovered your error (but after you had replaced the CPS), you were getting spark and the injectors were indeed firing, there just was no fuel at the injectors because of the switched fuel lines.

Anyway, that seemed as clear as muddy water, but ultimately, the point I am trying to get across is that a failed CPS will not trigger a spark (as a functioning CPS would), but at the same time, keep the injectors from firing. All the CPS does is send an electrical pulse signal the DME to tell it where the crankshaft is in its rotation. That way, the DME knows when to generate the spark at the coils and when to tell the injectors to fire. It either sends the pulse or it does not. It usually fails completely, all at once. There are some rare occasions where it will fail a little slowly and give some poor running conditions.

It is of course possible that I am wrong, but I donít think I am.

Steve
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It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

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  #10  
Old 10-17-2011, 07:00 AM
robertobaggio20 robertobaggio20 is offline
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Originally Posted by BMR_LVR View Post

It is of course possible that I am wrong, but I donít think I am.

Steve
The ghost is never wrong. !
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  #11  
Old 10-17-2011, 08:19 AM
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BMR_LVR BMR_LVR is offline
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Originally Posted by robertobaggio20 View Post
The ghost is never wrong. !
Au contraire mon ami

Steve
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Most problems are usually something simple !

Quote:
Originally Posted by noego View Post
It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

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  #12  
Old 10-17-2011, 04:37 PM
robertobaggio20 robertobaggio20 is offline
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Au contraire mon ami

Steve
The ghost speaks french !! lololol
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  #13  
Old 10-17-2011, 04:42 PM
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_Ethrty-Andy_ _Ethrty-Andy_ is offline
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Quote:
Originally Posted by BMR_LVR View Post
I'm not sure I quite agree with the first sentence in the statement. If the DME does not get a signal from the faulty CPS, it will not send the signal to the coils to spark and there will be no signal to the injectors to pulse, or to the fuel pump to energize for that matter.

If I understand your situation correctly, you had a no start situation. You replaced fuel pump, fuel pump relay, crank position sensor, intake boot and the MAF (incase it was an air issue) and your fuses looked fine. The car would not crank still. At this point you had spark, but no fuel to the engine. Once you realized your mistake about switching the fuel lines at the pump and corrected it, the car started.

My hypothesis of this is, originally, you likely had a failed CPS which meant no spark and no fuel. After you replaced all of the items, the car would have run if you had not made the innocent mistake of switching the fuel lines.

So, before you discovered your error (but after you had replaced the CPS), you were getting spark and the injectors were indeed firing, there just was no fuel at the injectors because of the switched fuel lines.

Anyway, that seemed as clear as muddy water, but ultimately, the point I am trying to get across is that a failed CPS will not trigger a spark (as a functioning CPS would), but at the same time, keep the injectors from firing. All the CPS does is send an electrical pulse signal the DME to tell it where the crankshaft is in its rotation. That way, the DME knows when to generate the spark at the coils and when to tell the injectors to fire. It either sends the pulse or it does not. It usually fails completely, all at once. There are some rare occasions where it will fail a little slowly and give some poor running conditions.

It is of course possible that I am wrong, but I don't think I am.

Steve
well i had spark but no injectors. after talking with a fried he said that it almost always a faulty CPS. in any case its fixed now!

can you think of any other component that would cause spark but no fuel (but fuel pump working, just not injectors)
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Last edited by _Ethrty-Andy_; 10-17-2011 at 04:43 PM.
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  #14  
Old 10-17-2011, 05:27 PM
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BMR_LVR BMR_LVR is offline
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Quote:
Originally Posted by Ethrty View Post
well i had spark but no injectors. after talking with a fried he said that it almost always a faulty CPS. in any case its fixed now!

can you think of any other component that would cause spark but no fuel (but fuel pump working, just not injectors)
I'm certainly glad it is running now. The only other component that I can think of that could cause positive spark in the presence of no fuel injector firing would be the DME. Hopefully thatís not the case. But, if it is, used red label DMEís are not very expensive and are super easy to replace on the E34.

Steve
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Most problems are usually something simple !

Quote:
Originally Posted by noego View Post
It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

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  #15  
Old 10-17-2011, 07:51 PM
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_Ethrty-Andy_ _Ethrty-Andy_ is offline
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Quote:
Originally Posted by BMR_LVR View Post
I'm certainly glad it is running now. The only other component that I can think of that could cause positive spark in the presence of no fuel injector firing would be the DME. Hopefully thatís not the case. But, if it is, used red label DMEís are not very expensive and are super easy to replace on the E34.

Steve
the red label isnt available in NZ, thats for USA cars, but yes i knew that. i am going to replace that next. the car runs and goes 95% perfect, but there are still occassions where it cuts out. everything in my fuel system has been replaced in the past week, the only thing left is the ECU so thats next. but at least i can get to work etc now!
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