Author Topic: Help!! Car won't start!  (Read 7003 times)

mk2vr6

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Help!! Car won't start!
« Reply #15 on: January 04, 2010, 01:43:07 PM »
CPS is as close as I can possibly get it to the trigger wheel without grinding down the bracket that holds it, which would be just ridiculous.  

It has to be something else, it measured at 814 ohms at the plug.  The fuel pump fuse (7.5A as stated in the manual) is good.  I will try replacing the new relay with the old one JIC, but if that's not it, I think it might be time to just suck it up and tow it to the stealership.  I have to be back to school in less than a week and I don't know what else to do.

RED IS 91

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Help!! Car won't start!
« Reply #16 on: January 04, 2010, 04:57:27 PM »
Quote from: mk2vr6;84019
CPS is as close as I can possibly get it to the trigger wheel without grinding down the bracket that holds it, which would be just ridiculous.  

It has to be something else, it measured at 814 ohms at the plug.  The fuel pump fuse (7.5A as stated in the manual) is good.  I will try replacing the new relay with the old one JIC, but if that's not it, I think it might be time to just suck it up and tow it to the stealership.  I have to be back to school in less than a week and I don't know what else to do.

814 ohms seems  too high for the crank sensor. What did your original sensor ohm out at ?
« Last Edit: January 04, 2010, 05:08:56 PM by RED IS 91 »
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mk2vr6

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« Reply #17 on: January 04, 2010, 05:25:29 PM »
Quote from: RED IS 91;84035
814 ohms seems  too high for the crank sensor. What did your original sensor ohm out at ?


Original came in at 498.  

I read that it shouldn't be below 550.  I didn't hear about an upper range.

DesktopDave

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Help!! Car won't start!
« Reply #18 on: January 04, 2010, 05:29:18 PM »
Quote from: mk2vr6;84018
Ok.

The fuel pump does turn on when terminal 30 & 87 are jumped.  So that means the wiring and plug are ok.

I am going to reinstall the CPS and see if that helps.  Maybe it is too far from the wheel.  

Otherwise I am really at a loss, what else could possibly be wrong?

When I turn the key, there is nothing from the fuel pump.  Does the ECU need to receive a signal then? Or is it only when cranking.  I will check the resistance of the CPS again just to be sure.

When the DME gets a signal from the CPS, it powers up the FP relay.  It's a safety feature...so that a non-running engine won't receive fuel.  In most cases that's a good thing, but in our cars it makes the CPS a critical part.  If the DME doesn't sense the crank trigger signal, the car will not start.  It also won't set a code!

I still suspect your relay is dead or even the wrong part...they have diode & resistor relays that'll fit but not function properly.  Either that or the CPS isn't right or you have the cam & crank sensors swapped...

Closer to the trigger wheel is best from what I've heard.  At least you know the fuel pump is OK!  That's the expensive one...
« Last Edit: January 04, 2010, 05:32:11 PM by DesktopDave »
'08 Karmesinrot 128i 6MT
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mk2vr6

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Help!! Car won't start!
« Reply #19 on: January 04, 2010, 05:39:46 PM »
Quote from: DesktopDave;84041
When the DME gets a signal from the CPS, it powers up the FP relay.  It's a safety feature...so that a non-running engine won't receive fuel.  In most cases that's a good thing, but in our cars it makes the CPS a critical part.  If the DME doesn't sense the crank trigger signal, the car will not start.  It also won't set a code!

I still suspect your relay is dead or even the wrong part...they have diode & resistor relays that'll fit but not function properly.  Either that or the CPS isn't right or you have the cam & crank sensors swapped...

Closer to the trigger wheel is best from what I've heard.  At least you know the fuel pump is OK!  That's the expensive one...


Amen on the fuel pump!

I put in the old relay just to check as well as the new one, the PN off the new one matches up as best as I can tell.  

I can say for certain the CPS/CMS are ok and in the correct spots.

The only thing I guess I'm not positive about is whether the CPS is good.  I measured it at the plug so I know it works but maybe 814 is too high?

RED IS 91

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Help!! Car won't start!
« Reply #20 on: January 04, 2010, 07:12:44 PM »
1) extra crank ps = 500 ohms
2) crank ps in good running car = 525 ohms

I copied this from the other thread when I thought I had sensor problems.
My old (extra) was 500 ohms.
My new one was 525. I remember testing it right out of the box.
I'm not saying yours is no good it just seems high .Is there anyone else on this board who has testing there crank PS and can post???
When you turn your key on do you hear the relay click ?

Good luck
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mk2vr6

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Help!! Car won't start!
« Reply #21 on: January 11, 2010, 09:55:35 PM »
I figured I'd update this thread because this experience provided a bit of valuable info.

First off, I need multimeter lessons.

Secondly, my first hunch was right.

I just got the car back from the dealer (ouch.), it was the fuel pump.

The replacement pump that I purchased at autozone (Airtek IIRC) was faulty.  My replacement/soldering job was fine, dealer reported that the pump did receive power, but it wouldn't pump, leading me down the CPS/relay road.

I could have sworn I used the multimeter to measure the plug properly, but reality states otherwise.

So to sum up:

1.  New fuel pumps aren't always good.
2.  814 Ohms isn't too high of a reading for a new crank sensor as my car runs perfectly now.
3.  Learn to use a multimeter to measure things other than resistance.

DesktopDave

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Help!! Car won't start!
« Reply #22 on: January 12, 2010, 07:10:05 AM »
I'm glad you got it sorted.  Sorry I wasn't 100% on the troubleshooting...I'll file that away for future reference.

Good lessons; I'll be doing some of the same myself with the low speed coolant fan...car's overheating a bit now & again.
'08 Karmesinrot 128i 6MT
'86 Zinnoberrot 635CSi (M30B32/G265/3.46 torsen LSD)

Sold: '97 Montrealblau 318iS, '91 Brilliantrot 318i, '91 Brilliantrot 318iS