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Old 11-30-2015, 02:47 PM   #1
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Default Fuel pump shuts off at low RPM

New to MS3X, here is the problem I have:

When trying to set the idle (tried with AFR from 11-15, on ID1000's) it sounds really good until I get to 850 RPM, then I can hear what I believe is the fuel pump relay, click, then instantly the engine dies. Its not like the idle is too low, and it stumbled to dead, but it is actually idling very steady, and if I go 1 RPM below 850, I hear the click and it dies.

This happens on both open and closed loop idle.
Any Ideas?

Last edited by ryansmoneypit; 12-01-2015 at 08:47 AM.
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Old 12-01-2015, 11:52 AM   #2
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Just thrusting in the dark here but the ecu cuts the fuel pump if the engine isn't running (in case of accident). Perhaps your setting rpm for changing from "crank" to "run" is at 850rpm? Just a guess of where to start since no one else if jumping in. Check your cranking settings.
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Old 12-01-2015, 12:24 PM   #3
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Quote:
Originally Posted by sixshooter View Post
Just thrusting in the dark here but the ecu cuts the fuel pump if the engine isn't running (in case of accident). Perhaps your setting rpm for changing from "crank" to "run" is at 850rpm? Just a guess of where to start since no one else if jumping in. Check your cranking settings.
Great thrust. I'll check that tonight!
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Old 12-02-2015, 09:15 AM   #4
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Nope. Was set to 300 rpm crank to run.
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Old 12-02-2015, 11:45 AM   #5
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Does it instantly die, or does it cough and stumble?
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Old 12-02-2015, 11:47 AM   #6
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Does it instantly die, or does it cough and stumble?
Dies instantly.

Low idle, low idle, click, dead. Low like 850, which doesn't seem that low to me.
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Old 12-02-2015, 12:21 PM   #7
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Can you post an MSQ and a data log of the problem?
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Old 12-02-2015, 12:26 PM   #8
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I will tonight.
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Old 12-02-2015, 03:18 PM   #9
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The last time you sent me a log, I told you YOU HAVE A SYNC ISSUE.

If you still have a sync issue, then you still have to fix that.
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Old 12-02-2015, 03:29 PM   #10
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Crap, you're right. I thought it was just related to my wrong ignition setting. I will try and figure out this sync issue tonight.
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Old 12-02-2015, 03:36 PM   #11
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If it dies instantly, it's not the fuel pump.
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Old 12-02-2015, 05:04 PM   #12
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Quote:
Originally Posted by ryansmoneypit View Post
Crap, you're right. I thought it was just related to my wrong ignition setting. I will try and figure out this sync issue tonight.
Try what I already told you. Or try adjusting the pots on the MS3X. There is a method to adjusting them, and it may be the cause of your problem.
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Old 12-02-2015, 08:35 PM   #13
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I captured a tooth log, but without understanding what I am looking at or for, I am sure not going to start tuning ***** inside the ms. can someone help me decipher? this is a 32-2 wheel

One tooth log and one big LOG.

I accidentally ate my bridge last year and had a toothy log. Hurts.

[ATTACH]2015-12-02_18.49.55.msl wednesday night.msl[/ATTACH]
Attached Files
File Type: csv 2015-12-02_19.13.12.csv wednesdat tooth.csv (66.5 KB, 30 views)
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Old 12-02-2015, 09:04 PM   #14
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I think it was the fuel map and injector settings.
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Old 12-02-2015, 09:06 PM   #15
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So what about the tooth log? Normal, abnormal?
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Old 12-02-2015, 09:19 PM   #16
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Quote:
Originally Posted by ryansmoneypit View Post
So what about the tooth log? Normal, abnormal?
You need to do a composite lot, not just a tooth log.

But the last composite log you sent me showed the cam sensor dropping out as per the picture/description I gave you, and it reported lost sync reason 2. Will post picture here too.

The .msl log you just posted shows you lost sync EIGHT TIMES and each time was reason 2.

Still the same.

Previous pic I sent you, same issue then as you have now.
Attached Thumbnails
Fuel pump shuts off at low RPM-sync_zpsuhoh3v7w.png  
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Old 12-02-2015, 09:27 PM   #17
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Heah, it happens under 1000 rpm.
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Old 12-02-2015, 09:28 PM   #18
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New stuff coming soon.
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Old 12-03-2015, 10:51 AM   #19
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You are sometimes getting a noise pulse in the gap on the crank trigger. I see one such event in frame 12 of the tooth log. If this were a VR sensor, I'd say try running a 10K resistor inline with the crank sensor.
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Old 12-03-2015, 04:44 PM   #20
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When viewed with the composite log, using this 36-2 wheel, should I be seeing TWO long lines, representing the two missing teeth? I'm wondering if maybe the signal voltage is justadjusted too low?
I ask because I see 1 long one, 1 that is much shorter right next to it, then the bar.

Last edited by ryansmoneypit; 12-04-2015 at 12:49 PM.
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