E38 computer fuel cut, why?

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Apr 18, 2025 | 02:54 PM

Greasy Gabe

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E38 computer fuel cut, why?

Im trying to fire up this lc9 5.3 on my stand, but the ECM is not sending ground to my injectors, I’ve determined that something it cutting the fuel. My BARO is reading at 27 and the MAP is at 36, I also have code p0108, this is the only thing that could possibly be cutting my fuel as I have already gone through every other possibility. I tried a different sensor and still not luck WTH, someone please help.

Apr 20, 2025 | 07:11 PM

Bbknucks

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P0108 is map signal high...

What does it read unplugged?

Stock harness?

Apr 21, 2025 | 02:45 PM

Greasy Gabe

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Quote:

Originally Posted by Bbknucks

P0108 is map signal high...

What does it read unplugged?

Stock harness?

It’s an aftermarket harness I checked the wiring, when it’s unplugged I get p0107 and p0108

Apr 21, 2025 | 03:05 PM

Bbknucks

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What does the map data read unplugged?

Apr 21, 2025 | 03:08 PM

Greasy Gabe

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Quote:

Originally Posted by Bbknucks

What does the map data read unplugged?

I’m not sure I’ll have to check when I get home, before I go chasing this any further I’d really like to know if the p0108 code is what is causing my fuel cut

Apr 21, 2025 | 05:42 PM

Bbknucks

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What harness are you using?

Apr 21, 2025 | 06:58 PM

Greasy Gabe

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Quote:

Originally Posted by Bbknucks

What harness are you using?

just an eBay harness like I said I checked the wiring, it’s all good so it’s not a wiring issue, I just need to know if this code is what’s causing the fuel cut.

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Apr 21, 2025 | 09:21 PM

Greasy Gabe

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Quote:

Originally Posted by Bbknucks

That code will not cause a fuel cut

The problem causing the code might..

If one of the sensors is pinned wrong it could bring down the 5v line causing an issue with any sensors on it

I’m going to verify at work tomorrow that that code won’t cause a fuel cut, but if it’s not my reason for the fuel cut then I’m not too concerned about it right now, I’m mostly concerned with the cause of my fuel cut. I’ve checked over everything with my tuner and we can’t seem to find a cause for my fuel cut besides this p0108 code.

Apr 23, 2025 | 06:19 AM

#10

Greasy Gabe

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Quote:

Originally Posted by Bbknucks

That code will not cause a fuel cut

The problem causing the code might..

If one of the sensors is pinned wrong it could bring down the 5v line causing an issue with any sensors on it

ok so I verified that, that codes is not responsible to my no start, you were correct. The pinning is correct and the ECM is receiving 4.7v. So I’m assuming because that code is in pending that it will leave once I fire this thing up. Side note, did some searching around some HPtuner forums and found a couple other possibilities to my no start. I found that you need to disable starter checks in the tune, so at some point hopefully this week my tuner is going to come and disable starter checks. And then we will see what that does. Also apparently there’s something you have to do with VATS with it being a Manuel swap. So I might have to look more into that.