540 troubleshooting MAP vs. mechanical gauge

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10-03-2019 | 04:11 PM

#11

tgorbett

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From: ATL

Quote:

Originally Posted by Trash

It is likely lean. But....do you have the correct MAP sensor? i.e. a 1 Bar sensor and not a 2 Bar?

If your motor is indicating lean try solve that issue first. I don't care if you think you have reversion, put some fuel into the lean spot and see what happens. Trust the wide band until proven otherwise.

Trash,
Yes. 1 Bar MAP sensor. Tried a known good sensor from one of my other spare motors and have virtually identical MAP vacuum readings at idle. Also 2 different ECM’s and both display roughly the same MAP vacuum readings at idle. I don’t have the ability to tune either ECM as my understanding is that they are password protected.

10-03-2019 | 04:30 PM

#12

AllDodge

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From: KY

Quote:

Originally Posted by tgorbett

MEFI wouldn't come password protected unless the folks that reprogramed it did password it. Call and ask
If no password, then just need MEFI Burn

10-03-2019 | 04:38 PM

#13

AllDodge

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From: KY

If they did password it I would *****. You paid money for a specific program for your motor.

If they didn't reprogram it and only said they did, this would put the motor in a real lean condition

10-03-2019 | 05:23 PM

#14

snapmorgan

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From: Cape Coral FL

Have you looked to see if they are password protected? Who did the tune? Bob at Mefiburn knows just about everyone's passwords, he has helped me unlock a couple

10-03-2019 | 06:37 PM

#15

GPM

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From: Pa

Quote:

Originally Posted by tgorbett

Looking at the MAP sensor vacuum reading on a Rinda, should MAP vacuum and the mechanical gauge vacuum match pretty closely?

Yes

10-03-2019 | 06:42 PM

#16

GPM

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From: Pa

Is there a vacuum port on your regulator ?

10-03-2019 | 07:58 PM

#17

tgorbett

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From: ATL

Quote:

Originally Posted by GPM

Is there a vacuum port on your regulator ?

Yes and it is tee’d to the MAP sensor. Have tried capping the side of the tee that goes to the regulator so that only the MAP sensor sees the vacuum. No change.

10-03-2019 | 08:00 PM

#18

tgorbett

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From: ATL

Quote:

Originally Posted by snapmorgan

Have you looked to see if they are password protected? Who did the tune? Bob at Mefiburn knows just about everyone's passwords, he has helped me unlock a couple

Have not looked to see. I do not have the MEFI burn software. That is good information. Thanks.

10-03-2019 | 08:04 PM

#19

GPM

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From: Pa

Quote:

Originally Posted by tgorbett

Yes and it is tee’d to the MAP sensor. Have tried capping the side of the tee that goes to the regulator so that only the MAP sensor sees the vacuum. No change.

Do you set the fuel pressure with or without the vacuum to the Map sensor

10-03-2019 | 08:10 PM

#20

GPM

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From: Pa

Just some thoughts. If this thing just started to run lean, maybe it's an injector failure. Check your plugs and see if you have one white one, or pull the injector plugs one at a time while the motor is running to see if it makes a change.

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