DIY_EFI Digest        Saturday, August 21 1999        Volume 04 : Number 480



In this issue:

	From digest: 2732 eprom changed caused SES light
	Re: DIY_EFI Digest V4 #479

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Date: Sat, 21 Aug 1999 08:53:33 EDT
From: ECMnut@xxx.com
Subject: From digest: 2732 eprom changed caused SES light

Hi Mike,
you didn't specifically mention changing the checksun.
Making the mods you've described, and ignoring
it colud cause the SES light.
Mike V
> 
>  I tried programming a 2732 eprom for my 1226870 ecm. I used gmedit to do 
it. 
> 
>  Everything checked out ok on the programmer. All I changed was the cooling 
>  fan temps and idle speed. I plugged it in and the car will start and run 
>  fine. The problem is that the SES light flickers very quickly. If I plug 
my 
>  scanner into the ALDL the flicker goes away even after unplugging it, but 
>  once I shut down the engine and restart it the flicker returns. 
>  
>  Am I using the wrong speed eprom? 
>  Does it matter if it's a 2732, 2732a, 2732b, or 27c32?
>  
>  Any suggestions or comments appreciated. I don't want to test drive the 
car 
>  until I am sure I it isn't going to melt.
>  
>  Mike Poore

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Date: Sat, 21 Aug 1999 07:09:47 -0600
From: bearbvd@xxx.net (Greg Hermann)
Subject: Re: DIY_EFI Digest V4 #479

>I think the simple answer to this question is  a fuel pump is designed to
>pump against head pressure.   In other words push fuel.  Fuel injection
>pumps are not engineered to act as a suction type device.  Therefore,
>restrictions on the inlet side must be kept to a minimum.  This is why the
>pump must always be at or below the fuel supply level to insure the pump
>never runs dry.
>
>If the fuel filter begins to restrict the flow of fuel and the pump runs
>dry it will fail.
>
If you look up and under stand the concept of minimum required NPSH--Net
Positive Suction Head--as one of a pump's performance
characteristics--either in a (good) thorough industrial pump catalogue or
in agood, practically oriented, fluids testbook, you will have gone a long
way toward understanding what is going on here.

A fuel pump has operational problems similar to those faced by a condensate
well pump (in a steam power plant), although not quite so demanding.

Regards, Greg

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End of DIY_EFI Digest V4 #480
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