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Home » Public Forums » GMCnet » [GMCnet] Fwd: [GMCMH-EFI] Gerald Downing EFI
[GMCnet] Fwd: [GMCMH-EFI] Gerald Downing EFI [message #325141] Wed, 18 October 2017 17:37
powerjon is currently offline  powerjon   United States
Messages: 2446
Registered: January 2004
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> Begin forwarded message:
>
> From: John Wright
> Subject: Re: [GMCMH-EFI] Re: Gerald Downing EFI
> Date: October 18, 2017 at 4:00:28 PM EDT
> To: gmcmh-efi@googlegroups.com
>
> Ken,
> At 30 to 40 PSIG it is TOO LOW! Needs to be up closer to 50 psig. See my latest post, my guess that the fuel pump might be bad and check the manifold vacuum line from the fuel regulator to the manifold to make sure that it does not have any holes or cracks.
>
> JR Wright
>
>
>
>> On Oct 18, 2017, at 3:21 PM, Ken H. wrote:
>>
>> Afternoon report:
>>
>> I was not successful getting the wide band Innovate LC-1 working -- seems I need a special adapter to connect to a tailpipe & I don't have it. So, I hot wired the heater in the O2 sensor, plugged in a millivoltmeter, and ran the engine. With the engine running roughly, the voltage never stabilized, but it did increase from >
>> HELP!!! :-)
>>
>> Ken H.
>>
>>
>> On Wednesday, October 18, 2017 at 12:11:27 PM UTC-4, Ken H. wrote:
>> Bruce,
>>
>> The throttle body is a two-port Bendix. I SUSPECT from a Saville, but since we know nothing about the system other than that it was on the coach when Gerald bought it two years ago, I can't be sure. The extruded aluminum fuel rails, visible in the photo, do not look OEM to me.
>>
>> The ECU is a box about the size of a 1227747, but not the same configuration; this one has a simple flat cap with 1/4" or so flanges over the basic box. On that lid, there's a fancy large lettered "Digital Fuel Injection" label. Below that in smaller letters (still 1/2"+) it says "Electronic Control Module". Not other labels that I've seen. On one end there are two large blue connectors, about like those on my 1227747, though I haven't counted the number of pins in them. Does that sound like the ECU's you rebuild?
>>
>> We have not checked the chain; without having experience with loose ones, I didn't expect this kind of symptoms; we'll check it after lunch.
>>
>> We've disconnected the O2 sensor and found that the engine runs at idle and in gear under a little load runs about the same or slightly worse than when it was connected. I'll check the output voltage after lunch. Problem with it is that it's so rusted into the bung that an open end wrench won't turn it. The connector on it's too big to use a closed end wrench. I won't be surprised if the sensor breaks off when we get a box end on it -- or the sorrily welded bung breaks out. The system's obviously been installed a LONG time. If the voltage looks OK, I won't risk trying to remove it. Problem is, it's 'way down the headers so probably won't get hot enough to react without jumpering the heater into operation. I'll try to do that too.
>>
>> I've got an Innovate wide band unit that I haven't used in years. I'll try to get it working for testing the mixture, but right now I have the impression that it's running very rich.
>>
>> Any other ideas appreciated. I'll report results later.
>>
>> Ken H.
>>


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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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