"Matt Ion" <soundy@moltenimage.com> wrote in message
news:PXcFg.419370$Mn5.171051@pd7tw3no...
> TeGGeR® wrote:
>> Matt Ion <soundy@moltenimage.com> wrote in
>> news:v3REg.410737$iF6.53449@pd7tw2no:
>>>TeGGeR® wrote:
>>>
>>>>Matt Ion <soundy@moltenimage.com> wrote in
>>>>news:vINEg.420523$IK3.280117@pd7tw1no:
>>>>
>>>>
>>>>
>>>>>He's GOT a Haynes manual for this thing, which he can't find... i'm
>>>>>SO much more useful with a good wiring schematic in front of me
>>>>>
>>>>
>>>>
>>>>Click Auto Repair Reference Center from the menu at left.
>>>>Navigate to your car. There are wiring diagrams.
>>>
>>>Sweet, thanks!
>>>
>>>Meanwhile... he's determined there's no power to the injectors. Ground
>>>is good, but no signal into them. Waiting to see if he'll actually
>>>bother to check the ECM codes (I sent him the link from your FAQ).
>>>
>>
>>
>>
>>
>> Power to the injectors is from the line that comes from Terminal 7 of the
>> Main Relay. The fuel pump and the injectors receive power from the same
>> basic source, so the trouble is probably a disconnected wire between the
>> Main Relay and the injector harness.
>
> Well, I actually got my hands on the car this afternoon and, with the help
> of the schematic (you ARE the man!), I think I found the source of the
> problem: the fuel pump is for some reason sinking TONS of current and
> causing the voltage throughout the car to drop excessively.
>
> Specifically: checking voltage at the injectors, I get only about 8.5V
> while they're activated, and closer to 5.5V when cranking. Voltage *at
> the battery* drops from about 12V to just barely over 8V for a few seconds
> as soon as the key is switched to Ignition, then jumps back up to 12V,
> nicely coinciding with the brief time the main relay switches on the pump
> and injectors. Connecting jumper cables to my running car, thus providing
> 14V to the system, allowed the car to ALMOST start as system voltage
> dropped to about 9.5V with ignition on, and 8.5V while cranking - it tried
> to catch a few times, but just couldn't quite fire up.
>
> After a little more tracing, I ruled out the injectors and internal wiring
> problems... looking at the schematic, there are only three things on that
> circuit - the two injectors and the fuel pump - so I figured either there
> was a "near-short" somewhere in its wire (a dead short would have blown
> the fuse), or the pump was having issues... as it turned out, unplugging
> the pump lead got rid of the strange voltage drop.
>
> So I'm thinking the pump probably has bad bearings or sleeves, or is badly
> gummed up, or in some other way is being prevented from turning freely,
> and thus is drawing excessive current, enough to drop the system voltage
> too low to operate the ECM and/or injectors, but not enough to pop the
> related fuse.
>
> Lordco was closed by this time, so my buddy's gonna pick up a new fuel
> pump tomorrow... but he'll be installing it on his own, as I'll be down at
> the football game!
>
> Hopefully that takes care of things... I'll let you know!

Say... you don't have a bunch of voltage between the engine block and the
chassis, do you? I'm just wondering how the fuel pump can drop the voltage
so much without blowing the fuse.

Mike