968Forums.com

[quote name='Cloud9...68' timestamp='1357570972' post='137107']

Ten bucks, huh? I would do it for that, but I haven't been able to find any heating pads for under $60. I went ahead and aimed a pair of space heaters at my oil pan for a few hours yesterday, and according to my oil temp gauge, got the oil up to 155 deg. Unfortunately, the engine start was a no-go. Not hearing the fuel pump whine, so it's got to be either the DME relay (I have two of them and the fuel pump doesn't make any sound with either of them in place, but that doesn't necessarily rule out the DME relay), or the pump itself. I knew starting an engine that's been disassembled/sitting for nearly two years wouldn't be straightforward...

[/quote]



Does anyone know if there is a way to just short out a link (on my Mazda there is one in the diagnostics link) to bypass everything and supply power to the fuel pump. If there it such a tap in the diagnostics link, it would be an easy way to make sure the pump will run if powered.

I believe you can jumper either the relay or just a couple fuses to get the fuel pump running. The <acronym title='previous owner'>PO</acronym>(S) had a jumper from the daytime running lights fuse to the fuel pump fuse. The pump would run as soon as you turned the key.

[quote name='MB968' timestamp='1357608324' post='137141']

Does anyone know if there is a way to just short out a link (on my Mazda there is one in the diagnostics link) to bypass everything and supply power to the fuel pump. If there it such a tap in the diagnostics link, it would be an easy way to make sure the pump will run if powered.

[/quote]

Yes - Go to clark's garage's web site:



http://www.clarks-garage.com/



and under site search, enter "DME relay" (not sure why I can't link to this directly). This brings up an excellent description of how the DME relay works, and how to jumper its connectors to energize the fuel pump. You have to make a three-lead jumper with male spade connectors at the ends, and connect the three leads to terminals 87, 87b, and 30 of the DME relay's connectors. Worked like a charm - I plan to keep this jumper in my glove box for emergencies. Many thanks to Lear35A for bringing this to my attention when my fuel pump wasn't turning on when I turned my key to the start position.

Cloud, did you finally get it started?

I tried on Sunday, but it cranked and cranked, and wouldn't fire. Then I noticed the fuel pump wasn't making any sound, so Lear35A recommended I jumper the DME relay's connections, as described above, which I did last night, and the fuel pump turned right on (meaning both of my DME relays are bad!). So, the plan is to try firing it up tonight. Fingers all crossed...

check the DME relay fuse

[quote name='flash' timestamp='1357670565' post='137174']

check the DME relay fuse

[/quote]

I checked the fuse box for any relays that from their description were in any way related to the fuel system, and all were OK. Is this what you mean, or some sort of fuse in the relay itself? I know there's a diode in the relay which is prone to failure, but I don't know of a fuse. I will also follow the procedure outlined in Clark's Garage on how to test my relays (I have two, neither of which seems to be working). But when I jumper the relay's connections as Clark's Garage describes, the fuel pump comes on immediately, which at least puts me in a position to try firing up my engine to check for obvious problems, like noises that shouldn't be there, and leaks.

#7

I carry those DME relay jumpers permanently with me along with a new relay. Paranoid.

[quote name='DaveN' timestamp='1357676972' post='137190']

I carry those DME relay jumpers permanently with me along with a new relay. Paranoid.

[/quote]

Planning to do the same. From my recent experience, the jumpers appear to be more reliable than the relays.