DME testing
09-29-2011, 05:21 PM
#2
Nordschleife Master
Well, it's a relay; and they're plenty simple.
So the Frankenstein-mad-scientist in me says zazzing its coil circuit should change the contact circuit's state.
I recall the schematic was printed on the case of the last DME I held.
A couple leads off a battery carefully applied to the coil circuit should make it 'click'.
Have the contacts' leads connected to a cheapo multimeter. (In case something goes zzz-SNAP.)
Watch to see if the schematic's logic is confirmed by the contact connection state.
Or -- just plugging it in and trying it works, too, I guess.
So the Frankenstein-mad-scientist in me says zazzing its coil circuit should change the contact circuit's state.
I recall the schematic was printed on the case of the last DME I held.
A couple leads off a battery carefully applied to the coil circuit should make it 'click'.
Have the contacts' leads connected to a cheapo multimeter. (In case something goes zzz-SNAP.)
Watch to see if the schematic's logic is confirmed by the contact connection state.
Or -- just plugging it in and trying it works, too, I guess.
09-29-2011, 05:29 PM
#3
Race Car
Thread Starter
Lonnie, my car doesn't start, so the car option not really viable. Trying to diagnose if it's relay, fuel pump, pressure regulator, or something else. What about testing fuel pressure? easiest way to do that?
09-29-2011, 05:38 PM
#4
Assuming this schematic is correct...
If you connect 12V across 86 & 85 and across 87 & 85b, you should get continuity across 30 and 87b.
Does that sound right?
You might be able to trigger it with a 9v battery.
If you connect 12V across 86 & 85 and across 87 & 85b, you should get continuity across 30 and 87b.
Does that sound right?
You might be able to trigger it with a 9v battery.
09-29-2011, 05:43 PM
#5
Race Director
I tested the fuel pump by disconnecting the fuel line after the fuel filter running a tube to a gas can, and having somebody turn on the car. It would be much safer to have an inline pressure sensor than having fuel pump into a container however. I'm trying for a Darwin award!
09-29-2011, 06:58 PM
#6
Seems like I would just put my 3 way jumper in and see if the car will fire and go from there this will at least tell you if the dme relay is the problem right off the bat for the most part..
09-29-2011, 09:17 PM
#7
Race Car
Thread Starter
I tried to find the jumper info and couldn't before. If you have it handy, I'd appreciate it. Pics too, as I'm electrically challenged. i can follow pitchers real good though 
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09-30-2011, 01:24 PM
#8
Nordschleife Master
A jumper can be used to bypass the DME relay
DME Relay Jumper
connect relay sockets 3, 5 and 7
which corresponds to relay pins 30, 87 and 87b.
Usually only used for a test as its constant power; always on (fuel pump!), but I suppose you could drive with the jumper and remove it when you stop? You'd need to ensure sufficient gauge wire.
DME Relay Jumper
connect relay sockets 3, 5 and 7
which corresponds to relay pins 30, 87 and 87b.
Usually only used for a test as its constant power; always on (fuel pump!), but I suppose you could drive with the jumper and remove it when you stop? You'd need to ensure sufficient gauge wire.
09-30-2011, 01:39 PM
#9
Nordschleife Master
Where the dme relay plugs in there are three large and three small , connect the three large with a jumper wire .
http://www.google.com/imgres?q=spade...w=1280&bih=659
http://www.google.com/imgres?q=spade...w=1280&bih=659
