peanut

the voltage at T86 on the DME relay socket should be checked with the DME relay removed .

If the feed to 86 does go through the factory alarm then yes it will need to be bypassed in the connector .Alternatively the op could simply run a tempoary bypass wire from the battery12v+ to T86 on the DME relay .

if he fits a 3x wire DME bypass the alarm connection would be irrelevant . I am curious as to why he has a voltage on T87 with no voltage on 86 ? also as you sayhe shouldn't have 12v+ to the injectors unless the second DME relay is energised.
Something doesn't add up here ?

Adker

You use small (22-28) solid wire and strip back about 1/2 inch of insulation. Bend the wire at a right angle were the bare wire meets the insulation. Place the bare wire in the terminal socket and plug in the relay. Measure the voltage on the other end of the wire.

Agreed, no voltage on 86 mean the DME relay is off so no voltage on 87. That also means no voltage to the injectors. Also, terminal 87 should be 12VDC....with the relay plugged in.

Power to the injectors comes from the first DME relay terminal 87. The fuel pump and O2 sensor are on the second DME relay, terminal 87b. The second DME relay is controlled by the DME (85b) which allows the DME to cut the fuel pump if the motor RPM drop below 400RPM to stop the fuel pump in a crash.

peanut

yes 85 should be at 12v+ but only if it is earthed and 86 is receiving 12v+ which it apparently isn't ?

Obviously the best step now is to either run a bypass from the battery + to DME relay socket 86 and try and start the car or fit the 3x wire bypass .

I'm off to hit the sack so its up to you now Adker .

stogie25

I will try the jumpers when I get back home. Thanks.

I did the voltage checks with the relay out.

Adker

With the relay out you can only check pins 30 and 86. With the ignition on they should both be 12VDC. Jumping the DME relay sounds like a good plan...good luck.

stogie25

I was following this diagram, and checking the wrong relay.
http://www.944online.com/cgi-bin/for...num=1294677603

Using this diagram I checked the correct relay.
http://www.clarks-garage.com/shop-manual/fuel-05.htm

Sorry about the confusion. I still plan to make a jumper tomorrow.

Checking the correct relay I found these results:
12v at 30 with ignition off = YES
85 nothing, 86 nothing, 87 nothing with ignition on
85 is not ground with ignition on or off.
The under dash brown wires all check to ground.
No tach bounce.
No spark.

peanut

Ah ! that makes more sense. well spotted

If you fit the 3x wire bypass in place of the DME relay the car should start or at least you'll get power to the ECU, injectors, fuel pump, sensors etc and it should try to start.

You have a problem with the wire from terminal 15 on the ignition switch to 86 on the DME relay base . As Adkin says, the loom may have a break or connector somewhere where the original factory alarm fitted.

Ultimately you'll need to find that break and bypass it. Or run a permanent bypass wire from T15 on the ignition switch to T86 on the DME relay base.If you go that route you could insert a hidden switch and have a very effective immobiliser . I take it one is not fitted to the car currently ?

peanut

good call !
I wasn't aware that the factory alarm cut into the feed to the DME relay terminal 86.
I'd never really considered the alarm to be honest as I've never read of anyone using it . Nearly all cars seem to have had it disconnected and an aftermarket alarm/immobiliser fitted.

I've learnt something important today thanks for the tip.

stogie25

I made a jumper for the DME relay. I installed it and it still won't start. There is tach bounce now.

peanut

ok well thats a good sign that you now have tach bounce

why don't you tell us a bit about what happened when you cranked the engine . remember we are not there and rely totally on your description.

When you fitted the 3x wire bypass you should have instantly heard the fuel pump ,pump continuously even with the ignition off ?? did you ???

Did you check for a spark at the plugs ???

Was there any fuel on the plugs ?

Did you have 12v+ at the injectors ?

Did the engine try and start cough, splutter etc ?

stogie25

I do not hear the fuel pump spin up when the jumper is installed.
No cough sputter etc.

I am working odd hours this week, and will find out about spark as soon as I find a victim to turn the key for me. I will also be able to check for injector signal at that time.

Thanks for all your continued help!!!

peanut

we seem to be going backwards here

Are you certain that you are testing the correct relay ?

Your fuse and relay layout should be printed underneath the lid to the fuse box.

Do you have 12v+ on terminal 30 of the DME relay socket with the ignition off.? if you haven't then we need to fix this before anything else.

stogie25

I found a victim, and have determined that I have spark now with the jumper in place. It is the right relay, it even says DME Relay on it. Neither of us could hear the fuel pump spin up. There is 12VDC at pin 30 with the ignition off, and it is jumped to 87 and 87b.

I only had a minute with a second set of hands, and I had to get to work. With the DME relay jumped, I should see 12VDC at both sides of the fuel pump fuse.
When I get home I will recheck the fuse and the voltages. All of the fuses were good when I checked a couple of days ago. I can't do the alarm bypass mod until I can trick it into running so I can move it away from the wall it is next to.

I had the whole fuse box disconnected at the modular connectors as part of the harness swap. I rechecked that all the connectors were tight. They are, and they are clipped in with a lever on the bottom of the fuse box. There is one connector that is not there. I found this pic on the forum of another car with the same connector missing, so I don't think that is it, but you never know.

stogie25

There is 12V through the fuel pump fuse.

peanut

ok thats great news that you have a spark and 12v+ at the fuel pump fuse.



Forget about the alarm jumper for now. If you fit the 3x wire bypass it bypasses the alarm , immobiliser , ignition switch and DME relay which is why I suggested it.

Now you need to go to the fuel pump and check that you have 12v+ at the pump.

The pump is permanently earthed in the trunk behind the carpet and above the registration plate lights just beneath the hatch lock. make sure that the earth is clean .

If you have 12v+ at the pump try running a seperate earth wire from the fuel pump to a good earth to make sure the earth isn't the problem.

If both the 12v+ and the earth are ok then you have a faulty fuel pump.

With the 3x wire bypass fitted ,Try giving the pump a couple of firm smacks with a rubber hammer in case it is jammed . If that doesn't get the fuel pump running continuously then you'll have to remove and service /replace the fuel pump.

Until you can get the pump running everything else is irrelevant so best to concentrate your effort here for now ok .
good luck