Engine/Electrical Issue...need help?

[vr4terry]

Hi all,

I am new to this forum and have just recently bought my first ever Galant....well its actually a Legnum but you all know what I mean.

Anyway its a 1998 2.5 TT VR4 model with the Auto box. All was going well and was moving it off the garden unto the driveway whenever the engine cut-out. Tried to start it but wouldnt fire. Engine was turning over but no go.

Checked fuses and the fuse for the ecu was blown (engine management symbol within engine bay fuse box).

Replaced fuse and the moment I turn the ignition on fresh fuse gets blown.

Any idea what is the cause of this?

There is a 1/3 of fresh fuel in the tank....

Any help/hints will be appreciated

[elnevio]

Guess there is a short somewhere. I would be having a look at the ECU plugs first, in case there is anything obvious there. Perhaps a look in the ECU itself to see if there are any component that look burnt out, etc. Then see if anything has been tapped into the loom and checking the wiring. There may be other directions to follow though!

[vr4terry]

Guess there is a short somewhere. I would be having a look at the ECU plugs first, in case there is anything obvious there. Perhaps a look in the ECU itself to see if there are any component that look burnt out, etc. Then see if anything has been tapped into the loom and checking the wiring. There may be other directions to follow though!

Many thanks for the reply..

Meant to say this on the original post...

I did disconnect the ecu then tried the ignition by reconnecting the plugs one by one and makes no difference still pops fuse...but i have found that it wont pop the fuse with one of the relays disconnected...(the two relays on the gold board beside the ecu) I think one is for the fuel pump and the other is for the ecu.

[elnevio]

We are talking about the ECU in the cabin behind the dash between the driver and passenger, with the four green plugs, yes?

[vr4terry]

We are talking about the ECU in the cabin behind the dash between the driver and passenger, with the four green plugs, yes?

Yes thats correct...on the floor behind the centre console.

Behind the radio are two relays on a gold bracket those are the two I am talking about.

Another when it was working and not blowing fuse, whenever you turned the ignition you heard a sound under the car like a pump priming or something spining...it might have been the CAS (or whatever sends the signal to the fuel pump) but whenever the fuse pops you dont hear that noise..hopefully that is well enough described.

[elnevio]

Have you got a pic of the relays/bracket? I can't think what they are or if they're standard.

[vr4terry]

I will take a picture of them this evening and hopefully post it on here tomorrow.

They both have E8T101 8X26 printed on them

[vr4terry]

Here is one of the two relays in question.

They are both exactly the same and our attached to the gold bracket.

IMG_8035.jpg

[elnevio]

Have you got a picture of them in situ? I'm not convinced these are standard, but may be wrong.

[vr4terry]

I could take a pic of them but dont know if it would come out..

But to describe where they are at...

If you remove your head-unit (double din) they are behind it on a bracket cabin side of the bulkhead.

One is for the ECU/M and the other is for the Fuel Pump Circuit. If you bypass the fuel pump one you can have the pump on continuous with the ignition.

[elnevio]

Oh yes, and I've found them in ASA too. I must have never clocked them as I've never needed to investigate or remove them.




Interestingly though, the item highlighted in red is shown as being the fuel pump relay. The item on the gold bracket is shown as the Engine Control relay. May be some mileage in checking all the wiring here anyway, and perhaps trying a replacement relay.

[vr4terry]

Many thanks for that.

Is there anywere that you know of where I can get electrical diagrams for my car? Its the EC5W shape.

[vr4terry]

After another look, its seems I tested the wrong ECU. I tested the Gearbox ECU rather than the Engine ECU. How do you remove the Engine ECU from its cage...I have the Gearbox ECU removed but the engine ecu doesnt want to budge.

[Davezj]

Engine cu is bolted in both sides. One nut in the passenger footwell and 2 or 3 bolts in the drivers side.
If you have removed the gear box ecu, I can't see how you can remove that one without removing the engine ecu first.
The engine ecu is on top with 4 connectors and the gear box ecu is on the bottom with 3 connectors.

[vr4terry]

Oh well then thats me back to square one...I though that the engine ECU was the middle one and not the top one. Must check the top one then maybe have a look inside at the main board to see if the capacitors have started to leak and causing my fuse to keep blowing.

[TAR]

I did disconnect the ecu then tried the ignition by reconnecting the plugs one by one and makes no difference still pops fuse...but i have found that it wont pop the fuse with one of the relays disconnected...(the two relays on the gold board beside the ecu)

Test the relays first and from the picture posted by Nev earlier, determine which relay is which. This will help with the diagnosis.

[vr4terry]

Checked by connecting the ecu connector by connector...
The main fuse blows when the 3rd connector is connected and the ignition is tried..
According to diagrams it is for the Oil Warning Light and a connector behind the clocks..

Could it be to do with a capacitor inside the ECU is causing the short?

[Davezj]

it is easy to take the dassh clocks out and do a point to point connection check between the dash and the ECU with help from a friend.
or take the engine ecu out and do a pin to pin short check on that connector, which is probably easier, and you take the case off and have a look inside as well to see if there is any obviouse damage if you find it is the ecu that has the short.

[vr4terry]

How do you split the case on the ECU? Dont see any screws and looks sealed. Its probably right in front of me tho.

[SEAN-NZ]

The case just clicks on at the top near the connectors, couple flat heads will get it off