P38A 1997 2.5 cranks dont start

hi court said:

Evening all,
I have a 1997 2.5 p38 with a starting issue, I apologise in advance for the story that follows....

I've had the car 15 years, almost no real issues in the time. I have used it as a daily doing 15k a year but over the last few years it only comes out the garage in dry weather covering only a few hundred miles a year. For the last 2 years I have had an intermittent starting issue, as in it cranks but don't start. Trouble being it was so intermittent I couldn't find a pattern, but over the last 2 years I have discovered; when it doesn't start it is when engine is warm. Also the glow plug light on the dash doesn't light up when it isn't going to start. It also says on the dash "abs fault" and "airbag fault" and "traction failure". (The car does not have traction control).

At first if I turned the key off and on a couple of times it would start. I initially considered ignition switch fault.

Next up i worked out if I grabbed the wires to the under bonnet fuse box it would then start. (I would leave ignition on then when wires were moved you would hear the ecu make noises and the abs pump start)

Next I found when I touched the abs relay (the black 70a one) it would start. However, I removed the relay and the car started fine so assumed this was a coincidence and wasn't the cause.

Couple of days ago it happened again, I wiggled every relay and nothing. Wiggled the wires, nothing. I took every relay out and refitted them,no difference. I slapped the top of the fusebox, it fired ito life.

Now I am certain it is a fusebox issue, today I removed the fusebox took the circuit board out and nothing obvious I could see. Obviously you can only see a small amount of the pcb without unsoldering both sides which I wouldn't attempt myself.
All the pictures online of damaged fuseboxes don't match mine, there is slight signs of over heating around one of the pins on the blue multiplug (purple/white wire) but the signs are minimal.

Reassembled and refitted, started straight away. Whilst I had it running for about half hour I noticed the fuel pump relay, relays for fans and the engine ecu relays all began to get warm. I have no idea if this is normal or not. On closer inspection the engine ecu relay was showing signs of previously melted around one of the pins. So I swapped this with another relay. Started it back up again all good. Packed away all my tools, switched it off and thought I would try again... exactly the same as it was before. Cranks dont start. Let it cool down, no start, left battery disconnected for an hour, still don't start. Removed fusebox, checked all connections, checked fuses all fine. I bridged ecu relay (19 I think) and the ecu bursts into life and it runs. So I have checked the relay trigger voltages..12v on both pins. So basicly I have 3 12v feeds going to a four pin relay.

This makes me wonder if the becm is not sending an earth signal to this relay. Or there is a wiring problem somewhere. Or it is that fusebox issue after all.

I have been looking at the syncmate wondering if that I am loosing sync between beam and ecu. It has puzzled me for 2 year why it is only when starting I have an issue, I mean once running it will run happily all day which makes me consider it can't be a wiring/fusebox issue as this would surely cause the car to cut out whilst driving?

I have bought a replacement fusebox from eBay and the issue is exactly the same. Cranks, no glow plug light on dash, does not start. No other warnings on the dash other than abs fault and traction failure. The remote fob works fine. Ive pulled all the loom apart under the fusebox and can't spot anything.

Any thoughts please gentleman? The only thing to be thankful for i suppose is atleast it is in my garage broken down...

I have searched Google non stop for the last 2 days and found several people who have this issue but no replies advising if they ever fixed it.

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hi court said:

Datatek, thanks for your reply, could it be the engine ecu has lost its code from from the BECM which a syncmate would fix?

I'm sure its a fusebox issue too, it can't be a coincidence originally when I hit the fusebox it would start. I did consider as I had the battery disconnected for a while when I removed the fusebox, took it apart then refitted it its the battery disconnection that has caused the loss of sync between the modules. However, it did start immediately after I refitted the fusebox so maybe not.

And I've had various flat battery events over 15 years of ownership and never had a issue before. Currently the battery is fully charged and about 2 years old, its the hankook mf1000 amp one so I'm relatively happy its not battery voltage related.

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hi court said:

Evening, ive had a bit of a productive day, ive checked earths, load tested wiring, cannot get to the bottom of the issue. I even checked pin grip of the pin on becm that earths relay 19. No issues found.

So I removed the pin that earths relay 19 from the becm multiplug. If I give this wire an earth the glow plug light comes on, abs pump runs and it fires up. No warnings on the dash, runs and drives fine. When I turn the key off the engine still runs however.

So I've made a temporary fix using an old mk3 escort heated rear screen switch and a bit of wire. I turn ignition on, flick the switch and it runs. Then turn the key off and press the switch to switch off.

My thinking is it has to be becm not giving an earth signal for relay 19. I don't know if this is a becm fault or if it is the becm preventing the signal from reaching engine ecu due to loss of sync?

Any thoughts?

Interestingly the blend door motors have started to work for the first time in 3 years so I now have hot AND cold air!!!

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