405 le mans non start

[nitr0uk]

Hi,

I have a 1994 Peugeot 405 Le Mans and it has the keypad in the centre console (code is unknown)

If you turn on the ignition the keypad shows a green light but the engine will only crank and not start.

I've noticed that pin 10 on the double relay for the fuel pump is not being grounded from pin 3 on the ECU (Bosch MP3.2)

I also have no central locking working, whether I try the key on the barrel on press the button on the keyfob.

Any advice would be appreciated as i'm a bit stuck.

[mickthemaverick]

You might find it helpful to read through this thread

[Oldpug]

It would be handy if you could find an old school Peugeot Specialist, who has the old Peugeot Diag 2000 tool to plug in and check codes. Your 405 should have a diag socket ??
As you have probably realised, if the key pad green light is on, it means a correct code has been entered so the car should start?
I think the problem lies else where, more than likely the fuel pump multi function relay, they often play up. You must get that poor wire sorted first though. When you order a relay make sure it’s the exact same part number, there are different ones. If you get the wrong one the slots on the plug will not line up.

When you get the car going it would be best to get rid of that key pad.
The best way is to get a specialist to remove the key pad from the car’s ECU, or supply an exchange unit. I wonder if ATP of Hednesford are still there?
The other way is, with the engine running, pull off the key pad multi plug and forget it. ( hopefully )

[xantia_v6]

You could try temporarily bypassing the pump relay to see if that is the only issue.

If you say what town you are in, there may be someone who can help.

[nitr0uk]

Thanks for your replies.

If I bypass and apply my own ground I can get the fuel pump running. The car still won't start unless I apply the throttle. Then it will run but cut out as soon as I let go of the throttle.

I did get a new one of those relays. I couldn't get the exact part number but found one with exactly the same pinout. The slots do not line up for the plug but I've cut slots off the relay for the time being to be able to plug it in. If I can get the car running I'll modify the plug to accept the new relay as a more permanent solution

Am I right in thinking the diagnostic port is the 2-pin green connector in the black compartment on the o/s of the engine bay?

I'm based in Essex.

[Oldpug]

Don’t modify the relay plug, it’s important to get the exact replacement relay. Search the net with the number on the old one, you will find the correct one, I did.
Yes, that green two pin is the diag port, but it’s the old Peugeot system, not much use to you.
Have a look around the fuse box next to the steering column. You may find a modern 16 pin Diag port.

You do need a Peugeot Specialist, try these guys https://www.peugeot-repairs.co.uk/

[PaulC5]

If a petrol, maybe the throttle plate/body need cleaning since there could be a build up of carbon so the air gap is not enough for tick over. Carb cleaner or white spirit/turps on a cloth will wipe it out.

[nitr0uk]

Don’t modify the relay plug, it’s important to get the exact replacement relay. Search the net with the number on the old one, you will find the correct one, I did.
Yes, that green two pin is the diag port, but it’s the old Peugeot system, not much use to you.
Have a look around the fuse box next to the steering column. You may find a modern 16 pin Diag port.

You do need a Peugeot Specialist, try these guys https://www.peugeot-repairs.co.uk/

I did try to look for a relay with the exact part number but I could not find any stock anywhere.

I'll have a look round inside for a diag port.

[nitr0uk]

If a petrol, maybe the throttle plate/body need cleaning since there could be a build up of carbon so the air gap is not enough for tick over. Carb cleaner or white spirit/turps on a cloth will wipe it out.

Thanks, I'll give that a clean and try it.

[xantia_v6]

It is likely that the ICV (Idle Control Valve) is not operating correctly. Sometimes they get gummed up, but sometimes they are just worn out.