Occasional starting problem - getting worse

[Warriorsquare]

The car is a 306hdi LX estate, 1999 model 90bhp. I've tried to keep this brief but its a long story.

I've had this problem for years and it's kept returning randomly. The engine can either be hot or cold, the weather wet or dry it makes no difference. Turn the key, it fires once and dies. Keep it turning over and nothing happens, it won't fire.

If i leave the car for a day or two and return to it it's 50/50 the engine will start, it ticks over like nothing was wrong and has plenty of power for silly driving. After that it starts on the button for weeks/months/years before the problem returns.

The first time it wouldn't start the AA man gave the tank a few taps and it started. I thought that it needed a lift pump and in time (after another non-starting episode) i had a new pump fitted. The problem persisted and threatened holidays etc. Oddly, i've driven it all over North Wales, Cornwall and the Yorkshire dales and it never let me down once. But 300+ miles or so is probably enough to keep the battery sharp (more on that later).

The local garage had a look at it and it puzzled them, they replaced the brown relay behind the battery and the fuel filter. They also managed to accidentally disable the fuel gauge somehow and that has never worked since, just shows empty all the time.

It went to a local specialist in Peugeot Citroen cars and a lengthy and expensive repair involved reconditioning the ECU.

The problem came back a few times and went again. Then a ECU light appeared on the dash. I noticed that the lift pump was actually not getting power when the car wouldn't start so i bought a small jump starter battery to keep in the car for emergencies. I would use crocodile clips to connect it to the lift pump. The car would start instantly and i could drive it to safety. After that it would normally start on the first turn.

This system worked fine until i ran out of fuel on the way home one night. Since it was recovered back to my home the sat for a while as i was really busy with work and it's MOT promptly ran out. I couldn't start it with or without self powering the lift pump anyway. I tried swapping the brown relay for a new one and it made no difference.

Since then it's started and had the cheapest MOT ever, passing the emission test with flying colours. During the MOT prep the mechanic (another local garage, spare me the warnings about safety please, it's temporary) wired the pump to the radio 'key on' feed so that it could be started normally. This appeared to work well until i got in one day and it wouldn't start.

The latest mechanic to look turned the key and it fired up on the button. He did a leak off test and confirmed the injectors are working fine. He checked the codes from the ECU and said it would be best to check when the problem returns. He cleared the codes and the ECU light has gone out on the dashboard.

It's still starting mostly fine except i had to turn the key about 15 times yesterday (would have called mechanic but had appointment) and i think it's getting worse. My theory is that there is wiring damage somewhere between the engine and the fuel tank and maybe a dodgy sender on the engine too like fuel pressure or something. There is no damage to the wiring that i've found yet but i haven't taken out the seats!

If i drive the car more often the problem seems to clear up. The reason for that might be the corrosion or damage to the wiring needs a fully powered up battery? Trouble is i tend not to drive it for many days and i work from home.

Apologies for the ramble. Any thoughts?

[Uberderv]

Worst type of fault... Has the plug for the brown relay been inspected? I've seen these burn out before.

[pug306driver]

Study all threads on here of a similar type and make notes.

Study wiring diagrams and suss out what goes where.

You will become aware of stuff like the brown relay and the noise the fuel tank lift pump makes, and if that is effected by the immobiliser system, also the live feed via the alternator and earths etc..

sorry I cant be more helpful as I am still a tyro with these cars and systems.

Get PP2000 which is most helpful, or a code reader at least.

You will come across on here system info and the helpful colour ( but in Spanish ?? ) engine system electronics and sensors etc., similar to the one in the Haynes manual.

[Warriorsquare]

Thanks for the replies.
@pug306driver I'm becoming all too familiar with those sounds!


Does anyone know where i can see an image of the earth points online? I was planning to go over the electrics at the weekend and search for damage.

Update: The (non) starting problem continues to get more frequent. It will run after about 5 - 10 tries though. Makes me think fuel pressure but the whole issue if too complicated and need to narrow it down one bit at a time.

I'll report back and write up any progress...

[pug306driver]

I am still a tyro on these cars, but..........I too have had some faults like the occasional loss of power for a few seconds on sharp left hand bends, the door lock going crazy and very occasional involving door locks a refusal to start.

I am currently thinking the crazy door locks may be due to the key fob, but not sure yet...........so its probably gunna be the locks control unit........

The immobiliser seems to disable the fuel injection via the electronic injectors rather than via the brown relay controlled fuel lift pump in the tank, but someone will confirm this I hope.

You will be able to hear the fuel lift pump when the engine is not running, when you turn on the ignition. It runs for a few seconds then stops, if the engine has not been started.

It was suggested to fit an idiot light to show when the lift pump is running, for my left hand problem.

Get a pp2000, or similar, else you will be going round in circles loosing your hair!! Its well worth the money and gives live info as well as logged faults.

A blocked fuel filter is an easy fix, when was the filter changed last. The tank lift pump also has a filter screen, see the "how to" threads.

I will try and find the earth's picture for you, but look around the forum for info and note stuff down, its a brilliant forum for these cars.

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The problem came back a few times and went again. Then a ECU light appeared on the dash. I noticed that the lift pump was actually not getting power when the car wouldn't start so i bought a small jump starter battery to keep in the car for emergencies. I would use crocodile clips to connect it to the lift pump. The car would start instantly and i could drive it to safety. After that it would normally start on the first turn.

you have had this problem for years ?

ecu repair by pug??

Hot wire pump and it starts all ok ???

I wonder, a make and break contact in the loom form the engine???

You need to be very methodical and have the kit ready when it misbehaves, else its a needle in a hat stack and you don't even know which field its in!

a loss of power to the lift pump when this problem happens.........there is a diagram on the relay for its internal wiring, one relay feeds the other....same relay on a citreon dispatch that I had to con the ecu into thinking all was well, via the brown relay.

[Mighty306]

Does anyone know where i can see an image of the earth points online? I was planning to go over the electrics at the weekend and search for damage.

Here you go (for HDi, but similar/same for most 306's I suspect) ....

   

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I noticed that the lift pump was actually not getting power when the car wouldn't start so i bought a small jump starter battery to keep in the car for emergencies. I would use crocodile clips to connect it to the lift pump.

If you do this it is highly advisable to include a fuse of the correct size in the circuit.

[Poodle]

When I had this problem it was the immobiliser. At the time I wanted a stage 1 map anyway, so just got Steve to de-immobilise the ecu at the same time.

[pug306driver]

At the time I wanted a stage 1 map anyway, so just got Steve to de-immobilise the ecu at the same time.

Interesting......it would be so easy to "add" an immobiliser of my own as the wiring is so complex and easily hidden, please could you give contact details for steve ?

[Uberderv]

HDItuning.com or https://www.306oc.co.uk/forum/member.php...e&uid=4006

[Warriorsquare]

Thanks for all that info and sorry for the late reply. Been over the earth points, cleaned, re-tightened. Then i had a closer look at the Brown relay socket. Ah...


What can i do? give it a clean?
I guess these burn out for a reason although the position of maximum damp from a a hole in the wheel arch might not help.

[Mighty306]

I'm not sure how easy it will be to clean up that multi plug as it looks like the plastic will have melted on to the contacts.  I'd be tempted to source a decent multiplug off a scrapped HDi and splice it in.  Then get a new relay as well - the fact multiple contacts seem to be affected would make me suspicious of the relay.   https://www.ebay.co.uk/sch/i.html?_odkw=...cat=131090  (Peugeot part number 19207L for an HDi as best I can tell).

Hopefully someone else will have a simpler fix!

[JTaylor2005]

Would that be something worth replacing as a service item if it's known to cause issues in the future?

Cheers

[Poodle]

It's possible to clean the contacts in situ, seeing several burnt pins is fairly normal thanks to poor contact as a result of corrosion from water ingress, it doesn't mean the relay is faulty.

Replacing the plug is not a job for the faint-hearted thanks to the resin covering on the wires at the back of the plug. While it certainly isn't worth replacing the plug as preventative maintenance, unplugging the brown relay regularly to clean the pins would be a good idea, apply a healthy amount of grease to the plug on reassembly to help avoid water getting in.

[Mighty306]

It's possible to clean the contacts in situ, seeing several burnt pins is fairly normal thanks to poor contact as a result of corrosion from water ingress, it doesn't mean the relay is faulty.

That's good to know - thanks. Any suggestions on best way of cleaning contacts? Had some concerns that mechanical methods might push them apart n still leave a poor connection. (Am facing same problem with fan relay sockets).

[Poodle]

Something sharp like a pick and a lot of patience, plus some electrical spray to flush it out. If the pins spread a bit you can always gently lever them back into place.

[Warriorsquare]

Been busy with work for a while and the car has started reliably(ish) so not had a go at cleaning the contacts till today. The socket is in really bad condition and some of the pins are breaking up. Others can't be found at all, just melted plastic goo in there.

As Mighty 306 suggested earlier i need to find a replacement and somehow replace the socket by soldering all the wires in. Could be a long job.

Why does the thing melt down in the first place? Might mean there are problems in the loom somewhere.

If i go ahead with it i'll post some pics.

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Anyone know where i can find a scrapped 306 hdi in the Hastings area or even a cache of old looms?

[pug306driver]

Citroen despatch uses the same double relay same part number so same plug ??

[Poodle]

They sit next to a hole in the wheel arch getting sprayed with water, the failure is fairly inevitable imo. There's a lot of current that flows through that relay, a poor connection as a result of corrosion causes high resistance so you get a lot of heat generated, which in turn melts the plug and surrounding wiring.

It is a pig of a job to repair, most of them have the back of plug covered in resin so you either need to cut that off very carefully or use a tester to work out which wire matches each pin before you can repair it.

[Magenta Sunset]

this double relay? what's the circuitry inside it? (curious)

[pug306driver]

There is a diagram on the top of the brown relay lid, one relay energising the other.....had to con the shitron despatch ecu via the double relay to get it to start and run, hot wired.........

The despatch has some very creative design ( design ha ! bloody abortion more like ) and no air con, but has a jockey wheel aux drive belt arrangement, to replace the 306 air con...........saves weight and preserves the 306 aux drive belt run......oe belt wrap around the alternator pulley, so no slip and oe drive belt, me thinks ?

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If the Haynes book of lies is correct with the wiring diagram, it should be possible to suss ouit what wire goes to what terminal for a "hard wire" and/or alternative connection method.....?

[Poodle]

Don't hardwire it, that would leave your lp fuel pump running constantly, not too clever. The relay rarely fails without external influence in my experience (ie getting soaked or burning out from poor connections).

[Mighty306]

Just done a quick search & found this thread about the same problem. https://www.205gtidrivers.com/forums/top...connector/

If you are unable to clean up the contacts of the connector it seems from above that the 307HDi also used the same relay n connector. If true it should be relatively easy to get hold of a good used one.  Although fiddly I would imagine it wouldn't be so bad with the ECU/battery & battery tray removed.  On my 306 the resin on the back of the plug doesn't go too far back along the loom so would have reasonable lengths of wire to work with. Maybe HDi's were different?

I can't advise on the best way to splice in a new connector (crimped connector or twist wires together / solder) but am sure someone else can.