Citroen Relay van - turns over fine but wont start but bumpstarts fine

Honest John Back Room » Technical matters
View Threaded
Wed 24 Sep 2014 14:30
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Russellaga

hi,

van recently started playing up, was difficult to start it with key, it turns over no problem but fails to start up - almost like it has an immobilizer problem

it will however bump start very easily, the turnover is nice and fast so i am sure it is not a battery problem, a friend has put a diagnostic on but the readings are a bit odd - it seemed to imply it had a POST-heat problem (not pre-heat)

any ideas?

cheers

Russell

Reply | Report as offensive | Link
Wed 24 Sep 2014 14:42
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Cyd

, the turnover is nice and fast so i am sure it is not a battery problem,

Unfortunately, the apparent willingness of an engine to turn over seemingly healthily is not a guarantee that the battery is ok.

Have you tried jump starting it? If it starts well with a jump start that would be a good indicator that the battery is the cause.

If little or no improvement with a jump start, try checking connections looking for any that are loose or corroded, especially earths.

I'd suggest having the battery tested anyway.

Reply | Report as offensive | Link
Wed 24 Sep 2014 14:50
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Russellaga

it is a new battery so will check connections as suggested

do you think the post heat pre heat stuff is a red herring?

Reply | Report as offensive | Link
Wed 24 Sep 2014 14:55
Citroen Relay van - turns over fine but wont start but bumpstarts fine - mss1tw

Post heat failure normally just makes them smokier, as far as I know.

Reply | Report as offensive | Link
Wed 24 Sep 2014 15:45
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Cyd

it is a new battery so will check connections

It may well be new (but you didn't tell us that....ggrrr), but is it fully charged?

Reply | Report as offensive | Link
Wed 24 Sep 2014 22:31
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Peter.N.

Does it have an Hdi engine? If so fuel rail pressure is critical and it needs a good speed to get it to come up, if the pressure is low for any reason it will only start when turned very fast.

Reply | Report as offensive | Link
Wed 24 Sep 2014 22:44
Citroen Relay van - turns over fine but wont start but bumpstarts fine - mss1tw

I've got something at the back of my mind that these actually will not inject fuel if crank speed is below a certain threshold. The person needed a new starter motor I believe, even though the old one did turn the engine over.

I wish I knew where I read that but hopefully someone else will know.

Reply | Report as offensive | Link
Thu 25 Sep 2014 17:03
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Railroad.
Common rail diesels must reach 10,000kpa or 100bar or 1450psi of fuel pressure in the common rail for the injectors to be activated and for the engine to start. Loss of pressure could be caused by a worn pump or excessive injector leak off. This could be why it fails to start on cranking but does when tow started. Never crack open an injector pipe on a common rail. Not only is this potentially dangerous, it won't achieve anything and you're very unlikely to get it to re-seat, meaning replacement new parts will be inevitable.
Reply | Report as offensive | Link
Fri 3 Oct 2014 09:50
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Russellaga

Thanks for all the responses, i will get the van hooked up and have the rail pressure tested as suggested

good site, thanks for the help

Russell

Reply | Report as offensive | Link
Fri 10 Oct 2014 21:44
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Russellaga
Not sure if anyone is still reading this one but further info

I have had the crank sensor changed ( thought it solved the problem but no)
A valve on the fuel pump ( is this right, maybe I misheard mechanic, part cost around the £100 mark a common problem apparently) but no luck
Have had the rail pressure tested and it is over the 1000 needed so according to mechanic that is not the problem
Two of the injectors needed some slight attention, they have been sorted but still same problem
Battery and starter have been rule out as problem
Mechanic stumped - no help from his snap-on diagnostic
There is a red fan symbol on the dash

So the van will still bump I presume, but we have now an intermittent starting problem, the mechanic and I started it off the key 3-4 times, then it didn't start a couple of times then it started, I have used it most of the day with it once failing to start on 1st and 2nd try but then started, then early this evening it didn't start and refused despite 15-20 attempts even leaving it for 30 mins and trying, locking and unlocking nothing... Hopefully it will start tomorrow

Any ideas?
Reply | Report as offensive | Link
Mon 13 Oct 2014 15:12
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Gibbo_Wirral

Get a Lexia diagnostic. Hopefully there should be someone on this map near you:

maps.google.co.uk/maps/ms?msid=2016842495272566318...e

Reply | Report as offensive | Link
Thu 26 Jan 2017 14:49
Citroen Relay van - turns over fine but wont start but bumpstarts fine - hardway

Good sugestion from Gibbo,

Only reliable daignostis on these is Citroen's "Lexia".

Definately not Snap On no matter what model/system.

I have see your type of fault caused by a starter generating electrical interfearance on crank interfearing with the Crank ~Angle sensor.

Only way to test is with a 'Scope at the ECU CAS terminals.

Should be a nice clear 'Scope trace pattern without spikes or anything else unwanted.

Like I stated interfearance or "noise" could be the starter or the screening around the wires from the CAS.

Good luck finding a tech with an ocillosope

Reply | Report as offensive | Link
Thu 26 Jan 2017 13:02
Citroen Relay van - turns over fine but wont start but bumpstarts fine - upside

this is about comment 7 by mss1tw

i know on vag 1.9 pd tdi edc15's have a warn start problem (summer months) in the ecu maps that when the engine is warm the engine needs to spin at a high speed to start hence new starter motors and batterys

it appear to fix the fault until they get slightly tired and cant spin the motor as fast but its normally winter time then when the fault does not appear as a lower tempreture climate then summer comes again and it starts playing up again

this is because the ecu will inject 0% fuel until a certain rpm spin speed is achieved when the external temperture is hot and engine tempreture is warm

this is not a mechanical fault rather a discrepancy in the injection map

just mentioning this as this sounds like what you said was in the back of your mind

Edited by upside on 26/01/2017 at 13:09

Reply | Report as offensive | Link
Sun 14 May 2017 14:00
Citroen Relay van - turns over fine but wont start but bumpstarts fine - bluefire

Just a question if using easy start sprayed right into air intake is this a way to test this, how can you test this out without getting a new battery or starter.

the problem i have with mine is after using the van and then turning it off it will not start again until its cool down even spraying easy start right into the engine it will not start it just turns over

Reply | Report as offensive | Link
Sun 14 May 2017 15:53
Citroen Relay van - turns over fine but wont start but bumpstarts fine - hardway

This sounds like heat related crank angle sensor failing.

Try "Maplins" for a can of freezing spray,

Which does as suggested,

You spray it right onto the CAS when it's hot and if it now works i.e starts the then CAS is giong open circuit when hot

Reply | Report as offensive | Link
Sun 14 May 2017 18:41
Citroen Relay van - turns over fine but wont start but bumpstarts fine - bluefire

Sounds like a good idea thanks, ill give that a go

Reply | Report as offensive | Link
Mon 15 May 2017 13:25
Citroen Relay van - turns over fine but wont start but bumpstarts fine - bluefire

I've been looking for the CAS sensor but cant find it, is it a TDC sensor? sounds like it does the same thing and if so where is it located ?? any idea's

Reply | Report as offensive | Link
Mon 15 May 2017 15:20
Citroen Relay van - turns over fine but wont start but bumpstarts fine - hardway

Crankshaft Angle Sensor.

As to where that is I'd need year engine size and fuel type to answer with accuracy.

Reply | Report as offensive | Link
Mon 15 May 2017 15:35
Citroen Relay van - turns over fine but wont start but bumpstarts fine - bluefire

OK so its JUMPY I & II TYPE 800 VAN SHORT 1.9 D 71 (DW8B) Manual gearbox 5 2006

i've been going through my manual and found a 000019209C SPEED SENSOR which attaches to the top of the crank casing, i did manage to find that one after an hour lol but yeah I nearly ready with the TNT on this one

Reply | Report as offensive | Link
Mon 15 May 2017 16:04
Citroen Relay van - turns over fine but wont start but bumpstarts fine - hardway

Think you'll find on that engine it's fitted into the gear box at the top towards the back,

signal taken from the flywheel.

Anyhoo take it out and clean any crap off it,

the thing is an electromagnet so they can come out looking "hairy",

Two wire device with and this is important an elecro magnetic sheild which sounds cool but is just some metalic silver paper covering the 2 wires then insulting over the lot.

The CAS or speed sensor or whatever Peug Cit call it is just a coil of a lot of thin wire,

The flywheel spinning past generates an A/C signal until there's a gap on the flywheel teeth and the signal "blips",

TDC CYL#1 which in French is the Cyl nearest the box.

So anyway if there is any kind of heat generated open circuit in the CAS obviously when it's hot the signal just drops out until the CAS cools down and the coil then works.

Soooo back to my O/P,

Maplins or any other electrical parts supplier sell "freezer spray" for a tenner or so,

When next it fails you've found the CAS and can keep spraying until there's frost on it,

You won't harm it,

If it then starts up you've identified a heat generated open circuit in the CAS.

If I'm wrong your down 10 squid.

Reply | Report as offensive | Link
Mon 15 May 2017 16:10
Citroen Relay van - turns over fine but wont start but bumpstarts fine - hardway

Whoops mist out a bit there,

if the screening on the connector wire is dammaged the Electro magnetic inerference generated by say a faulty starter motor can basically scramble the CAS generated signal,

Bump starting it means obviously no starter so no signal spikes so off it goes.

So could be faulty wiring fro CAS to ECU or a failing starter giving of EMF.

Reply | Report as offensive | Link
Mon 28 Jan 2019 02:04
Citroen Relay van - turns over fine but wont start but bumpstarts fine - edlithgow

Nice analysis/explanation of an interestingly subtle fault condition.

Almost makes me wish I had a modern car to play with. Like a big Rubics Cube on wheels.

Almost, but not quite.

Reply | Report as offensive | Link
Tue 29 Jan 2019 12:54
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Gibbo_Wirral

Failing starter is a good one. Happened on my Peugeot 308 recently, and known to happen on 407s.

Reply | Report as offensive | Link
Tue 23 Jan 2018 07:43
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Robert griffiths
Hi just wandering if you found the problem as by the sound of it my vans exactly the same. He’s changed all the same things to but still can’t get it starte
Reply | Report as offensive | Link
Tue 23 Jan 2018 12:46
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Gibbo_Wirral

Have a look at the Lexia owners map I mentioned. Bound to be someone local to give it a diagnostic check for a pint.

Reply | Report as offensive | Link
Sat 14 Dec 2019 09:35
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Guy Hollidge

Have a look at the Lexia owners map I mentioned. Bound to be someone local to give it a diagnostic check for a pint.

Am I looking for people on this forum? I am looking for Citroen Crazy but I can't seem to find anyone on the forum with that name. Ta

Reply | Report as offensive | Link
Sun 27 Jan 2019 12:42
Citroen Relay van - turns over fine but wont start but bumpstarts fine - wazz72

Did you get anywhere with this as mine is doing the same?

Reply | Report as offensive | Link
Sat 6 Jul 2019 20:49
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Jamiesas
Wazz72 did u find out problem
Reply | Report as offensive | Link
Sat 6 Jul 2019 22:24
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Carl Baxter
No jamiesas but I seen you up doggers lane with 20 dudes in back with strobe lights wired up to it probably blown a fuse did you have fun with big Leroy?
Reply | Report as offensive | Link
Fri 23 Oct 2020 11:35
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Rich Man

Hi i know this is a old thread but i came across it while looking for something else.

Before anyone buys parts, sensor, batteries, starter motors etc do this first

In my experience with doing youtube videos this is usually a ground fault

Connect (clip on) a jumper lead/cable from the metal on the engine near starter motor (make sure there is no rubber mounts etch between lead and starter motor, then negative side of the battery. And try starting normally.

If it starts then it is your earth strap going to the engine, they have a habit to corrode and break up, or break completely not allowing enough electrical flow to the starter motor.

Edited by Avant on 23/10/2020 at 14:03

Reply | Report as offensive | Link
Fri 7 Apr 2023 07:49
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Nathan Bayliss

Hi, Did this ever get resolved?

Our 2013 Berlingo has something similar..

Starts easily cold or bump started, won't hot start.

Garage changed coolant sensor, supposedly,

I changed started motor..crank sensor, had all injectors checked, but still won't hot start.

Any ideas, thinking fuel pump next ?

Reply | Report as offensive | Link
Fri 7 Apr 2023 12:35
Citroen Relay van - turns over fine but wont start but bumpstarts fine - Crickleymal

I had something similar. Turned out to be valve clearance. The bloke in the garage scoffed until it ate his feeler gauge.

Reply | Report as offensive | Link