DW8 engine, lucas pump

[Hitch]

Got the pug/citroen dw8 engine (1.9d) in her car, its a '53.
When its reallly very cold it cranks but takes a bit to start... it does start after 20 secs or so, but i get annoyed with minor things like that

First thought was heater plugs, so i changed them, not made any difference.
Checked the relay operation, it seems to be on for about 15 secs, voltage of about 11.7v. The plugs are marked 11v.

When it starts it seems to kick into action without chugging for a second or two, nor clouds of white smoke which i might expect if it were cold.
Starting from warm, its running as soon as the key is turned.


Reading up online earlier, sounds like the pump, mechanical type, has electronic advancment control, i imagine this is something to do with the black bit top right in pic below?
How does one check this out, and the yellow bit marked 2.58v, whats that about??

I have some basic knowledge of these things, but far from a mechanic/auto electrician! So relies in simples please!!

 

[rtbcomp]

Are you using winter diesel or an anti-waxing additive?

 

[Hitch]

Im using Morrisons Diesel
Surely theres no need to add stuff to it in this day and age?
I have virtually the same in my van, same engine, but fully mechanical pump, starts perfect. Filled up from the same garage.

 

[zzr1200]

Hitch, does the pug have rubber push on leak off pipes on the fuel injectors and return to filter/pump???

These have a habit of allowing air into the fuel system if fairly old, and causing the problem you discribe...

 

[bill_gj]

A couple of things:

1) JC!! Do you drive through seawater a lot? That pumps pretty corroded innit?

2) I'm not familiar with a DW8, but I have had dealings with DV4/DV6/DW10/DW12. All these have cam and crankshaft position sensors. If these sensors aren't sending good signals to the ECU then the ECU can't synchronise the control of injection correctly and the engine will be a bitch to start regardless of the weather. Does it just churn over without any firing at all at times?
If the connectors for the cam and crank sensors are subject to as much attack as the pump body perhaps a disconnect, a squirt with WD and a reconnect might help?

 

[KTMMICK]

Have you changed the filter lately? Sounds like it might have air in the system. I know you are thinking it would bleed itself but it could be drawing air. Are you sure the heater plugs are working correctly? Does the light come on and go off? Do you know it has a glow plug light? It is feasible you just get in turn ignition and wonder why it don't start........not being presumptuous just putting all the options on the table.

 

[pedrobedro]

In the really cold weather I used to turn the key till the light went out then do it again before trying to start it. It did seem to make a difference. The black thing looks like a throttle position sensor.

 

[Hitch]

Heating it a few times doesnt seem to make much difference. It has a light on the dash which goes out after 5-6 seconds ish, measuring the voltage to the plugs, comes on and goes off after 15-20 secs, presumably this is to aid in getting the engine running smooth.
Same times on my van, (15-20 secs, at 10.9v) I was going to swap the timers, but they are different.
As i said, its got new plugs, Wellman. Suppose i shouldnt rule out a faulty new one.
Is there an easy way to check without removing them and energising them?


Leak off pipes, yeah i think so, one to check i think, along with new fuel filter, thats on my list as possible causes. Temporarily putting a hose clamp on the return pipe just as it goes into fuel filter and trying that should eliminate that right....?
I did try operating the hand primer a a dozen times before trying to start, no difference.


Crank sensors, you can hear it trying to fire, and it does every time, its not like you need to try turning it over , turn off and try again. Seems to only do it when its been stood all night. I will pull a few plugs and check them out.

 

[eil]

You can test the plugs by removing the connecting bar or wire thats attached to all of them and then with a test lamp from the pos side of the battery to each plug terminal, each should light up if OK

 

[zzr1200]

Leak off pipes, yeah i think so, one to check i think, along with new fuel filter, thats on my list as possible causes. Temporarily putting a hose clamp on the return pipe just as it goes into fuel filter and trying that should eliminate that right....?
I did try operating the hand primer a a dozen times before trying to start, no difference.

Putting a hose clip on the return pipe won't prove anything, nor will operating the hand pump.

If the rubber pipe is perished/split or lost it grip on the unions, over night air enters the fuel system allowing the fuel to run back to tank including some of the fuel between the injection pump and injectors. When you try to start the engine the heater plugs are being cooled by the air but theres no fuel being injected until the injection pump has refilled the injectors. Once the injectors are full again and after the first cold start, starting not a problem until left for a while and fuel run back re-occurs.

Try replacing the rubber pipe, costs a couple of quid from your local car accessory shop and a few minutes work, well worth the time and effort. If the fuel filter hasn't been changed in a while I 'd be included to change it as a last resort, being as the engine runs ok once started in the morning, sort the fuel run back problem first.

 

[Hitch]

I see what you are saying.... if i was to park upfor the night , then immediatly clamp off the fuel hose, between tank and filter, that would prevent air being draw back down the fuel line to the tank....where the air can exit?

For starting purposes next morning, remove the clamp off, then try it...?

 

[zzr1200]

I see what you are saying.... if i was to park upfor the night , then immediatly clamp off the fuel hose, between tank and filter, that would prevent air being draw back down the fuel line to the tank....where the air can exit?

For starting purposes next morning, remove the clamp off, then try it...?

I can understand that clamping the pipe would seem to be the way to test it, but if theres a way air can leak in to the system, theres also a way fuel could leak out. Most rubber leak off pipe has a type of cloth outer braid which can soak up the leaked fuel, it takes very little fuel to leak out to cause the problem you are describing. I'm not guaranteeing that changing the pipe will fix the problem, but it is the starting point where all mechanics will start. Mainly because it a well known problem and a must to remove from the equation before moving on, Mercs, BMW, Duetz Engines, Vauxhall, in fact any engine that uses flexible leak off pipes, will suffer at some stage.

Spend a few quid and change the pipes shouldn't be more than a fiver absolute max, even at Halford Rip Off Prices.

 

[Hitch]

Okay, i will try that, probably got some of that pipe at work...as i said, i have the basics, but am no mechanic.
I will do the fuel filter anyway, along with those pipes, and check the heater plugs while ive got the manifold top off.

 

[the snooper]

after reading first post you had a voltage reading of 11.7 volts is your battery ok should be reading 12 at least.
also as diesel are a compression ignition engine do you have the correct oil in as a slow crank will mean less heat from the compression and will take longer to start.
as regards air leaks start it up in the morning then leave it stood for the same period of time during the day when the temperature isnt as low if its an air leak it should show up as it does in a morning if on the other hand it starts up straight away you can discount the air leak and concentrate on it being temperature related.

 

[Hitch]

The battery v is about 12.85, i gather the heater plug circuit is supposed to restrict it, as it says on the plug 11v, and the speed of the crank sounds okay.

 

[stucktoweld]

double check the relay

Hi Hitch
Double check that glowplug relay
they are notorious for burning out one of the contacts
I had that problem last winter it went on for weeks sometime okay and other times difficult to start.
It was only when we took the relay out that we could see the problem
I since found out that is a common fault
At the time I though I was going mad cost me two new glowplugs relay a weak starter selonid and time in garage When a new relay would of done it also the garage was foiled by this one
Hope this helps

 

[daf45]

I think ZZR is closest so far - I had leaky fuel return pipe fom injectors on an old VW LT (found after new glow plugs and everything else didn't help...)

If it was my luck (and I hope for your sake its not) it is also possible that the pump internals/seals are wearing out and/or breaking up. My daf with cummins engine ran as sweet as a nut most of the time but occasionally wouldn't start - tried literally everything from tank, sedimentor, fuel and return lines, lift pump, fitting non return valves everywhere etc etc...
Fitted recon bosch pump last (single most expensive bit at circa 700) and never had a problem since.

Good luck - glad its not only me who finds these things annoying - intermittent faults are usually the hardest to find.

 

[Hitch]

I think ZZR is closest so far - I had leaky fuel return pipe fom injectors on an old VW LT (found after new glow plugs and everything else didn't help...)

My dad mentioned that a non return valve might be worth fitting, apparently it was common on LTs, he worked in parts at a vw main dealer

 

[KTMMICK]

I don't agree it is intermittent it does it all the time when cold....almost certainly drawing air or bleeding back to tank. Check as someone said condition of hoses. Have you changed filters? Could be the seal in that, seen them get pinched before and cause grief. Check systematically and you will find it easy enough.

 

[the snooper]

When its reallly very cold it cranks but takes a bit to start... it does start after 20 secs or so,
:

i dont buy into the air leak theory as hitch states above WHEN ITS REALLY COLD in theory it should not be temperature related if it is an air leak my transit takes longer to start when cold usually a flick of the key and it runs in this weather it takes a good few turns.

hitch have you timed the 20 seconds or is this just an estimate could actually be less then ten, when you sit there cranking away it seems like forever until the thing starts