Cold start problem - fuel pump seals?

[Rhod]

After being fine all summer my cold start problem has returned ('96 Diesel). Coincidentally it's come back after having the cooling system drained & refilled, along with a new radiator, but I can't see how this would affect starting.

What happens is this:
Following the usual start procedure of waiting for the glow plug light to go off, the engine starts fine. After a minute or so of idling, starts to run very roughly,vibrating & quickly dying. After a fair bit of churning on the starter & about half throttle it will eventually restart, amid clouds of smoke, and will keep running as long as I keep my foot on the throttle. Ease of the throttle & she dies again. From memory I think that the smoke is blue - difficult to tell in the dark last night & tonight! Once warmed up the engine runs perfectly & is smoke free. No signkificant useage of oil either.

I recall someone suggesting that this is symptomatic of leaking seals on the fuel pump? No signs of diesel leaking from the pump that I can see. The problem first appeared towards the end of last winter & then disappeared shortly afterwards. It's now reappeared, but it's not that cold just now & it's been fine in the last few weeks of lower temperatures.

Any suggestions anyone

[dandywarhol]

Either a blocked banjo filter of dodgy glowplug timer relay - do you hear any clicking from behind the main battery as the engine becomes rough?

[Rhod]

Have only noticed the normal clicking of the relay switching the glowplugs on & off. I'll keep an extra careful ear open though. I'll check the banjo filter as well. What is the reasoning behind a blocked banjo filter only affecting running before the engine warms up?
Many Thanks for the advice
Rhod

[dandywarhol]

Ermmm, none

[Rhod]

Just wondered. So far it's always been fine once the engine's warmed up. Idled as normal when I started her up to bleed the second time tonight. A new set of glowplugs might be next on the elimination list - if the relay is ok, then I guess an intermittently failing glowplug could produce the symptoms. It's probably worth checking/cleaning the connections in the relay circuit as well. Going to be busy tomorrow afternoon!

[dandywarhol]

Go for NGK Y701J plugs if you do - I've changed a few ADL Blueprint ones which have only lasted 6 months NGK are only around £8 each from factors

[Rhod]

Mine has the long plugs fitted, but I'll go with NGKs if I can get them. Will be leaving it until next months paycheck though, after paying for the radiator & hoses this month though. And having to pay someone else to fit them too Just hope that the sniffer test is negative

Air cooled flat twin engines have something to be said for them

[mikexgough]

Air cooled flat twin engines have something to be said for them

I know what you mean I was a 2cv owner for 20 years........

[francophile1947]

Air cooled flat twin engines have something to be said for them I know what you mean I was a 2cv owner for 20 years........

And I used to have a Douglas Dragonfly

[Rhod]

After replacing the fuel filter (12 months old) and cleaning the banjo filter, which didn't seem particularly dirty, a fortnight ago, the Bongo is back to perfect starting despite the cold weather. Too early yet to say if it's cured, given that it's been fine all summer but fingers crossed...

[MattK]

I've got EXACTLY the same symptoms as you describe and was also thinking it may be related to fuel pump seals after reading something on here a while back.

I have just changed my glowplugs (NGK), and clean my Banjo filter fairly often and the problem is still there.

I'll change my fuel filter and let you know how I get on (Changing the fuel filter has got to be easier than getting at those durned fuel pump seals).

Anyone else got any ideas what could cause this?

[francophile1947]

It sounds as if the glow plugs are cutting out too early - they should stay on for quite a long time (unless accelerating). I don't know how the system works, but someone more knowledgeable should be along soon.

[Rhod]

It sounds as if the glow plugs are cutting out too early - they should stay on for quite a long time (unless accelerating). I don't know how the system works, but someone more knowledgeable should be along soon.

With mine it would alwasy fire up ok & then start running roughly & die. After churning the starter for a couple of cycles it would start up again & usually run ok. Latterly however, I had a couple of occassions where after 5-10 minutes of driving, with the engine getting up to 11 o'clock on the gauge, I would take my foot off the throttle for a junction, & the engine would just die quietly. After turning over a few times she'd fire up & everything would be fine. Although changing/cleaning the fuel filters appears to have cured the problem, I'm dubious since I can't quite make the link between sypmtoms & cure!

Reading through the workshop manual, I couldn't quite make sense of the diagnostics, but there seemed to be a suggestion that a sticking EGR valve could cause something similar, so I was planning blanking off the EGR as the next stage. Certainly the fact that the problem occurs with a cold engine & clears completely when it's warmed up seems to me to fit with a valve that sometimes sticks when cold, but is fine once the engine warms up & the metal expands slightly. Anyone out there got any thooughts on whether a sticking EGR valve could actually cause this The manual also mentioned another potentially sticky valve in relation to stalling problems - a 3 letter abbreviation that began with F, I think. Will check the manual when I get home. I was getting well beyond the limits of my technical knowledge by that point

[conga]

I too have had the exact same problems as described at the top of this thread. Also, wierdly enough after I replaced the radiator. I wondered if it was a head gasket problem or warped head but have seen no 'white smoke' (would this be all of the time whilst the engine is running?) - although the coolant is slowly disappearing somewhere I fitted a new heavy duty battery, which seemed to sort the problem for a couple of days, then it returned. I also did the resistance check on the glow plugs, all read 1 and a bit ohms each, so no problem there. I increased the fast idle rate a bit while I was poking around in that area, which again seemed to solve the problem, for a couple of days again!
There are definitely all the right clicking noises from under the bonnet, however I haven't done the lamp test on the glow plug rail. I'll try that next. It's something to do with being cold, as once warmed up, there is no problem at all......

[Rhod]

Still starting perfectly, so looks like changing/cleaning the filters did the trick for me....