1.9td 440 lumpy idle on cold start up.

[carl4u44]

Ok folks well I bought myself 18 liters of desiel in a drum from a friend who works at the airport. Having put it in the night before, from nearly an empty tank, i started my car the next morning.....

Now I note that every morning my car starts first pop, no smoke, no winding, just starts, idles high at 1100 with the lucas choke cold start then settles to the 1000rpm and sits there all day.

However I have noticed that upon a cold start up it idles as it should but upon giving it a little rev, it tends to become erratic from around 800 - 1100 then settles but only when you give it a little rev....

This goes on untill the engine is warm then it runs perfect.

Im hoping there was water in the fuel and perhaps the cold weather has created ice crystals in it. Now I have filled up the tank with a further 40 liters of real fuel from the garage just to dilute.

Apart from that she runs perfect, as i regulary clean my engine with a tooth brush.

Anyone any ideas on this little problem??

I know these cars dont have a water in fuel filter warning light but i'd be tempted to drain whatevers in the bottom of it.

[NI_Volvo_Nut]

I'm thinking glow plugs possibily too, they stay on after starting I think, be worth maybe testing them, but I'd expect poor starting if one was away.

Other than that I'd expect something to do with the cold start system, but I don't knwo enough about it to say what.

[carl4u44]

Glow plugs seem ok as it starts first pop , plus there not that old. Im thinking cold start too but then again it all starting when I put that fuel into it.. Gonna have a look now.

The cold start comes on and clicks off after 20 secs as it always has done.

[Baffler]

Probably some water in the drum of fuel you got off your mate. Also, with this type of weather we're having, condensation can build up in the tank and make its way to the fuel filter. There's a plastic screw type valve at the bottom of the fuel filter especially for this reason, although, some water will inevitably get to the injectors. Slaken off the plastic valve, drain off any water, and re-bleed the system. Might be a good idea to replace the fuel filter after a tank or two of good fuel

[carl4u44]

Sounds like a plan. It seems the next morning, im hoping water settles to the bottom of the fuel tank overnight. Then on start up behing sucked up. After a while it clears probably as it mixes with movement. I guess i'll waiting and see if it clears over time but untill then i'll drain the filter....

[Richard_TD]

Whenever I've checked glow plugs due to poor starting I've found two down. That suggests to me that having one plug down is barely noticeable- except possibly the slight misfire you mention.

[carl4u44]

Having found the water drain plug a little loose i have tightened this, but im not sure if its the cause. There appeared to be no water in the drain bowl either.

Plugs are a possibility, but it starts on the button in minus weather..
I also began to notice that upon deceleration, when warm, the revs dip down to 800 before return to my normal idle of 1000. This has been a bit low than before as it used to simply climb down to the 1000. I'm reading the 405 Haynes manual which covers this Lucas pump. My next plan is to adjust the anti stall screw to see if that makes a difference.

Now, I cant seem to get my head around the cold start cable/wax stat. Regardless of the engine being warm or cold it always activates for around 15 secs before shutting off. This is not a concern as its done this for a while but i do believe its meant to stay on until water temp reaches around 60 degrees.

I cant wait until the morning when I start it again. I like challenges, solving the Rubik's cube was lasts weeks!

[Baffler]

See Clans method of testing the glow plugs in this post.

[carl4u44]

Cheers for that post.

I adjusted the anti stall screw a fraction and it has eased the dropping idle, now falling back to the 1000 and no lower, just as before. The cold waxstat choke cable thing is working as it should.

Still thinking its that fuel tho, cant wait to get it all burnt off, then i'll give it a good service which the old donkey is due, may even change then plugs too as there a year old. I remember my old 406 td's heater plugs lasted 6 months.

[carl4u44]

Anyone know the colour of real diesel in the uk? Sounds like a silly question but i thought it was clear with a blue tinge to it...