1.4 Petrol - Poor idle, now misfire

[jharrawa]

I hope someone may be able to give me some pointers on places to start with my 2004 1.4 petrol Berlingo.

For a while now it's had a bit of a rough idle, then it started cutting out randomly when stuck in slow moving traffic (It was fine driving around town, you had to get caught in traffic for 5 minutes).  It would always start up again on the second turn of the key, and be fine.  It only seemed to occur when the fuel level was at a quarter or less.  Running around with a full tank has helped, and I've tried some Redex which seems (and I know Redex has it's doubters!) to have improved the idle.

Yesterday and today, when cold, it idles fine but lacks power at low revs when you pull away.  Seems to be pretty much OK when warm.

 So I'm not sure if I have one or more problems, and really where to start looking.  New plugs going in at the weekend, but are there any other things that I can check?  I don't mind spending some money to replace the most likely cause, but I didn't just want to throw a new lambda sensor (as an example) on if that isn't even likely to be the issue.

 Thanks,  Jon.

[Kokain]

A little list that can affect all of this are spark plugs, coil pack, fuel injectors, fuel filter and fuel pump. Based on your symptom I can feel like narrowing it down to fuel pump. Well from at least what you are saying.
Before you go spending money can you check the easiest things for free like spark plugs, fuel filter? Have you not got some old plugs from any car that you can try on? Filter wise just bypass it with a pipe or something. Fuel injectors are also not hard to find if there is a bad one, you need a volt meter and just compare the resistance between each other. It should be around 14.6 but any -/+2.0 difference shows a bad one. I really doubt it's lambda but that's another item you can resurrect for free. You need a blow torch and heat it up till it glows red and clears the carbon.
http://i.imgur.com/DuOrTgX.jpg

When was the last time you serviced the car?

[jharrawa]

K,

Thanks for taking the time to reply. Plugs have done 12k miles, so I'll change them at the weekend. Oil and filters done 6k miles ago, fuel filter changed about 1k miles ago when problem got worse.

I can test the resistance of the injectors at the weekend (they look like a pig to get to?) and have a go at resurrecting the lambda sensor.

Fuel pump was one of the things on my list, but I was (and still am!) hoping that it might be something a bit easier to fix!

Thanks again,

J.

[jharrawa]

Weekend update

Problem got a little worse at the end of the last week, and you can now feel it hesitating slightly at all revs, warm and cold.
Checked injector resistance - values are 12.7/12.8/12.8/13 which seems close enough to be OK (unless they are all bad).
Managed to change three plugs, but one is jammed solid, so needs some WD40 and love. A quick test drive shows that the problem is still there.

So next weekend I definitely need to get that last plug sorted. Is there any point taking the injectors off and giving them a blast through with brake cleaner, or is this just a pointless waste of time.
After that are there any suggestions for next steps? I'm leaning towards pulling the tank out and check the mesh on the fuel pump inlet.

Thanks, Jon.

[Kokain]

I'm really sorry to hear buddy, seems like its going towards the fuel pump. Your injectors are fine no need to replace any of them, also the cleaning technique is waste of time, it's more about visual inspection of the stream rather than trying to get a hard stuck object out of the gap. A brake cleaner won't magically dissolve dirt with a few squirts and AAA battery. Try it if you like, it doesn't hurt anything (if you already got them out). Just remember to pulse them instead of holding them open as that apparently can burn them out or something.
That stuck plug doesn't sound good, hope you can sort it out, keep soaking it in WD40 and should make life a lot easier. I never tighten my plugs, especially with these new alloy head engines. Always have a bad feeling like that, plus I never got problems for tightening screw driver style instead of handle leverage. No leakage, lost compression or anything.
I would definitely get the tank out next, it shouldn't be hard because it's not like it's a RWD where you have to disconnect diff and drive shaft. If you want let me know I've got a Haynes manual here, I can give you the photos as early as tomorrow. Pretty much get the handbrake cables loose and maybe sort the area around the fuel filter. It should drop right down.

By the way I remember looking on ebay about fuel pumps. You have 2 options. They are not cheap but plenty of second hand once which you get the full unit. That's option A. Or you can get just the solenoid and faff around with the plastic, option B.

[Kokain]

Here, I hope this helps. How to remove fuel tank Haynes Manual
http://i.imgur.com/a83Fhi0.jpg
http://i.imgur.com/bKc8jW2.jpg
http://i.imgur.com/OrVOMB6.jpg
http://i.imgur.com/UIJavTY.jpg

[jharrawa]

Just a quick update, in case anyone else stumbles across this thread.

Managed to get running on LPG last week. None of the problems experienced with running on petrol occurred - which seemed to prove that it was fuel related, probably fuel pump as above.
However switched back to petrol at the end of the week, and it ran beautifully!

Managed to get the stuck spark plug out today (thank god for WD40!), and also spotted a split in the hose from the inlet to the LPG vaporiser / ECU. New plug and split repaired and it's running better than it has for a long time.

In summary;
Possible dirt in the fuel system, dislodged with a couple of treatments of Redex.
Split in hose, possibly affected air metering and therefore idle / fuel mixture.
Spark plugs need to be changed more frequently than 12k miles.

I'm sure there's a chance that I might still have to pull the fuel tank out, but for now I'm going to use it as is, and see what happens.

Kokain, thanks for taking the time to reply and for your help. It is really appreciated.