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Madcowz

200 tdi - Poor starting issues when not started for a while

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Hi,

My 200 tdi has suddenly become hard to start if it hasn't run for a while. If it has just run it fires up straight away.

When starting it will crank over and over and over then catch and stop then catch again, run very lumpily then start running normally with a blip of the throttle. There is always white smoke on start up which clears as it heats up. Once running it is fine, there is plenty of power and I can't detect any issues. No hunting, surging etc etc.

My plugs are only a few years old but I haven't taken them out to test on the bench.
I'm getting 10v at each one
My battery is at 12.5v
Earth strap is fine (tested with jump cable from battery negative to chassis and also engine)
Starter isn't sluggish and spins at normal speed
New fuel filter fitted
New leak off pipes between injectors fitted (but not pipe back to FIP)
FIP was replaced in 2011
Injectors have had no love since I bought the car (100K +) so that is on the list to do.

Today I took out the fuel filter housing bleed screw and unplugged the FIP stop solenoid wire and cranked the engine over while watching it on a video camera. There was no fuel coming out of the bleed hole despite plenty of cranking. I then replaced the solenoid wire and tried again and there was instantly a gush of fuel from the bleed hole.

Now. I'm not the brightest sandwich in the tool box but I'm pretty sure the lift pump is manual so I think the FIP solenoid wire has no bearing on the lift pump and this was a coincidence. Which means that fuel is possibly leaking back from the filter back to the tank and I had to crank it a lot to prime the line again.

Based on the symptoms and bits and  bobs I've played with. What tests should I try and what should I be looking at next?

Many thanks.

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Ok. Been out and spent some more time under the bonnet. 

I opened the bleed screw and had to pump the lift pump quite a few times before any fuel came out so it seems that the leak is between the tank and lift pump.

I've had the original pipe replaced with rubber pipe so tightened up the rubber sleeves where it joins the tank metal pipe and also changes to narrow bore before it goes into the pump. Also tightened up the fuel filter as that was a little loose.

Will report back when I've given it a few hours to drain off or not hopefully.

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could also be the lift pump diaphragm allowing air in so fuel runs back  

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Lift pump check valve or a leak somewhere.

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Have a look at the fuel return pipe on top of the tank. 

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10 minutes ago, western said:

Have a look at the fuel return pipe on top of the tank. 

I had a look at this tonight and it did seem a little damp where it joins to the rubber sleeve so I gave it a wipe and will check it later tonight/tomorrow to see if it is damp again without me having driven it and got it wet.

The metal pipe isn't looking too pretty so I may replace it.

 

15 minutes ago, Red90 said:

Lift pump check valve or a leak somewhere.

I will Google check valve as I'm clueless on that.

 

39 minutes ago, Tim2809 said:

could also be the lift pump diaphragm allowing air in so fuel runs back  

Are there any tests I can run to check this or is it easier to just replace the lift pump?

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Try starting it with the fuel cap off. 

Mo

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2 hours ago, Madcowz said:

I will Google check valve as I'm clueless on that.

There is a one valve valve built into the lift pump.  If it see any dirt, it gets stuck open and the fuel drains back to the tank when off.  It is quite common, especially if you do not have a sedimenter.

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There have been a few reports on here that the lift pumps fail with apparent ease, even genuine ones. I always have a spare Bearmach lift pump handy in case. I would say it would be wise and relatively inexpensive to replace it any way and see if that helps. As Red90 says, it only takes a bit of rubbish in the fuel to stop the valve in the lift pump from being effective. Also wise to double check the security of all the joints in the fuel system pipes to make sure it can't pull air from anywhere when you stop the engine.

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I've bought a 300tdi lift pump which I will fit at the weekend to at least rule it out.

Yesterday the car started very quickly but today I had to crank it for ages. Odd.

If I was to replace the pipe from the tank to the lift pump, would SAE J30 R6 5/16" do the job. It's the right size to slip on to the pump. Also, what is the pipe that runs between the pump and the filter and the filter and the FIP? It's thinner and a hard plastic. Thinking I might replace all of them to rule them out as well.

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I know you said leakoff pipes had been replaced, but I have had identical problems, traced to a dodgy leakoff pipe letting in air. They are buttons to replace, so do check them.

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1 minute ago, cackshifter said:

I know you said leakoff pipes had been replaced, but I have had identical problems, traced to a dodgy leakoff pipe letting in air. They are buttons to replace, so do check them.

Yeah, I've replaced the 3 little ones between the injectors. haven't replaced the longer one from 4 back to the FIP. If I can find out what the pipe is I'll buy stack of it and replace everything in there just to be sure.

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I put about 12mm of heatshrink over the ends of the leakoff pipe, so that its a sliding fit. It stops the braid from fraying and as soon as the engine warms up makes the pipes grip tight

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18 hours ago, Madcowz said:

Yeah, I've replaced the 3 little ones between the injectors. haven't replaced the longer one from 4 back to the FIP. If I can find out what the pipe is I'll buy stack of it and replace everything in there just to be sure.

It is nylon tubing.

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Right, got a chance to look at this over the weekend and managed the few hours on Sunday when it was raining. The rest of the day, both before and afterwards was lovely blue skies.

Anyway. This is looking good. Fitted newer 300tdi pump so had to sleeve the existing pipes with rubber to fit but so far this morning it started almost instantly. It didn't start on the very first turn but almost immediately afterwards. I'm happy with that and it's a huge improvement on it sitting cranking away for 5 - 15 seconds like it was before.

Thanks for all your help and advice.  

DSC_4094.JPG

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