Hello,

I'm hoping some of you with knowledge and wisdom can help me sort out what is wrong with my 1998 300tdi.

For the last couple of months it has been increasingly difficult to start; the starter turns over fine but the engine is very reluctant to fire. When it does cough into life it then runs fine and is easier to start later in the day. As the battery was old I thought that was the problem, so that was replaced with new. No change to starting.

The fuel filter was changed a week ago for a new one. No improvement. Local advise thought it was some sort of fuel starvation problem.

This evening I tried putting a jump lead from the -ve battery terminal to the engine block. Again no improvement in starting. Visual inspection and wiggling of the earth makes me think it's pretty solid anyway.

Then, having tried the jump lead trick and sat with the engine running for a couple of minutes I turned off the ignition and pulled out the key. The engine continued to run for a further minute or so before turning itself off. This has never happened before.

I tried it again twice, both times it was reluctant to start, one time it turned off when the key was turned to off, the other time it ran on for sixty seconds before stopping.

Can anyone please advise what is wrong and what I need to do to sort this out. My next step was going to be the fuel sedimenter and I have the O-rings on order to do that.

Thanks in advance for any clues.

M

Dodgy fuel solenoid would be my first thing to check

Marmaduke said:

Dodgy fuel solenoid would be my first thing to check

Click to expand...

+1 - and last time I needed one, they were only about £12...

Sounds like it's staying "off" for a while after power is applied..... and staying(sticking) on for a while after power is removed - inconsiderate IMHO

OP - I'm assuming its a manual, with the DDS pump which has a black plastic cover over the solenoid, which is on the rear of the pump and has three black wires going to it.... ( you can guess how I know this )

Mine got gunked up after wocking loads of cooking oil in

McBad said:

Hello,

I'm hoping some of you with knowledge and wisdom can help me sort out what is wrong with my 1998 300tdi.

For the last couple of months it has been increasingly difficult to start; the starter turns over fine but the engine is very reluctant to fire. When it does cough into life it then runs fine and is easier to start later in the day. As the battery was old I thought that was the problem, so that was replaced with new. No change to starting.

The fuel filter was changed a week ago for a new one. No improvement. Local advise thought it was some sort of fuel starvation problem.

This evening I tried putting a jump lead from the -ve battery terminal to the engine block. Again no improvement in starting. Visual inspection and wiggling of the earth makes me think it's pretty solid anyway.

Then, having tried the jump lead trick and sat with the engine running for a couple of minutes I turned off the ignition and pulled out the key. The engine continued to run for a further minute or so before turning itself off. This has never happened before.

I tried it again twice, both times it was reluctant to start, one time it turned off when the key was turned to off, the other time it ran on for sixty seconds before stopping.

Can anyone please advise what is wrong and what I need to do to sort this out. My next step was going to be the fuel sedimenter and I have the O-rings on order to do that.

Thanks in advance for any clues.

M

Click to expand...

Plus, plus, plus on the sticky fuel solenoid, remove, clean and test or completely replace with a new one.

When I did mine, I had to grind an old spanner for the job. I don't know if this is normally required, but the gap I needed to get too was small.

I mention it in cas you look at the job and wonder...

(I would also bet on it being the solenoid)

Hello, many thanks all. Yet again this forum proves its worth! Until now I knew nothing about fuel solenoids, but I can see how if it was sticking it would produce exactly the problems I'm experiencing.

I've been out to have a look and mine is the black plastic security box version, with the three wires going into it, so as far as I'm concerned that's a garage job. I'll ask them to replace it with the single wire version, in case the problem ever happens again in the future. (I will pop back in a few days and confirm whether or not replacing the solenoid fixed the problem.)

Right, I thought I'd post an update on this saga and would welcome anyone's further thoughts...

The fuel solenoid was replaced by the garage in June, and made no difference to the starting (the engine hasn't run on after being turned off since though, so maybe a new one did some good).

Having replaced the solenoid the next suspect was the fuel lift pump, I've got a new one sitting here but have been putting off doing the job due to other demands on my time and because I've been unable to work out how to get at the forward bolt holding the pump to the block. It's easy to see but there's no room to get a socket or spanner in, with lots of brackets and the fuel feed lines from the injector pump in the way. Anyway, I was leaning on the wing looking at this problem again this morning when I noticed that the inner wing rear of the battery was all wet. Although there is a brake line crossing this area the likely source of the fluid was the coolant reservoir, so I took the lid off and found it was all but empty. I topped it up and coolant immediately started ****ing out of the bottom of the reservoir somewhere; even with a mirror and torch I couldn't see where, but it's not the top cap and I don't think it's the joins to either of the hoses that attach to the tank. Whatever the main problem is I'm going to need a new fluid reservoir.

The vehicle has done a couple of long runs over the last few days (although has only done about 500 miles since the new solenoid) and with the window open yesterday I do remember hearing an odd 'tssssing' noise now and again but couldn't work out if it was coming from front back or underneath. I dismissed it thinking it was something rattling, but now wonder if it was steam or hot fluid escaping from the reservoir. I note that the sound proofing lining the bonnet is very damp above the reservoir as well. However, temperature gauge behaved exactly as normal over the last couple of days so I don't think the engine got any hotter than usual.

With the engine started and the coolant filled there were no bubbles coming up in the coolant reservoir (although it's hard to tell when the coolant is running out as fast as you put it in). There is no sign of water in the oil. However with the bonnet open it is obvious the engine hesitates or misses a beat every ten seconds or so at idle. The other symptom to record is that shortly after starting (trying to pull out of the drive or at the bottom of the street for example) sometimes you put your foot down and the engine does nothing; no power there at all, the engine just seems to idle or even slow below idle. My wife was stuck in the middle of a busy junction for a moment because of this, and yesterday I had to have three goes at pulling up a steep hill out of a carpark where I'd left the vehicle for a few hours. (Eventually I went up in low first but that's just plain embarrassing when you are following a Fiat 500C which has no problems at all.) When the engine has warmed up everything is fine and normal power is restored.

I think my next step (apart from ordering a new coolant reservoir) will be to ask the garage to check for a head gasket failure; see if any two cylinder pressures are the same, or if there are combustion products in the coolant. Would be grateful if anyone else has any ideas on this one. Could a cylinder head gasket failure produce these starting and running problems?

Thanks,
M

Hopefully final update on this. Garage checked fuel sedimenter (again) and found nothing wrong (again) and then replaced the fuel pump. Starting was immediately restored to first flick of the key and the power problems resolved. Coolant header tank was also replaced; garage say they've had to do a few when they've split, it's a known problem when they get old. Decided this was probably not related to power / starting problem.

McBad said:

Hello,

I'm hoping some of you with knowledge and wisdom can help me sort out what is wrong with my 1998 300tdi.

For the last couple of months it has been increasingly difficult to start; the starter turns over fine but the engine is very reluctant to fire. When it does cough into life it then runs fine and is easier to start later in the day. As the battery was old I thought that was the problem, so that was replaced with new. No change to starting.

The fuel filter was changed a week ago for a new one. No improvement. Local advise thought it was some sort of fuel starvation problem.

This evening I tried putting a jump lead from the -ve battery terminal to the engine block. Again no improvement in starting. Visual inspection and wiggling of the earth makes me think it's pretty solid anyway.

Then, having tried the jump lead trick and sat with the engine running for a couple of minutes I turned off the ignition and pulled out the key. The engine continued to run for a further minute or so before turning itself off. This has never happened before.

I tried it again twice, both times it was reluctant to start, one time it turned off when the key was turned to off, the other time it ran on for sixty seconds before stopping.

Can anyone please advise what is wrong and what I need to do to sort this out. My next step was going to be the fuel sedimenter and I have the O-rings on order to do that.

Thanks in advance for any clues.

M

Click to expand...

common problems to check
leak off pipes leaking
pipes that enter sender unit on tank rusty and drawing in air
sedimenter
lift pump

Thanks, it's all sorted now. M

Fuel stop solenoid, check the cable/connection on it.

McBad said:

Thanks, it's all sorted now. M

Click to expand...

So what was it? These threads are pretty useless with no punchline.

In case you all missed it the first time -

McBad said:

Hopefully final update on this. Garage checked fuel sedimenter (again) and found nothing wrong (again) and then replaced the fuel pump. Starting was immediately restored to first flick of the key and the power problems resolved. Coolant header tank was also replaced; garage say they've had to do a few when they've split, it's a known problem when they get old. Decided this was probably not related to power / starting problem.

Click to expand...

Yep. I missed it the first time!