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Strange starting woes - two separate issues?


Turbocharger

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Problem 1:

Engine turns over and over and over and over and over and over and over and over before it finally fires, no smoke while it's cranking. When it finally kicks it misfires for a few seconds. It feels as if it has to pull up fuel before it reaches the injectors.

If I restart it immediately, it's fine. If I restart it after 8 hours in the work car park, it's ok. If I leave it at home for 24hrs and then try, it cranks and cranks and cranks before it'll eventually fire.

I changed the fuel filter (which was full) hoping there was an air leak there, no joy. The problem has been around all summer, and it coped ok in the warm, however... Where could air be getting in?

Problem 2:

now it's cold, it's testing the battery harder with all this cranking, and sometimes failing to start. However, it'll crank and go

wuh-wuh-wuh-wuuuh-wuuuuh-wuuuuh.

Given a minute to recover it'll go

wuh-wuh-wuh-wuuuh-wuuuuh-waclickclick

But then if I turn the key again I'll get a happy sound

wawawawawawawawawawawawawa

If it doesn't start then, the next effort returns to

wuh-wuh-wuh-wuuuh-wuuuuh-waclickclick

How do you get an intermittent starter fault? Dirty solenoid contacts I guess, but I've changed the starter and battery (same fault with both, though it's worse when it's cold).

I've not run round it with a volt meter or amp-clamp yet, but what should I be looking for?

Vehicle is a 300Tdi, mechanical fuel pump, autobox (if it matters).

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Just had your second problem, in my case it was a faulty earth strap. Put a new one directly from the battery to the gearbox, and all is fine.

About your first problem, i would guess its air, check the return pipes on the injectors, as i had a similar problem with my dads 110, 300tdi. Found one of the pipes cracked and it sucked air in on starting then leaked ever so slightly while started, was rather difficult to spot, but after i changed the pipe it never did it again.

G

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Your problem 1 sounds like what I had a few years back - dodgy lift pump, internal valves leaking.

Check your battery voltage, engine and all electrics off, should be at least 12.6v, ideally 13v. If right on 12.6V or less, battery is knackered.

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I've had exactly the same as problem 1 on two separate vehicles, both times it was the injector leak-off (return) lines. On one vehicle the rubber tubing had perished, on the other (which had a different, earlier, setup on the pipes) it was the copper washers on the banjo bolts attaching the lines to the injectors themselves.

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I had similar problems to your #1, that was simply glow plugs not working. 8 hours in our car park (having warmed up the engine on the way) seemed to be just about enough to not need the plugs, but overnight (typically 12-15 hours of not running) was just too much cold. It is interesting to read the other ideas though, I have what I think is a leaking injector, but perhaps I have a leaky fuel return/recovery pipe?

Struggling to imagine your sound effects by the way!

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Thanks guys - some really good pointers here.

Hmm. I've a memory that I replaced the leak-off pipe "recently", though for me that's probably five years ago.

Problem 1:

For completeness I'll do the leakoff pipe and the lift pump at the weekend and see if it makes things better or worse.

It's never had the glowplugs wired up, so at least I know they've not stopped working... maybe now it's got 100k miles on the engine it's starting to need them.

Problem 2:

I've added an earth strap from the battery to the starter, that didn't work and that's when I replaced the starter (assuming it had a dirty connection). I'll clip up my multimeter and see where my voltage is going missing at the weekend too.

I suspect if it didn't need to crank for 60 seconds first, the second problem would go away by default...

Scott - you should hear me doing my "Never mind the Buzzcocks" intros - chicka wow wow.

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I suspect if it didn't need to crank for 60 seconds first, the second problem would go away by default...

That's probably true, all the cranking won't be doing the electrical system any good however you look at it.

On one of mine the banjo bolts were so loose you could move them freely with a finger. Over-did it tightening one and sheered it off, do I'd avoid that if possible! There is a torque figure in the manual but I found it damn near impossible to get a torque wrench on there, so I just went by feel.

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Had the second problem before, only in cold weather. Not long after the battery died, so you might want to take it to a battery place and have it checked - its usually free. I have a theory that in cold weather like this, an battery thats thinking about going needs 'waking up'. Other people have reported the same thing in the past, and I did see some science about it once somewhere.

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My input for what it is worth...... Any starting issue with a landrover? Take a ruddy great jump lead direct from -ve earth post on the battery - direct to the engine block - nowhere else is 100% despite what logic says! I have no idea why and Ive been in the game a long long time! I recently had a genuine 200 tdi 90 which just would not start, so I stripped off the starter (which means exhaust downpipe off) only to find it brand new (obviously happened before!) checked everything - but no luck. Turn the key - no click - no nothing - headlights on - no dipping of dash lights - just dead. Stuck the gurt big jump lead on - which I should have done first! and bingo. checked where earth goes to chassis (again) removed cleaned polished and problem gone - forever! So problem was earth strap 100%. but can someone explain how the lights still stayed bright but the starter didnt even click?

A friend had a novel one - started his 110 then couldnt release the hand brake? Yep the earth starting current hand used the handbrake cable and melted the nylon liner!! Who would have guess that one?

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Update:

Problem 1: some of the injector spill banjos took a little more torque but I don't think they were leaking. It cranked a little less this morning but I'll swap the rail anyway, for the cost of the thing. If this was letting air in (or if the lift pump was letting fuel drop back to the tank), how would the filter still be full when I swapped it?

Problem 2: after lots of time with jump leads, volt meters and measuring voltages while it was cranking, the starter is seeing 0.5v less than the battery voltage during cranking, but the battery voltage drops to 9v within five seconds of starting to crank. The battery is 14 months old, but came with a 3-year guarantee and I've still got the receipt :)

I also found the negative clamp was loose because the clamp bolt thread had stripped. With the post and clamp cleaned and the bolt replaced, it still cranks slowly or quickly, at random though. I found yesterday it'll crank slowly, drag the battery voltage down until the starter solenoid would 'bounce' a few times (clickclickclick), and then it'd find better voltage and crank quite happily.

I'll swap the battery and the fuel rail, then cross my fingers for a reliable car at Christmas - and take the jump leads!

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OK, battery was checked by the vendor. It's showing 560CCA against its new spec at 700CCA = 80%. Acceptable? He doesn't want to swap it, though it's still in warranty.

I managed to capture the weird behaviour on video this morning. It cranked slowly without firing, so I gave it 5 mins to recover and then shot the attached video, showing the voltage at the battery:

- 12.8v at rest

- 7 to 8v for 2 sec while cranking slowly, it's really lugging.

- Then the voltage drops low enough to bounce the solenoid momentarily

- Then 8.5-9v and a nice fast crank, which then starts the engine.

(The misfiring and poor cold performance is due to the fuel problem, which I'm still changing pipes to try to cure).

Is it a high resistance somewhere drawing more current and the battery can't cope, or is the battery struggling to maintain voltage but is better after a moment's recovery? Remember that it's done this with two starter motors so it's not a dirty solenoid.

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My top suspicion would be the starter motor!

Intermittent slow cranking and pulling the battery that low points to a short in the windings (draws more current but generates less torque). It could just be a dirty commutator - which is connecting more than one set of coils at a time (also increases the current draw and reduces torque). The motor spinning is either burning off the carbon shorting the coils or wiping some of it off. Might be worth stripping & cleaning the starter motor.

You should wire up the glow plugs - they do make starting much easier in cold weather! Why don't you try them with jump leads to see if it makes a difference?

Si

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Hmm x2 on the starter unless you have a loose connection somewhere. Mine was doing the same thing but the slow cranking did not turn into a quick crank like yours. I had to sit and wait and try again then it would fire right up. I added the new earth strap and the problem went away.

G

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x2 on the glowplugs. I'm no expert on batteries, but if he's happy, and the results do look ok, then I'd rule that out for now, although that does seem to be down more than I'd have thought. I would definatly rig the glowplugs and try again, they do make a difference for sure, I really noticed the difference when I finally got the 88's done, The 109's still aren't done and she's not so quick to start. If you're into it, replacing the main feed to the starter may not hurt, seeing as you've already inspected the earth. I have the wherewithal to do it easily, other people don't I appreciate that.

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Problem 2 - weird starting behaviour:

But I've changed the starter two months ago and the symptoms are the same??

On review, at work we spec commercial batteries to 90% of their CCA as a failure limit (for commercial 24v systems) and 80% for vans (12v systems). Mine's at 80% so I'm going to hump it back and try to replace it. Though I won't know if the stronger battery is just masking a voltage drop somewhere else...

Problem 1 - long cranking time before firing:

It's never needed glowplugs before in the ten years that I've had the engine, so something's changed? The lift pump is working well, plenty of fuel from the filter when I slacken the top banjo. I've changed the injector spill rail, the pipe from the filter to the injector pump and now I'm running out of ideas but it's still cranking significantly before it starts.

For both problems, I don't like throwing parts at the problem until something fixes it but for an intermittent issue like this I'm struggling to see other options... :blink:

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The video looks like a clamp meter? Does it measure DC current? If so, lets see the same test measuring current on one of the battery leads.

When it's cranking slowly, if the current is higher than when it's cranking fast, it's a problem with the starter motor. If it's lower, its a problem with the battery.

The fact that you replaced it two months ago does not mean it's not at fault.

Get another known good battery and connect it with jump leads directly to the starter motor. If it runs OK, problem is either the wiring or battery.

Disconnect the wire on the output of the solenoid to the motor. Get a friend to turn key so solenoid engages the drive to the flywheel then connect jump lead to wire into motor. If it runs OK, problem is solenoid.

I'm not saying the glow plugs are the problem - just that they are fitted for a reason!

Si

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