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Engine turning over but not starting (Isuzu IM4LB33)


james2
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Hi all! Need help with an Isuzu IM4LB33 in a narrowboat that's suddenly not starting.


Turns over, smoke coming out the exhaust but doesn't get going. Fuel tank was filled a few weeks ago. I also have a diesel heater which seems to be working fine. Have tried glowing for up to 30 seconds, and have tried with throttle in idle position and forward to what would be about medium-revs, and all the same - turns over, smoke coming out but doesn't start. 


I'm not experienced in diagnosing or fixing engines so any basic/obvious things to check appreciated. I'm safe and warm but need the engine semi-urgently to be able to charge my batteries. I'm attempting to find the service manual for this engine and have found manuals for similar looking engines but not this exact one. 


Engine has been in use a few times a week for last few months, has started totally fine first time up until today and previous owner had it serviced before I took ownership this year. Last use was a couple of days ago when it was run for an hour for charging batteries. Didn't notice any problems.

 

Only small issue I'm aware of from previous owner is the stop solenoid sometimes does *not* stop the engine, but this can be solved by repeatedly pressing the button. 

 

Thanks very much for any help/advice.

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How much smoke? Some wisps or clouds? How fast is it turning over? Compare it with another boat that starts if you can. What is the battery voltage while cranking?

 

I hope the answers are clouds of smoke and slow cranking (less than about 10V when cranking) because that indicates a poor/discharged start battery and the first really cold weather. Otherwise clouds of smoke tends to indicate a loss of compression or some other serious problems. A few wisps of smoke tends t indicate a fuel problem.

1 minute ago, robtheplod said:

I know nothing about engines, but if the solenoid is suspect for not stopping the engine could it have seized stopping it from starting?

 

That would show as no smoke or a few wisps of smoke.

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Just a thought - the diesel heater will usually take fuel from higher up the tank than the engine, so if you have got water in the tank it is possible the engine has a problem when the boiler doesn’t.  Probably not the problem but easy to run of some fuel from the engine supply hose to check, or better still if you have a water separator drain that to see.

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1 hour ago, robtheplod said:

I know nothing about engines, but if the solenoid is suspect for not stopping the engine could it have seized stopping it from starting?

The engine stop button makes a good sounding click like the solenoid is engaging and disengaging properly, and I did not have any problems starting/stopping the engine previously. 

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1 hour ago, Tony Brooks said:

How much smoke? Some wisps or clouds? How fast is it turning over? Compare it with another boat that starts if you can. What is the battery voltage while cranking?

 

I hope the answers are clouds of smoke and slow cranking (less than about 10V when cranking) because that indicates a poor/discharged start battery and the first really cold weather. Otherwise clouds of smoke tends to indicate a loss of compression or some other serious problems. A few wisps of smoke tends t indicate a fuel problem.

 

That would show as no smoke or a few wisps of smoke.

 

Yep clouds of grey smoke that chug in time to the engine turning over (Not sure how we define clouds or wisps but certainly very visible grey cloud more than a light wisp as if there was no fuel to burn). I don't have a multimeter handy to check but going by the sound the battery / starter motor sound healthy to me - no hint of that whine like when a car battery is dead. 

 

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11 minutes ago, Chewbacka said:

Just a thought - the diesel heater will usually take fuel from higher up the tank than the engine, so if you have got water in the tank it is possible the engine has a problem when the boiler doesn’t.

 

This was my immediate thought too, given the time of year and condensation starting to occur overnight in the diesel tank.

 

Water in the fuel really messes up the starting once it gets to the injectors! Does it run if you give it a whiff of EzyStart? Or run then stop again? Or still not run at all?

 

 

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Are you sure that the preheaters are actually working and not burnt out or not getting any power?

 

White smoke could be because the engine is too cold to start, hence my question of the preheaters. It must be getting fuel and unless the engine is badly worn it will have sufficient compression.

 

To get it started can you get some  heat into the air going in to the air filter from a blow lamp or something?

 

As a last resort a whiff of Acetone Easy Start into the air cleaner.

 

By the By, an hour is not sufficient to charge the batteries, if you continue to do this you will sulfate the cells and need new batteries.

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1 hour ago, MtB said:

 

This was my immediate thought too, given the time of year and condensation starting to occur overnight in the diesel tank.

 

Water in the fuel really messes up the starting once it gets to the injectors! Does it run if you give it a whiff of EzyStart? Or run then stop again? Or still not run at all?

 

 

 

I don't have any EzyStart - that might be first thing I'll try tomorrow.

 

Would running the diesel heater help at all with this? Temporarily clear the condensation maybe?

 

1 hour ago, Tracy D'arth said:

Are you sure that the preheaters are actually working and not burnt out or not getting any power?

 

Nope - this would be something that definitely sounds like worth checking, but that I have no idea how to check. Is it something explainable online and easy to do assuming I'm reasonably handy and have a decent toolbox?

 

1 hour ago, Tracy D'arth said:

 

White smoke could be because the engine is too cold to start, hence my question of the preheaters. It must be getting fuel and unless the engine is badly worn it will have sufficient compression.

 

To get it started can you get some  heat into the air going in to the air filter from a blow lamp or something?

 

As a last resort a whiff of Acetone Easy Start into the air cleaner.

 

By the By, an hour is not sufficient to charge the batteries, if you continue to do this you will sulfate the cells and need new batteries.

 

Ah, the batteries have been getting up to full charge with solar until recently. So it damages the battery to only partially recharge and then start using it again, compared to a full charge?

 

Thanks for the advice :)

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1 minute ago, james2 said:

 

I don't have any EzyStart - that might be first thing I'll try tomorrow.

 

Would running the diesel heater help at all with this? Temporarily clear the condensation maybe?

 

Do you have any nail varnish remover? Its acetone.

The heater won't help, it will just flatten batteries.

 

You could try connecting the cabin battery positive to the engine battery positive with a jump cable, the extra capacity may spin it over a bit faster enabling it to start cold.

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1 hour ago, Tracy D'arth said:

Do you have any nail varnish remover? Its acetone.

The heater won't help, it will just flatten batteries.

 

Nope. Also don't have safe way to get heat into the air intake tonight, but possibly can try this tomorrow. 

 

1 hour ago, Tracy D'arth said:

 

You could try connecting the cabin battery positive to the engine battery positive with a jump cable, the extra capacity may spin it over a bit faster enabling it to start cold.

 

Is that to check if the starter battery was low? I feel like it's not, but thanks it's handy having extra things to try to diagnose

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6 minutes ago, james2 said:

Nope - this would be something that definitely sounds like worth checking, but that I have no idea how to check. Is it something explainable online and easy to do assuming I'm reasonably handy and have a decent toolbox?

 

 

Ah, the batteries have been getting up to full charge with solar until recently. So it damages the battery to only partially recharge and then start using it again, compared to a full charge?

 

Thanks for the advice :)

Your engine is also known as a 4LB1, instruction manual here but it doesn't really give you any useful info - these are very simple engines. https://www.wincogen.com/wp-content/uploads/PD/Engines/isuzu_4le1_opm.pdf

 

I have a similar vintage of Isuzu engine, and if I forget to preheat it'll do the same thing with grey smoke. Do you have a multimeter which can measure DC volts? If not, buy one from Screwfix, under £10. How the glowplugs are wired depends on the boatbuilder - some switch the high current with the keyswitch, others use a relay. No preheat could be a number of electrical faults - bad ignition switch/relay, broken wire etc.

 

Have someone activate the preheat while you check for voltage between the engine block (find a clean, unpainted spot) and the very top of the plug with the wire/bar on it. Have a look at the image below - only the top part from the hexagonal nut upwards is visible, the rest is inside the engine. You want the probe of the meter to be on the small threaded bit on top. Can you take a photo if you're in doubt? With the preheat on, you should see at least 11.5v. If it's a couple of volts less, you may have a dead starter battery but as it's cranking the engine, i don't think this is the case. If the meter reads zero, you've got an electrical issue and the plugs aren't heating.

 

On the batteries - yes, if you have lead based batteries, a partial recharge again and again will kill them, especially if it's from say 30% to 50% or lower. Every other day they should be brought up to a full charge, depending on the size of your bank this may be 4-5hrs. 

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2 minutes ago, james2 said:

 

Nope. Also don't have safe way to get heat into the air intake tonight, but possibly can try this tomorrow. 

 

 

Is that to check if the starter battery was low? I feel like it's not, but thanks it's handy having extra things to try to diagnose

About taking care of batteries, you could read  Tony Brooks battery primer,   http://www.tb-training.co.uk/MarineE05.html   the later part gives good advice on care for batteries.

 

If you even put a candle near the air intake so that the flame is sucked in it will help substantially. You will not light up diesel fuel unless it is soaked into something to act as a wick.

I have used a fire lighter in a can on occasions to get an engine running in winter.

 

To check the preheaters, you could check the voltage at the connection on the heater elements when you are preheating. If the voltage is absent you could have a wiring fault or a duff relay, If the voltage is the almost same as the voltage on the battery terminals, then all the heaters are burnt out.

Its not uncommon to find this, in warm weather it will make no difference to starting but when the cold weather arrives you need the heaters to work!

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If using Acetone or Easy Start (Ether) - get a tin or jar and put a piece of rag in it, spray the easy start on this rag. Remove the air filter and then hold the tin under the air intake and crank the engine allowing it to draw the fumes from the tin (ensuring that it cannot drag the rag in). This is much kinder to the engine. If you have a tin or jar with a tight fitting lid it can be capped and kept for future use, hopefully not needed. Easy start should only be used sparingly when absolutely necessary.

 

springy

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The words "chug in time" suggest to me that the cranking speed MIGHT be low but heaters plugs not working may wll be the cause.

 

The manual above does not mention an air cleaner so your engine may well have the little triangular air intake at the front right side of the head/rocker cover. Apart from damaged paint I don't think putting a fire lighter against that intake will do any harm.

 

 

Edited by Tony Brooks
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These engines have an electric fuel pump. You should hear it ticking and possibly fuel going back into the tank with the ignition switch on and the engine not running. You can break into the return line and check you have clean fuel circulating. There is a multiway connector on the engine loom that can cause problems (on the usual HMI marinisation). This would be my first port of call since you seem to have problems with the solenoid. If you have a voltmeter on the system check that when you engage the heater plugs the voltage drops indicating that there is current being taken. Like any engine you need a minimum cranking speed to get it going so check the battery for voltage and battery/starter connections and terminals. The stop solenoid is activated to stop the engine so unlikely to be the cause. Remember you only need enough fuel, working heater plugs and enough speed from the starter to get going unless the engine has a serious mechanical problem. There is a mechanical stop on the engine - just check that hasn't been used and got stuck somehow.

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It it turns over at all ,the glow plugs will set it off.....the tips are near white hot.....I suggest a new set of plugs ,rather than mucking about one by one......most chamber engines wont start without glow or a bit of ether......warning....only a whiff of spray should be sufficient.....if its flooded with spray there is a good chance it may kick backwards and damage the starter.

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I spent ages trying to start a Peugeot car diesel. Engine turned over reasonably fast but it would not go. Jump leads to another battery and it started straight away. Diesels need to compress the air in the cylinders pretty quickly to heat it up and if it is not good and hot the so and so will not go. Heater plugs need to be working too.  Most run of the mill problems with diesels are down to fuel though.

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On 24/11/2021 at 18:57, Tony Brooks said:

The words "chug in time" suggest to me that the cranking speed MIGHT be low but heaters plugs not working may wll be the cause.

 

The manual above does not mention an air cleaner so your engine may well have the little triangular air intake at the front right side of the head/rocker cover. Apart from damaged paint I don't think putting a fire lighter against that intake will do any harm.

 

 

 

On 24/11/2021 at 18:13, Tracy D'arth said:

Do you have any nail varnish remover? Its acetone.

The heater won't help, it will just flatten batteries.

 

You could try connecting the cabin battery positive to the engine battery positive with a jump cable, the extra capacity may spin it over a bit faster enabling it to start cold.

 

Thank you *very* much to everyone who helped me out here. I'm very eager to learn how to fix my own engine but in the end realised that I basically know (knew!) nothing and didn't have time or emotional energy to figure everything out with the time pressure of needing to be able to charge my battery so I can do my work, so I called RCR. 

 

That turned out to be a pretty good investment because in the hour or two the guy was here I learned a TON about where everything is on my engine and a whole bunc of basic diagnostics that would have taken me hours to figure out on my own and now much better prepared for similar stuff in future and could diagnose similar issue in 5 minutes. 

 

The problem was, get ready for it, the heater circuit indicator bulb/socket !!@£$%^^!!@£. On my boat the indicator bulb is directly inline with the glowplugs and the bulb/socket had a ton of corrosion as it was broken and exposed to the elements and cleaning it up seemed to be all that was required. (Now I understand why relays are used in circuits like this. Add a bit of complexity but isolate the control side of the circuit from the operational side of the circuit and allow them to be tested separately).

 

Thanks again all in this thread

 

 

  • Greenie 1
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12 minutes ago, james2 said:

 

 

 

 

The problem was, get ready for it, the heater circuit indicator bulb/socket !!@£$%^^!!@£. On my boat the indicator bulb is directly inline with the glowplugs and the bulb/socket had a ton of corrosion as it was broken and exposed to the elements and cleaning it up seemed to be all that was required. (Now I understand why relays are used in circuits like this. Add a bit of complexity but isolate the control side of the circuit from the operational side of the circuit and allow them to be tested separately).

 

 

 

 

Sounds unlikely, do you mean the switch?

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23 minutes ago, Tracy D'arth said:

Sounds unlikely, do you mean the switch?

 

I agree, stick  a low power bulb in series with the glow plugs and no heat. Put it in series with a relay coil and then there is every chnace the relay will not pull in and be unreliable.

 

Put a bulb in parallel and then it would not the affect operation of either except the bulb would not work, the glow plugs will.

 

I can't see Engines Plus using some fancy relay but you never know, there just might be  electronics involved.

 

Now, if the positive lamp terminal was used as a junction box for an onward feed to the plugs then corrosion on the terminal may well cause glow pug problems but not the socket itself.

 

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40 minutes ago, Tracy D'arth said:

Sounds unlikely, do you mean the switch?

Only think I can think of is that the indicator is actually a series resistor indicator for the plugs, as used on some tractors and old Pentas (I think!). The plugs' resistance is low when cold, drawing lots of current through the resistor, causing it to glow red. When the plugs are hot, their resistance increases, current decreases and the series resistor doesn't pass enough current to glow. 

 

As it's in series, if it blows, then you lose power to the glowplugs. 

 

Attached is what they look like, before the chrome burns off and it gets all rusty.

s-l400.jpg

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25 minutes ago, cheesegas said:

Only think I can think of is that the indicator is actually a series resistor indicator for the plugs, as used on some tractors and old Pentas (I think!). The plugs' resistance is low when cold, drawing lots of current through the resistor, causing it to glow red. When the plugs are hot, their resistance increases, current decreases and the series resistor doesn't pass enough current to glow. 

 

As it's in series, if it blows, then you lose power to the glowplugs. 

 

Attached is what they look like, before the chrome burns off and it gets all rusty.

s-l400.jpg

 

That is  a possibility but in this case I feel a remote one, and I seem to remember those indicators get hot in use and did not glow as bright as a bulb type warning lamp. I have not seen one on a boat with a modern engine but that does not mean there aren't any though.

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49 minutes ago, Tony Brooks said:

 

That is  a possibility but in this case I feel a remote one, and I seem to remember those indicators get hot in use and did not glow as bright as a bulb type warning lamp. I have not seen one on a boat with a modern engine but that does not mean there aren't any though.

I had one on my Isuzu engined Liverpool boat which someone had bodged another control panel into. It would glow bright orange, but not visible in sunlight at all and if it got wet it would sizzle and pop. Replaced it with a relay very quickly!

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25 minutes ago, cheesegas said:

I had one on my Isuzu engined Liverpool boat which someone had bodged another control panel into. It would glow bright orange, but not visible in sunlight at all and if it got wet it would sizzle and pop. Replaced it with a relay very quickly!

 

Thanks, learned something new. That seems to confirm RCR's diagnosis.

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